Sample records for hadron collider lhc

  1. Cryogenic safety aspect of the low -$\\beta$ magnest systems at the Large Hadron Collider (LHC)

    SciTech Connect (OSTI)

    Darve, C.; /Fermilab

    2010-07-01T23:59:59.000Z

    The low-{beta} magnet systems are located in the LHC insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process and will allow proton collisions at a luminosity of up to 10{sup 34}cm{sup -2}s{sup -1}. Large radiation dose deposited at the proximity of the beam collisions dictate stringent requirements for the design and operation of the systems. The hardware commissioning phase of the LHC was completed in the winter of 2010 and permitted to validate this system safe operation. This paper presents the analysis used to qualify and quantify the safe operation of the low-{beta} magnet systems in the Large Hadron Collider (LHC) for the first years of operation.

  2. Instrumentation status of the low-b magnet systems at the Large Hadron Collider (LHC)

    SciTech Connect (OSTI)

    Darve, C.; /Fermilab; Balle, C.; Casas-Cubillos, J.; Perin, A.; Vauthier, N.; /CERN

    2011-05-01T23:59:59.000Z

    The low-{beta} magnet systems are located in the Large Hadron Collider (LHC) insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process allowing proton collisions at luminosity up to 10{sup 34}cm{sup -2}s{sup -1}. Those systems are a contribution of the US-LHC Accelerator project. The systems are mainly composed of the quadrupole magnets (triplets), the separation dipoles and their respective electrical feed-boxes (DFBX). The low-{beta} magnet systems operate in an environment of extreme radiation, high gradient magnetic field and high heat load to the cryogenic system due to the beam dynamic effect. Due to the severe environment, the robustness of the diagnostics is primordial for the operation of the triplets. The hardware commissioning phase of the LHC was completed in February 2010. In the sake of a safer and more user-friendly operation, several consolidations and instrumentation modifications were implemented during this commissioning phase. This paper presents the instrumentation used to optimize the engineering process and operation of the final focusing/defocusing quadrupole magnets for the first years of operation.

  3. Future Electron-Hadron Colliders

    SciTech Connect (OSTI)

    Litvinenko, V.

    2010-05-23T23:59:59.000Z

    Outstanding research potential of electron-hadron colliders (EHC) was clearly demonstrated by first - and the only - electron-proton collider HERA (DESY, Germany). Physics data from HERA revealed new previously unknown facets of Quantum Chromo-Dynamics (QCD). EHC is an ultimate microscope probing QCD in its natural environment, i.e. inside the hadrons. In contrast with hadrons, electrons are elementary particles with known initial state. Hence, scattering electrons from hadrons provides a clearest pass to their secrets. It turns EHC into an ultimate machine for high precision QCD studies and opens access to rich physics with a great discovery potential: solving proton spin puzzle, observing gluon saturation or physics beyond standard model. Access to this physics requires high-energy high-luminosity EHCs and a wide reach in the center-of-mass (CM) energies. This paper gives a brief overview of four proposed electron-hadron colliders: ENC at GSI (Darmstadt, Germany), ELIC/MEIC at TJNAF (Newport News, VA, USA), eRHIC at BNL (Upton, NY, USA) and LHeC at CERN (Geneva, Switzerland). Future electron-hadron colliders promise to deliver very rich physics not only in the quantity but also in the precision. They are aiming at very high luminosity two-to-four orders of magnitude beyond the luminosity demonstrated by the very successful HERA. While ENC and LHeC are on opposite side of the energy spectrum, eRHIC and ELIC are competing for becoming an electron-ion collider (EIC) in the U.S. Administrations of BNL and Jlab, in concert with US DoE office of Nuclear Physics, work on the strategy for down-selecting between eRHIC and ELIC. The ENC, EIC and LHeC QCD physics programs to a large degree are complimentary to each other and to the LHC physics. In last decade, an Electron Ion Collider (EIC) collaboration held about 25 collaboration meetings to develop physics program for EIC with CM energy {approx}100 GeV. One of these meetings was held at GSI, where ENC topic was in the center of discussions. First dedicated LHeC workshop was held in 2008, with a number of dedicated workshops following it. Intense accelerator R&D program is needed to address the challenges posed by the EIC.

  4. Higgs boson production at hadron colliders: Signal and background processes

    SciTech Connect (OSTI)

    David Rainwater; Michael Spira; Dieter Zeppenfeld

    2004-01-12T23:59:59.000Z

    We review the theoretical status of signal and background calculations for Higgs boson production at hadron colliders. Particular emphasis is given to missing NLO results, which will play a crucial role for the Tevatron and the LHC.

  5. Jet production at hadron colliders

    E-Print Network [OSTI]

    Jouttenus, Teppo T. (Teppo Tapani)

    2012-01-01T23:59:59.000Z

    Hadronic jets feature in many final states of interest in modern collider experiments. They form a significant Standard Model background for many proposed new physics processes and also probe QCD interactions at several ...

  6. Spin rotation and depolarization of high-energy particles in crystals at Hadron Collider (LHC) and Future Circular Collider (FCC) energies and the possibility to measure the anomalous magnetic moments of short-lived particles

    E-Print Network [OSTI]

    Baryshevsky, V G

    2015-01-01T23:59:59.000Z

    We study the phenomena of spin rotation and depolarization of high-energy particles in crystals in the range of high energies that will be available at Hadron Collider (LHC) and Future Circular Collider (FCC). It is shown that these phenomena can be used to measure the anomalous magnetic moments of short-lived particles in this range of energies. We also demonstrate that the phenomenon of particle spin depolarization in crystals provides a unique possibility of measuring the anomalous magnetic moment of negatively-charged particles (e.g., beauty baryons), for which the channeling effect is hampered due to far more rapid dechanneling as compared to that for positively-charged particles. Channeling of particles in either straight or bent crystals with polarized nuclei could be used for polarization and the analysis thereof of high-energy particles.

  7. tt Charge asymmetry at hadron colliders

    E-Print Network [OSTI]

    Chapelain, Antoine

    2013-01-01T23:59:59.000Z

    We present the current status for the measurements of the ttbar charge asymmetry at the Tevatron and LHC colliders.

  8. A Large Hadron Electron Collider at CERN

    E-Print Network [OSTI]

    J. L. Abelleira Fernandez; C. Adolphsen; P. Adzic; A. N. Akay; H. Aksakal; J. L. Albacete; B. Allanach; S. Alekhin; P. Allport; V. Andreev; R. B. Appleby; E. Arikan; N. Armesto; G. Azuelos; M. Bai; D. Barber; J. Bartels; O. Behnke; J. Behr; A. S. Belyaev; I. Ben-Zvi; N. Bernard; S. Bertolucci; S. Bettoni; S. Biswal; J. Blümlein; H. Böttcher; A. Bogacz; C. Bracco; J. Bracinik; G. Brandt; H. Braun; S. Brodsky; O. Brüning; E. Bulyak; A. Buniatyan; H. Burkhardt; I. T. Cakir; O. Cakir; R. Calaga; A. Caldwell; V. Cetinkaya; V. Chekelian; E. Ciapala; R. Ciftci; A. K. Ciftci; B. A. Cole; J. C. Collins; O. Dadoun; J. Dainton; A. De. Roeck; D. d'Enterria; P. DiNezza; M. D'Onofrio; A. Dudarev; A. Eide; R. Enberg; E. Eroglu; K. J. Eskola; L. Favart; M. Fitterer; S. Forte; A. Gaddi; P. Gambino; H. García Morales; T. Gehrmann; P. Gladkikh; C. Glasman; A. Glazov; R. Godbole; B. Goddard; T. Greenshaw; A. Guffanti; V. Guzey; C. Gwenlan; T. Han; Y. Hao; F. Haug; W. Herr; A. Hervé; B. J. Holzer; M. Ishitsuka; M. Jacquet; B. Jeanneret; E. Jensen; J. M. Jimenez; J. M. Jowett; H. Jung; H. Karadeniz; D. Kayran; A. Kilic; K. Kimura; R. Klees; M. Klein; U. Klein; T. Kluge; F. Kocak; M. Korostelev; A. Kosmicki; P. Kostka; H. Kowalski; M. Kraemer; G. Kramer; D. Kuchler; M. Kuze; T. Lappi; P. Laycock; E. Levichev; S. Levonian; V. N. Litvinenko; A. Lombardi; J. Maeda; C. Marquet; B. Mellado; K. H. Mess; A. Milanese; J. G. Milhano; S. Moch; I. I. Morozov; Y. Muttoni; S. Myers; S. Nandi; Z. Nergiz; P. R. Newman; T. Omori; J. Osborne; E. Paoloni; Y. Papaphilippou; C. Pascaud; H. Paukkunen; E. Perez; T. Pieloni; E. Pilicer; B. Pire; R. Placakyte; A. Polini; V. Ptitsyn; Y. Pupkov; V. Radescu; S. Raychaudhuri; L. Rinolfi; E. Rizvi; R. Rohini; J. Rojo; S. Russenschuck; M. Sahin; C. A. Salgado; K. Sampei; R. Sassot; E. Sauvan; M. Schaefer; U. Schneekloth; T. Schörner-Sadenius; D. Schulte; A. Senol; A. Seryi; P. Sievers; A. N. Skrinsky; W. Smith; D. South; H. Spiesberger; A. M. Stasto; M. Strikman; M. Sullivan; S. Sultansoy; Y. P. Sun; B. Surrow; L. Szymanowski; P. Taels; I. Tapan; T. Tasci; E. Tassi; H. Ten. Kate; J. Terron; H. Thiesen; L. Thompson; P. Thompson; K. Tokushuku; R. Tomás García; D. Tommasini; D. Trbojevic; N. Tsoupas; J. Tuckmantel; S. Turkoz; T. N. Trinh; K. Tywoniuk; G. Unel; T. Ullrich; J. Urakawa; P. VanMechelen; A. Variola; R. Veness; A. Vivoli; P. Vobly; J. Wagner; R. Wallny; S. Wallon; G. Watt; C. Weiss; U. A. Wiedemann; U. Wienands; F. Willeke; B. -W. Xiao; V. Yakimenko; A. F. Zarnecki; Z. Zhang; F. Zimmermann; R. Zlebcik; F. Zomer

    2013-01-09T23:59:59.000Z

    This document provides a brief overview of the recently published report on the design of the Large Hadron Electron Collider (LHeC), which comprises its physics programme, accelerator physics, technology and main detector concepts. The LHeC exploits and develops challenging, though principally existing, accelerator and detector technologies. This summary is complemented by brief illustrations of some of the highlights of the physics programme, which relies on a vastly extended kinematic range, luminosity and unprecedented precision in deep inelastic scattering. Illustrations are provided regarding high precision QCD, new physics (Higgs, SUSY) and electron-ion physics. The LHeC is designed to run synchronously with the LHC in the twenties and to achieve an integrated luminosity of O(100) fb$^{-1}$. It will become the cleanest high resolution microscope of mankind and will substantially extend as well as complement the investigation of the physics of the TeV energy scale, which has been enabled by the LHC.

  9. A Large Hadron Electron Collider at CERN

    E-Print Network [OSTI]

    Abelleira Fernandez, J L; Adzic, P; Akay, A N; Aksakal, H; Albacete, J L; Allanach, B; Alekhin, S; Allport, P; Andreev, V; Appleby, R B; Arikan, E; Armesto, N; Azuelos, G; Bai, M; Barber, D; Bartels, J; Behnke, O; Behr, J; Belyaev, A S; Ben-Zvi, I; Bernard, N; Bertolucci, S; Bettoni, S; Biswal, S; Blumlein, J; Bottcher, H; Bogacz, A; Bracco, C; Bracinik, J; Brandt, G; Braun, H; Brodsky, S; Bruning, O; Bulyak, E; Buniatyan, A; Burkhardt, H; Cakir, I T; Cakir, O; Calaga, R; Caldwell, A; Cetinkaya, V; Chekelian, V; Ciapala, E; Ciftci, R; Ciftci, A K; Cole, B A; Collins, J C; Dadoun, O; Dainton, J; Roeck, A.De; d'Enterria, D; DiNezza, P; Dudarev, A; Eide, A; Enberg, R; Eroglu, E; Eskola, K J; Favart, L; Fitterer, M; Forte, S; Gaddi, A; Gambino, P; Garcia Morales, H; Gehrmann, T; Gladkikh, P; Glasman, C; Glazov, A; Godbole, R; Goddard, B; Greenshaw, T; Guffanti, A; Guzey, V; Gwenlan, C; Han, T; Hao, Y; Haug, F; Herr, W; Herve, A; Holzer, B J; Ishitsuka, M; Jacquet, M; Jeanneret, B; Jensen, E; Jimenez, J M; Jowett, J M; Jung, H; Karadeniz, H; Kayran, D; Kilic, A; Kimura, K; Klees, R; Klein, M; Klein, U; Kluge, T; Kocak, F; Korostelev, M; Kosmicki, A; Kostka, P; Kowalski, H; Kraemer, M; Kramer, G; Kuchler, D; Kuze, M; Lappi, T; Laycock, P; Levichev, E; Levonian, S; Litvinenko, V N; Lombardi, A; Maeda, J; Marquet, C; Mellado, B; Mess, K H; Milanese, A; Milhano, J G; Moch, S; Morozov, I I; Muttoni, Y; Myers, S; Nandi, S; Nergiz, Z; Newman, P R; Omori, T; Osborne, J; Paoloni, E; Papaphilippou, Y; Pascaud, C; Paukkunen, H; Perez, E; Pieloni, T; Pilicer, E; Pire, B; Placakyte, R; Polini, A; Ptitsyn, V; Pupkov, Y; Radescu, V; Raychaudhuri, S; Rinolfi, L; Rizvi, E; Rohini, R; Rojo, J; Russenschuck, S; Sahin, M; Salgado, C A; Sampei, K; Sassot, R; Sauvan, E; Schaefer, M; Schneekloth, U; Schorner-Sadenius, T; Schulte, D; Senol, A; Seryi, A; Sievers, P; Skrinsky, A N; Smith, W; South, D; Spiesberger, H; Stasto, A M; Strikman, M; Sullivan, M; Sultansoy, S; Sun, Y P; Surrow, B; Szymanowski, L; Taels, P; Tapan, I; Tasci, T; Tassi, E; Kate, H.Ten; Terron, J; Thiesen, H; Thompson, L; Thompson, P; Tokushuku, K; Tomas Garcia, R; Tommasini, D; Trbojevic, D; Tsoupas, N; Tuckmantel, J; Turkoz, S; Trinh, T N; Tywoniuk, K; Unel, G; Ullrich, T; Urakawa, J; VanMechelen, P; Variola, A; Veness, R; Vivoli, A; Vobly, P; Wagner, J; Wallny, R; Wallon, S; Watt, G; Weiss, C; Wiedemann, U A; Wienands, U; Willeke, F; Xiao, B W; Yakimenko, V; Zarnecki, A F; Zhang, Z; Zimmermann, F; Zlebcik, R; Zomer, F

    2012-01-01T23:59:59.000Z

    This document provides a brief overview of the recently published report on the design of the Large Hadron Electron Collider (LHeC), which comprises its physics programme, accelerator physics, technology and main detector concepts. The LHeC exploits and develops challenging, though principally existing, accelerator and detector technologies. This summary is complemented by brief illustrations of some of the highlights of the physics programme, which relies on a vastly extended kinematic range, luminosity and unprecedented precision in deep inelastic scattering. Illustrations are provided regarding high precision QCD, new physics (Higgs, SUSY) and electron-ion physics. The LHeC is designed to run synchronously with the LHC in the twenties and to achieve an integrated luminosity of O(100) fb$^{-1}$. It will become the cleanest high resolution microscope of mankind and will substantially extend as well as complement the investigation of the physics of the TeV energy scale, which has been enabled by the LHC.

  10. Luminosity Tuning at the Large Hadron Collider

    E-Print Network [OSTI]

    Wittmer, W

    2006-01-01T23:59:59.000Z

    By measuring and adjusting the beta-functions at the interaction point (IP the luminosity is being optimized. In LEP (Large Electron Positron Collider) this was done with the two closest doublet magnets. This approach is not applicable for the LHC (Large Hadron Collider) and RHIC (Relativistic Heavy Ion Collider) due to the asymmetric lattice. In addition in the LHC both beams share a common beam pipe through the inner triplet magnets (in these region changes of the magnetic field act on both beams). To control and adjust the beta-functions without perturbation of other optics functions, quadrupole groups situated on both sides further away from the IP have to be used where the two beams are already separated. The quadrupoles are excited in specific linear combinations, forming the so-called "tuning knobs" for the IP beta-functions. For a specific correction one of these knobs is scaled by a common multiplier. The different methods which were used to compute such knobs are discussed: (1) matching in MAD, (2)i...

  11. Bose-Einstein condensation of pions in heavy-ion collisions at the CERN Large Hadron Collider (LHC) energies

    E-Print Network [OSTI]

    Viktor Begun; Wojciech Florkowski

    2015-04-22T23:59:59.000Z

    We analyse in detail the possibility of Bose-Einstein condensation of pions produced in heavy-ion collisions at the beam energy $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV. Our approach is based on the chemical non-equilibrium thermal model of hadron production which has been generalised to include separately the contribution from the local zero-momentum state. In order to study both the hadronic multiplicities and the transverse-momentum spectra, we use the Cracow freeze-out model which parameterises the flow and space-time geometry of the system at freeze-out in a very economic way. Our analysis indicates that about 5% of all pions may form the Bose-Einstein condensate.

  12. Neutrino experiments and the Large Hadron Collider: friends across 14 orders of magnitude

    E-Print Network [OSTI]

    Conrad, Janet

    This paper explores some of the questions that connect the Large Hadron Collider (LHC) and neutrino experiments. What is the origin of mass? What is the meaning of flavor? Is there direct evidence of new forces or particles? ...

  13. NLO QCD corrections to ZZ jet production at hadron colliders

    SciTech Connect (OSTI)

    Binoth, T.; /Edinburgh U.; Gleisberg, T.; /SLAC; Karg, S.; /RWTH Aachen U.; Kauer, N.; /Royal Holloway, U. of London /Southampton U.; Sanguinetti, G.; /Annecy, LAPTH

    2010-05-26T23:59:59.000Z

    A fully differential calculation of the next-to-leading order QCD corrections to the production of Z-boson pairs in association with a hard jet at the Tevatron and LHC is presented. This process is an important background for Higgs particle and new physics searches at hadron colliders. We find sizable corrections for cross sections and differential distributions, particularly at the LHC. Residual scale uncertainties are typically at the 10% level and can be further reduced by applying a veto against the emission of a second hard jet. Our results confirm that NLO corrections do not simply rescale LO predictions.

  14. Beyond the Large Hadron Collider: a first look at cryogenics for CERN future circular colliders

    E-Print Network [OSTI]

    Lebrun, Ph

    2014-01-01T23:59:59.000Z

    Following the first experimental discoveries at the Large Hadron Collider (LHC) and the recent update of the European strategy in particle physics, CERN has undertaken an international study of possible future circular colliders beyond the LHC. The study, conducted with the collaborative participation of interested institutes world-wide, considers several options for very high energy hadron-hadron, electron-positron and hadron-electron colliders to be installed in a quasi-circular underground tunnel in the Geneva basin, with a circumference of 80 km to 100 km. All these machines would make intensive use of advanced superconducting devices, i.e. high-field bending and focusing magnets and/or accelerating RF cavities, thus requiring large helium cryogenic systems operating at 4.5 K or below. Based on preliminary sets of parameters and layouts for the particle colliders under study, we discuss the main challenges of their cryogenic systems and present first estimates of the cryogenic refrigeration capacities req...

  15. Weak Boson Emission in Hadron Collider Processes

    E-Print Network [OSTI]

    U. Baur

    2006-11-17T23:59:59.000Z

    The O(alpha) virtual weak radiative corrections to many hadron collider processes are known to become large and negative at high energies, due to the appearance of Sudakov-like logarithms. At the same order in perturbation theory, weak boson emission diagrams contribute. Since the W and Z bosons are massive, the O(alpha) virtual weak radiative corrections and the contributions from weak boson emission are separately finite. Thus, unlike in QED or QCD calculations, there is no technical reason for including gauge boson emission diagrams in calculations of electroweak radiative corrections. In most calculations of the O(alpha) electroweak radiative corrections, weak boson emission diagrams are therefore not taken into account. Another reason for not including these diagrams is that they lead to final states which differ from that of the original process. However, in experiment, one usually considers partially inclusive final states. Weak boson emission diagrams thus should be included in calculations of electroweak radiative corrections. In this paper, I examine the role of weak boson emission in those processes at the Fermilab Tevatron and the CERN LHC for which the one-loop electroweak radiative corrections are known to become large at high energies (inclusive jet, isolated photon, Z+1 jet, Drell-Yan, di-boson, t-bar t, and single top production). In general, I find that the cross section for weak boson emission is substantial at high energies and that weak boson emission and the O(alpha) virtual weak radiative corrections partially cancel.

  16. Higgs Boson Searches at Hadron Colliders (1/4)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and strategies to measured Higgs boson parameters and the investigation of alternative symmetry breaking scenarios are addressed.

  17. Higgs Boson Searches at Hadron Colliders (1/4)

    SciTech Connect (OSTI)

    None

    2010-06-21T23:59:59.000Z

    In these Academic Training lectures, the phenomenology of Higgs bosons and search strategies at hadron colliders are discussed. After a brief introduction on Higgs bosons in the Standard Model and a discussion of present direct and indirect constraints on its mass the status of the theoretical cross section calculations for Higgs boson production at hadron colliders is reviewed. In the following lectures important experimental issues relevant for Higgs boson searches (trigger, measurements of leptons, jets and missing transverse energy) are presented. This is followed by a detailed discussion of the discovery potential for the Standard Model Higgs boson for both the Tevatron and the LHC experiments. In addition, various scenarios beyond the Standard Model, primarily the MSSM, are considered. Finally, the potential and strategies to measured Higgs boson parameters and the investigation of alternative symmetry breaking scenarios are addressed.

  18. Top quark studies at hadron colliders

    SciTech Connect (OSTI)

    Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)

    1997-01-01T23:59:59.000Z

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO Collaborations are reviewed, including the top quark cross section, mass, branching fractions, and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.

  19. Really large hadron collider working group summary

    SciTech Connect (OSTI)

    Dugan, G. [Cornell Univ., Ithaca, NY (United States); Limon, P. [Fermilab, Batavia, IL (United States); Syphers, M. [Brookhaven National Lab., Upton, NY (United States)

    1996-12-01T23:59:59.000Z

    A summary is presented of preliminary studies of three 100 TeV center-of-mass hadron colliders made with magnets of different field strengths, 1.8T, 9.5T and 12.6T. Descriptions of the machines, and some of the major and most challenging subsystems, are presented, along with parameter lists and the major issues for future study.

  20. The Tevatron Hadron Collider: A short history

    SciTech Connect (OSTI)

    Tollestrup, A.V.

    1994-11-01T23:59:59.000Z

    The subject of this presentation was intended to cover the history of hadron colliders. However this broad topic is probably better left to historians. I will cover a much smaller portion of this subject and specialize my subject to the history of the Tevatron. As we will see, the Tevatron project is tightly entwined with the progress in collider technology. It occupies a unique place among accelerators in that it was the first to make use of superconducting magnets and indeed the basic design now forms a template for all machines using this technology. It was spawned in an incredibly productive era when new ideas were being generated almost monthly and it has matured into our highest energy collider complete with two large detectors that provide the major facility in the US for probing high Pt physics for the coming decade.

  1. The $B-L$ Supersymmetric Standard Model with Inverse Seesaw at the Large Hadron Collider

    E-Print Network [OSTI]

    Khalil, S

    2015-01-01T23:59:59.000Z

    We review the TeV scale $B-L$ extension of the Minimal Supersymmetric Standard Model (BLSSM) where an inverse seesaw mechanism of light neutrino mass generation is naturally implemented and concentrate on its hallmark manifestations at the Large Hadron Collider (LHC).

  2. Signatures for Right-Handed Neutrinos at the Large Hadron Collider

    SciTech Connect (OSTI)

    Huitu, Katri; Rai, Santosh Kumar [Department of Physics, University of Helsinki and Helsinki Institute of Physics, P.O. Box 64, FIN-00014 University of Helsinki (Finland); Khalil, Shaaban [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No, 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo, 11566 (Egypt); Okada, Hiroshi [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No, 11837, P.O. Box 43 (Egypt)

    2008-10-31T23:59:59.000Z

    We explore possible signatures for right-handed neutrinos in a TeV scale B-L extension of the standard model at the Large Hadron Collider. The studied four lepton signal has a tiny standard model background. We find the signal experimentally accessible at the LHC for the considered parameter regions.

  3. Rare b hadron decays at the LHC

    E-Print Network [OSTI]

    Blake, T; Hiller, G

    2015-01-01T23:59:59.000Z

    With the completion of Run~I of the CERN Large Hadron Collider, particle physics has entered a new era. The production of unprecedented numbers of heavy-flavoured hadrons in high energy proton-proton collisions allows detailed studies of flavour-changing processes. The increasingly precise measurements allow to probe the Standard Model with a new level of accuracy. Rare $b$ hadron decays provide some of the most promising approaches for such tests, since there are several observables which can be cleanly interpreted from a theoretical viewpoint. In this article, the status and prospects in this field are reviewed, with a focus on precision measurements and null tests.

  4. Jet Substructure at the Large Hadron Collider

    E-Print Network [OSTI]

    Christopher K. Vermilion

    2011-01-07T23:59:59.000Z

    I explore many aspects of jet substructure at the Large Hadron Collider, ranging from theoretical techniques for jet calculations, to phenomenological tools for better searches with jets, to software for implementing and comparing such tools. I begin with an application of soft-collinear effective theory, an effective theory of QCD applied to high-energy quarks and gluons. This material is taken from Ref. 1, in which we demonstrate factorization and logarithmic resummation for a certain class of observables in electron-positron collisions. I then explore various phenomenological aspects of jet substructure in simulated events. After observing numerous features of jets at hadron colliders, I describe a method -- jet pruning -- for improving searches for heavy particles that decay to one or more jets. This material is a greatly expanded version of Ref. 2. Finally, I give an overview of the software tools available for these kinds of studies, with a focus on SpartyJet, a package for implementing and comparing jet-based analyses I have collaborated on. Several detailed calculations and software examples are given in the appendices. Sections with no new content are italic in the Table of Contents.

  5. Search for Heavy Resonances Decaying to Taus in 7 TeV Proton-Proton Collisions at the Large Hadron Collider

    E-Print Network [OSTI]

    Gurrola, Alfredo

    2011-10-21T23:59:59.000Z

    to energies of the electroweak scale. Extensions to the SM have been developed as a means of explaining experimental observation. If these extensions are indeed the correct mathematical descriptions of nature, the Large Hadron Collider (LHC), located...

  6. A feedback microprocessor for hadron colliders

    SciTech Connect (OSTI)

    Herrup, D.A.; Chapman, L.; Franck, A.; Groves, T.; Lublinsky, B.

    1992-12-01T23:59:59.000Z

    A feedback microprocessor has been built for the TEVATRON. It has been constructed to be applicable to hadron colliders in general. Its inputs are realtime accelerator measurements, data describing the state of the TEVATRON, and ramp tables. The microprocessor software includes a finite state machine. Each state corresponds to a specific TEVATRON operation and has a state-specific TEVATRON model. Transitions between states are initiated by the global TEVATRON clock. Each state includes a cyclic routine which is called periodically and where all calculations are performed. The output corrections are inserted onto a fast TEVATRON-wide link from which the power supplies will read the realtime corrections. We also store all of the input data and output corrections in a set of buffers which can easily be retrieved for diagnostic analysis. In this paper we will describe this device and its use to control the TEVATRON tunes as well as other possible applications.

  7. First electron-cloud studies at the Large Hadron Collider

    E-Print Network [OSTI]

    Dominguez, O; Arduini, G; Metral, E; Rumolo, G; Zimmermann, F; Maury Cuna, H

    2013-01-01T23:59:59.000Z

    During the beam commissioning of the Large Hadron Collider (LHC) with 150, 75, 50, and 25-ns bunch spacing, important electron-cloud effects, like pressure rise, cryogenic heat load, beam instabilities, or emittance growth, were observed. Methods have been developed to infer different key beam-pipe surface parameters by benchmarking simulations and pressure rise as well as heat-load observations. These methods allow us to monitor the scrubbing process, i.e., the reduction of the secondary emission yield as a function of time, in order to decide on the most appropriate strategies for machine operation. To better understand the influence of electron clouds on the beam dynamics, simulations have been carried out to examine both the coherent and the incoherent effects on the beam. In this paper we present the methodology and first results for the scrubbing monitoring process at the LHC. We also review simulated instability thresholds and tune footprints for beams of different emittance, interacting with an electr...

  8. CLIC Drive Beam and LHC Based Fel-Nucleus Collider

    E-Print Network [OSTI]

    H. Braun; R. Corsini; S. Sultansoy; O. Yavas

    2005-08-09T23:59:59.000Z

    The feasibility of a CLIC-LHC based FEL-nucleus collider is investigated. It is shown that the proposed scheme satisfies all requirements of an ideal photon source for the Nuclear Resonance Fluorescence method. The physics potential of the proposed collider is illustrated for a beam of Pb nuclei.

  9. A feedback microprocessor for hadron colliders

    SciTech Connect (OSTI)

    Herrup, D.A.; Chapman, L.; Franck, A.; Groves, T.; Lublinsky, B. (Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States))

    1995-02-01T23:59:59.000Z

    A feedback microprocessor has been built for the Tevatron. It has been constructed to be applicable to hadron colliders in general. Its inputs are realtime accelerator measurements, data describing the state of the Tevatron, and ramp tables. The microprocessor software includes a finite-state machine. Each state corresponds to a specific Tevatron operation and has a state-specific Tevatron model. Transitions between states are initiated by the global Tevatron clock. Each state includes a cyclic routine, which is called periodically and where all calculations are performed. The output corrections are inserted onto a fast Tevatron-wide link from which the power supplies will read the real time corrections. We also store all of the input data and output corrections in a set of buffers that can easily be retrieved for diagnostic analysis. In this paper we describe this device and its use to control the Tevatron tunes as well as other possible applications. [copyright] 1995 [ital American] [ital Institute] [ital of] [ital Physics

  10. US/LHC - Large Hadron Collider

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    theory of how matter obtains mass. Their work was confirmed by the discovery of a Higgs boson at CERN on July 4, 2012. (Image credit: CERN) Learn more On July 4, 2012,...

  11. Higgs bosons, electroweak symmetry breaking, and the physics of the Large Hadron Collider

    SciTech Connect (OSTI)

    Quigg, Chris; /Fermilab /CERN

    2007-02-01T23:59:59.000Z

    The Large Hadron Collider, a 7 {circle_plus} 7 TeV proton-proton collider under construction at CERN (the European Laboratory for Particle Physics in Geneva), will take experiments squarely into a new energy domain where mysteries of the electroweak interaction will be unveiled. What marks the 1-TeV scale as an important target? Why is understanding how the electroweak symmetry is hidden important to our conception of the world around us? What expectations do we have for the agent that hides the electroweak symmetry? Why do particle physicists anticipate a great harvest of discoveries within reach of the LHC?

  12. Crab dispersion and its impact on the CERN Large Hadron Collider collimation

    E-Print Network [OSTI]

    Sun, P; Tomàs, R; Zimmermann, F

    2010-01-01T23:59:59.000Z

    Crab cavities are proposed to be used for a luminosity upgrade of the Large Hadron Collider (LHC). Crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The crab cavity introduces another kind of dispersion to the particles which is z dependent, and thus could complicate the beam dynamics and have an impact on the LHC collimation system. As for LHC, the off-momentum beta-beat and dispersion-beat already compromise the performance of the collimation system; the crab dispersion introduced by global crab cavities might do the same, and should be carefully evaluated. In this paper, we present a definition for the crab dispersion, and study its impact on the LHC collimation system.

  13. Time evolution of the luminosity of colliding heavy-ion beams in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider

    E-Print Network [OSTI]

    Bruce, R; Fischer, W; Jowett, J M

    2010-01-01T23:59:59.000Z

    We have studied the time evolution of the heavy ion luminosity and bunch intensities in the Relativistic Heavy Ion Collider (RHIC), at BNL, and in the Large Hadron Collider (LHC), at CERN. First, we present measurements from a large number of RHIC stores (from Run 7), colliding 100 GeV/nucleon 197Au79+ beams without stochastic cooling. These are compared with two different calculation methods. The first is a simulation based on multi-particle tracking taking into account collisions, intrabeam scattering, radiation damping, and synchrotron and betatron motion. In the second, faster, method, a system of ordinary differential equations with terms describing the corresponding effects on emittances and bunch populations is solved numerically. Results of the tracking method agree very well with the RHIC data. With the faster method, significant discrepancies are found since the losses of particles diffusing out of the RF bucket due to intrabeam scattering are not modeled accurately enough. Finally, we use both meth...

  14. Sextupole correction magnets for the Large Hadron Collider

    E-Print Network [OSTI]

    Meinke, R B; Senti, M; Op de Beeck, W J; De Ryck, C; MacKay, W W

    1999-01-01T23:59:59.000Z

    About 2500 superconducting sextupole corrector magnets (MCS) are needed for the Large Hadron Collider (LHC) at CERN to compensate persistent current sextupole fields of the main dipoles. The MCS is a cold bore magnet with iron yoke. The coils are made from a NbTi conductor, which is cooled to 1.9 K. In the original CERN design 6 individual sub-coils, made from a monolithic composite conductor, are assembled and spliced together to form the sextupole. The coils are individually wound around precision-machined central islands and stabilized with matching saddle pieces at both ends. The Advanced Magnet Lab, Inc. (AML) has produced an alternative design, which gives improved performance and reliability at reduced manufacturing cost. In the AML design, the magnet consists of three splice-free sub-coils, which are placed with an automated winding process into pockets of prefabricated G-11 support cylinders. Any assembly process of sub-coils with potential misalignment is eliminated. The AML magnet uses a Kapton-wra...

  15. ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders

    E-Print Network [OSTI]

    Papotti, G; BB2013; BB 2013

    2014-01-01T23:59:59.000Z

    This report contains the Proceedings of the ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders held at CERN from 18 to 22 March 2013. It was the first of its kind after the successful start of LHC operation where a vast amount of beam-beam observations emerged. It brought together 58 international experts in the field and the purpose of this workshop was to review the present knowledge in the fields of beam-beam theory, simulations and observations. In the summary session the participants acknowledged the enormous progress made in recent years and the introduction of new concepts and tools. The workshop was concluded by a discussion on future research work with emphasis on the LHC operation and future circular colliders.

  16. Long-Lived Sleptons at the LHC and a 100 TeV Proton Collider

    E-Print Network [OSTI]

    Feng, Jonathan L; Shadmi, Yael; Tarem, Shlomit

    2015-01-01T23:59:59.000Z

    We study the prospects for long-lived charged particle (LLCP) searches at current and future LHC runs and at a 100 TeV pp collider, using Drell-Yan slepton pair production as an example. Because momentum measurements become more challenging for very energetic particles, we carefully treat the expected momentum resolution. At the same time, a novel feature of 100 TeV collisions is the significant energy loss of energetic muons in detectors. We use this to help discriminate between muons and LLCPs. We find that the 14 TeV LHC with an integrated luminosity of 3 ab$^{-1}$ can probe LLCP slepton masses up to 1.2 TeV, and a 100 TeV pp collider with 3 ab$^{-1}$ can probe LLCP slepton masses up to 4 TeV, using time-of-flight measurements. These searches will have striking implications for dark matter, with the LHC definitively testing the possibility of slepton-neutralino co-annihilating WIMP dark matter, and with the LHC and future hadron colliders having a strong potential for discovering LLCPs in models with super...

  17. Long-Lived Sleptons at the LHC and a 100 TeV Proton Collider

    E-Print Network [OSTI]

    Jonathan L. Feng; Sho Iwamoto; Yael Shadmi; Shlomit Tarem

    2015-05-12T23:59:59.000Z

    We study the prospects for long-lived charged particle (LLCP) searches at current and future LHC runs and at a 100 TeV pp collider, using Drell-Yan slepton pair production as an example. Because momentum measurements become more challenging for very energetic particles, we carefully treat the expected momentum resolution. At the same time, a novel feature of 100 TeV collisions is the significant energy loss of energetic muons in detectors. We use this to help discriminate between muons and LLCPs. We find that the 14 TeV LHC with an integrated luminosity of 3 ab$^{-1}$ can probe LLCP slepton masses up to 1.2 TeV, and a 100 TeV pp collider with 3 ab$^{-1}$ can probe LLCP slepton masses up to 4 TeV, using time-of-flight measurements. These searches will have striking implications for dark matter, with the LHC definitively testing the possibility of slepton-neutralino co-annihilating WIMP dark matter, and with the LHC and future hadron colliders having a strong potential for discovering LLCPs in models with superWIMP dark matter.

  18. TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS

    SciTech Connect (OSTI)

    Jabeen, Shabnam

    2013-10-20T23:59:59.000Z

    This review summarizes the recent results for top quark and Higgs boson measurements from experiments at Tevatron, a proton–antiproton collider at a center-of-mass energy of ? s =1 . 96 TeV, and the Large Hadron Collider, a proton–proton collider at a center- of-mass energy of ? s = 7 TeV. These results include the discovery of a Higgs-like boson and measurement of its various properties, and measurements in the top quark sector, e.g. top quark mass, spin, charge asymmetry and production of single top quark.

  19. Proton annihilation at hadron colliders and Kamioka: high-energy versus high-luminosity

    E-Print Network [OSTI]

    Joseph Bramante; Jason Kumar; John Learned

    2014-12-05T23:59:59.000Z

    We examine models and prospects for proton annihilation to dileptons, a process which violates baryon and lepton number each by two. We determine that currently Super-Kamiokande would place the most draconian bound on $pp \\rightarrow \\ell^+ \\ell^+$, ruling out new physics below a scale of $\\sim 1.6$ TeV. We also find present and future hadron collider sensitivity to these processes. While 8 TeV LHC data excludes new physics at a scale below $\\sim 800$ GeV, the reach of a 14 TeV LHC run is $\\sim 1.8$ TeV, putting it on par with the sensitivity of Super-Kamiokande. On the other hand, a 100 TeV proton-proton collider would be sensitive to proton annihilation at a scale up to 10 TeV, allowing it to far exceed the reach of both Super-Kamiokande and the projected 2 TeV reach of Hyper-Kamiokande. Constraints from neutron star observation and cosmological evolution are not competitive. Therefore, although high-luminosity water Cherenkov experiments currently place the leading bounds on baryon and lepton number violation, next generation high-energy hadron colliders will begin surpassing them in sensitivity to some $B/L$-violating processes.

  20. Large Hadron Collider probe of supersymmetric neutrinoless double beta decay mechanism.

    E-Print Network [OSTI]

    Allanach, B C; Kom, C H; Pas, H

    ar X iv :0 90 2. 46 97 v1 [ he p- ph ] 26 Fe b 2 00 9 CAVENDISH-HEP-2009-03, DAMTP-2009-15, DO-TH-09/01 Large Hadron Collider probe of supersymmetric neutrinoless double beta decay mechanism B. C. Allanach? DAMTP, University of Cambridge... ) In the minimal supersymmetric extension to the Standard Model, a non-zero lepton number violating coupling ??111 predicts both neutrinoless double beta decay and resonant single slepton production at the LHC. We show that, in this case, if neutrinoless double...

  1. Time evolution of the luminosity of colliding heavy-ion beams in BNL Relativistic Heavy Ion Collider and CERN Large Hadron Collider

    E-Print Network [OSTI]

    R. Bruce; M. Blaskiewicz; W. Fischer; J. M. Jowett

    2010-09-08T23:59:59.000Z

    We have studied the time evolution of the heavy ion luminosity and bunch intensities in the Relativistic Heavy Ion Collider (RHIC), at BNL, and in the Large Hadron Collider (LHC), at CERN. First, we present measurements from a large number of RHIC stores (from Run 7), colliding 100 GeV/nucleon Au beams without stochastic cooling. These are compared with two different calculation methods. The first is a simulation based on multi-particle tracking taking into account collisions, intrabeam scattering, radiation damping, and synchrotron and betatron motion. In the second, faster, method, a system of ordinary differential equations with terms describing the corresponding effects on emittances and bunch populations is solved numerically. Results of the tracking method agree very well with the RHIC data. With the faster method, significant discrepancies are found since the losses of particles diffusing out of the RF bucket due to intrabeam scattering are not modeled accurately enough. Finally, we use both methods to make predictions of the time evolution of the future Pb beams in the LHC at injection and collision energy. For this machine, the two methods agree well.

  2. A study of beam-beam effects in hadron colliders with a large number of bunches

    E-Print Network [OSTI]

    Pieloni, Tatiana; Bay, Aurelio; Rivkin, Leonid

    2008-01-01T23:59:59.000Z

    A particle beam is a collection of a large number of charges and represents an electromagnetic potential for other charges, therefore exerting forces on itself and other beams. The control of this so called Beam-Beam Interactions (BBIs) in particle colliders is fundamental to preserve beam stability and achieve the collider maximal luminosity. In the case of the Large Hadron Collider (LHC) at CERN, these forces are experienced as localized periodic distortions when the two beams cross each other in the four experimental areas. The forces are most important for high density beams, i.e. high intensity and small beam sizes. Each LHC beam is composed of 2808 bunches, each containing $10^{11}$ protons and with a transverse size of 16~$\\mu $m at the interaction points. These extreme parameters are the key to obtain high ``luminosity'', i. e. the number of collisions per second needed to study rare physics phenomena. The BBI is therefore often the limiting factor for the luminosity of colliders. Within all BB effect...

  3. Collider Detector at Fermilab (CDF): Data from B Hadrons Research

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The Collider Detector at Fermilab (CDF) is a Tevatron experiment at Fermilab. The Tevatron, a powerful particle accelerator, accelerates protons and antiprotons close to the speed of light, and then makes them collide head-on inside the CDF detector. The CDF detector is used to study the products of such collisions. The CDF Physics Group is organized into six working groups, each with a specific focus. The Bottom group studies the production and decay of B hadrons. Their public web page makes data and numerous figures available from both CDF Runs I and II.

  4. High Luminosity Large Hadron Collider A description for the European Strategy Preparatory Group

    E-Print Network [OSTI]

    Rossi, L

    2012-01-01T23:59:59.000Z

    The Large Hadron Collider (LHC) is the largest scientific instrument ever built. It has been exploring the new energy frontier since 2009, gathering a global user community of 7,000 scientists. It will remain the most powerful accelerator in the world for at least two decades, and its full exploitation is the highest priority in the European Strategy for Particle Physics, adopted by the CERN Council and integrated into the ESFRI Roadmap. To extend its discovery potential, the LHC will need a major upgrade around 2020 to increase its luminosity (rate of collisions) by a factor of 10 beyond its design value. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about 10 years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 13 tesla superconducting magnets, very compact and ultra-precise superconduc...

  5. Calibration of the CMS Pixel Detector at the Large Hadron Collider

    E-Print Network [OSTI]

    Vami, Tamas Almos

    2015-01-01T23:59:59.000Z

    The Compact Muon Solenoid (CMS) detector is one of two general-purpose detectors that reconstruct the products of high energy particle interactions at the Large Hadron Collider (LHC) at CERN. The silicon pixel detector is the innermost component of the CMS tracking system. It determines the trajectories of charged particles originating from the interaction region in three points with high resolution enabling precise momentum and impact parameter measurements in the tracker. The pixel detector is exposed to intense ionizing radiation generated by particle collisions in the LHC. This irradiation could result in temporary or permanent malfunctions of the sensors and could decrease the efficiency of the detector. We have developed procedures in order to correct for these effects. In this paper, we present the types of malfunctions and the offline calibration procedures. We will also show the efficiency and the resolution of the detector in 2012.

  6. B-quark production at hadron colliders

    SciTech Connect (OSTI)

    Meng, Ruibin [Argonne National Lab., IL (United States); Riemersma, S. [Southern Methodist Univ., Dallas, TX (United States)

    1993-08-01T23:59:59.000Z

    Studying B-physics at hadron accelerators requires a good understanding of the total and differential cross sections for b-quark production. This knowledge gives those involved in B{bar B} mixing, rare B decays, and those trying to determine the CKM angles {alpha}, {beta}, and {gamma} an idea of how many events they can expect, given the luminosity and the branching ratios. It is particularly important for those studying rare B decays as they set limits on where we can hope to see new physics. For these reasons and others, the complete {Omicron}({alpha}{sub s}{sup 3}) corrections to heavy-quark production at hadron accelerators were calculated in. Also three groups have attempted to calculate heavy-quark production using resummation techniques in the small-x kinematic region. These resummation techniques are necessary since the b-quark mass m{sub b} is small relative to the center-of-mass energies {radical}S of the TeVatron and the SSC. While these techniques offer some hope of obtaining reasonable predictions for b-production at these machines, the current results can best be considered as preliminary. Thus we must turn to fixed-order perturbative QCD for guidance, as we have no other real choice at this point. However, let us submit a caveat here: fixed-order perturbative QCD works best when all the scales are roughly comparable, i.e. {radical}s {approx} m{sub b} {approx} p{sub t}, {radical}s being the partonic center-of-mass energy. When we are not in this regime, for example at the TeVatron and the SSC, our predictions will then be less reliable. Bearing this in mind, let use continue to the results section.

  7. Learning to See at the Large Hadron Collider

    SciTech Connect (OSTI)

    Quigg, Chris

    2010-01-01T23:59:59.000Z

    The staged commissioning of the Large Hadron Collider presents an opportunity to map gross features of particle production over a significant energy range. I suggest a visual tool - event displays in (pseudo)rapidity-transverse-momentum space - as a scenic route that may help sharpen intuition, identify interesting classes of events for further investigation, and test expectations about the underlying event that accompanies large-transverse-momentum phenomena.

  8. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    E-Print Network [OSTI]

    Bruce, R; Boccone, V; Bracco, C; Brugger, M; Cauchi, M; Cerutti, F; Deboy, D; Ferrari, A; Lari, L; Marsili, A; Mereghetti, A; Mirarchi, D; Quaranta, E; Redaelli, S; Robert-Demolaize, G; Rossi, A; Salvachua, B; Skordis, E; Tambasco, C; Valentino, G; Weiler, T; Vlachoudis, V; Wollmann, D

    2014-01-01T23:59:59.000Z

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the co...

  9. Independent measurement of the top quark mass and the light- and bottom-jet energy scales at hadron colliders

    E-Print Network [OSTI]

    Frank Fiedler

    2007-06-12T23:59:59.000Z

    A method for the simultaneous determination of the energy scales for b-quark jets and light jets, the jet energy resolution, and the top quark mass at hadron colliders is presented. The method exploits the unique kinematics of events with top-antitop pair production, where one of the top quarks involves a leptonic and one a hadronic W boson decay. The paper shows a feasibility study of how this simultaneous measurement can be performed at the upcoming LHC experiments ATLAS and CMS.

  10. Next-to-Leading-Order QCD Corrections to W{sup +}W{sup -}bb Production at Hadron Colliders

    SciTech Connect (OSTI)

    Denner, A. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Dittmaier, S. [Physikalisches Institut, Albert-Ludwigs-Universitaet Freiburg, 79104 Freiburg (Germany); Kallweit, S. [Paul Scherrer Institut, Wuerenlingen und Villigen, 5232 Villigen PSI (Switzerland); Pozzorini, S. [Institut fuer Theoretische Physik, Universitaet Zuerich, 8057 Zuerich (Switzerland)

    2011-02-04T23:59:59.000Z

    Top-antitop quark pairs belong to the most abundantly produced and precisely measurable heavy-particle signatures at hadron colliders and allow for crucial tests of the standard model and new physics searches. Here we report on the calculation of the next-to-leading order (NLO) QCD corrections to hadronic W{sup +}W{sup -}bb production, which provides a complete NLO description of the production of top-antitop pairs and their subsequent decay into W bosons and bottom quarks, including interferences, off-shell effects, and nonresonant backgrounds. Numerical predictions for the Tevatron and the LHC are presented.

  11. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    E-Print Network [OSTI]

    R. Bruce; R. W. Assmann; V. Boccone; C. Bracco; M. Brugger; M. Cauchi; F. Cerutti; D. Deboy; A. Ferrari; L. Lari; A. Marsili; A. Mereghetti; D. Mirarchi; E. Quaranta; S. Redaelli; G. Robert-Demolaize; A. Rossi; B. Salvachua; E. Skordis; C. Tambasco; G. Valentino; T. Weiler; V. Vlachoudis; D. Wollmann

    2014-09-10T23:59:59.000Z

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010--2013, the LHC was routinely storing protons at 3.5--4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An un-controlled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multi-stage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte-Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  12. Physics and Analysis at a Hadron Collider - An Introduction (1/3)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    This is the first lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This first lecture provides a brief introduction to hadron collider physics and collider detector experiments as well as offers some analysis guidelines. The lectures are aimed at graduate students.

  13. A High Field Magnet Design for A Future Hadron Collider==== R. Gupta, K. Chow, D. Dietderich, S. Gourlay, G. Millos, A. McInturff, R. Scanlan

    E-Print Network [OSTI]

    Gupta, Ramesh

    A High Field Magnet Design for A Future Hadron Collider==== R. Gupta, K. Chow, D. Dietderich, S the completion of LHC. This paper presents a high field magnet design option based on Nb3Sn technology. A preliminary magnetic and mechanical design of a 14-16 T, 2-in-1 dipole based on the "common coil design

  14. A 233 km tunnel for lepton and hadron colliders

    SciTech Connect (OSTI)

    Summers, D. J.; Cremaldi, L. M.; Datta, A.; Duraisamy, M.; Luo, T.; Lyons, G. T. [Dept. of Physics and Astronomy, University of Mississippi-Oxford, University, MS 38677 (United States)

    2012-12-21T23:59:59.000Z

    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e{sup +}e{sup -}, pp-bar , and {mu}{sup +}{mu}{sup -} collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e{sup +}e{sup -} colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e{sup +}e{sup -} collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV pp-bar collider uses the high intensity Fermilab p-bar source, exploits high cross sections for pp-bar production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.

  15. NNLO Benchmarks for Gauge and Higgs Boson Production at TeV Hadron Colliders

    E-Print Network [OSTI]

    S. Alekhin; J. Blümlein; P. Jimenez-Delgado; S. Moch; E. Reya

    2010-11-29T23:59:59.000Z

    The inclusive production cross sections for $W^+, W^-$ and $Z^0$-bosons form important benchmarks for the physics at hadron colliders. We perform a detailed comparison of the predictions for these standard candles based on recent next-to-next-to-leading order (NNLO) parton parameterizations and new analyses including the combined HERA data, compare to all available experimental results, and discuss the predictions for present and upcoming RHIC, SPS, Tevatron and LHC energies. The rates for gauge boson production at the LHC can be rather confidently predicted with an accuracy of better than about 10% at NNLO. We also present detailed NNLO predictions for the Higgs boson production cross sections for Tevatron and LHC energies (1.96, 7, 8, 14 TeV), and propose a possible method to monitor the gluon distribution experimentally in the kinematic region close to the mass range expected for the Higgs boson. The production cross sections of the Higgs boson at the LHC are presently predicted with an accuracy of about 10--17%. The inclusion of the NNLO contributions is mandatory for achieving such accuracies since the total uncertainties are substantially larger at NLO.

  16. Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider

    E-Print Network [OSTI]

    Sun, Y P; Barranco, J; Tomàs, R; Weiler, T; Zimmermann, F; Calaga, R; Morita, A

    2009-01-01T23:59:59.000Z

    Modern colliders bring into collision a large number of bunches to achieve a high luminosity. The longrange beam-beam effects arising from parasitic encounters at such colliders are mitigated by introducing acrossing angle. Under these conditions, crab cavities (CC) can be used to restore effective head-on collisions and thereby to increase the geometric luminosity. Such crab cavities have been proposed for both linear and circular colliders. The crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The use of crab cavities in the Large Hadron Collider (LHC) may not only raise the luminosity, but it could also complicate the beam dynamics, e.g., crab cavities might not only cancel synchrobetatron resonances excited by the crossing angle but they could also excite new ones, they could reduce the dynamic aperture for off-momentum particles, they could influence the aperture and orbit, ...

  17. Beam dynamics aspects of crab cavities in the CERN Large Hadron Collider

    E-Print Network [OSTI]

    Sun, Y P; Barranco, J; Tomás, R; Weiler, T; Zimmermann, F; Calaga, R; Morita, A

    2009-01-01T23:59:59.000Z

    Modern colliders bring into collision a large number of bunches to achieve a high luminosity. The long-range beam-beam effects arising from parasitic encounters at such colliders are mitigated by introducing a crossing angle. Under these conditions, crab cavities (CC) can be used to restore effective head-on collisions and thereby to increase the geometric luminosity. Such crab cavities have been proposed for both linear and circular colliders. The crab cavities are rf cavities operated in a transverse dipole mode, which imparts on the beam particles a transverse kick that varies with the longitudinal position along the bunch. The use of crab cavities in the Large Hadron Collider (LHC) may not only raise the luminosity, but it could also complicate the beam dynamics, e.g., crab cavities might not only cancel synchrobetatron resonances excited by the crossing angle but they could also excite new ones, they could reduce the dynamic aperture for off-momentum particles, they could influence the aperture and orbit...

  18. Exploring higher dimensional black holes at the large hadron collider.

    E-Print Network [OSTI]

    Harris, Chris M; Palmer, M J; Parker, Michael A; Richardson, P

    cross section for production of black holes not too much heavier than the fundamental Planck scale corresponds to a production rate of a few Hertz at the LHC design luminosity. In the following sections, the process of the black hole production and decay... scattering in quantum gravity, hep-th/9906038. [7] R. Emparan, G. T. Horowitz, and R. C. Myers, Exact description of black holes on branes, JHEP 01 (2000) 007, [hep-th/9911043]. [8] S. B. Giddings and S. Thomas, High energy colliders as black hole factories...

  19. Compressed supersymmetry after 1 fb?¹ at the Large Hadron Collider

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    LeCompte, Thomas J.; Martin, Stephen P.

    2012-02-01T23:59:59.000Z

    We study the reach of the Large Hadron Collider with 1 fb?¹ of data at ?s=7 TeV for several classes of supersymmetric models with compressed mass spectra, using jets and missing transverse energy cuts like those employed by ATLAS for summer 2011 data. In the limit of extreme compression, the best limits come from signal regions that do not require more than 2 or 3 jets and that remove backgrounds by requiring more missing energy rather than a higher effective mass.

  20. A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector

    E-Print Network [OSTI]

    J. L. Abelleira Fernandez; C. Adolphsen; A. N. Akay; H. Aksakal; J. L. Albacete; S. Alekhin; P. Allport; V. Andreev; R. B. Appleby; E. Arikan; N. Armesto; G. Azuelos; M. Bai; D. Barber; J. Bartels; O. Behnke; J. Behr; A. S. Belyaev; I. Ben-Zvi; N. Bernard; S. Bertolucci; S. Bettoni; S. Biswal; J. Blümlein; H. Böttcher; A. Bogacz; C. Bracco; G. Brandt; H. Braun; S. Brodsky; O. Brüning; E. Bulyak; A. Buniatyan; H. Burkhardt; I. T. Cakir; O. Cakir; R. Calaga; V. Cetinkaya; E. Ciapala; R. Ciftci; A. K. Ciftci; B. A. Cole; J. C. Collins; O. Dadoun; J. Dainton; A. De. Roeck; D. d'Enterria; A. Dudarev; A. Eide; R. Enberg; E. Eroglu; K. J. Eskola; L. Favart; M. Fitterer; S. Forte; A. Gaddi; P. Gambino; H. García Morales; T. Gehrmann; P. Gladkikh; C. Glasman; R. Godbole; B. Goddard; T. Greenshaw; A. Guffanti; V. Guzey; C. Gwenlan; T. Han; Y. Hao; F. Haug; W. Herr; A. Hervé; B. J. Holzer; M. Ishitsuka; M. Jacquet; B. Jeanneret; J. M. Jimenez; J. M. Jowett; H. Jung; H. Karadeniz; D. Kayran; A. Kilic; K. Kimura; M. Klein; U. Klein; T. Kluge; F. Kocak; M. Korostelev; A. Kosmicki; P. Kostka; H. Kowalski; G. Kramer; D. Kuchler; M. Kuze; T. Lappi; P. Laycock; E. Levichev; S. Levonian; V. N. Litvinenko; A. Lombardi; J. Maeda; C. Marquet; S. J. Maxfield; B. Mellado; K. H. Mess; A. Milanese; S. Moch; I. I. Morozov; Y. Muttoni; S. Myers; S. Nandi; Z. Nergiz; P. R. Newman; T. Omori; J. Osborne; E. Paoloni; Y. Papaphilippou; C. Pascaud; H. Paukkunen; E. Perez; T. Pieloni; E. Pilicer; B. Pire; R. Placakyte; A. Polini; V. Ptitsyn; Y. Pupkov; V. Radescu; S. Raychaudhuri; L. Rinolfi; R. Rohini; J. Rojo; S. Russenschuck; M. Sahin; C. A. Salgado; K. Sampei; R. Sassot; E. Sauvan; U. Schneekloth; T. Schörner-Sadenius; D. Schulte; A. Senol; A. Seryi; P. Sievers; A. N. Skrinsky; W. Smith; H. Spiesberger; A. M. Stasto; M. Strikman; M. Sullivan; S. Sultansoy; Y. P. Sun; B. Surrow; L. Szymanowski; P. Taels; I. Tapan; A. T. Tasci; E. Tassi; H. Ten. Kate; J. Terron; H. Thiesen; L. Thompson; K. Tokushuku; R. Tomás García; D. Tommasini; D. Trbojevic; N. Tsoupas; J. Tuckmantel; S. Turkoz; T. N. Trinh; K. Tywoniuk; G. Unel; J. Urakawa; P. VanMechelen; A. Variola; R. Veness; A. Vivoli; P. Vobly; J. Wagner; R. Wallny; S. Wallon; G. Watt; C. Weiss; U. A. Wiedemann; U. Wienands; F. Willeke; B. -W. Xiao; V. Yakimenko; A. F. Zarnecki; Z. Zhang; F. Zimmermann; R. Zlebcik; F. Zomer

    2012-09-07T23:59:59.000Z

    The physics programme and the design are described of a new collider for particle and nuclear physics, the Large Hadron Electron Collider (LHeC), in which a newly built electron beam of 60 GeV, up to possibly 140 GeV, energy collides with the intense hadron beams of the LHC. Compared to HERA, the kinematic range covered is extended by a factor of twenty in the negative four-momentum squared, $Q^2$, and in the inverse Bjorken $x$, while with the design luminosity of $10^{33}$ cm$^{-2}$s$^{-1}$ the LHeC is projected to exceed the integrated HERA luminosity by two orders of magnitude. The physics programme is devoted to an exploration of the energy frontier, complementing the LHC and its discovery potential for physics beyond the Standard Model with high precision deep inelastic scattering measurements. These are designed to investigate a variety of fundamental questions in strong and electroweak interactions. The physics programme also includes electron-deuteron and electron-ion scattering in a $(Q^2, 1/x)$ range extended by four orders of magnitude as compared to previous lepton-nucleus DIS experiments for novel investigations of neutron's and nuclear structure, the initial conditions of Quark-Gluon Plasma formation and further quantum chromodynamic phenomena. The LHeC may be realised either as a ring-ring or as a linac-ring collider. Optics and beam dynamics studies are presented for both versions, along with technical design considerations on the interaction region, magnets and further components, together with a design study for a high acceptance detector. Civil engineering and installation studies are presented for the accelerator and the detector. The LHeC can be built within a decade and thus be operated while the LHC runs in its high-luminosity phase. It thus represents a major opportunity for progress in particle physics exploiting the investment made in the LHC.

  1. Operational Experience and Consolidations for the Current Lead Control Valves of the Large Hadron Collider

    E-Print Network [OSTI]

    Perin, A; Pirotte, O; Krieger, B; Widmer, A

    2012-01-01T23:59:59.000Z

    The Large Hadron Collider superconducting magnets are powered by more than 1400 gas cooled current leads ranging from 120 A to 13000 A. The gas flow required by the leads is controlled by solenoid proportional valves with dimensions from DN 1.8 mm to DN 10 mm. During the first months of operation, signs of premature wear were found in the active parts of the valves. This created major problems for the functioning of the current leads threatening the availability of the LHC. Following the detection of the problems, a series of measures were implemented to keep the LHC running, to launch a development program to solve the premature wear problem and to prepare for a global consolidation of the gas flow control system. This article describes first the difficulties encountered and the measures taken to ensure a continuous operation of the LHC during the first year of operation. The development of new friction free valves is then presented along with the consolidation program and the test equipment developed to val...

  2. Precise Predictions for W 4 Jet Production at the Large Hadron Collider

    SciTech Connect (OSTI)

    Berger, C.F.; /MIT, LNS; Bern, Z.; /UCLA; Dixon, Lance J.; /CERN /SLAC; Cordero, F.Febres; /Simon Bolivar U.; Forde, D.; /CERN /NIKHEF, Amsterdam; Gleisberg, T.; /SLAC; Ita, H.; /UCLA; Kosower, D.A.; /Saclay, SPhT; Maitre, D.; /Durham U.

    2010-09-14T23:59:59.000Z

    We present the first next-to-leading order QCD results for W + 4-jet production at hadron colliders. Total cross sections, as well as distributions in the jet transverse momenta and in the total transverse energy HT, are provided for the initial LHC energy of {radical}s = 7 TeV. We use a leading-color approximation, known to be accurate to 3% for W production with fewer jets. The virtual matrix elements and the most complicated real-emission matrix elements are handled by the BlackHat library, based on on-shell methods. The remaining parts of the calculation, including the integration over phase space, are performed by the SHERPA package.

  3. Benchmarking Electron-Cloud Build-Up and Heat-Load Simulations against Large-Hadron-Collider Observations

    E-Print Network [OSTI]

    Dominguez, O; Maury, H; Rumolo, G; Zimmermann, F

    2011-01-01T23:59:59.000Z

    After reviewing the basic features of electron clouds in particle accelerators, the pertinent vacuum-chamber surface properties, and the electron-cloud simulation tools in use at CERN, we report recent observations of electron-cloud phenomena at the Large Hadron Collider (LHC) and ongoing attempts to benchmark the measured LHC vacuum pressure increases and heat loads against electron-cloud build-up simulations aimed at determining the actual surface parameters and at monitoring the so-called scrubbing process. Finally, some other electron-cloud studies related to the LHC are mentioned, and future study plans are described. Presented at MulCoPim2011, Valencia, Spain, 21-23 September 2011.

  4. Precise Predictions for W+4-Jet Production at the Large Hadron Collider

    E-Print Network [OSTI]

    Berger, Carola

    We present the next-to-leading order (NLO) QCD results for W+4-jet production at hadron colliders. This is the first hadron-collider process with five final-state objects to be computed at NLO. It represents an important ...

  5. A Large Hadron Electron Collider at CERN: Report on the Physics and Design Concepts for Machine and Detector

    E-Print Network [OSTI]

    Abelleira Fernandez, J L; Akay, A N; Aksakal, H; Albacete, J L; Alekhin, S; Allport, P; Andreev, V; Appleby, R B; Arikan, E; Armesto, N; Azuelos, G; Bai, M; Barber, D; Bartels, J; Behnke, O; Behr, J; Belyaev, A S; Ben-Zvi, I; Bernard, N; Bertolucci, S; Bettoni, S; Biswal, S; Blumlein, J; Bottcher, H; Bogacz, A; Bracco, C; Brandt, G; Braun, H; Brodsky, S; Brüning, O; Bulyak, E; Buniatyan, A; Burkhardt, H; Cakir, I T; Cakir, O; Calaga, R; Cetinkaya, V; Ciapala, E; Ciftci, R; Ciftci, A K; Cole, B A; Collins, J C; Dadoun, O; Dainton, J; De Roeck, A; d'Enterria, D; Dudarev, A; Eide, A; Enberg, R; Eroglu, E; Eskola, K J; Favart, L; Fitterer, M; Forte, S; Gaddi, A; Gambino, P; Garcia Morales, H; Gehrmann, T; Gladkikh, P; Glasman, C; Godbole, R; Goddard, B; Greenshaw, T; Guffanti, A; Guzey, V; Gwenlan, C; Han, T; Hao, Y; Haug, F; Herr, W; Herve, A; Holzer, B J; Ishitsuka, M; Jacquet, M; Jeanneret, B; Jimenez, J M; Jowett, J M; Jung, H; Karadeniz, H; Kayran, D; Kilic, A; Kimura, K; Klein, M; Klein, U; Kluge, T; Kocak, F; Korostelev, M; Kosmicki, A; Kostka, P; Kowalski, H; Kramer, G; Kuchler, D; Kuze, M; Lappi, T; Laycock, P; Levichev, E; Levonian, S; Litvinenko, V N; Lombardi, A; Maeda, J; Marquet, C; Mellado, B; Mess, K H; Milanese, A; Moch, S; Morozov, I I; Muttoni, Y; Myers, S; Nandi, S; Nergiz, Z; Newman, P R; Omori, T; Osborne, J; Paoloni, E; Papaphilippou, Y; Pascaud, C; Paukkunen, H; Perez, E; Pieloni, T; Pilicer, E; Pire, B; Placakyte, R; Polini, A; Ptitsyn, V; Pupkov, Y; Radescu, V; Raychaudhuri, S; Rinol, L; Rohini, R; Rojo, J; Russenschuck, S; Sahin, M; Salgado, C A; Sampei, K; Sassot, R; Sauvan, E; Schneekloth, U; Schorner-Sadenius, T; Schulte, D; Senol, A; Seryi, A; Sievers, P; Skrinsky, A N; Smith, W; Spiesberger, H; Stasto, A M; Strikman, M; Sullivan, M; Sultansoy, S; Sun, Y P; Surrow, B; Szymanowski, L; Taels, P; Tapan, I; Tasci, T; Tassi, E; Ten Kate, H; Terron, J; Thiesen, H; Thompson, L; Tokushuku, K; Tomas Garcia, R; Tommasini, D; Trbojevic, D; Tsoupas, N; Tuckmantel, J; Turkoz, S; Trinh, T N; Tywoniuk, K; Unel, G; Urakawa, J; VanMechelen, P; Variola, A; Veness, R; Vivoli, A; Vobly, P; Wagner, J; Wallny, R; Wallon, S; Watt, G; Weiss, C; Wiedemann, U A; Wienands, U; Willeke, F; Xiao, B W; Yakimenko, V; Zarnecki, A F; Zhang, Z; Zimmermann, F; Zlebcik, R; Zomer, F

    2012-01-01T23:59:59.000Z

    The physics programme and the design are described of a new collider for particle and nuclear physics, the Large Hadron Electron Collider (LHeC), in which a newly built electron beam of 60 GeV, up to possibly 140 GeV, energy collides with the intense hadron beams of the LHC. Compared to HERA, the kinematic range covered is extended by a factor of twenty in the negative four-momentum squared, $Q^2$, and in the inverse Bjorken $x$, while with the design luminosity of $10^{33}$ cm$^{-2}$s$^{-1}$ the LHeC is projected to exceed the integrated HERA luminosity by two orders of magnitude. The physics programme is devoted to an exploration of the energy frontier, complementing the LHC and its discovery potential for physics beyond the Standard Model with high precision deep inelastic scattering measurements. These are designed to investigate a variety of fundamental questions in strong and electroweak interactions. The physics programme also includes electron-deuteron and electron-ion scattering in a $(Q^2, 1/x)$ ran...

  6. Precise Predictions for Z + 4 Jets at Hadron Colliders

    SciTech Connect (OSTI)

    Ita, H.; Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Kosower, D.A.; Maitre, D.

    2011-12-09T23:59:59.000Z

    We present the cross section for production of a Z boson in association with four jets at the Large Hadron Collider, at next-to-leading order in the QCD coupling. When the Z decays to neutrinos, this process is a key irreducible background to many searches for new physics. Its computation has been made feasible through the development of the on-shell approach to perturbative quantum field theory. We present the total cross section for pp collisions at {radical}s = 7 TeV, after folding in the decay of the Z boson, or virtual photon, to a charged-lepton pair. We also provide distributions of the transverse momenta of the four jets, and we compare cross sections and distributions to the corresponding ones for the production of a W boson with accompanying jets.

  7. $W^+W^-$ production at hadron colliders in NNLO QCD

    E-Print Network [OSTI]

    T. Gehrmann; M. Grazzini; S. Kallweit; P. Maierhöfer; A. von Manteuffel; S. Pozzorini; D. Rathlev; L. Tancredi

    2014-08-22T23:59:59.000Z

    Charged gauge boson pair production at the Large Hadron Collider allows detailed probes of the fundamental structure of electroweak interactions. We present precise theoretical predictions for on-shell $W^+W^-$ production that include, for the first time, QCD effects up to next-to-next-to-leading order in perturbation theory. As compared to next-to-leading order, the inclusive $W^+W^-$ cross section is enhanced by 9% at 7 TeV and 12% at 14 TeV. The residual perturbative uncertainty is at the 3% level. The severe contamination of the $W^+W^-$ cross section due to top-quark resonances is discussed in detail. Comparing different definitions of top-free $W^+W^-$ production in the four and five flavour number schemes, we demonstrate that top-quark resonances can be separated from the inclusive $W^+W^-$ cross section without significant loss of theoretical precision.

  8. Study of Drell-Yan process in CMS experiment at Large Hadron Collider

    E-Print Network [OSTI]

    Jindal, Monika

    The proton-proton collisions at the Large Hadron Collider (LHC) is the begining of a new era in the high energy physics. It enables the possibility of the discoveries at high-energy frontier and also allows the study of Standard Model physics with high precision. The new physics discoveries and the precision measurements can be achieved with highly efficient and accurate detectors like Compact Muon Solenoid. In this thesis, we report the measurement of the differential production cross-section of the Drell-Yan process, $q ar{q} ightarrow Z/gamma^{*} ightarrowmu^{+}mu^{-}$ in proton-proton collisions at the center-of-mass energy $sqrt{s}=$ 7 TeV using CMS experiment at the LHC. This measurement is based on the analysis of data which corresponds to an integrated luminosity of $intmath{L}dt$ = 36.0 $pm$ 1.4 pb$^{-1}$. The measurement of the production cross-section of the Drell-Yan process provides a first test of the Standard Model in a new energy domain and may reveal exotic physics processes. The Drell...

  9. A Novel method for modeling the recoil in W boson events at hadron collider

    SciTech Connect (OSTI)

    Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; /Oklahoma U.; Abolins, Maris A.; /Michigan State U.; Acharya, Bannanje Sripath; /Tata Inst.; Adams, Mark Raymond; /Illinois U., Chicago; Adams, Todd; /Florida State U.; Aguilo, Ernest; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, Mahsana; /Kansas State U.; Alexeev, Guennadi D.; /Dubna, JINR; Alkhazov, Georgiy D.; /St. Petersburg, INP; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls /Northeastern U.

    2009-07-01T23:59:59.000Z

    We present a new method for modeling the hadronic recoil in W {yields} {ell}{nu} events produced at hadron colliders. The recoil is chosen from a library of recoils in Z {yields} {ell}{ell} data events and overlaid on a simulated W {yields} {ell}{nu} event. Implementation of this method requires that the data recoil library describe the properties of the measured recoil as a function of the true, rather than the measured, transverse momentum of the boson. We address this issue using a multidimensional Bayesian unfolding technique. We estimate the statistical and systematic uncertainties from this method for the W boson mass and width measurements assuming 1 fb{sup -1} of data from the Fermilab Tevatron. The uncertainties are found to be small and comparable to those of a more traditional parameterized recoil model. For the high precision measurements that will be possible with data from Run II of the Fermilab Tevatron and from the CERN LHC, the method presented in this paper may be advantageous, since it does not require an understanding of the measured recoil from first principles.

  10. Enhancing $t\\bar{t}hh$ production through CP-violating top-Higgs interaction at the LHC, ILC and a 100 TeV collider

    E-Print Network [OSTI]

    Ning Liu; Yanming Zhang; Jinzhong Han; Bingfang Yang

    2015-03-30T23:59:59.000Z

    The measurement of Higgs self-coupling is one of the most crucial physics goals at the future colliders. At the LHC, the di-Higgs production is a main way to measure the Higgs trilinear coupling. As a complementary to the di-Higgs production, $t \\bar{t} hh$ process may open a new avenue to measure di-Higgs physics at the LHC and a future 100 TeV $pp$ collider or a high energy $e^+e^-$ collider since the extra $t\\bar t$ in the final states may efficiently suppress the backgrounds. However, such a kind of process is also controlled by the top-Higgs coupling. In this work, we investigate the impact of CP-violating top-Higgs coupling on $t\\bar{t}hh$ production at the LHC, ILC and a 100 TeV hadron collider under the current Higgs data. Within 2$\\sigma$ Higgs data allowed parameter region, we find that the cross section of $t\\bar{t}hh$ at the LHC-14 TeV, ILC-1 TeV and VHE-LHC/SPPC-100 TeV can be enhanced up to 2.1 times the SM predictions. The future precise measurement of Higgs coupling will reveal the nature of top-Higgs interaction and improve the sensitivity of the determination of Higgs self-coupling through $t\\bar{t}hh$ production.

  11. Enhancing $t\\bar{t}hh$ production through CP-violating top-Higgs interaction at the LHC, ILC and a 100 TeV collider

    E-Print Network [OSTI]

    Liu, Ning; Han, Jinzhong; Yang, Bingfang

    2015-01-01T23:59:59.000Z

    The measurement of Higgs self-coupling is one of the most crucial physics goals at the future colliders. At the LHC, the di-Higgs production is a main way to measure the Higgs trilinear coupling. As a complementary to the di-Higgs production, $t \\bar{t} hh$ process may open a new avenue to measure di-Higgs physics at the LHC and a future 100 TeV $pp$ collider or a high energy $e^+e^-$ collider since the extra $t\\bar t$ in the final states may efficiently suppress the backgrounds. However, such a kind of process is also controlled by the top-Higgs coupling. In this work, we investigate the impact of CP-violating top-Higgs coupling on $t\\bar{t}hh$ production at the LHC, ILC and a 100 TeV hadron collider under the current Higgs data. Within 2$\\sigma$ Higgs data allowed parameter region, we find that the cross section of $t\\bar{t}hh$ at the LHC-14 TeV, ILC-1 TeV and VHE-LHC/SPPC-100 TeV can be enhanced up to 2.1 times the SM predictions. The future precise measurement of Higgs coupling will reveal the nature of t...

  12. Top-Quark Initiated Processes at High-Energy Hadron Colliders

    E-Print Network [OSTI]

    Tao Han; Joshua Sayre; Susanne Westhoff

    2014-11-10T23:59:59.000Z

    In hadronic collisions at high energies, the top-quark may be treated as a parton inside a hadron. Top-quark initiated processes become increasingly important since the top-quark luminosity can reach a few percent of the bottom-quark luminosity. In the production of a heavy particle $H$ with mass $m_H > m_t$, treating the top-quark as a parton allows us to resum large logarithms $\\log(m_{H}^{2}/m_{t}^{2}$) arising from collinear splitting in the initial state. We quantify the effect of collinear resummation at the 14-TeV LHC and a future 100-TeV hadron collider, focusing on the top-quark open-flavor process $gg\\to t\\bar t H$ in comparison with $t\\bar t \\to H$ and $tg\\rightarrow tH$ at the leading order (LO) in QCD. We employ top-quark parton distribution functions with appropriate collinear subtraction and power counting. We find that (1) Collinear resummation enhances the inclusive production of a heavy particle with $m_H\\approx$ 5 TeV (0.5 TeV) by more than a factor of two compared to the open-flavor process at a 100-TeV (14-TeV) collider; (2) Top-quark mass effects are important for scales $m_H$ near the top-quark threshold, where the cross section is largest. We advocate a modification of the ACOT factorization scheme, dubbed m-ACOT, to consistently treat heavy-quark masses in hadronic collisions; (3) The scale uncertainty of the total cross section in m-ACOT is of about 20 percent at the LO. While a higher-order calculation is indispensable for a precise prediction, the LO cross section is well described by the process $t\\bar t\\to H$ using an effective factorization scale significantly lower than $m_H$. We illustrate our results by the example of a heavy spin-0 particle. Our main results also apply to the production of particles with spin-1 and 2.

  13. Modeling exclusive meson pair production at hadron colliders

    E-Print Network [OSTI]

    L. A. Harland-Lang; V. A. Khoze; M. G. Ryskin

    2014-07-21T23:59:59.000Z

    We present a study of the central exclusive production of light meson pairs, concentrating on the region of lower invariant masses of the central system and/or meson transverse momentum, where perturbative QCD cannot be reliably applied. We describe in detail a phenomenological model, using the tools of Regge theory, that may be applied with some success in this regime, and we present the new, publicly available, Dime Monte Carlo (MC) implementation of this for $\\pi\\pi$, $KK$ and $\\rho\\rho$ production. The MC includes a fully differential treatment of the survival factor, which in general depends on all kinematic variables, as well as allowing for the so far reasonably unconstrained model parameters to be set by the user. We present predictions for the Tevatron and LHC and show how future measurements may further test this Regge--based approach, as well as the soft hadronic model required to calculate the survival factor, in particular in the presence of tagged protons.

  14. Hadron production at LHC in dipole momentum space

    SciTech Connect (OSTI)

    Basso, E. A.; Gay Ducati, M. B. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 - Porto Alegre, RS (Brazil); De Oliveira, E. G. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil)

    2013-03-25T23:59:59.000Z

    The dipole color approach is the framework that considers the quark-antiquark pair scattering off the target. The rapidity evolution of color dipoles is given by the nonlinear Balitsky-Kovchegov (BK) equation, for which analytical solutions are not yet known. A good way to explore the asymptotic BK solutions is through the traveling wave method of QCD, that uses a correspondence between the BK evolution equation in momentum space and reaction-diffusion physics. Using the traveling wave based AGBS model for the dipole amplitude in momentum space, and within the k{sub t}-factorization formalism, we describe the LHC data on single inclusive hadron yield for p-p collisions.

  15. Sources of machine-induced background in the ATLAS and CMS detectors at the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Bruce, R.; et al.,

    2013-11-21T23:59:59.000Z

    One source of experimental background in the CERN Large Hadron Collider (LHC) is particles entering the detectors from the machine. These particles are created in cascades, caused by upstream interactions of beam protons with residual gas molecules or collimators. We estimate the losses on the collimators with SixTrack and simulate the showers with FLUKA and MARS to obtain the flux and distribution of particles entering the ATLAS and CMS detectors. We consider some machine configurations used in the first LHC run, with focus on 3.5 TeV operation as in 2011. Results from FLUKA and MARS are compared and a very good agreement is found. An analysis of logged LHC data provides, for different processes, absolute beam loss rates, which are used together with further simulations of vacuum conditions to normalize the results to rates of particles entering the detectors. We assess the relative importance of background from elastic and inelastic beam-gas interactions, and the leakage out of the LHC collimation system, and show that beam-gas interactions are the dominating source of machine-induced background for the studied machine scenarios. Our results serve as a starting point for the experiments to perform further simulations in order to estimate the resulting signals in the detectors.

  16. The Large Hadron Collider - At Discover's Horizon | Online Resources

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Benefits to society Accelerators for America's Future Interactions - Benefits to Society CERN Knowledge & Technology Transfer CERN CERN's Web site Twitter US LHC ALICE...

  17. CLIC-LHC Based FEL-Nucleus Collider: Feasibility and Physics Search Potential

    E-Print Network [OSTI]

    H. Braun; R. Corsini; J. P. Delahaye; E. Guliyev; A. Ozcan; S. Sultansoy; O. Yavas; S. Yigit

    2005-03-25T23:59:59.000Z

    The feasibility of a CLIC-LHC based FEL-nucleus collider is investigated. It is shown that the proposed scheme satisfies all requirements of an ideal photon source for the Nuclear Resonance Fluorescence method. The tunability, monochromaticity and high polarization of the FEL beam together with high statistics and huge energy of LHC nucleus beams will give an unique opportunity to determine different characteristics of excited nuclear levels. The physics potential of the proposed collider is illustrated for a beam of Pb nuclei.

  18. Impact of high energy high intensity proton beams on targets: Case studies for Super Proton Synchrotron and Large Hadron Collider

    E-Print Network [OSTI]

    Tahir, N A; Shutov, A; Schmidt, R; Piriz, A R

    2012-01-01T23:59:59.000Z

    The Large Hadron Collider (LHC) is designed to collide two proton beams with unprecedented particle energy of 7 TeV. Each beam comprises 2808 bunches and the separation between two neighboring bunches is 25 ns. The energy stored in each beam is 362 MJ, sufficient to melt 500 kg copper. Safety of operation is very important when working with such powerful beams. An accidental release of even a very small fraction of the beam energy can result in severe damage to the equipment. The machine protection system is essential to handle all types of possible accidental hazards; however, it is important to know about possible consequences of failures. One of the critical failure scenarios is when the entire beam is lost at a single point. In this paper we present detailed numerical simulations of the full impact of one LHC beam on a cylindrical solid carbon target. First, the energy deposition by the protons is calculated with the FLUKA code and this energy deposition is used in the BIG2 code to study the corresponding...

  19. Physics studies at a future linear collider 

    E-Print Network [OSTI]

    Tabassam, Hajrah

    2012-06-22T23:59:59.000Z

    With the start of the Large Hadron Collider(LHC) at CERN, we will obtain a new understanding of the physics beyond our current limits. New discoveries will be made; but we will require a deeper understanding, which the ...

  20. QCD effects in Higgs boson production at hadron colliders

    E-Print Network [OSTI]

    M. Grazzini

    2010-01-21T23:59:59.000Z

    We present updated predictions for Higgs boson production at the Tevatron and the LHC and we review their corresponding uncertainties. We report on a study of the impact of QCD radiative corrections on the Higgs boson search at the Tevatron.

  1. TESLA*HERA as Lepton (Photon)-Hadron Collider

    E-Print Network [OSTI]

    O. Yavas; A. K. Ciftci; S. Sultansoy

    2000-04-11T23:59:59.000Z

    New facilities for particle and nuclear physics research, which will be available due to constructing the TESLA linear electron-positron collider tangentially to the HERA proton ring, are discussed.

  2. QGP viscosity at RHIC and the LHC - a 2012 status report

    E-Print Network [OSTI]

    Huichao Song

    2012-11-26T23:59:59.000Z

    In this article, we briefly review the recent progress related to extracting the quark-gluon plasma (QGP) specific shear viscosity from the flow data measured at Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC).

  3. Measurement of Hadronic Event Shapes and Jet Substructure in Proton-Proton Collisions at 7.0 TeV Center-of-Mass Energy with the ATLAS Detector at the Large Hadron Collider

    SciTech Connect (OSTI)

    Miller, David Wilkins

    2012-03-20T23:59:59.000Z

    This thesis presents the first measurement of 6 hadronic event shapes in proton-proton collisions at a center-of-mass energy of {radical}s = 7 TeV using the ATLAS detector at the Large Hadron Collider. Results are presented at the particle-level, permitting comparisons to multiple Monte Carlo event generator tools. Numerous tools and techniques that enable detailed analysis of the hadronic final state at high luminosity are described. The approaches presented utilize the dual strengths of the ATLAS calorimeter and tracking systems to provide high resolution and robust measurements of the hadronic jets that constitute both a background and a signal throughout ATLAS physics analyses. The study of the hadronic final state is then extended to jet substructure, where the energy flow and topology within individual jets is studied at the detector level and techniques for estimating systematic uncertainties for such measurements are commissioned in the first data. These first substructure measurements in ATLAS include the jet mass and sub-jet multiplicity as well as those concerned with multi-body hadronic decays and color flow within jets. Finally, the first boosted hadronic object observed at the LHC - the decay of the top quark to a single jet - is presented.

  4. Physics and Analysis at a Hadron Collider - Searching for New Physics (2/3)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    This is the second lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This second lecture discusses techniques important for analyses searching for new physics using the CDF B_s --> mu+ mu- search as a specific example. The lectures are aimed at graduate students.

  5. Physics and Analysis at a Hadron Collider - Searching for New Physics (2/3)

    SciTech Connect (OSTI)

    None

    2010-01-20T23:59:59.000Z

    This is the second lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This second lecture discusses techniques important for analyses searching for new physics using the CDF B_s --> mu+ mu- search as a specific example. The lectures are aimed at graduate students.

  6. Top Physics at LHC

    E-Print Network [OSTI]

    M. Vander Donckt; for the CMS; ATLAS Collaborations

    2008-05-21T23:59:59.000Z

    The Large Hadron Collider (LHC) will provide a huge amount of top-antitop events, making the LHC a top quark factory, producing 1 tt pair per second at a luminosity of 10^33cm-2s-1. A large top quark sample will be available from the start of LHC and will play an important role in commissioning the CMS and ATLAS detectors. An overview of the top quark measurements during the first data-taking period is given.

  7. Top Quark Production at the LHC

    E-Print Network [OSTI]

    Francesco Spanò; for the ATLAS; CMS collaborations

    2011-12-16T23:59:59.000Z

    Top quark production in proton proton collisions at the Large Hadron Collider (LHC) is reviewed using data collected by the ATLAS and CMS detectors. Most recent results on searches for new physics related to top quark production mechanism are included.

  8. Top quark physics at the LHC

    E-Print Network [OSTI]

    Werner Bernreuther

    2008-05-09T23:59:59.000Z

    The physics perspectives of the production and decay of single top quarks and top quark pairs at the CERN Large Hadron Collider (LHC) are reviewed from a phenomenological point of view.

  9. Colliding During the Squeeze and ?* Levelling in the LHC

    E-Print Network [OSTI]

    Buffat, X; Lamont, M; Pieloni, T; Redaelli, S; Wenninger, J

    2013-01-01T23:59:59.000Z

    While significantly more complicated in term of operation, bringing the beams into collisions prior to the ? squeeze rather than after presents some advantages. Indeed, the large tune spread arising from the non-linearity of head-on beam-beam interactions is profitable, as it can damp impedance driven instabilities much more efficiently than external non-linearity such as octupoles. Moreover, this operation allows to level the luminosity in the case when the peak luminosity is too high for the experiments. Operational issues are discussed and experimental results from the LHC are presented.

  10. Non-extensivity Parameter of Thermodynamical Model of Hadronic Interactions at LHC energies

    E-Print Network [OSTI]

    Tadeusz Wibig

    2010-05-31T23:59:59.000Z

    The LHC measurements above SPS and Tevatron energies give the opportunity to test predictions of non-extensive thermodynamical picture of hadronic interaction to examine measured transverse momenta distributions for new interaction energy range. We determined Tsallis model non-extensivity parameter for the hadronization process before short-lived particles decayed and distort the initial p_t distribution. We have shown that it follows exactly smooth rise determined at lower energies below present LHC record. The shape of the q parameter energy dependence is consistent with expectations and the evidence of the asymptotic limit may be seen.

  11. Quarkonia production and polarization at the hadron colliders

    E-Print Network [OSTI]

    Bryan Fulsom

    2014-09-09T23:59:59.000Z

    This talk presents a review of recent results for quarkonium production at the LHC from ATLAS, CMS, LHCb, and ALICE. Production cross sections for $J/\\psi$, $\\psi(2S)$, and $\\Upsilon(mS)$, and production ratios for $\\chi_{c,bJ}$ are found to be in good agreement with predictions from non-relativistic QCD. In contrast, spin-alignment (polarization) measurements seem to disagree with all theoretical predictions. Some other production channels useful for investigating quarkonium hadroproduction mechanisms are also considered.

  12. Precision Studies of Hadronic and Electro-Weak Interactions for Collider Physics. Final Report

    SciTech Connect (OSTI)

    Yost, Scott A [The Citadel, Charleston, SC (United States)] [The Citadel, Charleston, SC (United States)

    2014-04-02T23:59:59.000Z

    This project was directed toward developing precision computational tools for proton collisions at the Large Hadron Collider, focusing primarily on electroweak boson production and electroweak radiative corrections. The programs developed under this project carried the name HERWIRI, for High Energy Radiation With Infra-Red Improvements, and are the first steps in an ongoing program to develop a set of hadronic event generators based on combined QCD and QED exponentiation. HERWIRI1 applied these improvements to the hadronic shower, while HERWIRI2 will apply the electroweak corrections from the program KKMC developed for electron-positron scattering to a hadronic event generator, including exponentiated initial and final state radiation together with first-order electroweak corrections to the hard process. Some progress was also made on developing differential reduction techniques for hypergeometric functions, for application to the computation of Feynman diagrams.

  13. Nuclear shadowing and prompt photons at relativistic hadron colliders

    E-Print Network [OSTI]

    C. Brenner Mariotto; V. P. Goncalves

    2008-08-26T23:59:59.000Z

    The production of prompt photons at high energies provides a direct probe of the dynamics of the strong interactions. In particular, one expect that it could be used to constrain the behavior of the nuclear gluon distribution in $pA$ and $AA$ collisions. In this letter we investigate the influence of nuclear effects in the production of prompt photons and estimate the transverse momentum dependence of the nuclear ratios $R_{pA} = {\\frac{d\\sigma (pA)}{dy d^2 p_T}} / A {\\frac{d\\sigma (pp)}{dy d^2 p_T}}$ and $R_{AA} = {\\frac{d\\sigma (AA)}{dy d^2 p_T}} / A^2 {\\frac{d\\sigma (pp)}{dy d^2 p_T}}$ at RHIC and LHC energies. We demonstrate that the study of these observables can be useful to determine the magnitude of the shadowing and antishadowing effects in the nuclear gluon distribution.

  14. Simulations of electron-cloud heat load for the cold arcs of the CERN Large Hadron Collider and its high-luminosity upgrade scenarios

    E-Print Network [OSTI]

    Maury Cuna, H; Zimmermann, F

    2012-01-01T23:59:59.000Z

    The heat load generated by an electron cloud in the cold arcs of the Large Hadron Collider (LHC) is a concern for operation near and beyond nominal beam current. We report the results of simulation studies, with updated secondary- emission models, which examine the severity of the electron heat load over a range of possible operation parameters, both for the nominal LHC and for various luminosity-upgrade scenarios, such as the so-called ‘‘full crab crossing’’ and ‘‘early separation’’ schemes, the ‘‘large Piwinski angle’’ scheme, and a variant of the latter providing ‘‘compatibility’’ with the (upgraded) LHCb experiment. The variable parameters considered are the maximum secondary-emission yield, the number of particles per bunch, and the spacing between bunches. In addition, the dependence of the heat load on the longitudinal bunch profile is investigated.

  15. Second order QCD corrections to gluonic jet production at hadron colliders

    E-Print Network [OSTI]

    James Currie; Aude Gehrmann-De Ridder; Thomas Gehrmann; Nigel Glover; Joao Pires; Steven Wells

    2014-07-21T23:59:59.000Z

    We report on the calculation of the next-to-next-to-leading order (NNLO) QCD corrections to the production of two gluonic jets at hadron colliders. In previous work, we discussed gluonic dijet production in the gluon-gluon channel. Here, for the first time, we update our numerical results to include the leading colour contribution to the production of two gluonic jets via quark-antiquark scattering.

  16. Nucleon Decay and Neutrino Experiments, Experiments at High Energy Hadron Colliders, and String Theor

    SciTech Connect (OSTI)

    Jung, Chang Kee [State University of New York at Stony Brook; Douglas, Michaek [State University of New York at Stony Brook; Hobbs, John [State University of New York at Stony Brook; McGrew, Clark [State University of New York at Stony Brook; Rijssenbeek, Michael [State University of New York at Stony Brook

    2013-07-29T23:59:59.000Z

    This is the final report of the DOE grant DEFG0292ER40697 that supported the research activities of the Stony Brook High Energy Physics Group from November 15, 1991 to April 30, 2013. During the grant period, the grant supported the research of three Stony Brook particle physics research groups: The Nucleon Decay and Neutrino group, the Hadron Collider Group, and the Theory Group.

  17. Physics and Analysis at a Hadron Collider - Making Measurements (3/3)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    This is the third lecture of three which together discuss the physics of hadron colliders with an emphasis on experimental techniques used for data analysis. This third lecture discusses techniques important for analyses making a measurement (e.g. determining a cross section or a particle property such as its mass or lifetime) using some CDF top-quark analyses as specific examples. The lectures are aimed at graduate students.

  18. Toward particle-level filtering of individual collision events at the Large Hadron Collider and beyond

    E-Print Network [OSTI]

    Federico Colecchia

    2014-12-19T23:59:59.000Z

    Low-energy strong interactions are a major source of background at hadron colliders, and methods of subtracting the associated energy flow are well established in the field. Traditional approaches treat the contamination as diffuse, and estimate background energy levels either by averaging over large data sets or by restricting to given kinematic regions inside individual collision events. On the other hand, more recent techniques take into account the discrete nature of background, most notably by exploiting the presence of substructure inside hard jets, i.e. inside collections of particles originating from scattered hard quarks and gluons. However, none of the existing methods subtract background at the level of individual particles inside events. We illustrate the use of an algorithm that can enable particle-by-particle background discrimination at the Large Hadron Collider, and we envisage this as the basis for a novel event filtering procedure upstream of the official jet reconstruction pipelines. Our hope is that this new technique will improve physics analysis when used in combination with state-of-the-art algorithms in high-luminosity hadron collider environments.

  19. Measurement of very forward neutron energy spectra for 7 TeV proton--proton collisions at the Large Hadron Collider

    E-Print Network [OSTI]

    Adriani, O; Bonechi, L; Bongi, M; Castellini, G; D'Alessandro, R; Del Prete, M; Haguenauer, M; Itow, Y; Kasahara, K; Kawade, K; Makino, Y; Masuda, K; Matsubayashi, E; Menjo, H; Mitsuka, G; Muraki, Y; Okuno, Y; Papini, P; Perrot, A-L; Ricciarini, S; Sako, T; Sakurai, N; Sugiura, Y; Suzuki, T; Tamura, T; Tiberio, A; Torii, S; Tricomi, A; Turner, W C; Zhou, Q D

    2015-01-01T23:59:59.000Z

    The Large Hadron Collider forward (LHCf) experiment is designed to use the LHC to verify the hadronic-interaction models used in cosmic-ray physics. Forward baryon production is one of the crucial points to understand the development of cosmic-ray showers. We report the neutron-energy spectra for LHC $\\sqrt{s}$ = 7 TeV proton--proton collisions with the pseudo-rapidity $\\eta$ ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The measured energy spectra obtained from the two independent calorimeters of Arm1 and Arm2 show the same characteristic feature before unfolding the difference in the detector responses. We unfolded the measured spectra by using the multidimensional unfolding method based on Bayesian theory, and the unfolded spectra were compared with current hadronic-interaction models. The QGSJET II-03 model predicts a high neutron production rate at the highest pseudo-rapidity range similar to our results and the DPMJET 3.04 model describes our results well at the lower pseudo-...

  20. Exclusive $?$ photoproduction in hadronic collisions at CERN LHC energies

    E-Print Network [OSTI]

    V. P. Goncalves; B. D. Moreira; F. S. Navarra

    2015-01-26T23:59:59.000Z

    The exclusive $\\Upsilon$ photoproduction in proton-proton and proton - nucleus collisions at LHC energies is investigated using the color dipole formalism and considering different models for the $\\Upsilon$ wave function and forward dipole - target scattering amplitude. Our goal is to update the color dipole predictions and estimate the theoretical uncertainty present in these predictions. We present predictions for the kinematical ranges probed by the ALICE, CMS and LHCb Collaborations.

  1. Diphoton production at hadron colliders: a fully-differential QCD calculation at NNLO

    E-Print Network [OSTI]

    Stefano Catani; Leandro Cieri; Daniel de Florian; Giancarlo Ferrera; Massimiliano Grazzini

    2011-10-11T23:59:59.000Z

    We consider direct diphoton production in hadron collisions, and we compute the next-to-next-to-leading order (NNLO) QCD radiative corrections at the fully-differential level. Our calculation uses the $q_T$ subtraction formalism and it is implemented in a parton level Monte Carlo program. The program allows the user to apply arbitrary kinematical cuts on the final-state photons and the associated jet activity, and to compute the corresponding distributions in the form of bin histograms. We present selected numerical results related to Higgs boson searches at the LHC and corresponding results at the Tevatron.

  2. A new micro-strip tracker for the new generation of experiments at hadron colliders

    SciTech Connect (OSTI)

    Dinardo, Mauro E.; /Milan U.

    2005-12-01T23:59:59.000Z

    This thesis concerns the development and characterization of a prototype Silicon micro-strip detector that can be used in the forward (high rapidity) region of a hadron collider. These detectors must operate in a high radiation environment without any important degradation of their performance. The innovative feature of these detectors is the readout electronics, which, being completely data-driven, allows for the direct use of the detector information at the lowest level of the trigger. All the particle hits on the detector can be readout in real-time without any external trigger and any particular limitation due to dead-time. In this way, all the detector information is available to elaborate a very selective trigger decision based on a fast reconstruction of tracks and vertex topology. These detectors, together with the new approach to the trigger, have been developed in the context of the BTeV R&D program; our aim was to define the features and the design parameters of an optimal experiment for heavy flavour physics at hadron colliders. Application of these detectors goes well beyond the BTeV project and, in particular, involves the future upgrades of experiments at hadron colliders, such as Atlas, CMS and LHCb. These experiments, indeed, are already considering for their future high-intensity runs a new trigger strategy a la BTeV. Their aim is to select directly at trigger level events containing Bhadrons, which, on several cases, come from the decay of Higgs bosons, Z{sup o}'s or W{sup {+-}}'s; the track information can also help on improving the performance of the electron and muon selection at the trigger level. For this reason, they are going to develop new detectors with practically the same characteristics as those of BTeV. To this extent, the work accomplished in this thesis could serve as guide-line for those upgrades.

  3. Measuring the Higgs boson mass in dileptonic W-boson decays at hadron colliders

    E-Print Network [OSTI]

    Barr, Alan; Gripaios, Ben; Lester, Christopher G

    2009-01-01T23:59:59.000Z

    ar X iv :0 90 2. 48 64 v2 [ he p- ph ] 22 Ju l 2 00 9 Cavendish-HEP-09/04 Measuring the Higgs boson mass in dileptonic W -boson decays at hadron colliders Alan J. Barr,1, ? Ben Gripaios,2, † and Christopher G. Lester3, ‡ 1Denys Wilkinson... measurements of the Higgs boson mass using the decay h ? W+W?, followed by the leptonic decay of each W -boson, will be performed by fitting the shape of a distribution that is sensitive to the Higgs mass. We demonstrate that the variable most commonly used...

  4. Observable T{sub 7} Lepton Flavor Symmetry at the Large Hadron Collider

    SciTech Connect (OSTI)

    Cao Qinghong [High Energy Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States); Khalil, Shaaban [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo 11566 (Egypt); Ma, Ernest [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Okada, Hiroshi [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt)

    2011-04-01T23:59:59.000Z

    More often than not, models of flavor symmetry rely on the use of nonrenormalizable operators (in the guise of flavons) to accomplish the phenomenologically successful tribimaximal mixing of neutrinos. We show instead how a simple renormalizable two-parameter neutrino mass model of tribimaximal mixing can be constructed with the non-Abelian discrete symmetry T{sub 7} and the gauging of B-L. This is also achieved without the addition of auxiliary symmetries and particles present in almost all other proposals. Most importantly, it is verifiable at the Large Hadron Collider.

  5. LHC Division EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH

    E-Print Network [OSTI]

    Laughlin, Robert B.

    source. The main technological challenges of the machine are the superconducting magnet system, in total of the LHC, gives an overview of the different machine components and characteristics and describes in more, Large Hadron Collider Project CERN CH - 1211 Geneva 23 Switzerland LHC Project Report 71 Abstract 09

  6. Universe in the light of LHC

    E-Print Network [OSTI]

    Maria Krawczyk; Malgorzata Matej; Dorota Sokolowska; Bogumila Swiezewska

    2015-01-19T23:59:59.000Z

    The Large Hadron Collider (LHC) provides data which give information on dark matter. In particular, measurements related to the Higgs sector lead to strong constraints on the invisible sector which are competitive with astrophysical limits. Some recent LHC results on dark matter coming from the Higgs sector in the Inert Doublet Model (IDM) are presented.

  7. Universe in the light of LHC

    E-Print Network [OSTI]

    Krawczyk, Maria; Sokolowska, Dorota; Swiezewska, Bogumila

    2015-01-01T23:59:59.000Z

    The Large Hadron Collider (LHC) provides data which give information on dark matter. In particular, measurements related to the Higgs sector lead to strong constraints on the invisible sector which are competitive with astrophysical limits. Some recent LHC results on dark matter coming from the Higgs sector in the Inert Doublet Model (IDM) are presented.

  8. Ion colliders

    SciTech Connect (OSTI)

    Fischer, W.

    2011-12-01T23:59:59.000Z

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the RHIC and LHC injector chains for the heaviest ion species used to date. The RHIC pulsed sputter source (PSC) and Tandem electrostatic accelerator are being replaced by an Electron Beam Ion Source (EBIS), Radio Frequency Quadrupole (RFQ) and short linac [08Ale1]. With EBIS beams of any element can be prepared for RHIC including uranium and spin-polarized 3He. At CERN an ECR ion source is used, followed by an RFQ and Linac. The ions are then accumulated, electron cooled, and accelerated in LEIR. After transfer to and acceleration in the PS, ion beams are injected into the SPS.

  9. DETERMINING THE RATIO OF THE H+ YIELDS TV TO H+ YIELDS TB DECAY RATES FOR LARGE TAN BETA AT THE LARGE HADRON COLLIDER.

    SciTech Connect (OSTI)

    ASSAMAGAN,K.A.GUASCH,J.MORETTI,S.PENARANDA,S.

    2003-05-27T23:59:59.000Z

    We present results on the determination of the observable ratio R = BR(H{sup +} {yields} {tau}{sup +}{nu}{sup -})/BR(H{sup +} {yields} t{bar b}) of charged Higgs boson decay rates as a discriminant quantity between Supersymmetric and non-Supersymmetric models. Simulation of measurements of this quantity through the analysis of the charged Higgs production process gb {yields} tbH{sup +} and relative backgrounds in the two above decay channels has been performed in the context of ATLAS. A {approx} 12-14% accuracy on R can be achieved for tan {beta} = 50, m{sub H{sup {+-}}} = 300-500 GeV and after an integrated luminosity of 300 fb{sup -1}. With this precision measurement, the Large Hadron Collider (LHC) can easily discriminate between models for the two above scenarios, so long as tan {beta} > 20.

  10. Dark energy, colored anti-de Sitter vacuum, and the CERN Large Hadron Collider phenomenology

    SciTech Connect (OSTI)

    Stojkovic, Dejan [HEPCOS, Department of Physics, SUNY at Buffalo, Buffalo, New York 14260-1500 (United States); Starkman, Glenn D.; Matsuo, Reijiro [CERCA, Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106-7079 (United States)

    2008-03-15T23:59:59.000Z

    We study the possibility that the current accelerated expansion of the universe is driven by the vacuum energy density of a colored scalar field which is responsible for a phase transition in which the gauge SU(3){sub c} symmetry breaks. We show that if we are stuck in a SU(3){sub c}-preserving false vacuum, then SU(3){sub c} symmetry breaking can be accommodated without violating any experimental QCD bounds or bounds from cosmological observations. Moreover, unless there is an unnatural fine-tuning beyond the usual cosmological constant fine-tuning, the true vacuum state of the universe is anti-de Sitter. The model can likely be tested at the LHC. A possible (though not necessary) consequence of the model is the existence of fractionally charged massive hadrons. The model can be embedded in supersymmetric theories where massive colored scalar fields appear naturally.

  11. A Test Stand for the Muon Trigger Development for the CMS Experiment at the LHC 

    E-Print Network [OSTI]

    Lakdawala, Samir

    2013-05-02T23:59:59.000Z

    Compact Muon Solenoid (CMS) is one of the flagship experiments in particle physics operating at the Large Hadron Collider (LHC). CMS was built to search for signatures of Higgs bosons, supersymmetry, and other new phenomena. The coming upgrade...

  12. Supersymmetry At LHC

    SciTech Connect (OSTI)

    Khalil, Shaaban [Centre for Theoretical Physics, British University in Egypt, El Sherouk City, Postal No. 11837, P.O. Box 43 (Egypt); Department of Mathematics, Ain Shams University, Faculty of Science, Cairo, 11566 (Egypt)

    2008-04-21T23:59:59.000Z

    One of the main motivation of the experiments at the Large Hadron Collider (LHC), scheduled to start around 2006, is to search for supersymmetric particles. The region of the parameter space of the minimal supersymmetric standard model, where supersymmetry can be discovered is investigated. We show that if supersymmetry exists at electroweak scale, it would be easy to find signals for it at the LHC. If the LHC does find supersymmetry, this would be one of the greatest achievements in the history of theoretical physics.

  13. Modeling of the very low pressure helium flow in the LHC Cryogenic Distribution Line after a quench

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    - search (CERN) started the most powerful particle accel- erator of the world, the Large Hadron Collider Benjamin Bradua,b, , Philippe Gayeta, , Silviu-Iulian Niculescub, , Emmanuel Witrantc, aCERN, EN Department in the Cryogenic Distribution Line (QRL) used in the Large Hadron Collider (LHC) at CERN. The study is focused

  14. Central exclusive production in the ALICE experiment at the LHC

    E-Print Network [OSTI]

    R. Schicker

    2014-11-04T23:59:59.000Z

    The ALICE experiment at the Large Hadron Collider (LHC) at CERN consists of a central barrel, a muon spectrometer and additional detectors for trigger and event classification purposes. The low transverse momentum threshold of the central barrel gives ALICE a unique opportunity to study the low mass sector of central exclusive production at the LHC.

  15. LHC Startup

    E-Print Network [OSTI]

    Wesley H. Smith

    2008-08-22T23:59:59.000Z

    The Large Hadron Collider will commence operations in the latter half of 2008. The plans of the LHC experiments ALICE, ATLAS, CMS and LHCb are described. The scenario for progression of luminosity and the strategies of these 4 experiments to use the initial data are detailed. There are significant measurements possible with integrated luminosities of 1, 10 and 100 pb^-1. These measurements will provide essential calibration and tests of the detectors, understanding of the Standard Model backgrounds and a first oportunity to look for new physics.

  16. The Need for a Photon-Photon Collider in addition to LHC & ILC for Unraveling the Scalar Sector of the Randall-Sundrum Model

    E-Print Network [OSTI]

    Gunion, J F

    2004-01-01T23:59:59.000Z

    In the Randall-Sundrum model there can be a rich new phenomenology associated with Higgs-radion mixing. A photon-photon collider would provide a crucial complement to the LHC and a future ILC collider for fully determining the parameters of the model and definitively testing it.

  17. Forward hadron production in ultraperipheral proton-heavy-ion collisions at the LHC and RHIC

    E-Print Network [OSTI]

    Mitsuka, Gaku

    2015-01-01T23:59:59.000Z

    We discuss hadron production in the forward rapidity region in ultraperipheral proton-lead collisions at the LHC and proton-gold collisions at RHIC. Our discussion is based on the Monte Carlo simulations of the interactions of virtual photons emitted by a fast moving nucleus with a proton beam. We simulate the virtual photon flux with the STARLIGHT event generator and then particle production with the SOPHIA, DPMJET, and PYTHIA event generators. We show the rapidity distributions of charged and neutral particles, and the momentum distributions of neutral pions and neutrons at forward rapidities. According to the Monte Carlo simulations, we find large cross sections of ultraperipheral collisions for particle production especially in the very forward region, leading to substantial background contributions to investigations of collective nuclear effects and spin physics. Finally we can distinguish between proton-nucleus inelastic interactions and ultraperipheral collisions with additional requirements of either ...

  18. Longitudinal Decorrelation of Anisotropic Flows in Heavy-ion Collisions at the CERN Large Hadron Collider

    E-Print Network [OSTI]

    Long-Gang Pang; Guang-You Qin; Victor Roy; Xin-Nian Wang; Guo-Liang Ma

    2015-04-22T23:59:59.000Z

    Fluctuations in the initial transverse energy-density distribution lead to anisotropic flows as observed in central high-energy heavy-ion collisions. Studies of longitudinal fluctuations of the anisotropic flows can shed further light on the initial conditions and dynamical evolution of the hot quark-gluon matter in these collisions. Correlations between anisotropic flows with varying pseudorapidity gaps in Pb+Pb collisions at the CERN Large Hadron Collider are investigated using both an event-by-event (3+1)-D ideal hydrodynamical model with fluctuating initial conditions and the a multiphase transport (AMPT) Monte Carlo model for high-energy heavy-ion collisions. Anisotropic flows at different pseudorapidities are found to become significantly decorrelated with increasing pseudo-rapidity gaps due to longitudinal fluctuations in the initial states of heavy-ion collisions. The longitudinal correlation of the elliptic flow shows a strong centrality dependence while the correlation of the triangular flow is independent of the centrality. Longitudinal fluctuations as a source of the decorrelation are further shown to consist of a twist or gradual rotation in flow angles between the forward and backward direction and additional fluctuations on top of the twist. Within the AMPT model, longitudinal correlations of anisotropic flows are also found to depend on the value of partonic cross sections. The implicatiosn of constraining the initial conditions and shear viscosity to entropy density ratio of the partonic matter in high-energy heavy-ion collisions are also discussed.

  19. Next-to-Next-to-Leading-Order Subtraction Formalism in Hadron Collisions and its Application to Higgs-Boson Production at the Large Hadron Collider

    SciTech Connect (OSTI)

    Catani, Stefano; Grazzini, Massimiliano [INFN, Sezione di Firenze and Dipartimento di Fisica, Universita di Firenze, I-50019 Sesto Fiorentino, Florence (Italy)

    2007-06-01T23:59:59.000Z

    We consider higher-order QCD corrections to the production of colorless high-mass systems (lepton pairs, vector bosons, Higgs bosons, etc.) in hadron collisions. We propose a new formulation of the subtraction method to numerically compute arbitrary infrared-safe observables for this class of processes. To cancel the infrared divergences, we exploit the universal behavior of the associated transverse-momentum (q{sub T}) distributions in the small-q{sub T} region. The method is illustrated in general terms up to the next-to-next-to-leading order in QCD perturbation theory. As a first explicit application, we study Higgs-boson production through gluon fusion. Our calculation is implemented in a parton level Monte Carlo program that includes the decay of the Higgs boson into two photons. We present selected numerical results at the CERN Large Hadron Collider.

  20. New Physics at the LHC: A Les Houches Report. Physics at Tev Colliders 2007 - New Physics Working Group

    SciTech Connect (OSTI)

    Brooijmans, Gustaaf H.; /Columbia U.; Delgado, A.; /Notre Dame U.; Dobrescu, Bogdan A.; /Fermilab; Grojean, C.; /CERN /Saclay, SPhT; Narain, Meenakshi; /Brown U.; Alwall, Johan; /SLAC; Azuelos, Georges; /Montreal U. /TRIUMF; Black, K.; /Harvard U.; Boos, E.; /SINP, Moscow; Bose, Tulika; /Brown U.; Bunichev, V.; /SINP, Moscow; Chivukula, R.S.; /Michigan State U.; Contino, R.; /CERN; Djouadi, A.; /Louis Pasteur U., Strasbourg I /Orsay, LAL; Dudko, Lev V.; /Durham U.; Ferland, J.; /Montreal U.; Gershtein, Yuri S.; /Florida State U.; Gigg, M.; /Durham U.; Gonzalez de la Hoz, S.; /Valencia U., IFIC; Herquet, M.; /Louvain U.; Hirn, J.; /Yale U. /Brown U. /Boston U. /Annecy, LAPTH /INFN, Turin /Valencia U., IFIC /Yale U. /Arizona U. /Louis Pasteur U., Strasbourg I /Orsay, LAL /KEK, Tsukuba /Moscow State U. /Lisbon, LIFEP /CERN /Durham U. /Valencia U., IFIC /Sao Paulo, IFT /Fermilab /Zurich, ETH /Boston U. /DESY /CERN /Saclay, SPhT /Durham U. /Cambridge U. /Michigan State U. /Louis Pasteur U., Strasbourg I /Orsay, LAL /Annecy, LAPTH /Fermilab /CERN /Arizona U. /Northwestern U. /Argonne /Kyoto U. /Valencia U., IFIC /UC, Berkeley /LBL, Berkeley

    2011-12-05T23:59:59.000Z

    We present a collection of signatures for physics beyond the standard model that need to be explored at the LHC. The signatures are organized according to the experimental objects that appear in the final state, and in particular the number of high p{sub T} leptons. Our report, which includes brief experimental and theoretical reviews as well as original results, summarizes the activities of the 'New Physics' working group for the 'Physics at TeV Colliders' workshop (Les Houches, France, 11-29 June, 2007).

  1. Forward hadron production in ultraperipheral proton-heavy-ion collisions at the LHC and RHIC

    E-Print Network [OSTI]

    Gaku Mitsuka

    2015-03-12T23:59:59.000Z

    We discuss hadron production in the forward rapidity region in ultraperipheral proton-lead collisions at the LHC and proton-gold collisions at RHIC. Our discussion is based on the Monte Carlo simulations of the interactions of virtual photons emitted by a fast moving nucleus with a proton beam. We simulate the virtual photon flux with the STARLIGHT event generator and then particle production with the SOPHIA, DPMJET, and PYTHIA event generators. We show the rapidity distributions of charged and neutral particles, and the momentum distributions of neutral pions and neutrons at forward rapidities. According to the Monte Carlo simulations, we find large cross sections of ultraperipheral collisions for particle production especially in the very forward region, leading to substantial background contributions to investigations of collective nuclear effects and spin physics. Finally we can distinguish between proton-nucleus inelastic interactions and ultraperipheral collisions with additional requirements of either of the charged particles at midrapidity and a certain level of activities at negative forward rapidity.

  2. Higgs Production in Neutralino Decays in the MSSM - The LHC and a Future e+e- Collider

    E-Print Network [OSTI]

    Alexandre Arbey; Marco Battaglia; Farvah Mahmoudi

    2015-02-10T23:59:59.000Z

    The search for the production of weakly-interacting SUSY particles at the LHC is crucial for testing supersymmetry in relation to dark matter. Decays of neutralinos into Higgs bosons occur over some significant part of the SUSY parameter space and represent the most important source of $h$ boson production in SUSY decay chains in the MSSM. We study h production in neutralino decays using scans of the phenomenological MSSM. Whilst in constrained MSSM scenarios the decay chi^0_2 -> h chi^0_1 is the dominant channel, this does not hold in more general MSSM scenarios. On the other hand, the chi^0_2,3 -> h chi^0_1 decays remain important and are highly complementary to multi-lepton final states in the LHC searches. The perspectives for the LHC analyses at 8 and 14 TeV as well as the reach of an e+e- collider at 0.5, 1, 1.5 and 3 TeV are discussed.

  3. Large Hadron Collider probe of supersymmetric neutrinoless double beta decay mechanism

    E-Print Network [OSTI]

    B. C. Allanach; C. H. Kom; H. Päs

    2009-02-26T23:59:59.000Z

    In the minimal supersymmetric extension to the Standard Model, a non-zero lepton number violating coupling lambda'_111 predicts both neutrinoless double beta decay and resonant single slepton production at the LHC. We show that, in this case, if neutrinoless double beta decay is discovered in the next generation of experiments, there exist good prospects to observe single slepton production at the LHC. Neutrinoless double beta decay could otherwise result from a different source (such as a non-zero Majorana neutrino mass). Resonant single slepton production at the LHC can therefore discriminate between the lambda'_111 neutrinoless double beta decay mechanism and others.

  4. Large Hadron Collider Probe of Supersymmetric Neutrinoless Double-Beta-Decay Mechanism

    SciTech Connect (OSTI)

    Allanach, B. C.; Kom, C. H.; Paes, H. [DAMTP, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Fakultaet fuer Physik, Technische Universitaet Dortmund, D-44221, Dortmund (Germany)

    2009-08-28T23:59:59.000Z

    In the minimal supersymmetric extension to the standard model, a nonzero lepton number violating coupling {lambda}{sub 111}{sup '} predicts both neutrinoless double-beta-decay and resonant single slepton production at the LHC. We show that, in this case, if neutrinoless double beta decay is discovered in the next generation of experiments, there exist good prospects to observe single slepton production at the LHC. Neutrinoless double beta decay could otherwise result from a different source (such as a nonzero Majorana neutrino mass). Resonant single slepton production at the LHC can therefore discriminate between the {lambda}{sub 111}{sup '} neutrinoless double-beta-decay mechanism and others.

  5. Search for Signatures of Extra Dimensions in the Diphoton Mass Spectrum at the Large Hadron Collider

    E-Print Network [OSTI]

    Bauer, Gerry P.

    A search for signatures of extra spatial dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a ...

  6. Klystron switching power supplies for the Internation Linear Collider

    SciTech Connect (OSTI)

    Fraioli, Andrea; /Cassino U. /INFN, Pisa

    2009-12-01T23:59:59.000Z

    The International Linear Collider is a majestic High Energy Physics particle accelerator that will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. ILC will complement the Large Hadron Collider (LHC), a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, by producing electron-positron collisions at center of mass energy of about 500 GeV. In particular, the subject of this dissertation is the R&D for a solid state Marx Modulator and relative switching power supply for the International Linear Collider Main LINAC Radio Frequency stations.

  7. Jet finding techniques at LHC

    E-Print Network [OSTI]

    BOUMEDIENE, D; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    Jet finding techniques at hadron colliders, including pile-up removal tricks, jet deconstruction, etc

  8. Vector Boson Production at Hadron Colliders: A Fully Exclusive QCD Calculation at Next-to-Next-to-Leading Order

    SciTech Connect (OSTI)

    Catani, Stefano; Ferrera, Giancarlo; Grazzini, Massimiliano [INFN, Sezione di Firenze and Dipartimento di Fisica, Universita di Firenze, I-50019 Sesto Fiorentino, Florence (Italy); Cieri, Leandro; Florian, Daniel de [Departamento de Fisica, FCEYN, Universidad de Buenos Aires, (1428) Pabellon 1 Ciudad Universitaria, Capital Federal (Argentina)

    2009-08-21T23:59:59.000Z

    We consider QCD radiative corrections to the production of W and Z bosons in hadron collisions. We present a fully exclusive calculation up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform this NNLO computation, we use a recently proposed version of the subtraction formalism. The calculation includes the gamma-Z interference, finite-width effects, the leptonic decay of the vector bosons, and the corresponding spin correlations. Our calculation is implemented in a parton level Monte Carlo program. The program allows the user to apply arbitrary kinematical cuts on the final-state leptons and the associated jet activity and to compute the corresponding distributions in the form of bin histograms. We show selected numerical results at the Fermilab Tevatron and the LHC.

  9. Les Houches guidebook to Monte Carlo generators for hadron collider physics

    SciTech Connect (OSTI)

    Dobbs, Matt A.; Frixione, Stefano; Laenen, Eric; Tollefson, Kirsten

    2004-03-01T23:59:59.000Z

    Recently the collider physics community has seen significant advances in the formalisms and implementations of event generators. This review is a primer of the methods commonly used for the simulation of high energy physics events at particle colliders. We provide brief descriptions, references, and links to the specific computer codes which implement the methods. The aim is to provide an overview of the available tools, allowing the reader to ascertain which tool is best for a particular application, but also making clear the limitations of each tool.

  10. Searching for an Axion-like Particle at the Large Hadron Collider

    E-Print Network [OSTI]

    Claudio Coriano; Marco Guzzi; Antonio Mariano

    2009-05-27T23:59:59.000Z

    Axion-like particles are an important part of the spectrum of anomalous gauge theories involving modified mechanisms of cancellation of the gauge anomalies. Among these are intersecting brane models, which are characterized by the presence of one physical axion. We overview a recent study of their supersymmetric construction and some LHC studies of the productions rates for a gauged axion.

  11. First Observation of Vector Boson Pairs in a Hadronic Final State at the Tevatron Collider

    E-Print Network [OSTI]

    Paus, Christoph M. E.

    We present the first observation in hadronic collisions of the electroweak production of vector boson pairs (VV, V=W, Z) where one boson decays to a dijet final state. The data correspond to 3.5??fb[superscript -1] of ...

  12. Strange prospects for LHC energies

    E-Print Network [OSTI]

    B. Hippolyte

    2006-08-31T23:59:59.000Z

    Strange quark and hadron production will be studied at the Large Hadron Collider (LHC) energies in order to explore the properties of both pp and heavy-ion collisions. The ALICE experiment will be specifically efficient in the strange sector with the identification of baryons and mesons over a wide range of transverse momentum. Dedicated measurements are proposed for investigating chemical equilibration and bulk properties. Strange particles can also help to probe kinematical regions where hard processes and pQCD dominate. We try to anticipate here several ALICE analyses to be performed as the first Pb--Pb and pp data will be available.

  13. Off-shell effects in Higgs processes at a linear collider and implications for the LHC

    E-Print Network [OSTI]

    Stefan Liebler; Gudrid Moortgat-Pick; Georg Weiglein

    2015-02-27T23:59:59.000Z

    The importance of off-shell contributions is discussed for $H\\to VV^{(*)}$ with $V\\in\\{Z,W\\}$ for large invariant masses $m_{VV}$ involving a standard model (SM)-like Higgs boson with $m_H=125$GeV at a linear collider (LC). Both dominant production processes $e^+e^-\\to ZH\\to ZVV^{(*)}$ and $e^+e^-\\to\

  14. Off-shell effects in Higgs processes at a linear collider and implications for the LHC

    E-Print Network [OSTI]

    Liebler, Stefan; Weiglein, Georg

    2015-01-01T23:59:59.000Z

    The importance of off-shell contributions is discussed for $H\\to VV^{(*)}$ with $V\\in\\{Z,W\\}$ for large invariant masses $m_{VV}$ involving a standard model (SM)-like Higgs boson with $m_H=125$GeV at a linear collider (LC). Both dominant production processes $e^+e^-\\to ZH\\to ZVV^{(*)}$ and $e^+e^-\\to\

  15. Light vector meson photoproduction in hadron-hadron and nucleus-nucleus collisions at the energies available at the CERN Large Hadron Collider

    E-Print Network [OSTI]

    G. Sampaio dos Santos; M. V. T. Machado

    2015-01-30T23:59:59.000Z

    In this work we analyse the theoretical uncertainties on the predictions for the photoproduction of light vector mesons in coherent pp, pA and AA collisions at the LHC energies using the color dipole approach. In particular, we present our predictions for the rapidity distribution for rh0 and phi photoproduction and perform an analysis on the uncertainties associated to the choice of vector meson wavefunctionand the phenomenological models for the dipole cross section. Comparison is done with the recent ALICE analysis on coherent production of rho at 2.76 TeV in PbPb collisions.

  16. CERN and LHC - their place in global science

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    The Large Hadron Collider (LHC) is the largest scientific instrument in the world. It brings into collision intense beams of protons and ions to explore the structure of matter and investigate the forces of nature at an unprecedented energy scale, thus serving a community of some 7,000 particle physicists from all over the world.

  17. Heavy Ion Collisions at the LHC - Last Call for Predictions

    E-Print Network [OSTI]

    S. Abreu; S. V. Akkelin; J. Alam; J. L. Albacete; A. Andronic; D. Antonov; F. Arleo; N. Armesto; I. C. Arsene; G. G. Barnafoldi; J. Barrette; B. Bauchle; F. Becattini; B. Betz; M. Bleicher; M. Bluhm; D. Boer; F. W. Bopp; P. Braun-Munzinger; L. Bravina; W. Busza; M. Cacciari; A. Capella; J. Casalderrey-Solana; R. Chatterjee; L. -W. Chen; J. Cleymans; B. A. Cole; Z. Conesa Del Valle; L. P. Csernai; L. Cunqueiro; A. Dainese; J. Dias de Deus H. -T. Ding; M. Djordjevic; H. Drescher; I. M. Dremin A. Dumitru; A. El; R. Engel; D. d'Enterria; K. J. Eskola; G. Fai; E. G. Ferreiro; R. J. Fries; E. Frodermann; H. Fujii; C. Gale; F. Gelis; V. P. Goncalves; V. Greco; C. Greiner; M. Gyulassy; H. van Hees; U. Heinz; H. Honkanen; W. A. Horowitz; E. Iancu; G. Ingelman; J. Jalilian-Marian; S. Jeon; A. B. Kaidalov; B. Kampfer; Z. -B. Kang; Iu. A. Karpenko; G. Kestin; D. Kharzeev; C. M. Ko; B. Koch; B. Kopeliovich; M. Kozlov; I. Kraus; I. Kuznetsova; S. H. Lee; R. Lednicky; J. Letessier; E. Levin; B. -A. Li; Z. -W. Lin; H. Liu; W. Liu; C. Loizides; I. P. Lokhtin; M. V. T. Machado; L. V. Malinina; A. M. Managadze; M. L. Mangano; M. Mannarelli; C. Manuel; G. Martinez; J. G. Milhano; A. Mocsy; D. Molnar; M. Nardi; J. K. Nayak; H. Niemi; H. Oeschler; J. -Y. Ollitrault; G. Paic; C. Pajares; V. S. Pantuev; G. Papp; D. Peressounko; P. Petreczky; S. V. Petrushanko; F. Piccinini; T. Pierog; H. J. Pirner; S. Porteboeuf; I. Potashnikova; G. Y. Qin; J. -W. Qiu; J. Rafelski; K. Rajagopal; J. Ranft; R. Rapp; S. S. Rasanen; J. Rathsman; P. Rau; K. Redlich; T. Renk; A. H. Rezaeian; D. Rischke; S. Roesler; J. Ruppert; P. V. Ruuskanen; C. A. Salgado; S. Sapeta; I. Sarcevic; S. Sarkar; L. I. Sarycheva; I. Schmidt; A. I. Shoshi; B. Sinha; Yu. M. Sinyukov; A. M. Snigirev; D. K. Srivastava; J. Stachel; A. Stasto; H. Stocker; C. Yu. Teplov; R. L. Thews; G. Torrieri; V. Topor Pop; D. N. Triantafyllopoulos; K. L. Tuchin; S. Turbide; K. Tywoniuk; A. Utermann; R. Venugopalan; I. Vitev; R. Vogt; E. Wang; X. N. Wang; K. Werner; E. Wessels; S. Wheaton; S. Wicks; U. A. Wiedemann; G. Wolschin; B. -W. Xiao; Z. Xu; S. Yasui; E. Zabrodin; K. Zapp; B. Zhang; B. -W. Zhang; H. Zhang; D. Zhou

    2007-11-06T23:59:59.000Z

    This writeup is a compilation of the predictions for the forthcoming Heavy Ion Program at the Large Hadron Collider, as presented at the CERN Theory Institute 'Heavy Ion Collisions at the LHC - Last Call for Predictions', held from May 14th to June 10th 2007.

  18. Energy deposition studies for the High-Luminosity Large Hadron Collider inner triplet magnets

    E-Print Network [OSTI]

    Mokhov, N V; Tropin, I S; Cerutti, F; Esposito, L S; Lechner, A

    2015-01-01T23:59:59.000Z

    A detailed model of the High Luminosity LHC inner triplet region with new large-aperture Nb3Sn magnets, field maps, corrector packages, and segmented tungsten inner absorbers was built and implemented into the FLUKA and MARS15 codes. In the optimized configuration, the peak power density averaged over the magnet inner cable width is safely below the quench limit. For the integrated luminosity of 3000 fb-1, the peak dose in the innermost magnet insulator ranges from 20 to 35 MGy. Dynamic heat loads to the triplet magnet cold mass are calculated to evaluate the cryogenic capability. In general, FLUKA and MARS results are in a very good agreement.

  19. Pair Production of Heavy Quarkonium and $B_c(^*)$ Mesons at Hadron Colliders

    E-Print Network [OSTI]

    Rong Li; Yu-Jie Zhang; Kuang-Ta Chao

    2009-03-12T23:59:59.000Z

    We investigate the pair production of S-wave heavy quarkonium at the LHC in the color-singlet mechanism (CSM) and estimate the contribution from the gluon fragmentation process in the color-octet mechanism (COM) for comparison. With the matrix elements extracted previously in the leading order calculations, the numerical results show that the production rates are quite large for the pair production processes at the LHC. The $p_t$ distribution of double $J/\\psi$ production in the CSM is dominant over that in the COM when $p_t$ is smaller than about 8GeV. For the production of double $\\Upsilon$, the contribution of the COM is always larger than that in the CSM. The large differences in the theoretical predictions between the CSM and COM for the $p_t$ distributions in the large $p_t$ region are useful in clarifying the effects of COM on the quarkonium production. We also investigate the pair production of S-wave $B_c$ and $B_c^*$ mesons, and the measurement of these processes is useful to test the CSM and extract the LDMEs for the $B_c$ and $B_c^*$ mesons.

  20. Discovery Prospects for NMSSM Higgs Bosons at the High-Energy Large Hadron Collider

    E-Print Network [OSTI]

    S. F. King; M. Muhlleitner; R. Nevzorov; K. Walz

    2014-08-05T23:59:59.000Z

    We investigate the discovery prospects for NMSSM Higgs bosons during the 13~TeV run of the LHC. While one of the neutral Higgs bosons is demanded to have a mass around 125~GeV and Standard Model (SM)-like properties, there can be substantially lighter, nearby or heavier Higgs bosons, that have not been excluded yet by LEP, Tevatron or the 8~TeV run of the LHC. The challenge consists in discovering the whole NMSSM Higgs mass spectrum. We present the rates for production and subsequent decay of the neutral NMSSM Higgs bosons in the most promising final states and discuss their possible discovery. The prospects for pinning down the Higgs sector of the Natural NMSSM will be analysed taking into account alternative search channels. We give a series of benchmark scenarios compatible with the experimental constraints, that feature Higgs-to-Higgs decays and entail (exotic) signatures with multi-fermion and/or multi-photon final states. These decay chains furthermore give access to the trilinear Higgs self-couplings. We briefly discuss the possibility of exploiting coupling sum rules in case not all the NMSSM Higgs bosons are discovered.

  1. Discovery Prospects for NMSSM Higgs Bosons at the High-Energy Large Hadron Collider

    E-Print Network [OSTI]

    King, S F; Nevzorov, R; Walz, K

    2014-01-01T23:59:59.000Z

    We investigate the discovery prospects for NMSSM Higgs bosons during the 13~TeV run of the LHC. While one of the neutral Higgs bosons is demanded to have a mass around 125~GeV and Standard Model (SM)-like properties, there can be substantially lighter, nearby or heavier Higgs bosons, that have not been excluded yet by LEP, Tevatron or the 8~TeV run of the LHC. The challenge consists in discovering the whole NMSSM Higgs mass spectrum. We present the rates for production and subsequent decay of the neutral NMSSM Higgs bosons in the most promising final states and discuss their possible discovery. The prospects for pinning down the Higgs sector of the Natural NMSSM will be analysed taking into account alternative search channels. We give a series of benchmark scenarios compatible with the experimental constraints, that feature Higgs-to-Higgs decays and entail (exotic) signatures with multi-fermion and/or multi-photon final states. These decay chains furthermore give access to the trilinear Higgs self-couplings. ...

  2. Lepton number violating processes mediated by Majorana neutrinos at hadron colliders

    SciTech Connect (OSTI)

    Kovalenko, Sergey; Lu Zhun; Schmidt, Ivan [Departamento de Fisica, Universidad Tecnica Federico, Santa Maria, Casilla 110-V, Valparaiso (Chile) and Center of Subatomic Physics, Valparaiso (Chile)

    2009-10-01T23:59:59.000Z

    We study the lepton number violating like-sign dilepton processes h{sub 1}h{sub 2}{yields}l{sup {+-}}l{sup '{+-}}jjX and h{sub 1}h{sub 2}{yields}l{sup {+-}}l{sup '{+-}}W{sup {+-}}X, mediated by heavy GeV scale Majorana neutrinos. We focus on the resonantly enhanced contributions with a nearly on-mass-shell Majorana neutrino in the s channel. We study the constraints on like-sign dilepton production at the Tevatron and the LHC on the basis of the existing experimental limits on the masses of heavy neutrinos and their mixings U{sub {alpha}}{sub N} with {alpha}={nu}{sub e}, {nu}{sub {mu}}, {nu}{sub {tau}}. Special attention is paid to the constraints from neutrinoless double beta decay. We note that searches for like-sign e{sup {+-}}e{sup {+-}} events at Tevatron and LHC may provide evidence of CP violation in the neutrino sector. We also discuss the conditions under which it is possible to extract individual constraints on the mixing matrix elements in a model independent way.

  3. Indications of Conical Emission of Charged Hadrons at the BNL Relativistic HeavyIon Collider

    SciTech Connect (OSTI)

    STAR Coll

    2009-02-09T23:59:59.000Z

    Three-particle azimuthal correlation measurements with a high transverse momentum trigger particle are reported for pp, d + Au, and Au + Au collisions at {radical}s{sub NN} = 200 GeV by the STAR experiment. Dijet structures are observed in pp, d + Au and peripheral Au + Au collisions. An additional structure is observed in central Au + Au data, signaling conical emission of correlated charged hadrons. The conical emission angle is found to be {theta} = 1.37 {+-} 0.02(stat){sub -0.07}{sup +0.06}(syst), independent of p{sub {perpendicular}}.

  4. Hadronization

    E-Print Network [OSTI]

    Bryan Webber

    1994-11-30T23:59:59.000Z

    Hadronization corrections to the predictions of perturbative QCD are reviewed. The existing models for the conversion of quarks and gluons into hadrons are summarized. The most successful models give a good description of the data on $e^+e^-$ event shapes and jet fragmentation functions, and suggest that the dominant hadronization effects have a $1/Q$ dependence on the hard process energy scale $Q$. In several cases the $1/Q$ terms can be understood in terms of a simple longitudinal phase-space model. They can also be inferred by relating non-perturbative renormalon effects to the infrared cutoff dependence of perturbative contributions.

  5. Wideband Precision Current Transformer for the Magnet Current of the Beam Extraction Kicker Magnet of the Large Hadron Collider

    E-Print Network [OSTI]

    Gräwer, G

    2004-01-01T23:59:59.000Z

    The LHC beam extraction system is composed of 15 fast kicker magnets per beam to extract the particles in one turn of the collider and to safely dispose them on external absorbers. Each magnet is powered by a separate pulse generator. The generator produces a magnet current pulse with 3 us rise time, 20 kA amplitude and 1.8 ms fall time, of which 90 us are needed to dump the beam. The beam extraction system requires a high level of reliability. To detect any change in the magnet current characteristics, which might indicate a slow degradation of the pulse generator, a high precision wideband current transformer will be installed. For redundancy reasons, the results obtained with this device will be cross-checked with a Rogowski coil, installed adjacent to the transformer. A prototype transformer has been successfully tested at nominal current levels and showed satisfactory results compared with the output of a high frequency resistive coaxial shunt. The annular core of the ring type transformer is composed of...

  6. Comparison of cosmic ray flux at sqrt(s) > 14 TeV with LHC luminosity

    E-Print Network [OSTI]

    Frank E. Taylor

    2008-05-29T23:59:59.000Z

    The high energy cosmic ray flux impinging on the sun and earth for 4 Gyr is compared to the operation of the CERN Large Hadron Collider (LHC) at design energy and luminosity. It is shown by two different calculations that both the integrated luminosity and the total hadronic interaction rate from the cosmic ray flux of comparable energy are many orders of magnitude larger than that of the LHC operated for 10 years. This study indicates that it is extremely unlikely that pernicious exotic particles, such as mini-black holes, would be produced by the LHC that would destroy the earth.

  7. The ATLAS Experiment: Getting Ready for the LHC

    SciTech Connect (OSTI)

    Jenni, Peter (CERN) [CERN

    2006-05-15T23:59:59.000Z

    At CERN the Large Hadron Collider (LHC) project is well advanced. First proton-proton collisions at the high-energy frontier are expected for the second half of 2007. In parallel to the collider construction the powerful general-purpose ATLAS detector is being assembled in its underground cavern by a world-wide collaboration. ATLAS will explore new domains of particle physics. After briefly overviewing the LHC construction and installation progress, the status of the ATLAS experiment will be presented, including examples of the exciting prospects for new physics.

  8. Radiative Return Capabilities of a High-Energy, High-Luminosity $e^+e^-$ Collider

    E-Print Network [OSTI]

    Karliner, Marek; Rosner, Jonathan L; Wang, Lian-Tao

    2015-01-01T23:59:59.000Z

    An electron-positron collider operating at a center-of-mass energy $E_{CM}$ can collect events at all lower energies through initial-state radiation (ISR or radiative return). We explore the capabilities for radiative return studies by a proposed high-luminosity collider at $E_{CM}$ = 250 or 90 GeV, to fill in gaps left by lower-energy colliders such as PEP, PETRA, TRISTAN, and LEP. These capabilities are compared with those of the lower-energy $e^+e^-$ colliders as well as hadron colliders such as the Tevatron and the CERN Large Hadron Collider (LHC). Some examples of accessible questions in dark photon searches and heavy flavor spectroscopy are given.

  9. Charm and bottom production in inclusive double Pomeron exchange in heavy-ion collisions at energies available at the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Gay Ducati, M. B.; Machado, M. M.; Machado, M. V. T. [High Energy Physics Phenomenology Group, GFPAE, IF-UFRGS Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

    2011-01-15T23:59:59.000Z

    The inclusive double Pomeron exchange cross section for heavy-quark pair production is calculated for nucleus-nucleus collisions at the Large Hadron Collider. The present estimate is based on hard diffractive factorization, corrected by absorptive corrections and nuclear effects. The theoretical uncertainties for nuclear collisions are investigated and a comparison to other approaches is presented. The production channels giving a similar final state configuration are discussed as well.

  10. Hydrodynamic radial and elliptic flow in heavy-ion collisions from AGS to LHC energies

    E-Print Network [OSTI]

    Gregory Kestin; Ulrich W Heinz

    2008-11-28T23:59:59.000Z

    Using ideal relativistic hydrodynamics in 2+1 dimensions, we study the collision energy dependence of radial and elliptic flow, of the emitted hadron spectra, and of the transverse momentum dependence of several hadronic particle ratios, covering the range from Alternating Gradient Synchrotron (AGS) to Large Hadron Collider (LHC) energies. These calculations establish an ideal fluid dynamic baseline that can be used to assess non-equilibrium features manifest in future LHC heavy-ion experiments. Contrary to earlier suggestions we find that a saturation and even decrease of the differential elliptic flow v_2(p_T) with increasing collision energy cannot be unambiguously associated with the QCD phase transition.

  11. Present status and future prospects for a Higgs boson discovery at the Tevatron and LHC

    E-Print Network [OSTI]

    Howard E. Haber

    2010-11-04T23:59:59.000Z

    Discovering the Higgs boson is one of the primary goals of both the Tevatron and the Large Hadron Collider (LHC). The present status of the Higgs search is reviewed and future prospects for discovery at the Tevatron and LHC are considered. This talk focuses primarily on the Higgs boson of the Standard Model and its minimal supersymmetric extension. Theoretical expectations for the Higgs boson and its phenomenological consequences are reviewed.

  12. Top physics prospects at LHC

    E-Print Network [OSTI]

    Florian Beaudette

    2005-06-24T23:59:59.000Z

    With a high instantaneous luminosity and the large top quark pair production cross section, the Large Hadron Collider (LHC) will be a "top factory" allowing the analysis of millions of top events. After a short description of the top quark pair production mechanism and the cross section measurement, the accuracy of the top mass measurement needed for a sound consistency check of the Standard Model is briefly discussed. Different top mass measurement methods are presented. The observability of the single top quark production is described. Finally the observation of the Higgs boson produced in association with a top quark pair is discussed.

  13. Off-momentum collimation and cleaning in the energy ramp in the LHC

    E-Print Network [OSTI]

    Quaranta, Elena; Giulini Castiglioni Agosteo, Stefano Luigi Maria

    This Master thesis work has been carried out at CERN in the framework of the LHC (Large Hadron Collider) Collimation project. The LHC is a two-beam proton collider, built to handle a stored energy of 360MJ for each beam. Since the energy deposition from particle losses could quench the superconducting magnets, a system of collimators has been installed in two cleaning insertions in the ring and in the experimental areas. The achievable LHC beam intensity is directly coupled to the beam loss rate and, consequently, to the cleaning eciency of the collimation system. This study analyses the collimation cleaning performance in dierent scenarios inside the accelerator. First, simulations are performed of the transverse losses in the LHC collimation system during the acceleration process. The results are compared with data taken during a dedicated session at the LHC machine. Simulations are also performed to predict the collimation eciency during future operation at higher energy. Furthermore, an investigation of t...

  14. RHIC-tested predictions for low-$p_T$ and high-$p_T$ hadron spectra in nearly central Pb+Pb collisions at the LHC

    E-Print Network [OSTI]

    K. J. Eskola; H. Honkanen; H. Niemi; P. V. Ruuskanen; S. S. Rasanen

    2005-06-06T23:59:59.000Z

    We study the hadron spectra in nearly central $A$+$A$ collisions at RHIC and LHC in a broad transverse momentum range. We cover the low-$p_T$ spectra using longitudinally boost-invariant hydrodynamics with initial energy and net-baryon number densities from the perturbative QCD (pQCD)+saturation model. Build-up of the transverse flow and sensitivity of the spectra to a single decoupling temperature $\\Tdec$ are studied. Comparison with RHIC data at $\\ssNN=130$ and 200 GeV suggests a rather high value $\\Tdec=150$ MeV. The high-$p_T$ spectra are computed using factorized pQCD cross sections, nuclear parton distributions, fragmentation functions, and describing partonic energy loss in the quark-gluon plasma by quenching weights. Overall normalization is fixed on the basis of p+$\\bar{\\rm p}$(p) data and the strength of energy loss is determined from RHIC Au+Au data. Uncertainties are discussed. With constraints from RHIC data, we predict the $p_T$ spectra of hadrons in 5 % most central Pb+Pb collisions at the LHC energy $\\ssNN=5500$ GeV. Due to the closed framework for primary production, we can also predict the net-baryon number at midrapidity, as well as the strength of partonic energy losses at the LHC. Both at the LHC and RHIC, we recognize a rather narrow crossover region in the $p_T$ spectra, where the hydrodynamic and pQCD fragmentation components become of equal size. We argue that in this crossover region the two contributions are to a good approximation mutually independent. In particular, our results suggest a wider $p_T$-region of applicability for hydrodynamical models at the LHC than at RHIC.

  15. Searches for Physics Beyond the Standard Model and Triggering on Proton-Proton Collisions at 14 TEV LHC

    SciTech Connect (OSTI)

    Wittich, Peter

    2011-10-14T23:59:59.000Z

    This document describes the work achieved under the OJI award received May 2008 by Peter Wittich as Principal Investigator. The proposal covers experimental particle physics project searching for physics beyond the standard model at the Large Hadron Collider (LHC) at the European Organization for Nuclear Research.

  16. Jet Quenching in Heavy-Ion Collisions - The Transition Era from RHIC to LHC

    E-Print Network [OSTI]

    Barbara Betz

    2012-11-26T23:59:59.000Z

    A status report on the jet quenching physics in heavy-ion collisions is given as it appears after more than 10 years of collecting and analysing data at the Relativistic Heavy Ion Collider (RHIC) and ~1.5 years of physics at the Large Hadron Collider (LHC). The (theoretical) predictions and expectations before the start of the LHC program are contrasted with the most recent experimental results, focussing on the nuclear modification factor R_{AA}, the elliptic flow v_2 of high-p_T particles, and on the problem of initial conditions.

  17. Prospects on the search for invisible Higgs decays in the ZH channel at the LHC and HL-LHC: A Snowmass White Paper

    E-Print Network [OSTI]

    Hideki Okawa; Josh Kunkle; Elliot Lipeles

    2014-12-16T23:59:59.000Z

    We show prospects on a search for invisible decays of a Higgs boson at the Large Hadron Collider (LHC) and High Luminosity LHC (HL-LHC). This search is performed on a Higgs boson produced in association with a Z boson. We expect that the branching ratio of 17-22% (6-14%) could be excluded at 95% confidence level with 300 fb^{-1} (3000 fb^{-1}) of data at sqrt(s)=14 TeV. The range indicates different assumptions on the control of systematic uncertainties. Interpretations with Higgs-portal dark matter models are also considered.

  18. Searches for BSM and Higgs boson at LHC

    SciTech Connect (OSTI)

    Jinnouchi, O. [Tokyo Institute of Technology, Department of Physics, Graduate School of Science and Engineering (Japan); Collaboration: ATLAS Collaboration; CMS Collaboration

    2012-07-27T23:59:59.000Z

    This article reviews the recent results from the two energy frontier experiments, ATLAS and CMS at the large hadron collider (LHC), using the data collected during 2011 corresponding up to 4.9 fb{sup -1} integrated luminosity of {radical}(s) = 7TeV proton proton collisions. The recent results of searches for the Standard Model Higgs boson, and searches for beyond Standard Model physics based on supersymmetry and other new exotic models are presented.

  19. Heavy flavour production at LHC

    E-Print Network [OSTI]

    Alessandro Grelli; Andre Mischke

    2009-09-25T23:59:59.000Z

    The Large Hadron Collider (LHC) will open a new era in high energy physics. The expected large cross section for heavy flavour production in proton-proton collisions at $\\sqrt{s}$ = 14 TeV will allow detailed studies of the production mechanisms and an extensive test of Quantum Chromodynamics. Since charm and beauty has been proposed as a good probe to study hot and dense QCD matter, the understanding of the production mechanisms in elementary proton-proton collisions is of primary importance as a reference for studies in heavy-ion collisions. In the early phase of LHC operation the experiments will focus on the investigation of the heavy flavour production mechanisms.

  20. LHC RF System Time-Domain Simulation

    SciTech Connect (OSTI)

    Mastorides, T.; Rivetta, C.; /SLAC

    2010-09-14T23:59:59.000Z

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  1. Linear Collider Physics Resource Book Snowmass 2001

    SciTech Connect (OSTI)

    Ronan (Editor), M.T.

    2001-06-01T23:59:59.000Z

    The American particle physics community can look forward to a well-conceived and vital program of experimentation for the next ten years, using both colliders and fixed target beams to study a wide variety of pressing questions. Beyond 2010, these programs will be reaching the end of their expected lives. The CERN LHC will provide an experimental program of the first importance. But beyond the LHC, the American community needs a coherent plan. The Snowmass 2001 Workshop and the deliberations of the HEPAP subpanel offer a rare opportunity to engage the full community in planning our future for the next decade or more. A major accelerator project requires a decade from the beginning of an engineering design to the receipt of the first data. So it is now time to decide whether to begin a new accelerator project that will operate in the years soon after 2010. We believe that the world high-energy physics community needs such a project. With the great promise of discovery in physics at the next energy scale, and with the opportunity for the uncovering of profound insights, we cannot allow our field to contract to a single experimental program at a single laboratory in the world. We believe that an e{sup +}e{sup -} linear collider is an excellent choice for the next major project in high-energy physics. Applying experimental techniques very different from those used at hadron colliders, an e{sup +}e{sup -} linear collider will allow us to build on the discoveries made at the Tevatron and the LHC, and to add a level of precision and clarity that will be necessary to understand the physics of the next energy scale. It is not necessary to anticipate specific results from the hadron collider programs to argue for constructing an e{sup +}e{sup -} linear collider; in any scenario that is now discussed, physics will benefit from the new information that e{sup +}e{sup -} experiments can provide. This last point merits further emphasis. If a new accelerator could be designed and built in a few years, it would make sense to wait for the results of each accelerator before planning the next one. Thus, we would wait for the results from the Tevatron before planning the LHC experiments, and wait for the LHC before planning any later stage. In reality accelerators require a long time to construct, and they require such specialized resources and human talent that delay can cripple what would be promising opportunities. In any event, we believe that the case for the linear collider is so compelling and robust that we can justify this facility on the basis of our current knowledge, even before the Tevatron and LHC experiments are done. The physics prospects for the linear collider have been studied intensively for more than a decade, and arguments for the importance of its experimental program have been developed from many different points of view. This book provides an introduction and a guide to this literature. We hope that it will allow physicists new to the consideration of linear collider physics to start from their own personal perspectives and develop their own assessments of the opportunities afforded by a linear collider.

  2. A Software Suite for Testing the Performance of the Optical Trigger Motherboard Electronics System for the CMS Experiment at the LHC

    E-Print Network [OSTI]

    Schneider, Austin William

    2013-09-28T23:59:59.000Z

    on testing. 2 NOMENCLATURE CERN European Organization for Nuclear Research (Organisation europenne pour la recherche nuclaire) LHC Large Hadron Collider CMS Compact Muon Solenoid, also refers to the CMS detector system Muon An elementary particle similar... Organization of Nuclear Research (CERN), performs proton-proton collisions at high energy. Proton bunches are accelerated to near the speed of light through a series of booster rings until they reach the 27 km (circumference) LHC ring where protons...

  3. Top-Quark Physics Results From LHC

    E-Print Network [OSTI]

    Luca Fiorini

    2012-01-30T23:59:59.000Z

    The top-quark is a fundamental element of the physics program at the Large Hadron Collider (LHC). We review the current status of the top-quark measurements performed by ATLAS and CMS experiments in pp collisions at sqrt(s)=7 TeV by presenting the recent results of the top-quark production rates, top mass measurements and additional top quark properties. We will also describe the recent searches for physics beyond the Standard Model in the top-quark sector.

  4. Wideband current transformers for the surveillance of the beam extraction kicker system of the Large Hadron Collider

    E-Print Network [OSTI]

    Defrance, C; Ducimetière, L; Vossenberg, E

    2007-01-01T23:59:59.000Z

    The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. A separate high voltage pulse generator powers each magnet. Because of the high beam energy and the consequences which could result from significant beam loss due to a malfunctioning of the dump system the magnets and generators are continuously surveyed in order to generate a beam abort as soon as an internal fault is detected. Amongst these surveillance systems, wideband current transformers have been designed to detect any erratic start in one of the generators. Output power should be enough to directly re-trigger all the power trigger units of the remaining 14 generators. The current transformers were developed in collaboration with industry. To minimize losses, high-resistivity cobalt alloy was chosen for the cores. The annealing techniques originally developed for LEP b...

  5. Diffraction at collider energies

    SciTech Connect (OSTI)

    Frankfurt, L.L.

    1992-12-31T23:59:59.000Z

    Lessons with ``soft`` hadron physics to explain (a) feasibility to observe and to investigate color transparency, color opacity effects at colliders; (b) significant probability and specific features of hard diffractive processes; (c) feasibility to investigate components of parton wave functions of hadrons with minimal number of constituents. This new physics would be more important with increase of collision energy.

  6. Diffraction at collider energies

    SciTech Connect (OSTI)

    Frankfurt, L.L.

    1992-01-01T23:59:59.000Z

    Lessons with soft'' hadron physics to explain (a) feasibility to observe and to investigate color transparency, color opacity effects at colliders; (b) significant probability and specific features of hard diffractive processes; (c) feasibility to investigate components of parton wave functions of hadrons with minimal number of constituents. This new physics would be more important with increase of collision energy.

  7. Dark matter and Higgs boson collider implications of fermions in an abelian-gauged hidden sector

    E-Print Network [OSTI]

    Shrihari Gopalakrishna; Seung J. Lee; James D. Wells

    2009-04-13T23:59:59.000Z

    We add fermions to an abelian-gauged hidden sector. We show that the lightest can be the dark matter with the right thermal relic abundance, and discovery is within reach of upcoming dark matter detectors. We also show that these fermions change Higgs boson phenomenology at the Large Hadron Collider (LHC), and in particular could induce a large invisible width to the lightest Higgs boson state. Such an invisibly decaying Higgs boson can be discovered with good significance in the vector boson fusion channel at the LHC.

  8. Measurement of the charged-hadron multiplicity in proton-proton collisions at LHC with the CMS detector

    E-Print Network [OSTI]

    Lee, Yen-Jie

    2011-01-01T23:59:59.000Z

    Charged-hadron pseudorapidity densities and multiplicity distributions in protonproton collisions at [the square root of sigma] = 0.9, 2.36, 7.0 TeV were measured with the inner tracking system of the CMS detector at the ...

  9. Top Jets at the LHC

    E-Print Network [OSTI]

    Almeida, L.G.

    2009-01-01T23:59:59.000Z

    Top Jets at the LHC Leandro G. Almeida, Seung J. Lee, GiladSB-08-37; WIS/17/08-SEPT-DPP Top Jets at the LHC Leandro G.p T hadronically-decaying top quarks at the Large Hadron

  10. Quark-lepton symmetric model at the LHC

    E-Print Network [OSTI]

    Jackson D. Clarke; Robert Foot; Raymond R. Volkas

    2012-02-04T23:59:59.000Z

    We investigate the quark-lepton symmetric model of Foot and Lew in the context of the Large Hadron Collider (LHC). In this `bottom-up' extension to the Standard Model, quark-lepton symmetry is achieved by introducing a gauged `leptonic colour' symmetry which is spontaneously broken above the electroweak scale. If this breaking occurs at the TeV scale, then we expect new physics to be discovered at the LHC. We examine three areas of interest: the Z$'$ heavy neutral gauge boson, charge $\\pm1/2$ exotic leptons, and a colour triplet scalar diquark. We find that the LHC has already explored and/or will explore new parameter space for these particles over the course of its lifetime.

  11. Detector and System Developments for LHC Detector Upgrades

    E-Print Network [OSTI]

    Mandelli, Beatrice; Guida, Roberto; Rohne, Ole; Stapnes, Steinar

    2015-05-12T23:59:59.000Z

    The future Large Hadron Collider (LHC) Physics program and the consequent improvement of the LHC accelerator performance set important challenges to all detector systems. This PhD thesis delineates the studies and strategies adopted to improve two different types of detectors: the replacement of precision trackers with ever increasingly performing silicon detectors, and the improvement of large gaseous detector systems by optimizing their gas mixtures and operation modes. Within the LHC tracker upgrade programs, the ATLAS Insertable B-layer (IBL) is the first major upgrade of a silicon-pixel detector. Indeed the overall ATLAS Pixel Detector performance is expected to degrade with the increase of luminosity and the IBL will recover the performance by adding a fourth innermost layer. The IBL Detector makes use of new pixel and front-end electronics technologies as well as a novel thermal management approach and light support and service structures. These innovations required complex developments and Quality Ass...

  12. Synchrotron radiation damping, intrabeam scattering and beam-beam simulations for HE-LHC

    SciTech Connect (OSTI)

    Valishev, A.; /Fermilab

    2011-03-01T23:59:59.000Z

    The proposed High-Energy LHC project presents an unusual combination of strong synchrotron radiation damping and intrabeam scattering, which is not seen in present-day hadron colliders. The subject of investigation reported in this paper was the simulation of beam-beam effect for the HE-LHC parameters. Parameters of SR and IBS are calculated, and the luminosity evolution is simulated in the absence of beam-beam interaction. Then, a weak-strong numerical simulation is used to predict the effect of beam-beam interaction on particle losses and emittance evolution.

  13. Neutralinos in Vector Boson Fusion at High Energy Colliders

    E-Print Network [OSTI]

    Berlin, Asher; Low, Matthew; Wang, Lian-Tao

    2015-01-01T23:59:59.000Z

    Discovering dark matter at high energy colliders continues to be a compelling and well-motivated possibility. Weakly interacting massive particles are a particularly interesting class in which the dark matter particles interact with the standard model weak gauge bosons. Neutralinos are a prototypical example that arise in supersymmetric models. In the limit where all other superpartners are decoupled, it is known that for relic density motivated masses, the rates for neutralinos are too small to be discovered at the Large Hadron Collider (LHC), but that they may be large enough for a 100 TeV collider to observe. In this work we perform a careful study in the vector boson fusion channel for pure winos and pure higgsinos. We find that given a systematic uncertainty of 1% (5%), with 3000 fb$^{-1}$, the LHC is sensitive to winos of 240 GeV (125 GeV) and higgsinos of 125 GeV (55 GeV). A future 100 TeV collider would be sensitive to winos of 1.1 TeV (750 GeV) and higgsinos of 530 GeV (180 GeV) with a 1% (5%) uncert...

  14. International linear collider reference design report

    SciTech Connect (OSTI)

    Aarons, G.

    2007-06-22T23:59:59.000Z

    The International Linear Collider will give physicists a new cosmic doorway to explore energy regimes beyond the reach of today's accelerators. A proposed electron-positron collider, the ILC will complement the Large Hadron Collider, a proton-proton collider at the European Center for Nuclear Research (CERN) in Geneva, Switzerland, together unlocking some of the deepest mysteries in the universe. With LHC discoveries pointing the way, the ILC -- a true precision machine -- will provide the missing pieces of the puzzle. Consisting of two linear accelerators that face each other, the ILC will hurl some 10 billion electrons and their anti-particles, positrons, toward each other at nearly the speed of light. Superconducting accelerator cavities operating at temperatures near absolute zero give the particles more and more energy until they smash in a blazing crossfire at the centre of the machine. Stretching approximately 35 kilometres in length, the beams collide 14,000 times every second at extremely high energies -- 500 billion-electron-volts (GeV). Each spectacular collision creates an array of new particles that could answer some of the most fundamental questions of all time. The current baseline design allows for an upgrade to a 50-kilometre, 1 trillion-electron-volt (TeV) machine during the second stage of the project. This reference design provides the first detailed technical snapshot of the proposed future electron-positron collider, defining in detail the technical parameters and components that make up each section of the 31-kilometer long accelerator. The report will guide the development of the worldwide R&D program, motivate international industrial studies and serve as the basis for the final engineering design needed to make an official project proposal later this decade.

  15. The versatile link, a common project for super-LHC

    SciTech Connect (OSTI)

    Amaral, Luis; Dris, Stefanos; Gerardin, Alexandre; Huffman, Todd; Issever, Cigdem; Pacheco, Alberto Jimenez; Jones, Mark; Kwan, Simon; Lee, Shih-Chang; Lian, Zhijun; Liu, Tiankuan; /CERN /Oxford U. /Fermilab /Taipei, Computing Ctr. /Southern Methodist U.

    2009-07-01T23:59:59.000Z

    Radiation tolerant, high speed optoelectronic data transmission links are fundamental building blocks in today's large scale High Energy Physics (HEP) detectors, as exemplified by the four experiments currently under commissioning at the Large Hadron Collider (LHC), see for example. New experiments or upgrades will impose even more stringent demands on these systems from the point of view of performance and radiation tolerance. This can already be seen from the developments underway for the Super Large Hadron Collider (SLHC) project, a proposed upgrade to the LHC aiming at increasing the luminosity of the machine by factor of 10 to 10{sup 35} cm{sup -2}s{sup -1}, and thus providing a better chance to see rare processes and improving statistically marginal measurements. In the past, specific data transmission links have been independently developed by each LHC experiment for data acquisition (DAQ), detector control as well as trigger and timing distribution (TTC). This was justified by the different types of applications being targeted as well as by technological limitations preventing one single solution from fitting all requirements. However with today's maturity of optoelectronic and CMOS technologies it is possible to envisage the development of a general purpose optical link which can cover most transmission applications: a Versatile Link. Such an approach has the clear advantage of concentrating the development effort on one single project targeting an optical link whose final functionality will only result from the topology and configuration settings adopted.

  16. Long-range two-particle correlations of strange hadrons with charged particles in pPb and PbPb collisions at LHC energies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V.; et al.,

    2015-03-01T23:59:59.000Z

    Measurements of two-particle angular correlations between an identified strange hadron (K0S or Lambda/anti-Lambda) and a charged particle, emitted in pPb collisions, are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 35 inverse nanobarns, were collected at a nucleon-nucleon center-of-mass energy (sqrt(s[NN])) of 5.02 TeV with the CMS detector at the LHC. The results are compared to semi-peripheral PbPb collision data at sqrt(s[NN]) = 2.76 TeV, covering similar charged-particle multiplicities in the events. The observed azimuthal correlations at large relative pseudorapidity are used to extract the second-order (v[2]) and third-ordermore »(v[3]) anisotropy harmonics of K0S and Lambda/anti-Lambda particles. These quantities are studied as a function of the charged-particle multiplicity in the event and the transverse momentum of the particles. For high-multiplicity pPb events, a clear particle species dependence of v[2] and v[3] is observed. For pt « less

  17. Higgs Boson Properties and BSM Higgs Boson Searches at LHC

    E-Print Network [OSTI]

    Wolfgang F. Mader

    2008-09-24T23:59:59.000Z

    At the end of 2008, the Large Hadron Collider (LHC) will come into operation and the two experiments ATLAS and CMS will start taking data from proton-proton collisions at a center-of-mass energy of \\sqrt{s}=14 TeV. In preparation for the data taking period, the discovery potential for Higgs bosons beyond the Standard Model has been updated by both experiments and is reviewed here. In addition, the prospects for measuring the properties of a Higgs boson like its mass and width, its CP eigenvalues and its couplings to fermions and gauge bosons are discussed.

  18. Parton distributions at the dawn of the LHC

    E-Print Network [OSTI]

    Stefano Forte

    2010-12-06T23:59:59.000Z

    We review basic ideas and recent developments on the determination of the parton substructure of the nucleon, in view of applications to precision hadron collider physics. We review the way information on parton distributions (PDFs) is extracted from the data exploiting QCD factorization, and discuss the current main two approaches to parton determination (Hessian and Monte Carlo) and their use in conjunction with different kinds of parton parametrization. We summarize the way different physical processes can be used to constrain different aspects of PDFs. We discuss the meaning, determination and use of parton uncertainties. We briefly summarize the current state of the art on PDFs for LHC physics.

  19. Diffraction at collider energies

    SciTech Connect (OSTI)

    Frankfurt, L.L. (Department of Physics, FM-15, University of Washington, Seattle, Washington 98195 (United States))

    1992-02-01T23:59:59.000Z

    The aim of this talk is to outline lessons with soft'' hadron physics to explain (a) feasibility to observe and to investigate color transparency, color opacity effects at colliders; (b) significant probability and specific features of hard diffractive processes; (c) feasibility to investigate components of parton wave functions of hadrons with minimal number of constituents. This new physics would be more important with increase of collision energy.

  20. First Results of the LHC Longitudinal Density Monitor

    SciTech Connect (OSTI)

    Jeff, A.; /CERN /Liverpool U.; Boccardi, A.; /CERN; Bravin, E.; /CERN; Fisher, A.S.; /SLAC; Lefevre, T.; /CERN; Rabiller, A.; /CERN; Roncarolo, F.; /CERN; Welsch, C.P.; /Liverpool U. /Cockcroft Inst. Accel. Sci. Tech.

    2012-04-19T23:59:59.000Z

    The Large Hadron Collider (LHC) at CERN is the world's largest particle accelerator. It is designed to accelerate and collide protons or heavy ions up to the center-of-mass energies of 14 TeV. Knowledge of the longitudinal distribution of particles is important for various aspects of accelerator operation, in particular to check the injection quality and to measure the proportion of charge outside the nominally filled bunches during the physics periods. In order to study this so-called ghost charge at levels very much smaller than the main bunches, a longitudinal profile measurement with a very high dynamic range is needed. A new detector, the LHC Longitudinal Density Monitor (LDM) is a single-photon counting system measuring synchrotron light by means of an avalanche photodiode detector. The unprecedented energies reached in the LHC allow synchrotron light diagnostics to be used with both protons and heavy ions. A prototype was installed during the 2010 LHC run and was able to longitudinally profile the whole ring with a resolution close to the target of 50 ps. On-line correction for the effects of the detector deadtime, pile-up and afterpulsing allow a dynamic range of 105 to be achieved. First measurements with the LDM are presented here along with an analysis of its performance and an outlook for future upgrades.

  1. The ATLAS Trigger Core Configuration and Execution System in Light of the ATLAS Upgrade for LHC Run 2

    E-Print Network [OSTI]

    Heinrich, Lukas; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    During the 2013/14 shutdown of the Large Hadron Collider (LHC) the ATLAS first level trigger (L1) and the data acquisition system (DAQ) were substantially upgraded to cope with the increase in luminosity and collision multiplicity, expected to be delivered by the LHC in 2015. Upgrades were performed at both the L1 stage and the single combined subsequent high level trigger (HLT) stage that has been introduced to replace the two-tiered HLT stage used in Run 1. Because of these changes, the HLT execution framework and the trigger configuration system had to be upgraded. Also, tools and data content were adapted to the new ATLAS analysis model.

  2. The Dark Penguin Shines Light at Colliders

    E-Print Network [OSTI]

    Primulando, Reinard; Tsai, Yuhsin

    2015-01-01T23:59:59.000Z

    Collider experiments are one of the most promising ways to constrain Dark Matter (DM) interactions. For several types of DM-Standard Model couplings, a meaningful interpretation of the results requires to go beyond effective field theory, considering simplified models with light mediators. This is especially important in the case of loop-mediated interactions. In this paper we perform the first simplified model study of the magnetic dipole interacting DM, by including the one-loop momentum-dependent form factors that mediate the coupling -- given by the Dark Penguin -- in collider processes. We compute bounds from the monojet, monophoton, and diphoton searches at the $8$ and $14$ TeV LHC, and compare the results to those of direct and indirect detection experiments. Future searches at the $100$ TeV hadron collider and at the ILC are also addressed. We find that the optimal search strategy requires loose cuts on the missing transverse energy, to capture the enhancement of the form factors near the threshold fo...

  3. LINEAR COLLIDER PHYSICS RESOURCE BOOK FOR SNOWMASS 2001.

    SciTech Connect (OSTI)

    ABE,T.; DAWSON,S.; HEINEMEYER,S.; MARCIANO,W.; PAIGE,F.; TURCOT,A.S.; ET AL

    2001-05-03T23:59:59.000Z

    The American particle physics community can look forward to a well-conceived and vital program of experimentation for the next ten years, using both colliders and fixed target beams to study a wide variety of pressing questions. Beyond 2010, these programs will be reaching the end of their expected lives. The CERN LHC will provide an experimental program of the first importance. But beyond the LHC, the American community needs a coherent plan. The Snowmass 2001 Workshop and the deliberations of the HEPAP subpanel offer a rare opportunity to engage the full community in planning our future for the next decade or more. A major accelerator project requires a decade from the beginning of an engineering design to the receipt of the first data. So it is now time to decide whether to begin a new accelerator project that will operate in the years soon after 2010. We believe that the world high-energy physics community needs such a project. With the great promise of discovery in physics at the next energy scale, and with the opportunity for the uncovering of profound insights, we cannot allow our field to contract to a single experimental program at a single laboratory in the world. We believe that an e{sup +}e{sup {minus}} linear collider is an excellent choice for the next major project in high-energy physics. Applying experimental techniques very different from those used at hadron colliders, an e{sup +}e{sup {minus}} linear collider will allow us to build on the discoveries made at the Tevatron and the LHC, and to add a level of precision and clarity that will be necessary to understand the physics of the next energy scale. It is not necessary to anticipate specific results from the hadron collider programs to argue for constructing an e{sup +}e{sup {minus}} linear collider; in any scenario that is now discussed, physics will benefit from the new information that e{sup +}e{sup {minus}} experiments can provide.

  4. ATLAS Jet Trigger Performance in LHC Run I and Initial Run II Results

    E-Print Network [OSTI]

    Shimizu, Shima; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    The immense rate of proton-proton collisions at the Large Hadron Collider (LHC) must be reduced from the nominal bunch-crossing rate of 40 MHz to approximately 1 kHz before the data can be written on disk offline. The ATLAS Trigger System performs real-time selection of these events in order to achieve this reduction. Dedicated selection of events containing jets is uniquely challenging at a hadron collider where nearly every event contains significant hadronic energy. Following the very successful first LHC run from 2010 to 2012, the ATLAS Trigger was much improved, including a new hardware topological module and a restructured High Level Trigger system, merging two previous software-based processing levels. This allowed the optimization of resources and a much greater re-use of the precise but costly offline software base. After summarising the overall performance of the jet trigger during the first LHC run, the software design choices and use of the topological module will be reviewed. The expected perform...

  5. Long-range two-particle correlations of strange hadrons with charged particles in pPb and PbPb collisions at LHC energies

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Khachatryan, V. [Yerevan Physics Institute (Armenia); et al.,

    2015-03-01T23:59:59.000Z

    Measurements of two-particle angular correlations between an identified strange hadron (K0S or Lambda/anti-Lambda) and a charged particle, emitted in pPb collisions, are presented over a wide range in pseudorapidity and full azimuth. The data, corresponding to an integrated luminosity of approximately 35 inverse nanobarns, were collected at a nucleon-nucleon center-of-mass energy (sqrt(s[NN])) of 5.02 TeV with the CMS detector at the LHC. The results are compared to semi-peripheral PbPb collision data at sqrt(s[NN]) = 2.76 TeV, covering similar charged-particle multiplicities in the events. The observed azimuthal correlations at large relative pseudorapidity are used to extract the second-order (v[2]) and third-order (v[3]) anisotropy harmonics of K0S and Lambda/anti-Lambda particles. These quantities are studied as a function of the charged-particle multiplicity in the event and the transverse momentum of the particles. For high-multiplicity pPb events, a clear particle species dependence of v[2] and v[3] is observed. For pt < 2 GeV, the v[2] and v[3] values of K0S particles are larger than those of Lambda/anti-Lambda particles at the same pt. This splitting effect between two particle species is found to be stronger in pPb than in PbPb collisions in the same multiplicity range. When divided by the number of constituent quarks and compared at the same transverse kinetic energy per quark, both v[2] and v[3] for K0S particles are observed to be consistent with those for Lambda/anti-Lambda particles at the 10% level in pPb collisions. This consistency extends over a wide range of particle transverse kinetic energy and event multiplicities.

  6. Lepton-flavor-violating decay {tau}{yields}{mu}{mu}{mu} at the CERN LHC

    SciTech Connect (OSTI)

    Giffels, M.; Stahl, A. [III. Physikalisches Institut, RWTH Aachen, 52056 Aachen (Germany); Kallarackal, J. [Institut fuer Theoretische Physik, RWTH Aachen, 52074 Aachen (Germany); Institut fuer Physik, Humboldt-Universitaet zu Berlin, 12489 Berlin (Germany); Kraemer, M.; O'Leary, B. [Institut fuer Theoretische Physik, RWTH Aachen, 52074 Aachen (Germany)

    2008-04-01T23:59:59.000Z

    Lepton-flavor-violating {tau} decays are predicted in many extensions of the standard model at a rate observable at future collider experiments. In this article we focus on the decay {tau}{yields}{mu}{mu}{mu}, which is a promising channel to observe lepton-flavor violation at the CERN Large Hadron Collider (LHC). We present analytic expressions for the differential decay width derived from a model-independent effective Lagrangian with general four-fermion operators, and estimate the experimental acceptance for detecting the decay {tau}{yields}{mu}{mu}{mu} at the LHC. Specific emphasis is given to decay angular distributions and how they can be used to discriminate new physics models. We provide specific predictions for various extensions of the standard model, including supersymmetric, little Higgs, and technicolor models.

  7. Torsion phenomenology at the CERN LHC

    SciTech Connect (OSTI)

    Belyaev, A. S. [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Shapiro, I. L. [Departamento de Fisica - ICE, Universidade Federal de Juiz de Fora, Juiz de Fora, 36036-330, MG (Brazil); Tomsk State Pedagogical University (Russian Federation); Vale, M. A. B. do [Departamento de Ciencias Naturais, Universidade Federal de Sao Joao del Rei, Sao Joao del Rei, 36301-160, MG (Brazil)

    2007-02-01T23:59:59.000Z

    We explore the potential of the CERN Large Hadron Collider (LHC) to test the dynamical torsion parameters. The form of the torsion action can be established from the requirements of consistency of effective quantum field theory. The most phenomenologically relevant part of the torsion tensor is dual to a massive axial vector field. This axial vector has geometric nature, that means it does not belong to any representation of the gauge group of the SM extension or GUT theory. At the same time, torsion should interact with all fermions, that opens the way for the phenomenological applications. We demonstrate that LHC collider can establish unique constraints on the interactions between fermions and torsion field considerably exceeding present experimental lower bounds on the torsion couplings and its mass. It is also shown how possible nonuniversal nature of torsion couplings due to the renormalization group running between the Planck and TeV energy scales can be tested via the combined analysis of Drell-Yan and tt production processes.

  8. Hadronic resonance production in d+Au collisions at root S(NN) = 200 GeV measured at the BNL Relativistic Heavy Ion Collider 

    E-Print Network [OSTI]

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sanchez, M. Calderon de la Barca; Callner, J.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopdhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; De Silva, C.; Dedovich, T. G.; DePhillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, Carl A.; Gaillard, L.; Gangaharan, D. R.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C. -H; LeVine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, M. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, Saskia; Mischke, A.; Mishra, D. K.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X-H; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; deToledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty; Tokarev, M.; Trainor, T. A.; Tram, V. N.; Trattner, A. L.; Trentalange, S.; Tribble, Robert E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Leeuwen, M.; Molen, A. M. Vander; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.

    2008-01-01T23:59:59.000Z

    system of deconfined partonic matter, the quark gluon plasma (QGP) [1]. Matter under such extreme conditions can be studied in the laboratory by colliding nuclei at very high energies. The Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National... C. Zhong,39 J. Zhou,36 R. Zoulkarneev,13 Y. Zoulkarneeva,13 and J. X. Zuo39 (STAR Collaboration) 1Argonne National Laboratory, Argonne, Illinois 60439, USA 2University of Birmingham, Birmingham, United Kingdom 3Brookhaven National Laboratory...

  9. Effects of Shower Partons on Soft and Semihard hadrons Produced in Pb-Pb Collisions at 2.76 TeV

    E-Print Network [OSTI]

    Lilin Zhu; Rudolph C. Hwa

    2014-11-05T23:59:59.000Z

    The production of all identified hadrons at the CERN Large Hadron Collider (LHC) is studied with emphasis on the $p_T$ distributions up to 20 GeV/c in central collisions. In the framework of the recombination model we find that the shower partons (due to the fragmentation of semihard partons) play an important role in the formation of hadrons in the low- and intermediate-$p_T$ regions. Parameters that control the energy loss of minijets are determined by fitting the upper half of the $p_T$ range of the pion distribution. The resultant soft shower partons are then found to dominate over the thermal partons in the non-strange sector, but not in the strange sector. Since the data on the $p_T$ spectra of all observed hadrons are well reproduced, there is no way out of the implication that any alternative dynamical model on particle production would be incomplete if it does not consider the effects of minijets even at very low $p_T$. Hydrodynamics that relies on rapid equilibration without accounting for the delayed thermalization effects of the hard and semihard partons copiously produced at LHC is an example of such models. The difference between the densities of shower partons produced at LHC and at BNL Relativistic Heavy-Ion Collider (RHIC) is quantified and discussed.

  10. Physics validation studies for muon collider detector background simulations

    SciTech Connect (OSTI)

    Morris, Aaron Owen; /Northern Illinois U.

    2011-07-01T23:59:59.000Z

    Within the broad discipline of physics, the study of the fundamental forces of nature and the most basic constituents of the universe belongs to the field of particle physics. While frequently referred to as 'high-energy physics,' or by the acronym 'HEP,' particle physics is not driven just by the quest for ever-greater energies in particle accelerators. Rather, particle physics is seen as having three distinct areas of focus: the cosmic, intensity, and energy frontiers. These three frontiers all provide different, but complementary, views of the basic building blocks of the universe. Currently, the energy frontier is the realm of hadron colliders like the Tevatron at Fermi National Accelerator Laboratory (Fermilab) or the Large Hadron Collider (LHC) at CERN. While the LHC is expected to be adequate for explorations up to 14 TeV for the next decade, the long development lead time for modern colliders necessitates research and development efforts in the present for the next generation of colliders. This paper focuses on one such next-generation machine: a muon collider. Specifically, this paper focuses on Monte Carlo simulations of beam-induced backgrounds vis-a-vis detector region contamination. Initial validation studies of a few muon collider physics background processes using G4beamline have been undertaken and results presented. While these investigations have revealed a number of hurdles to getting G4beamline up to the level of more established simulation suites, such as MARS, the close communication between us, as users, and the G4beamline developer, Tom Roberts, has allowed for rapid implementation of user-desired features. The main example of user-desired feature implementation, as it applies to this project, is Bethe-Heitler muon production. Regarding the neutron interaction issues, we continue to study the specifics of how GEANT4 implements nuclear interactions. The GEANT4 collaboration has been contacted regarding the minor discrepancies in the neutron interaction cross sections for boron. While corrections to the data files themselves are simple to implement and distribute, it is quite possible, however, that coding changes may be required in G4beamline or even in GEANT4 to fully correct nuclear interactions. Regardless, these studies are ongoing and future results will be reflected in updated releases of G4beamline.

  11. Hadronic resonance production in d+Au collisions at root S(NN) = 200 GeV measured at the BNL Relativistic Heavy Ion Collider

    E-Print Network [OSTI]

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sanchez, M. Calderon de la Barca; Callner, J.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopdhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; De Silva, C.; Dedovich, T. G.; DePhillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, Carl A.; Gaillard, L.; Gangaharan, D. R.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C. -H; LeVine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, M. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, Saskia; Mischke, A.; Mishra, D. K.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X-H; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; deToledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty; Tokarev, M.; Trainor, T. A.; Tram, V. N.; Trattner, A. L.; Trentalange, S.; Tribble, Robert E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Leeuwen, M.; Molen, A. M. Vander; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.

    2008-01-01T23:59:59.000Z

    We present the first measurements of the rho(770)(0),K(*)(892),Delta(1232)(++),Sigma(1385), and Lambda(1520) resonances in d+Au collisions at s(NN)=200 GeV, reconstructed via their hadronic decay channels using the STAR detector (the solenoidal...

  12. Tomography of a quark gluon plasma at RHIC and LHC energies

    E-Print Network [OSTI]

    P. B. Gossiaux; R. Bierkandt; J. Aichelin

    2009-03-23T23:59:59.000Z

    Using the recently published model for the collisional energy loss of heavy quarks (Q) in a Quark Gluon Plasma (QGP), based on perturbative QCD (pQCD) with a running coupling constant, we study the interaction between heavy quarks and plasma particles in detail. We discuss correlations between the simultaneously produced $c$ and $\\bar{c}$ quarks, study how central collisions can be experimentally selected, predict observable correlations and extend our model to the energy domain of the large hadron collider (LHC). We finally compare the predictions of our model with that of other approaches like AdS/CFT.

  13. Mueller Navelet jets at LHC: a clean test of QCD resummation effects at high energy?

    E-Print Network [OSTI]

    B. Ducloué; L. Szymanowski; S. Wallon

    2013-09-10T23:59:59.000Z

    Mueller Navelet jets were proposed more than 25 years ago as a decisive test of BFKL dynamics at hadron colliders. We here present a complete next-to-leading BFKL study of the azimuthal decorrelation of these jets. This includes both next-to-leading corrections to the Green's function and next-to-leading corrections to the jet vertices. We compare our results with recent data taken at the LHC and results obtained in a fixed order next-to-leading-order (NLO) calculation.

  14. Mueller Navelet jets at LHC: a clean test of QCD resummation effects at high energy?

    E-Print Network [OSTI]

    Ducloué, B; Wallon, S

    2013-01-01T23:59:59.000Z

    Mueller Navelet jets were proposed more than 25 years ago as a decisive test of BFKL dynamics at hadron colliders. We here present a complete next-to-leading BFKL study of the azimuthal decorrelation of these jets. This includes both next-to-leading corrections to the Green's function and next-to-leading corrections to the jet vertices. We compare our results with recent data taken at the LHC and results obtained in a fixed order next-to-leading-order (NLO) calculation.

  15. Mitigation of Radiation and EMI Effects on the Vacuum Control System of LHC

    E-Print Network [OSTI]

    Pigny, G; Krakowski, P; Rio, B

    2014-01-01T23:59:59.000Z

    The 26 km of vacuum chambers where circulates the beam of the Large Hadron Collider (LHC) must be maintained under Ultra High Vacuum (UHV) to minimize the beam interactions with residual gases, and allow the operation of specific systems. The vacuum level is measured by several thousands of gauges along the accelerator. Bad vacuum quality may trigger a beam dump and close the associated sector valves. The effects of radiation or Electromagnetic Interferences (EMI) on components that may stop the machine must be evaluated and minimized. We report on the actions implemented to mitigate their impact on the vacuum control system.

  16. Production of jets at forward rapidities in hadronic collisions

    E-Print Network [OSTI]

    F. Hautmann

    2009-09-07T23:59:59.000Z

    We discuss high-pT production processes at forward rapidities in hadron-hadron collisions, and describe recent results from using QCD high-energy factorization in forward jet production at the LHC.

  17. General-purpose event generators for LHC physics

    SciTech Connect (OSTI)

    Buckley, Andy; /Edinburgh U.; Butterworth, Jonathan; /University Coll. London; Gieseke, Stefan; /Karlsruhe U., ITP; Grellscheid, David; /Durham U., IPPP; Hoche, Stefan; /SLAC; Hoeth, Hendrik; Krauss, Frank; /Durham U., IPPP; Lonnblad, Leif; /Lund U., Dept. Theor. Phys. /CERN; Nurse, Emily; /University Coll. London; Richardson, Peter; /Durham U., IPPP; Schumann, Steffen; /Heidelberg U.; Seymour, Michael H.; /Manchester U.; Sjostrand, Torbjorn; /Lund U., Dept. Theor. Phys.; Skands, Peter; /CERN; Webber, Bryan; /Cambridge U.

    2011-03-03T23:59:59.000Z

    We review the physics basis, main features and use of general-purpose Monte Carlo event generators for the simulation of proton-proton collisions at the Large Hadron Collider. Topics included are: the generation of hard-scattering matrix elements for processes of interest, at both leading and next-to-leading QCD perturbative order; their matching to approximate treatments of higher orders based on the showering approximation; the parton and dipole shower formulations; parton distribution functions for event generators; non-perturbative aspects such as soft QCD collisions, the underlying event and diffractive processes; the string and cluster models for hadron formation; the treatment of hadron and tau decays; the inclusion of QED radiation and beyond-Standard-Model processes. We describe the principal features of the Ariadne, Herwig++, Pythia 8 and Sherpa generators, together with the Rivet and Professor validation and tuning tools, and discuss the physics philosophy behind the proper use of these generators and tools. This review is aimed at phenomenologists wishing to understand better how parton-level predictions are translated into hadron-level events as well as experimentalists wanting a deeper insight into the tools available for signal and background simulation at the LHC.

  18. Higgs-boson production at the Photon Collider at TESLA

    E-Print Network [OSTI]

    Piotr Niezurawski

    2005-03-31T23:59:59.000Z

    In this thesis feasibility of the precise measurement of the Higgs-boson production cross section gamma+gamma->higgs->b+bbar at the Photon Collider at TESLA is studied in detail. The study is based on the realistic luminosity spectra simulation. The heavy quark background is estimated using the dedicated code based on NLO QCD calculations. Other background processes, which were neglected in the earlier analyses, are also studied. Also the contribution from the overlaying events, gamma+gamma->hadrons, is taken into account. The non-zero beam crossing angle and the finite size of colliding bunches are included in the event generation. The analysis is based on the full detector simulation with realistic b-tagging, and the criteria of event selection are optimized separately for each considered Higgs-boson mass. For the Standard-Model Higgs boson with mass of 120 to 160 GeV the partial width \\Gamma(h->gamma+gamma)BR(h->b+bbar) can be measured with a statistical accuracy of 2.1-7.7% after one year of the Photon Collider running. The systematic uncertainties of the measurement are estimated to be of the order of 2%. For MSSM Higgs bosons A and H, for M_A=200-350 GeV and tan(beta)=7, the statistical precision of the cross-section measurement is estimated to be 8--34%, for four considered MSSM parameters sets. As heavy neutral Higgs bosons in this scenario may not be discovered at LHC or at the first stage of the e+e- collider, an opportunity of being a discovery machine is also studied for the Photon Collider.

  19. Rare exclusive hadronic W decays in a t-tbar environment

    E-Print Network [OSTI]

    Michelangelo Mangano; Tom Melia

    2014-10-28T23:59:59.000Z

    The large cross section for t-tbar production at the LHC and at any future hadron collider provides a high-statistics and relatively clean environment for a study of W boson properties: after tagging on a leptonic decay of one of the Ws and the two b-jets, an additional W still remains in the event. We study the prospect of making the first exclusive hadronic decay of a fundamental boson of the standard model, using the decay modes W to pi gamma and W to pi pi pi, and other related decays. By using strong isolation criteria, which we impose by searching for jets with a single particle constituent, we show that the three particle hadronic W decays have potential to be measured at the LHC. The possibility of measuring an involved spectrum of decay products could considerably expand our knowledge of how the W decays, and experimental techniques acquired in making these measurements would be useful for application to future measurements of exclusive hadronic Higgs boson decays.

  20. Measurement of heavy-flavor production in Pb-Pb collisions at the LHC with ALICE

    E-Print Network [OSTI]

    Robert Grajcarek; for the ALICE Collaboration

    2012-09-10T23:59:59.000Z

    A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC) has been built in order to study the Quark-Gluon Plasma (QGP) created in high-energy nuclear collisions. As heavy-flavor quarks are produced at the early stage of the collision, they serve as sensitive probes for the QGP. The ALICE detector with its capabilities such as particle identification, secondary vertexing and tracking in a high multiplicity environment can address, among other measurements, the heavy-flavor sector in heavy-ion collisions. We present latest results on the measurement of the nuclear modification factor of open heavy-flavors as well as on the measurement of open heavy-flavor azimuthal anisotropy v2 in Pb-Pb collisions at sqrt(s) = 2.76 TeV. Open charmed hadrons are reconstructed in the hadronic decay channels D0->Kpi, D+->Kpipi, and D*+->D0pi applying a secondary decay-vertex topology. Complementary measurements are performed by detecting electrons (muons) from semi-leptonic decays of open heavy-flavor hadrons in the central (forward) rapidity region.

  1. Correcting the LHC beta* at Collision

    E-Print Network [OSTI]

    Verdier, A; Zimmermann, Frank

    2003-01-01T23:59:59.000Z

    To correct the beta* at the main collision points (IP1 and IP5) simultaneously for the two counterrotating proton beams in the Large Hadron Collider (LHC), a set of specific quadrupoles in the non-common part of the machine is used. Due to the antisymmetric optics, several quadrupoles on each side of the insertion have to be employed. The change of beta* is accomplished by incrementing the quadrupole gradients. This set of increments is referred to as beta* tuning knob. The increments were calculated by rematching beta* in a range of + 20 % about the nominal value. Linear curves were fitted to the variation of increments to construct a linear tuning knob. This was done for each plane using MAD 8 [1] and repeated with MAD X [2]. The linear behaviour and the orthogonality of the knobs were investigated for the LHC lattices V6.2 and V6.4. Different field errors were introduced in the lattice and the correction efficiency of the knobs was studied.

  2. Event simulation for colliders - A basic overview

    E-Print Network [OSTI]

    Christian Reuschle

    2014-11-26T23:59:59.000Z

    In this article we will discuss the basic calculational concepts to simulate particle physics events at high energy colliders. We will mainly focus on the physics in hadron colliders and particularly on the simulation of the perturbative parts, where we will in turn focus on the next-to-leading order QCD corrections.

  3. The International Linear Collider

    E-Print Network [OSTI]

    Barish, Barry

    2013-01-01T23:59:59.000Z

    In this article, we describe the key features of the recently completed technical design for the International Linear Collider (ILC), a 200-500 GeV linear electron-positron collider (expandable to 1 TeV) that is based on 1.3 GHz superconducting radio-frequency (SCRF) technology. The machine parameters and detector characteristics have been chosen to complement the Large Hadron Collider physics, including the discovery of the Higgs boson, and to further exploit this new particle physics energy frontier with a precision instrument. The linear collider design is the result of nearly twenty years of R&D, resulting in a mature conceptual design for the ILC project that reflects an international consensus. We summarize the physics goals and capability of the ILC, the enabling R&D and resulting accelerator design, as well as the concepts for two complementary detectors. The ILC is technically ready to be proposed and built as a next generation lepton collider, perhaps to be built in stages beginning as a Hig...

  4. Measurement and Scaling Laws of the Sextupole Component in the LHC Dipole Magnets

    E-Print Network [OSTI]

    Walckiers, L; Bottura, L; Buzio, M; Dunkel, O; Fiscarelli, L; Montenero, G; Garcia Perez, J; Todesco, E

    2010-01-01T23:59:59.000Z

    One of the main requirements for the magnet operation of the Large Hadron Collider at CERN is the correction of the dynamic multipole errors produced. In particular, integrated sextupole errors in the main dipoles must be kept well below 0.1 units to ensure acceptable chromaticity. The feed-forward control of the LHC magnets is based on the Field Description for the LHC (FiDeL), a semi-empirical mathematical model capable of forecasting the magnet’s behaviours in order to suitably power the corrector scheme. Measurement campaign were recently undertaken to validate the model making use of a novel Fast rotating-coil Magnetic Measurement Equipment (FAME), able to detect superconductor decay and snapback transient with unprecedented accuracy and temporal resolution. We discuss in this paper the test setup and some measurement results confirming the FiDeL model.

  5. The LHC Cryogenic Operation Availability Results from the First Physics Run of Three Years

    E-Print Network [OSTI]

    Delikaris, D; Claudet, S; Ferlin, G; Tavian, L; Wagner, U

    2013-01-01T23:59:59.000Z

    The LHC (Large Hadron Collider) accelerator consists in eight cryogenically independent sectors, each 3.3 km long with a cold mass of 4’500 t cooled at 1.9 K. Each helium cryogenic plant combines an 18 kW at 4.5 K refrigerator and a 2.4 kW at 1.8 K refrigeration unit. Since early operation for physics in November 2009, the availability has been above 90% for more than 260 days per year, ending at 94.8% in 2012 and corresponding to an equivalent availability of more than 99% per independent sector. The operation and support methodology as well as the achieved performance results are presented. Emphasis is given on implementing operational return for short, medium and long term consolidations. Perspective for restart after the first long shutdown of the LHC works will be described.

  6. Comparison of LHC collimator beam-based alignment to BPM-Interpolated centers

    E-Print Network [OSTI]

    Valentino, G; Assmann, R W; Bruce, R; Muller, G J; Redaelli, S; Rossi, A; Lari, L

    2012-01-01T23:59:59.000Z

    The beam centers at the Large Hadron Collider collimators are determined by beam-based alignment, where both jaws of a collimator are moved in separately until a loss spike is detected on a Beam LossMonitor downstream. Orbit drifts of more than a few hundred micrometers cannot be tolerated, as they would compromise the performance of the collimation system. Beam Position Monitors (BPMs) are installed at various locations around the LHC ring, and a linear interpolation of the orbit can be obtained at the collimator positions. In this paper, the results obtained from beam-based alignment are compared with the orbit interpolated from the BPM data throughout the 2011 and 2012 LHC proton runs.

  7. Can one use Mueller-Navelet jets at LHC as a clean test of QCD resummation effects at high energy?

    E-Print Network [OSTI]

    B. Ducloué; L. Szymanowski; S. Wallon

    2013-12-09T23:59:59.000Z

    The measurement of azimuthal correlations of Mueller-Navelet jets is generally considered as a decisive test to reveal the effect of BFKL dynamics at hadron colliders. The first experimental study of these correlations at the LHC has been recently performed by the CMS collaboration. We show that the ratios of cosine moments of the azimuthal distribution are successfully described within our next-to-leading logarithmic BFKL treatment. The whole set of CMS data for the azimuthal correlations can also be consistently described provided that one uses a larger renormalization/factorization scale than its natural value.

  8. Can one use Mueller-Navelet jets at LHC as a clean test of QCD resummation effects at high energy?

    E-Print Network [OSTI]

    Ducloué, B; Wallon, S

    2013-01-01T23:59:59.000Z

    The measurement of azimuthal correlations of Mueller-Navelet jets is generally considered as a decisive test to reveal the effect of BFKL dynamics at hadron colliders. The first experimental study of these correlations at the LHC has been recently performed by the CMS collaboration. We show that the ratios of cosine moments of the azimuthal distribution are successfully described within our next-to-leading logarithmic BFKL treatment. The whole set of CMS data for the azimuthal correlations can also be consistently described provided that one uses a larger renormalization/factorization scale than its natural value.

  9. A light NMSSM pseudoscalar Higgs boson at the LHC Run 2

    E-Print Network [OSTI]

    Bomark, Nils-Erik; Munir, Shoaib; Roszkowski, Leszek

    2015-01-01T23:59:59.000Z

    We revisit the light pseudoscalar $A_1$ in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with partial universality at some high unification scale in order to delineate the parameter space regions consistent with up-to-date theoretical and experimental constraints and examine to what extent this state can be probed by the Large Hadron Collider (LHC) during Run 2. We find that it can be accessible through a variety of signatures proceeding via $A_1\\to \\tau^+\\tau^-$ and/or $b\\bar b$, the former assuming hadronic decays and the latter two $b$-tags within a fat jet or two separate slim ones. Herein, the light pseudoscalar state is produced from a heavy Higgs boson decay in either pairs or singly in association with a $Z$ boson (in turn decaying into electrons/muons).

  10. Neutrinos and Collider Physics

    E-Print Network [OSTI]

    Frank F. Deppisch; P. S. Bhupal Dev; Apostolos Pilaftsis

    2015-03-09T23:59:59.000Z

    We review the collider phenomenology of neutrino physics and the synergetic aspects at energy, intensity and cosmic frontiers to test the new physics behind the neutrino mass mechanism. In particular, we focus on seesaw models within the minimal setup as well as with extended gauge and/or Higgs sectors, and on supersymmetric neutrino mass models with seesaw mechanism and with $R$-parity violation. In the simplest Type-I seesaw scenario with sterile neutrinos, we summarize and update the current experimental constraints on the sterile neutrino mass and its mixing with the active neutrinos. We also discuss the future experimental prospects of testing the seesaw mechanism at colliders and in related low-energy searches for rare processes, such as lepton flavor violation and neutrinoless double beta decay. The implications of the discovery of lepton number violation at the LHC for leptogenesis are also studied.

  11. Neutrinos and Collider Physics

    E-Print Network [OSTI]

    Deppisch, Frank F; Pilaftsis, Apostolos

    2015-01-01T23:59:59.000Z

    We review the collider phenomenology of neutrino physics and the synergetic aspects at energy, intensity and cosmic frontiers to test the new physics behind the neutrino mass mechanism. In particular, we focus on seesaw models within the minimal setup as well as with extended gauge and/or Higgs sectors, and on supersymmetric neutrino mass models with seesaw mechanism and with $R$-parity violation. In the simplest Type-I seesaw scenario with sterile neutrinos, we summarize and update the current experimental constraints on the sterile neutrino mass and its mixing with the active neutrinos. We also discuss the future experimental prospects of testing the seesaw mechanism at colliders and in related low-energy searches for rare processes, such as lepton flavor violation and neutrinoless double beta decay. The implications of the discovery of lepton number violation at the LHC for leptogenesis are also studied.

  12. Upgrade of the LHC magnet interconnections thermal shielding

    SciTech Connect (OSTI)

    Musso, Andrea; Barlow, Graeme; Bastard, Alain; Charrondiere, Maryline; Deferne, Guy; Dib, Gaëlle; Duret, Max; Guinchard, Michael; Prin, Hervé; Craen, Arnaud Vande; Villiger, Gilles [CERN European Organization for Nuclear Research, Meyrin 1211, Geneva 23, CH (Switzerland); Chrul, Anna [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul.Radzikowskiego 152, 31-324 Krakow (Poland); Damianoglou, Dimitrios [NTUA National Technical University of Athens, Heeron Polytechniou 9, 15780 Zografou (Greece); Strychalski, Micha? [Wroclaw University of Technology, Faculty of Mechanical and Power Engineering, Wyb. Wyspianskiego 27, Wroclaw, 50-370 (Poland); Wright, Loren [Lancaster University, Bailrigg, Lancaster, LA1 4YW (United Kingdom)

    2014-01-29T23:59:59.000Z

    The about 1700 interconnections (ICs) between the Large Hadron Collider (LHC) superconducting magnets include thermal shielding at 50-75 K, providing continuity to the thermal shielding of the magnet cryostats to reduce the overall radiation heat loads to the 1.9 K helium bath of the magnets. The IC shield, made of aluminum, is conduction-cooled via a welded bridge to the thermal shield of the adjacent magnets which is actively cooled. TIG welding of these bridges made in the LHC tunnel at installation of the magnets induced a considerable risk of fire hazard due to the proximity of the multi-layer insulation of the magnet shields. A fire incident occurred in one of the machine sectors during machine installation, but fortunately with limited consequences thanks to prompt intervention of the operators. LHC is now undergoing a 2 years technical stop during which all magnet's ICs will have to be opened to consolidate the magnet electrical connections. The IC thermal shields will therefore have to be removed and re-installed after the work is completed. In order to eliminate the risk of fire hazard when re-welding, it has been decided to review the design of the IC shields, by replacing the welded bridges with a mechanical clamping which also preserves its thermal function. An additional advantage of this new solution is the ease in dismantling for maintenance, and eliminating weld-grinding operations at removal needing radioprotection measures because of material activation after long-term operation of the LHC. This paper describes the new design of the IC shields and in particular the theoretical and experimental validation of its thermal performance. Furthermore a status report of the on-going upgrade work in the LHC is given.

  13. Dynamical R-parity Breaking at the LHC

    E-Print Network [OSTI]

    Chen, Shao-Long; Mohapatra, Rabindra N; Zhang, Yue

    2010-01-01T23:59:59.000Z

    In a class of extensions of the minimal supersymmetric standard model with (B-L)/left-right symmetry that explains the neutrino masses, breaking R-parity symmetry is an essential and dynamical requirement for successful gauge symmetry breaking. Two consequences of these models are: (i) a new kind of R-parity breaking interaction that protects proton stability but adds new contributions to neutrinoless double beta decay and (ii) an upper bound on the extra gauge and parity symmetry breaking scale which is within the large hadron collider (LHC) energy range. We point out that an important prediction of such theories is a potentially large mixing between the right-handed charged lepton ($e^c$) and the superpartner of the right-handed gauge boson ($\\widetilde W_R^+$), which leads to a brand new class of R-parity violating interactions of type $\\widetilde{\\mu^c}^\\dagger\

  14. Nb3Sn Quadrupole Magnets for the LHC IR

    SciTech Connect (OSTI)

    Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.r.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

    2001-08-01T23:59:59.000Z

    The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10{sup 34} cm{sup -2}s{sup -1} at the Large Hadron Collider (LHC). At present, Nb{sub 3}Sn is the only practical conductor which can meet these requirements. Since Nb{sub 3}Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

  15. Research and Development for a Free-Running Readout System for the ATLAS LAr Calorimeters at the High Luminosity LHC

    E-Print Network [OSTI]

    Hils, Maximilian; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    The ATLAS Liquid Argon (LAr) Calorimeters were designed and built to measure electromagnetic and hadronic energy in proton-proton collisions produced at the Large Hadron Collider (LHC) at centre-of-mass energies up to \\SI{14}{\\tera\\electronvolt} and instantaneous luminosities up to \\SI{d34}{\\per\\centi\\meter\\squared\\per\\second}. The High Luminosity LHC (HL-LHC) programme is now developed for up to 5-7 times the design luminosity, with the goal of accumulating an integrated luminosity of \\SI{3000}{\\per\\femto\\barn}. In the HL-LHC phase, the increased radiation levels require a replacement of the front-end (FE) electronics of the LAr Calorimeters. Furthermore, the ATLAS trigger system is foreseen to increase the trigger accept rate and the trigger latency which requires a larger data volume to be buffered. Therefore, the LAr Calorimeter read-out will be exchanged with a new FE and a high bandwidth back-end (BE) system for receiving data from all \

  16. Testing Beam-Induced Quench Levels of LHC Superconducting Magnets in Run 1

    E-Print Network [OSTI]

    Auchmann, B; Bednarek, M; Bellodi, G; Bracco, C; Bruce, R; Cerutti, F; Chetvertkova, V; Dehning, B; Granieri, P P; Hofle, W; Holzer, E B; Lechner, A; Del Busto, E Nebot; Priebe, A; Redaelli, S; Salvachua, B; Sapinski, M; Schmidt, R; Shetty, N; Skordis, E; Solfaroli, M; Steckert, J; Valuch, D; Verweij, A; Wenninger, J; Wollmann, D; Zerlauth, M

    2015-01-01T23:59:59.000Z

    In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with the top beam energies of 3.5 TeV and 4 TeV per proton (from 2012) instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam- induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy depositio...

  17. LHCb : LHCbVELO: Performance and Radiation Damage in LHC Run I and Preparationfor Run II

    E-Print Network [OSTI]

    Szumlak, Tomasz

    2015-01-01T23:59:59.000Z

    LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. Heavy hadrons are identified through their flight distance in the Vertex Locator (VELO). The VELO comprises 42 modules made of two n+-on-n 300 um thick half-disc silicon sensors with R-measuring and Phi-measuring micro-strips. In order to allow retracting the detector, the VELO is installed as two movable halves containing 21 modules each. The detectors are operated in a secondary vacuum and are cooled by a bi-phase CO2 cooling system. During data taking in LHC Run 1 the LHCb VELO has operated with an extremely high efficiency and excellent performance. The track finding efficiency is typically greater than 98%. An impact parameter resolution of less than 35 um is achieved for particles with transverse momentum greater than 1 GeV/c. An overview of all important performance parameters will be given. The VELO sensors have received a large and non-uniform radiation dose of up to 1.2 x 10...

  18. Total Dose Dependence of Oxide Charge, Interstrip Capacitance and Breakdown Behavior of sLHC

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    . Keywords: Silicon microstrip detectors; Surface radiation damage; MOS capacitors PACS: 29.40 Gx; 29.40 Wk Collider, the Super-LHC (sLHC), requires a critical evaluation of the radiation hardness of the silicon

  19. Heavy Ion Collisions at the LHC - Last Call for Predictions

    SciTech Connect (OSTI)

    Armesto, N; Borghini, N; Jeon, S; Wiedemann, U A; Abreu, S; Akkelin, V; Alam, J; Albacete, J L; Andronic, A; Antonuv, D; Arleo, F; Armesto, N; Arsene, I C; Barnafoldi, G G; Barrette, J; Bauchle, B; Becattini, F; Betz, B; Bleicher, M; Bluhm, M; Boer, D; Bopp, F W; Braun-Munzinger, P; Bravina, L; Busza, W; Cacciari, M; Capella, A; Casalderrey-Solana, J; Chatterjee, R; Chen, L; Cleymans, J; Cole, B A; delValle, Z C; Csernai, L P; Cunqueiro, L; Dainese, A; de Deus, J D; Ding, H; Djordjevic, M; Drescher, H; Dremin, I M; Dumitru, A; El, A; Engel, R; d'Enterria, D; Eskola, K J; Fai, G; Ferreiro, E G; Fries, R J; Frodermann, E; Fujii, H; Gale, C; Gelis, F; Goncalves, V P; Greco, V; Gyulassy, M; van Hees, H; Heinz, U; Honkanen, H; Horowitz, W A; Iancu, E; Ingelman, G; Jalilian-Marian, J; Jeon, S; Kaidalov, A B; Kampfer, B; Kang, Z; Karpenko, I A; Kestin, G; Kharzeev, D; Ko, C M; Koch, B; Kopeliovich, B; Kozlov, M; Kraus, I; Kuznetsova, I; Lee, S H; Lednicky, R; Letessier, J; Levin, E; Li, B; Lin, Z; Liu, H; Liu, W; Loizides, C; Lokhtin, I P; Machado, M T; Malinina, L V; Managadze, A M; Mangano, M L; Mannarelli, M; Manuel, C; Martinez, G; Milhano, J G; Mocsy, A; Molnar, D; Nardi, M; Nayak, J K; Niemi, H; Oeschler, H; Ollitrault, J; Paic, G; Pajares, C; Pantuev, V S; Papp, G; Peressounko, D; Petreczky, P; Petrushanko, S V; Piccinini, F; Pierog, T; Pirner, H J; Porteboeuf, S; Potashnikova, I; Qin, G Y; Qiu, J; Rafelski, J; Rajagopal, K; Ranft, J; Rapp, R; Rasanen, S S; Rathsman, J; Rau, P; Redlich, K; Renk, T; Rezaeian, A H; Rischke, D; Roesler, S; Ruppert, J; Ruuskanen, P V; Salgado, C A; Sapeta, S; Sarcevic, I; Sarkar, S; Sarycheva, L I; Schmidt, I; Shoski, A I; Sinha, B; Sinyukov, Y M; Snigirev, A M; Srivastava, D K; Stachel, J; Stasto, A; Stocker, H; Teplov, C Y; Thews, R L; Torrieri, G; Pop, V T; Triantafyllopoulos, D N; Tuchin, K L; Turbide, S; Tywoniuk, K; Utermann, A; Venugopalan, R; Vitev, I; Vogt, R; Wang, E; Wang, X N; Werner, K; Wessels, E; Wheaton, S; Wicks, S; Wiedemann, U A; Wolschin, G; Xiao, B; Xu, Z; Yasui, S; Zabrodin, E; Zapp, K; Zhang, B

    2008-02-25T23:59:59.000Z

    In August 2006, the CERN Theory Unit announced to restructure its visitor program and to create a 'CERN Theory Institute', where 1-3 month long specific programs can take place. The first such Institute was held from 14 May to 10 June 2007, focusing on 'Heavy Ion Collisions at the LHC - Last Call for Predictions'. It brought together close to 100 scientists working on the theory of ultra-relativistic heavy ion collisions. The aim of this workshop was to review and document the status of expectations and predictions for the heavy ion program at the Large Hadron Collider LHC before its start. LHC will explore heavy ion collisions at {approx} 30 times higher center of mass energy than explored previously at the Relativistic Heavy Ion Collider RHIC. So, on the one hand, the charge of this workshop provided a natural forum for the exchange of the most recent ideas, and allowed to monitor how the understanding of heavy ion collisions has evolved in recent years with the data from RHIC, and with the preparation of the LHC experimental program. On the other hand, the workshop aimed at a documentation which helps to distinguish pre- from post-dictions. An analogous documentation of the 'Last Call for Predictions' [1] was prepared prior to the start of the heavy-ion program at the Relativistic Heavy Ion Collider RHIC, and it proved useful in the subsequent discussion and interpretation of RHIC data. The present write-up is the documentation of predictions for the LHC heavy ion program, received or presented during the CERN TH Institute. The set-up of the CERN TH Institute allowed us to aim for the wide-most coverage of predictions. There were more than 100 presentations and discussions during the workshop. Moreover, those unable to attend could still participate by submitting predictions in written form during the workshop. This followed the spirit that everybody interested in making a prediction had the right to be heard. To arrive at a concise document, we required that each prediction should be summarized on at most two pages, and that predictions should be presented, whenever possible, in figures which display measurable quantities. Full model descriptions were not accepted--the authors were encouraged to indicate the relevant references for the interested reader. Participants had the possibility to submit multiple contributions on different topics, but it was part of the subsequent editing process to ensure that predictions on neighboring topics were merged wherever possible. The contributions summarized here are organized in several sections,--though some of them contain material related with more than one section--roughly by going from low transverse momentum to high transverse momentum and from abundant to rare measurements. In the low transverse momentum regime, we start with predictions on multiplicity distributions, azimuthal asymmetries in particle production and hadronic flavor observables, followed by correlation and fluctuation measurements. The contributions on hard probes at the LHC start with predictions for single inclusive high transverse momentum spectra, and jets, followed by heavy quark and quarkonium measurements, leptonic probes and photons. A final section 'Others' encompasses those predictions which do not fall naturally within one of the above-mentioned categories, or discuss the more speculative phenomena that may be explored at the LHC.

  20. Steady state heat transfer experimental studies of LHC superconducting cables operating in cryogenic environment of superfluid helium

    E-Print Network [OSTI]

    Santandrea, Dario; Tuccillo, Raffaele; Granieri, Pier Paolo.

    The heat management is a basic and fundamental aspect of the superconducting magnets used in the CERN Large Hadron Collider. Indeed, the coil temperature must be kept below the critical value, despite the heat which can be generated or deposited in the magnet during the normal operations. Therefore, this thesis work aims at determining the heating power which can be extracted from the superconducting cables of the LHC, specially through their electrical insulation which represents the main thermal barrier. An experimental measurement campaign in superfluid helium bath was performed on several samples reproducting the main LHC magnets. The heating power was generated in the sample by Joule heating and the temperature increase was measured by means of Cernox bare chip and thermocouples. An innovative instrumentation technique which also includes the in-situ calibration of the thermocouples was developed. A thorough uncertainty analysis on the overall measurement chain concluded the experimental setup. The prese...

  1. ASSEMBLY AND TEST OF A 120 MM BORE 15 T NB3SN QUADRUPOLE FOR THE LHC UPGRADE

    SciTech Connect (OSTI)

    Felice, H.; Caspi, S.; Cheng, D.; Dietderich, D.; Ferracin, P.; Hafalia, R.; Joseph, J.; Lizarazo, J.; Sabbi, G. L.; Wang, X.; Anerella, M.; Ghosh, A. K.; Schmalzle, J.; Wanderer, P.; Ambrosio, G.; Bossert, R.; Zlobin, A. V.

    2010-05-23T23:59:59.000Z

    In support of the Large Hadron Collider (LHC) luminosity upgrade, the US LHC Accelerator Research Program (LARP) has been developing a 1-meter long, 120 mm bore Nb{sub 3}Sn IR quadrupole magnet (HQ). With a design short sample gradient of 219 T/m at 1.9 K and a peak field approaching 15 T, one of the main challenges of this magnet is to provide appropriate mechanical support to the coils. Compared to the previous LARP Technology Quadrupole and Long Quadrupole magnets, the purpose of HQ is also to demonstrate accelerator quality features such as alignment and cooling. So far, 8 HQ coils have been fabricated and 4 of them have been assembled and tested in HQ01a. This paper presents the mechanical assembly and test results of HQ01a.

  2. International Linear Collider-A Technical Progress Report

    SciTech Connect (OSTI)

    Elsen, Eckhard; /DESY; Harrison, Mike; /Brookhaven; Hesla, Leah; /Fermilab; Ross, Marc; /Fermilab; Royole-Degieux, Perrine; /Paris, IN2P3; Takahashi, Rika; /KEK, Tsukuba; Walker, Nicholas; /DESY; Warmbein, Barbara; /DESY; Yamamoto, Akira; /KEK, Tsukuba; Yokoya, Kaoru; /KEK, Tsukuba; Zhang, Min; /Beijing, Inst. High Energy Phys.

    2011-11-04T23:59:59.000Z

    The International Linear Collider: A Technical Progress Report marks the halfway point towards the Global Design Effort fulfilling its mandate to follow up the ILC Reference Design Report with a more optimised Technical Design Report (TDR) by the end of 2012. The TDR will be based on much of the work reported here and will contain all the elements needed to propose the ILC to collaborating governments, including a technical design and implementation plan that are realistic and have been better optimised for performance, cost and risk. We are on track to develop detailed plans for the ILC, such that once results from the Large Hadron Collider (LHC) at CERN establish the main science goals and parameters of the next machine, we will be in good position to make a strong proposal for this new major global project in particle physics. The two overriding issues for the ILC R&D programme are to demonstrate that the technical requirements for the accelerator are achievable with practical technologies, and that the ambitious physics goals can be addressed by realistic ILC detectors. This GDE interim report documents the impressive progress on the accelerator technologies that can make the ILC a reality. It highlights results of the technological demonstrations that are giving the community increased confidence that we will be ready to proceed with an ILC project following the TDR. The companion detector and physics report document likewise demonstrates how detector designs can meet the ambitious and detailed physics goals set out by the ILC Steering Committee. LHC results will likely affect the requirements for the machine design and the detectors, and we are monitoring that very closely, intending to adapt our design as those results become available.

  3. QCD and Hadron Physics

    E-Print Network [OSTI]

    Stanley J. Brodsky; Abhay L. Deshpande; Haiyan Gao; Robert D. McKeown; Curtis A. Meyer; Zein-Eddine Meziani; Richard G. Milner; Jianwei Qiu; David G. Richards; Craig D. Roberts

    2015-02-19T23:59:59.000Z

    This document presents the recommendations and scientific conclusions from the Town Meeting on QCD and Hadronic Physics that took place in the period 13-15 September 2014 at Temple University as part of the NSAC 2014 Long Range Planning process. It highlights progress in hadron physics in the seven years since the 2007 Long Range Plan (LRP07), and presents a vision for the future by identifying key questions and plausible paths to solutions which should define our next decade. In defining the priority of outstanding physics opportunities for the future, both prospects for the short (roughly 5 years) and longer term (beyond 10 years) are identified together with the facilities, personnel and other resources needed to maximize the discovery potential in hadronic physics worldwide. In this connection, the potential of an electron ion collider is highlighted.

  4. Practical Statistics for the LHC

    E-Print Network [OSTI]

    Cranmer, Kyle

    2015-01-01T23:59:59.000Z

    This document is a pedagogical introduction to statistics for particle physics. Emphasis is placed on the terminology, concepts, and methods being used at the Large Hadron Collider. The document addresses both the statistical tests applied to a model of the data and the modeling itself.

  5. Muon Collider Progress: Accelerators

    E-Print Network [OSTI]

    Michael S. Zisman

    2011-09-14T23:59:59.000Z

    A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 \\times 10^34 cm^-2s^-1. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance ("cooling"). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

  6. Measurement of the Oscillation Frequency of B_s Mesons in the Hadronic Decay Mode B_s-> pi D_s(phi pi)X$ with the D0 Detector at the Fermilab Tevatron Collider

    SciTech Connect (OSTI)

    Weber, Gernot August; /Mainz U., Inst. Phys.

    2009-03-01T23:59:59.000Z

    The standard model (SM) of particle physics is a theory, describing three out of four fundamental forces. In this model the Cabibbo-Kobayashi-Maskawa (CKM) matrix describes the transformation between the mass and weak eigenstates of quarks. The matrix properties can be visualized as triangles in the complex plane. A precise measurement of all triangle parameters can be used to verify the validity of the SM. The least precisely measured parameter of the triangle is related to the CKM element |V{sub td}|, accessible through the mixing frequency (oscillation) of neutral B mesons, where mixing is the transition of a neutral meson into its anti-particle and vice versa. It is possible to calculate the CKM element |V{sub td}| and a related element |V{sub ts}| by measuring the mass differences {Delta}m{sub d} ({Delta}m{sub s}) between neutral B{sub d} and {bar B}{sub d} (B{sub s} and {bar B}{sub s}) meson mass eigenstates. This measurement is accomplished by tagging the initial and final state of decaying B mesons and determining their lifetime. Currently the Fermilab Tevatron Collider (providing p{bar p} collisions at {radical}s = 1.96 TeV) is the only place, where B{sub s} oscillations can be studied. The first selection of the 'golden', fully hadronic decay mode B{sub s} {yields} {pi}D{sub s}({phi}{pi})X at D0 is presented in this thesis. All data, taken between April 2002 and August 2007 with the D0 detector, corresponding to an integrated luminosity of {integral} Ldt = 2.8 fb{sup -1} is used. The oscillation frequency {Delta}m{sub s} and the ratio |V{sub td}|/|V{sub ts}| are determined as {Delta}m{sub s} = (16.6{sub -0.4}{sup +0.5}(stat){sub -0.3}{sup +0.4}(sys)) ps{sup -1}, |V{sub td}|/|V{sub ts}| = 0.213{sub -0.003}{sup +0.004}(exp) {+-} 0.008(theor). These results are consistent with the standard model expectations and no evidence for new physics is observable.

  7. Event-wise mean-$\\bf p_t$ fluctuations vs minimum-bias jets (minijets) at the LHC

    E-Print Network [OSTI]

    Trainor, Thomas A

    2015-01-01T23:59:59.000Z

    Fluctuation measurements of event-wise mean transverse momentum $\\langle p_t \\rangle$ for p-p and Pb-Pb collisions at the large hadron collider (LHC) have been reported recently. In that study it was concluded that the strength of "nonstatistical" $\\langle p_t \\rangle$ fluctuations decreases with increasing particle multiplicity $n_{ch}$ (or A-A centrality) and is nearly independent of collision energy over a large interval. Among several potential mechanisms for those trends onset of thermalization and collectivity are mentioned. The LHC analysis employed one fluctuation measure selected from several possibilities. An alternative fluctuation measure reveals strong increase of $p_t$ fluctuations with $n_{ch}$ (or A-A centrality) and collision energy, consistent with previous measurements at the relativistic heavy ion collider (RHIC). The $p_t$ fluctuation data for LHC p-p collisions can be described accurately by a two-component (soft+hard) model (TCM) in which the hard component represents dijet production. ...

  8. Top-quark production in proton-nucleus and nucleus-nucleus collisions at LHC energies and beyond

    E-Print Network [OSTI]

    d'Enterria, David; Paukkunen, Hannu

    2015-01-01T23:59:59.000Z

    Single and pair top-quark production in proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions at the CERN Large Hadron Collider (LHC) and future circular collider (FCC) energies, are studied with next-to-leading-order perturbative QCD calculations including nuclear parton distribution functions. At the LHC, the pair-production cross sections amount to sigma(t-tbar) = 3.4 mub in Pb-Pb at sqrt(s) = 5.5 TeV, and sigma(t-tbar) = 60 nb in p-Pb at sqrt(s) = 8.8 TeV. At the FCC energies of sqrt(s) = 39 and 63 TeV, the same cross sections are factors of 90 and 55 times larger respectively. In the leptonic final-state t-tbar --> W+b W-bbar --> b bbar l+l- nu+nu-, after typical acceptance and efficiency cuts, one expects about 90 and 300 top-quarks per nominal LHC-year and 4.7 10^4 and 10^5 per FCC-year in Pb-Pb and p-Pb collisions respectively. The total t-tbar cross sections, dominated by gluon fusion processes, are enhanced by 3--8% in nuclear compared to p-p collisions due to an overall net gluon antishadowing, altho...

  9. Higgs Hunting at the Large Hadron Collider

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of the field on top of the vacuum value can be detected as a spin-0 boson (the Higgs boson). Think of those excitations as ripples (waves) on top of a body of water. SMP 1...

  10. Superconducting Magnet Technology for Future Hadron Colliders

    E-Print Network [OSTI]

    Scanlan, R.M.

    2011-01-01T23:59:59.000Z

    within the framework of HTS wires for use at 20 K and 77 K,HTS materials is limited, not so much by intrinsic intragrain Je as by the ability of the wire

  11. Superconducting Magnet Technology for Future Hadron Colliders

    E-Print Network [OSTI]

    Scanlan, R.M.

    2011-01-01T23:59:59.000Z

    must tum to new materials with higher critical fields thanfrom a critical field standpoint, HTS materials should beof HTS Materials as Accelerator Conductors Critical current

  12. Superconducting Magnet Technology for Future Hadron Colliders

    E-Print Network [OSTI]

    Scanlan, R.M.

    2011-01-01T23:59:59.000Z

    Trans. on Applied Superconductivity, 5 (1995), J.R. Millersummer study on superconductingdevices and acceleratorsGeneral. Advanced Superconductors (IGC). Waterbury.

  13. Superconducting Magnet Technology for Future Hadron Colliders

    E-Print Network [OSTI]

    Scanlan, R.M.

    2011-01-01T23:59:59.000Z

    I. Superconducting Magnet Technology for Future Hadl"On1994. M.N. Wilson, Superconducting Magnets (Clarendon Press,The application of superconducting magnets to large-scale

  14. Director's colloquium March 18 large hadron collider

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management FermiDavidDieselDirections BothFacilityDirector's

  15. High Energy Accelerator and Colliding Beam User Group

    SciTech Connect (OSTI)

    Snow, G.A.; Skuja, A.

    1992-05-01T23:59:59.000Z

    This report discusses research in the following areas: the study of e{sup +}e{sup {minus}} interactions; Hadron collider physics at Fermilab; fixed target physics and particle physics of general interest; and, the solenoidal detector collaboration at SSCL.

  16. Natural Priors, CMSSM Fits and LHC Weather Forecasts

    E-Print Network [OSTI]

    Ben C Allanach; Kyle Cranmer; Christopher G Lester; Arne M Weber

    2007-07-05T23:59:59.000Z

    Previous LHC forecasts for the constrained minimal supersymmetric standard model (CMSSM), based on current astrophysical and laboratory measurements, have used priors that are flat in the parameter tan beta, while being constrained to postdict the central experimental value of MZ. We construct a different, new and more natural prior with a measure in mu and B (the more fundamental MSSM parameters from which tan beta and MZ are actually derived). We find that as a consequence this choice leads to a well defined fine-tuning measure in the parameter space. We investigate the effect of such on global CMSSM fits to indirect constraints, providing posterior probability distributions for Large Hadron Collider (LHC) sparticle production cross sections. The change in priors has a significant effect, strongly suppressing the pseudoscalar Higgs boson dark matter annihilation region, and diminishing the probable values of sparticle masses. We also show how to interpret fit information from a Markov Chain Monte Carlo in a frequentist fashion; namely by using the profile likelihood. Bayesian and frequentist interpretations of CMSSM fits are compared and contrasted.

  17. Testing Radiative Neutrino Mass Models at the LHC

    E-Print Network [OSTI]

    Yi Cai; Jackson D. Clarke; Michael A. Schmidt; Raymond R. Volkas

    2015-02-07T23:59:59.000Z

    The Large Hadron Collider provides us new opportunities to search for the origin of neutrino mass. Beyond the minimal see-saw models a plethora of models exist which realise neutrino mass at tree- or loop-level, and it is important to be sure that these possibilities are satisfactorily covered by searches. The purpose of this paper is to advance a systematic approach to this problem. Majorana neutrino mass models can be organised by SM-gauge-invariant operators which violate lepton number by two units. In this paper we write down the minimal ultraviolet completions for all of the mass-dimension 7 operators. We predict vector-like quarks, vector-like leptons, scalar leptoquarks, a charged scalar, and a scalar doublet, whose properties are constrained by neutrino oscillation data. A detailed collider study is presented for $O_3=LLQ\\bar dH$ and $O_8 = L\\bar d\\bar e^\\dagger \\bar u^\\dagger H$ completions with a vector-like quark $\\chi\\sim(3, 2, -\\frac{5}{6})$ and a leptoquark $\\phi\\sim(\\bar 3,1,\\frac{1}{3})$. The existing LHC limits extracted from searches for vector-like fermions and sbottoms/stops are $m_\\chi \\gtrsim 620$ GeV and $m_\\phi\\gtrsim 600$ GeV.

  18. UFOs in the LHC

    E-Print Network [OSTI]

    Baer, T; Goddard, B; Holzer, E B; Jimenez, J M; Lechner, V; Mertens, V; Nebot Del Busto, E; Nordt, A; Uythoven, J; Velghe, B; Wenninger, J; Zimmermann, F

    2011-01-01T23:59:59.000Z

    One of the major known limitations for the performance of the Large Hadron Collider are so called UFOs (Unidentified Falling Objects). UFOs were first observed in July 2010 and caused numerous protection beam dumps since then. They are presumably micrometer sized dust particles that lead to fast beam losses with a duration of about 10 turns when they interact with the beam. In 2011, the diagnostics for such events are highly increased which allows estimations of the properties, dynamics and production mechanisms of the dust particles. The state of knowledge and mitigation strategies are presented.

  19. Future Colliders Beyond the Standard Model

    E-Print Network [OSTI]

    Murayama, Hitoshi

    . Of course, the lesson of high energy physics has been that higher energies have generally revealed new that the full exploration of the Standard Model was likely to require a very high energy hadron collider important, it is not possible to postpone indefinitely new physics associated with the Higgs boson. To see

  20. Superconducting link bus design for the accelerator project for upgrade of LHC

    SciTech Connect (OSTI)

    Nobrega, F.; Brandt, J.; Cheban, S.; Feher, S.; Kaducak, M.; Kashikhin, V.; Peterson, T.; /Fermilab

    2011-06-01T23:59:59.000Z

    The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. Fermi National Accelerator Laboratory in collaboration with Brookhaven National Laboratory was developing sub-systems for the upgrade of the LHC final focus magnet systems. Part of the upgrade called for various lengths of superconducting power transmission lines known as SC Links which were up to 100 m long. The SC Link electrically connects the current leads in the Distribution Feed Boxes to the interaction region magnets. The SC Link is an extension of the magnet bus housed within a cryostat. The present concept for the bus consists of 22 power cables, 4 x 13 kA, 2 x 7 kA, 8 x 2.5 kA and 8 x 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus design potentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus during installation at CERN. The round bus is very flexible and is suitable for pulling through the cryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented.

  1. Superconducting link bus design for the accelerator project for upgrade of LHC

    SciTech Connect (OSTI)

    Nobrega, F.; Brandt, J.; Cheban, S.; Feher, S.; Kaducak, M.; Kashikhin, V.; Peterson, T.; /Fermilab

    2010-08-01T23:59:59.000Z

    The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. Fermi National Accelerator Laboratory in collaboration with Brookhaven National Laboratory was developing sub-systems for the upgrade of the LHC final focus magnet systems. Part of the upgrade called for various lengths of superconducting power transmission lines known as SC Links which were up to 100 m long. The SC Link electrically connects the current leads in the Distribution Feed Boxes to the interaction region magnets. The SC Link is an extension of the magnet bus housed within a cryostat. The present concept for the bus consists of 22 power cables, 4 x 13 kA, 2 x 7 kA, 8 x 2.5 kA and 8 x 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus design potentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus during installation at CERN. The round bus is very flexible and is suitable for pulling through the cryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented.

  2. Large Extra Dimension effects through Light-by-Light Scattering at the CERN LHC

    E-Print Network [OSTI]

    Hao Sun

    2014-07-31T23:59:59.000Z

    Observing light-by-light scattering at the Large Hadron Collider (LHC) has received quite some attention and it is believed to be a clean and sensitive channel to possible new physics. In this paper, we study the diphoton production at the LHC via the process $\\rm pp\\rightarrow p\\gamma\\gamma p\\rightarrow p\\gamma\\gamma p$ through graviton exchange in the Large Extra Dimension (LED) model. Typically, when we do the background analysis, we also study the Double Pomeron Exchange (DPE) of $\\gamma\\gamma$ production. We compare its production in the quark-quark collision mode to the gluon-gluon collision mode and find that contributions from the gluon-gluon collision mode are comparable to the quark-quark one. Our result shows, for extra dimension $\\delta=4$, with an integrated luminosity $\\rm {\\cal L} = 200 fb^{-1}$ at the 14 TeV LHC, that diphoton production through graviton exchange can probe the LED effects up to the scale $\\rm M_S=5.06 (4.51, 5.11) TeV$ for the forward detector acceptance $\\xi_1 (\\xi_2, \\xi_3)$, respectively, where $0.00150.5$, $0.10.5$ and $0.0015<\\xi_3<0.15$.

  3. PanDA: Exascale Federation of Resources for the ATLAS Experiment at the LHC

    E-Print Network [OSTI]

    Barreiro Megino, Fernando Harald; The ATLAS collaboration; De, Kaushik; Hover, John; Klimentov, Alexei; Maeno, Tadashi; Nilsson, Paul; Oleynik, Danila; Padolski, Siarhei; Panitkin, Sergey; Petrosyan, Artem; Wenaus, Torre

    2015-01-01T23:59:59.000Z

    After a scheduled maintenance and upgrade period, the world’s largest and most powerful machine - the Large Hadron Collider(LHC) - is about to enter its second run at unprecedented energies. In order to exploit the scientific potential of the machine, the experiments at the LHC face computational challenges with enormous data volumes that need to be analysed by thousand of physics users and compared to simulated data. Given diverse funding constraints, the computational resources for the LHC have been deployed in a worldwide mesh of data centres, connected to each other through Grid technologies. The PanDA (Production and Distributed Analysis) system was developed in 2005 for the ATLAS experiment on top of this heterogeneous infrastructure to seamlessly integrate the computational resources and give the users the feeling of a unique system. Since its origins, PanDA has evolved together with upcoming computing paradigms in and outside HEP, such as changes in the networking model, Cloud Computing and HPC. It ...

  4. Discriminating among the theoretical origins of new heavy Majorana neutrinos at the CERN LHC

    E-Print Network [OSTI]

    F. M. L. de Almeida Jr.; Y. A. Coutinho; J. A. Martins Simoes; A. J. Ramalho; S. Wulck; M. A. B. do Vale

    2007-03-08T23:59:59.000Z

    A study on the possibility of distinguishing new heavy Majorana neutrino models at LHC energies is presented. The experimental confirmation of standard neutrinos with non-zero mass and the theoretical possibility of lepton number violation find a natural explanation when new heavy Majorana neutrinos exist. These new neutrinos appear in models with new right-handed singlets, in new doublets of some grand unified theories and left-right symmetrical models. It is expected that signals of new particles can be found at the CERN high-energy hadron collider (LHC). We present signatures and distributions that can indicate the theoretical origin of these new particles. The single and pair production of heavy Majorana neutrinos are calculated and the model dependence is discussed. Same-sign dileptons in the final state provide a clear signal for the Majorana nature of heavy neutrinos, since there is lepton number violation. Mass bounds on heavy Majorana neutrinos allowing model discrimination are estimated for three different LHC luminosities.

  5. Current Lead Design for the Accelerator Project for Upgrade of LHC

    SciTech Connect (OSTI)

    Brandt, Jeffrey S.; Cheban, Sergey; Feher, Sandor; Kaducak, Marc; Nobrega, Fred; Peterson, Tom

    2010-01-01T23:59:59.000Z

    The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. In collaboration with Brookhaven National Laboratory, Fermilab is developing sub-systems for an upgrade of the LHC final focus magnet systems. A concept of main and auxiliary helium flow was developed that allows the superconductor to remain cold while the lead body warms up to prevent upper section frosting. The auxiliary flow will subsequently cool the thermal shields of the feed box and the transmission line cryostats. A thermal analysis of the current lead central heat exchange section was performed using analytic and FEA techniques. A method of remote soldering was developed that allows the current leads to be field replaceable. The remote solder joint was designed to be made without flux or additional solder, and able to be remade up to ten full cycles. A method of upper section attachment was developed that allows high pressure sealing of the helium volume. Test fixtures for both remote soldering and upper section attachment for the 13 kA lead were produced. The cooling concept, thermal analyses, and test results from both remote soldering and upper section attachment fixtures are presented.

  6. First proton--proton collisions at the LHC as observed with the ALICE detector: measurement of the charged particle pseudorapidity density at sqrt(s) = 900 GeV

    E-Print Network [OSTI]

    The ALICE Collaboration; K. Aamodt; N. Abel; U. Abeysekara; A. Abrahantes Quintana; A. Acero; D. Adamova; M. M. Aggarwal; G. Aglieri Rinella; A. G. Agocs; S. Aguilar Salazar; Z. Ahammed; A. Ahmad; N. Ahmad; S. U. Ahn; R. Akimoto; A. Akindinov; D. Aleksandrov; B. Alessandro; R. Alfaro Molina; A. Alici; E. Almaraz Avina; J. Alme; T. Alt; V. Altini; S. Altinpinar; C. Andrei; A. Andronic; G. Anelli; V. Angelov; C. Anson; T. Anticic; F. Antinori; S. Antinori; K. Antipin; D. Antonczyk; P. Antonioli; A. Anzo; L. Aphecetche; H. Appelshauser; S. Arcelli; R. Arceo; A. Arend; N. Armesto; R. Arnaldi; T. Aronsson; I. C. Arsene; A. Asryan; A. Augustinus; R. Averbeck; T. C. Awes; J. Aysto; M. D. Azmi; S. Bablok; M. Bach; A. Badala; Y. W. Baek; S. Bagnasco; R. Bailhache; R. Bala; A. Baldisseri; A. Baldit; J. Ban; R. Barbera; G. G. Barnafoldi; L. Barnby; V. Barret; J. Bartke; F. Barile; M. Basile; V. Basmanov; N. Bastid; B. Bathen; G. Batigne; B. Batyunya; C. Baumann; I. G. Bearden; B. Becker; I. Belikov; R. Bellwied; E. Belmont-Moreno; A. Belogianni; L. Benhabib; S. Beole; I. Berceanu; A. Bercuci; E. Berdermann; Y. Berdnikov; L. Betev; A. Bhasin; A. K. Bhati; L. Bianchi; N. Bianchi; C. Bianchin; J. Bielcik; J. Bielcikova; A. Bilandzic; L. Bimbot; E. Biolcati; A. Blanc; F. Blanco; F. Blanco; D. Blau; C. Blume; M. Boccioli; N. Bock; A. Bogdanov; H. Boggild; M. Bogolyubsky; J. Bohm; L. Boldizsar; M. Bombara; C. Bombonati; M. Bondila; H. Borel; V. Borshchov; C. Bortolin; S. Bose; L. Bosisio; F. Bossu; M. Botje; S. Bottger; G. Bourdaud; B. Boyer; M. Braun; P. Braun-Munzinger; L. Bravina; M. Bregant; T. Breitner; G. Bruckner; R. Brun; E. Bruna; G. E. Bruno; D. Budnikov; H. Buesching; K. Bugaev; P. Buncic; O. Busch; Z. Buthelezi; D. Caffarri; X. Cai; H. Caines; E. Camacho; P. Camerini; M. Campbell; V. Canoa Roman; G. P. Capitani; G. Cara Romeo; F. Carena; W. Carena; F. Carminati; A. Casanova Diaz; M. Caselle; J. Castillo Castellanos; J. F. Castillo Hernandez; V. Catanescu; E. Cattaruzza; C. Cavicchioli; P. Cerello; V. Chambert; B. Chang; S. Chapeland; A. Charpy; J. L. Charvet; S. Chattopadhyay; S. Chattopadhyay; M. Cherney; C. Cheshkov; B. Cheynis; E. Chiavassa; V. Chibante Barroso; D. D. Chinellato; P. Chochula; K. Choi; M. Chojnacki; P. Christakoglou; C. H. Christensen; P. Christiansen; T. Chujo; F. Chuman; C. Cicalo; L. Cifarelli; F. Cindolo; J. Cleymans; O. Cobanoglu; J. -P. Coffin; S. Coli; A. Colla; G. Conesa Balbastre; Z. Conesa del Valle; E. S. Conner; P. Constantin; G. Contin; J. G. Contreras; Y. Corrales Morales; T. M. Cormier; P. Cortese; I. Cortes Maldonado; M. R. Cosentino; F. Costa; M. E. Cotallo; E. Crescio; P. Crochet; E. Cuautle; L. Cunqueiro; J. Cussonneau; A. Dainese; H. H. Dalsgaard; A. Danu; I. Das; S. Das; A. Dash; S. Dash; G. O. V. de Barros; A. De Caro; G. de Cataldo; J. de Cuveland; A. De Falco; M. de Gaspari; J. de Groot; D. De Gruttola; A. P. de Haas; N. De Marco; R. de Rooij; S. De Pasquale; G. de Vaux; H. Delagrange; G. Dellacasa; A. Deloff; V. Demanov; E. Denes; A. Deppman; G. D~RErasmo; D. Derkach; A. Devaux; D. Di Bari; C. Di Giglio; S. Di Liberto; A. Di Mauro; P. Di Nezza; M. Dialinas; L. Diaz; R. Diaz; T. Dietel; H. Ding; R. Divia; O. Djuvsland; G. do Amaral Valdiviesso; V. Dobretsov; A. Dobrin; T. Dobrowolski; B. Donigus; I. Dominguez; D. M. M. Don; O. Dordic; A. K. Dubey; J. Dubuisson; L. Ducroux; P. Dupieux; A. K. Dutta Majumdar; M. R. Dutta Majumdar; D. Elia; D. Emschermann; A. Enokizono; B. Espagnon; M. Estienne; D. Evans; S. Evrard; G. Eyyubova; C. W. Fabjan; D. Fabris; J. Faivre; D. Falchieri; A. Fantoni; M. Fasel; R. Fearick; A. Fedunov; D. Fehlker; V. Fekete; D. Felea; B. Fenton-Olsen; G. Feofilov; A. Fernandez Tellez; E. G. Ferreiro; A. Ferretti; R. Ferretti; M. A. S. Figueredo; S. Filchagin; R. Fini; F. M. Fionda; E. M. Fiore; M. Floris; Z. Fodor; S. Foertsch; P. Foka; S. Fokin; F. Formenti; E. Fragiacomo; M. Fragkiadakis; U. Frankenfeld; A. Frolov; U. Fuchs; F. Furano; C. Furget; M. Fusco Girard; J. J. Gaardhoje; S. Gadrat; M. Gagliardi; A. Gago; M. Gallio; P. Ganoti; M. S. Ganti; C. Garabatos; C. Garc; J. Gebelein; R. Gemme; M. Germain; A. Gheata; M. Gheata; B. Ghidini; P. Ghosh; G. Giraudo; P. Giubellino; E. Gladysz-Dziadus; R. Glasow; P. Glassel; A. Glenn; R. Gomez; H. Gonzalez Santos; L. H. Gonzalez-Trueba; P. Gonzalez-Zamora; S. Gorbunov; Y. Gorbunov; S. Gotovac; H. Gottschlag; V. Grabski; R. Grajcarek; A. Grelli; A. Grigoras; C. Grigoras; V. Grigoriev; A. Grigoryan; B. Grinyov; N. Grion; P. Gros; J. F. Grosse-Oetringhaus; J. -Y. Grossiord; R. Grosso; C. Guarnaccia; F. Guber; R. Guernane; B. Guerzoni; K. Gulbrandsen; H. Gulkanyan; T. Gunji; A. Gupta; R. Gupta; H. -A. Gustafsson; H. Gutbrod; O. Haaland; C. Hadjidakis; M. Haiduc; H. Hamagaki; G. Hamar; J. Hamblen; B. H. Han; J. W. Harris; M. Hartig; A. Harutyunyan

    2009-12-01T23:59:59.000Z

    On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in both the longitudinal and transverse directions and 284 events were recorded in coincidence with the two passing proton bunches. The events were immediately reconstructed and analyzed both online and offline. We have used these events to measure the pseudorapidity density of charged primary particles in the central region. In the range |eta| < 0.5, we obtain dNch/deta = 3.10 +- 0.13 (stat.) +- 0.22 (syst.) for all inelastic interactions, and dNch/deta = 3.51 +- 0.15 (stat.) +- 0.25 (syst.) for non-single diffractive interactions. These results are consistent with previous measurements in proton--antiproton interactions at the same centre-of-mass energy at the CERN SppS collider. They also illustrate the excellent functioning and rapid progress of the LHC accelerator, and of both the hardware and software of the ALICE experiment, in this early start-up phase.

  7. Main changes to LHC layout for reuse as FCC-hh High Energy Booster

    E-Print Network [OSTI]

    Brennan Goddard; Werner Herr; Philippe Lebrun; Attilio Milanese

    2015-01-01T23:59:59.000Z

    Reuse of the LHC is one option being investigated for a High Energy Booster for injection of 3.3 TeV protons (and heavy ions at equivalent rigidity) into the proposed 100 TeV centre of mass FCC-hh collider. In this note the major changes required to the LHC layout are listed, assuming beam transfer to the FCC collider is required from both LHC Points 1 and 8.

  8. Energy Efficiency of large Cryogenic Systems: the LHC Case and Beyond

    E-Print Network [OSTI]

    Claudet, S; Ferlin, G; Lebrun, P; Tavian, L; Wagner, U

    2013-01-01T23:59:59.000Z

    Research infrastructures for high-energy and nuclear physics, nuclear fusion and production of high magnetic fields are increasingly based on applied superconductivity and associated cryogenics in their quest for scientific breakthroughs at affordable capital and operation costs, a condition for their acceptance and sustained funding by society. The thermodynamic penalty for operating at low temperature makes energy efficiency a key requirement for their large cryogenic systems, from conceptual design to procurement, construction and operation. Meeting this requirement takes a combined approach on several fronts in parallel: management of heat loads and sizing of cooling duties, distribution of cooling power matching the needs of the superconducting devices, efficient production of refrigeration, optimal control resting on precise instrumentation and diagnostics, as well as a targeted industrial procurement policy. The case of the Large Hadron Collider (LHC) at CERN is presented. Potential improvements for fu...

  9. Validation and performance of the LHC cryogenic system through commissioning of the first sector

    SciTech Connect (OSTI)

    Serio, L.; Bouillot, A.; Casas-Cubillos, J.; /CERN; Chakravarty, A.; /Tata Inst.; Claudet, S.; /CERN; Gicquel, F.; /LBL, Berkeley; Gomes, P.; /CERN; Kumar, M.; Kush, P.K.; /Indore, Ctr. for Advanced Tech.; Millet, F.; Perin, A.; /CERN /Fermilab /Tata Inst. /CERN

    2007-12-01T23:59:59.000Z

    The cryogenic system [1] for the Large Hadron Collider accelerator is presently in its final phase of commissioning at nominal operating conditions. The refrigeration capacity for the LHC is produced using eight large cryogenic plants and eight 1.8 K refrigeration units installed on five cryogenic islands. Machine cryogenic equipment is installed in a 26.7-km circumference ring deep underground tunnel and are maintained at their nominal operating conditions via a distribution system consisting of transfer lines, cold interconnection boxes at each cryogenic island and a cryogenic distribution line. The functional analysis of the whole system during all operating conditions was established and validated during the first sector commissioning in order to maximize the system availability. Analysis, operating modes, main failure scenarios, results and performance of the cryogenic system are presented.

  10. Ionisation losses and wire scanner heating evaluation, possible solutions, application to the LHC

    E-Print Network [OSTI]

    Fischer, C

    2000-01-01T23:59:59.000Z

    Harmful heating mechanisms, resulting in wire breakage, limit the utilisation of wire scanner monitors to below a given beam intensity. This threshold depends on the accelerator design parameters. In lepton colliders, the short beam bunches generate strong wake-fields inside the vacuum pipe which are sensed by the wire and are the predominant current limit. These effects can be minimised by a smooth design of the monitor cross section and by choosing a wire made of an insulating material [1]. A second source of energy deposition inside the wire, also present in hadron machines, and even when the wire material is insulating, results from collision and ionisation of the wire material atoms by the incident beam particles. Calculations are presented to evaluate the efficiency of this process and a possible solution is suggested which may reduce this limitation. An example is given for the case of the LHC.

  11. Twistor Spinoffs for Collider Physics

    SciTech Connect (OSTI)

    Dixon, Lance

    2005-12-19T23:59:59.000Z

    Finding the adding up of Feynman diagrams tedious? Hidden symmetries found in the sums of diagrams suggest there is a better way to predict the results of particle collisions - in the past two years, spin-offs of a new theory, known as the Twistor String Theory, have led to the development of efficient alternatives to Feynman diagrams which can be useful for work at the Tevatron, the LHC and for future research at the International Linear Collider. Come see what this 'twistor' is all about!

  12. Tevatron instrumentation: boosting collider performance

    SciTech Connect (OSTI)

    Shiltsev, Vladimir; Jansson, Andreas; Moore, Ronald; /Fermilab

    2006-05-01T23:59:59.000Z

    The Tevatron in Collider Run II (2001-present) is operating with six times more bunches, many times higher beam intensities and luminosities than in Run I (1992-1995). Beam diagnostics were crucial for the machine start-up and the never-ending luminosity upgrade campaign. We present the overall picture of the Tevatron diagnostics development for Run II, outline machine needs for new instrumentation, present several notable examples that led to Tevatron performance improvements, and discuss the lessons for the next big machines--LHC and ILC.

  13. Muon Colliders: The Next Frontier

    ScienceCinema (OSTI)

    Yagmur Tourun

    2010-01-08T23:59:59.000Z

    Muon Colliders provide a path to the energy frontier in particle physics but have been regarded to be "at least 20 years away" for 20 years. I will review recent progress in design studies and hardware R&D and show that a Muon Collider can be established as a real option for the post-LHC era if the current vigorous R&D effort revitalized by the Muon Collider Task Force at Fermilab can be supported to its conclusion. All critical technologies are being addressed and no show-stoppers have emerged. Detector backgrounds have been studied in detail and appear to be manageable and the physics can be done with existing detector technology. A muon facility can be built through a staged scenario starting from a low-energy muon source with unprecedented intensity for exquisite reach for rare processes, followed by a Neutrino Factory with ultrapure neutrino beams with unparalleled sensitivity for disentangling neutrino mixing, leading to an energy frontier Muon Collider with excellent energy resolution.

  14. Response of colliding beam-beam system to harmonic excitation due to crab-cavity rf phase modulation

    E-Print Network [OSTI]

    Ohmi, K; Funakoshi, Y; Calaga, R; Ieiri, T; Morita, Y; Nakanishi, K; Oide, K; Ohnishi, Y; Sun, Y; Tobiyama, M; Zimmermann, F; 10.1103/PhysRevSTAB.14.111003

    2011-01-01T23:59:59.000Z

    During 2008 and 2009 dedicated beam experiments with crab cavities were performed in the KEKB. The goal was to measure the impact of crab-cavity radio frequency (rf ) noise on the beam quality. These experiments were performed as a validation of the crab-cavity beam dynamics models in view of the possible use of crab cavities in the upgrade of the CERN Large Hadron Collider (LHC). An unexpected strong beam-beam instability was observed during the course of the experiments as a kind of frequency response. Understanding this finding required extensive multiparticle and single particle simulations plus an extra experimental session to consolidate the observations. Published in PRST-AB 14:111003 (2011)

  15. Top-quark production in proton-nucleus and nucleus-nucleus collisions at LHC energies and beyond

    E-Print Network [OSTI]

    David d'Enterria; Krisztian Krajczar; Hannu Paukkunen

    2015-04-21T23:59:59.000Z

    Single and pair top-quark production in proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions at the CERN Large Hadron Collider (LHC) and future circular collider (FCC) energies, are studied with next-to-leading-order perturbative QCD calculations including nuclear parton distribution functions. At the LHC, the pair-production cross sections amount to sigma(t-tbar) = 3.4 mub in Pb-Pb at sqrt(s) = 5.5 TeV, and sigma(t-tbar) = 60 nb in p-Pb at sqrt(s) = 8.8 TeV. At the FCC energies of sqrt(s) = 39 and 63 TeV, the same cross sections are factors of 90 and 55 times larger respectively. In the leptonic final-state t-tbar --> W+b W-bbar --> b bbar l+l- nu+nu-, after typical acceptance and efficiency cuts, one expects about 90 and 300 top-quarks per nominal LHC-year and 4.7 10^4 and 10^5 per FCC-year in Pb-Pb and p-Pb collisions respectively. The total t-tbar cross sections, dominated by gluon fusion processes, are enhanced by 3--8% in nuclear compared to p-p collisions due to an overall net gluon antishadowing, although different regions of their differential distributions are depleted due to shadowing or EMC-effect corrections. The rapidity distributions of the decay leptons in t-tbar processes can be used to reduce the uncertainty on the Pb gluon density at high virtualities by up to 30% at the LHC (full heavy-ion programme), and by 70% per FCC-year. The cross sections for single-top production in electroweak processes are also computed, yielding about a factor of 30 smaller number of measurable top-quarks after cuts, per system and per year.

  16. Top-quark production in proton-nucleus and nucleus-nucleus collisions at LHC energies and beyond

    E-Print Network [OSTI]

    David d'Enterria; Krisztian Krajczar; Hannu Paukkunen

    2015-01-23T23:59:59.000Z

    Single and pair top-quark production in proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions at the CERN Large Hadron Collider (LHC) and future circular collider (FCC) energies, are studied with next-to-leading-order perturbative QCD calculations including nuclear parton distribution functions. At the LHC, the pair-production cross sections amount to sigma(t-tbar) = 3.4 mub in Pb-Pb at sqrt(s) = 5.5 TeV, and sigma(t-tbar) = 60 nb in p-Pb at sqrt(s) = 8.8 TeV. At the FCC energies of sqrt(s) = 39 and 63 TeV, the same cross sections are factors of 90 and 55 times larger respectively. In the leptonic final-state t-tbar --> W+b W-bbar --> b bbar l+l- nu+nu-, after typical acceptance and efficiency cuts, one expects about 90 and 300 top-quarks per nominal LHC-year and 4.7 10^4 and 10^5 per FCC-year in Pb-Pb and p-Pb collisions respectively. The total t-tbar cross sections, dominated by gluon fusion processes, are enhanced by 3--8% in nuclear compared to p-p collisions due to an overall net gluon antishadowing, although different regions of their differential distributions are depleted due to shadowing or EMC-effect corrections. The rapidity distributions of the decay leptons in t-tbar processes can be used to reduce the uncertainty on the Pb gluon density at high virtualities by up to 30% at the LHC (full heavy-ion programme), and by 70% per FCC-year. The cross sections for single-top production in electroweak processes are also computed, yielding about a factor of 30 smaller number of measurable top-quarks after cuts, per system and per year.

  17. Black Hole Chromosphere at the LHC

    E-Print Network [OSTI]

    Luis Anchordoqui; Haim Goldberg

    2003-02-26T23:59:59.000Z

    If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the LHC. In this work we study the main properties of the light descendants of these black holes. We show that the emitted partons are closely spaced outside the horizon, and hence they do not fragment into hadrons in vacuum but more likely into a kind of quark-gluon plasma. Consequently, the thermal emission occurs far from the horizon, at a temperature characteristic of the QCD scale. We analyze the energy spectrum of the particles emerging from the "chromosphere", and find that the hard hadronic jets are almost entirely suppressed. They are replaced by an isotropic distribution of soft photons and hadrons, with hundreds of particles in the GeV range. This provides a new distinctive signature for black hole events at LHC.

  18. Interim report on the Global Design Effort Global International Linear Collider (ILC) R&D

    SciTech Connect (OSTI)

    Harrison, M.

    2011-04-30T23:59:59.000Z

    The International Linear Collider: A Technical Progress Report marks the halfway point towards the Global Design Effort fulfilling its mandate to follow up the ILC Reference Design Report with a more optimised Technical Design Report (TDR) by the end of 2012. The TDR will be based on much of the work reported here and will contain all the elements needed to propose the ILC to collaborating governments, including a technical design and implementation plan that are realistic and have been better optimised for performance, cost and risk. We are on track to develop detailed plans for the ILC, such that once results from the Large Hadron Collider (LHC) at CERN establish the main science goals and parameters of the next machine, we will be in good position to make a strong proposal for this new major global project in particle physics. The two overriding issues for the ILC R&D programme are to demonstrate that the technical requirements for the accelerator are achievable with practical technologies, and that the ambitious physics goals can be addressed by realistic ILC detectors. This GDE interim report documents the impressive progress on the accelerator technologies that can make the ILC a reality. It highlights results of the technological demonstrations that are giving the community increased confidence that we will be ready to proceed with an ILC project following the TDR. The companion detector and physics report document likewise demonstrates how detector designs can meet the ambitious and detailed physics goals set out by the ILC Steering Committee. LHC results will likely affect the requirements for the machine design and the detectors, and we are monitoring that very closely, intending to adapt our design as those results become available.

  19. Muon Muon Collider: Feasibility Study

    SciTech Connect (OSTI)

    Gallardo, J.C.; Palmer, R.B.; /Brookhaven; Tollestrup, A.V.; /Fermilab; Sessler, A.M.; /LBL, Berkeley; Skrinsky, A.N.; /Novosibirsk, IYF; Ankenbrandt, C.; Geer, S.; Griffin, J.; Johnstone, C.; Lebrun, P.; McInturff, A.; Mills, Frederick E.; Mokhov, N.; Moretti, A.; Neuffer, D.; Ng, K.Y.; Noble, R.; Novitski, I.; Popovic, M.; Qian, C.; Van Ginneken, A. /Fermilab /Brookhaven /Wisconsin U., Madison /Tel Aviv U. /Indiana U. /UCLA /LBL, Berkeley /SLAC /Argonne /Sobolev IM, Novosibirsk /UC, Davis /Munich, Tech. U. /Virginia U. /KEK, Tsukuba /DESY /Novosibirsk, IYF /Jefferson Lab /Mississippi U. /SUNY, Stony Brook /MIT /Columbia U. /Fairfield U. /UC, Berkeley; ,

    2012-04-05T23:59:59.000Z

    A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10{sup 35} cm{sup -2}s{sup -1}. The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice - we believe - to allow us to make a credible case, that a muon collider is a serious possibility for particle physics and, therefore, worthy of R and D support so that the reality of, and interest in, a muon collider can be better assayed. The goal of this support would be to completely assess the physics potential and to evaluate the cost and development of the necessary technology. The muon collider complex consists of components which first produce copious pions, then capture the pions and the resulting muons from their decay; this is followed by an ionization cooling channel to reduce the longitudinal and transverse emittance of the muon beam. The next stage is to accelerate the muons and, finally, inject them into a collider ring wich has a small beta function at the colliding point. This is the first attempt at a point design and it will require further study and optimization. Experimental work will be needed to verify the validity of diverse crucial elements in the design. Muons because of their large mass compared to an electron, do not produce significant synchrotron radiation. As a result there is negligible beamstrahlung and high energy collisions are not limited by this phenomena. In addition, muons can be accelerated in circular devices which will be considerably smaller than two full-energy linacs as required in an e{sup +} - e{sup -} collider. A hadron collider would require a CM energy 5 to 10 times higher than 4 TeV to have an equivalent energy reach. Since the accelerator size is limited by the strength of bending magnets, the hadron collider for the same physics reach would have to be much larger than the muon collider. In addition, muon collisions should be cleaner than hadron collisions. There are many detailed particle reactions which are open to a muon collider and the physics of such reactions - what one learns and the necessary luminosity to see interesting events - are described in detail. Most of the physics accesible to an e{sup +} - e{sup -} collider could be studied in a muon collider. In addition the production of Higgs bosons in the s-channel will allow the measurement of Higgs masses and total widths to high precision; likewise, t{bar t} and W{sup +}W{sup -} threshold studies would yield m{sub t} and m{sub w} to great accuracy. These reactions are at low center of mass energy (if the MSSM is correct) and the luminosity and {Delta}p/p of the beams required for these measurements is detailed in the Physics Chapter. On the other hand, at 2 + 2 TeV, a luminosity of L {approx} 10{sup 35} cm{sup -2}s{sup -1} is desirable for studies such as, the scattering of longitudinal W bosons or the production of heavy scalar particles. Not explored in this work, but worth noting, are the opportunities for muon-proton and muon-heavy ion collisions as well as the enormous richness of such a facility for fixed target physics provided by the intense beams of neutrinos, muons, pions, kaons, antiprotons and spallation neutrons. To see all the interesting physics described herein requires a careful study of the operation of a detector in the very large background. Three sources of background have been identified. The first is from any halo accompanying the muon beams in the collider ring. Very carefully prepared beams will have to be injected and maintained. The second is due to the fact that on average 35% of the muon energy appears in its decay electron. The energy of the electron subsequently is converted into EM showers either from the synchrotron radiation they emit in the collider magnetic field or from direct collision with the surrounding material. The decays that occur as the beams traverse the low beta insert are of particular concern for detector backgrounds. A third source of background is e{sup +} - e{sup -} pair creation from {mu}{sup +} - {mu}{sup -} interaction. Studies of

  20. Top quark property measurements at the LHC

    E-Print Network [OSTI]

    Richard Hawkings

    2014-10-29T23:59:59.000Z

    Measurements of top quark properties performed at the Large Hadron Collider are reviewed, with a particular emphasis on top-pair charge asymmetries, spin correlations and polarization measurements performed by the ATLAS and CMS collaborations. The measurements are generally in good agreement with predictions from next-to-leading-order QCD calculations, and no deviations from Standard Model expectations have been seen.

  1. Signatures of black holes at the LHC

    E-Print Network [OSTI]

    Marco Cavaglia; Romulus Godang; Lucien M. Cremaldi; Donald J. Summers

    2007-07-02T23:59:59.000Z

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  2. R-parity violating effects in top quark flavor-changing neutral-current production at LHC

    SciTech Connect (OSTI)

    Cao Junjie [College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007 (China); Ottawa-Carleton Institute for Physics, Carleton University, Ottawa, K1S 5B6 (Canada); Heng Zhaoxia; Yang Jinmin [Institute of Theoretical Physics and Kavli Institute for Theoretical Physics China, Academia Sinica, Beijing 100190 (China); Wu Lei [College of Physics and Information Engineering, Henan Normal University, Xinxiang 453007 (China)

    2009-03-01T23:59:59.000Z

    In the minimal supersymmetric model the R-parity violating top quark interactions, which are so far weakly constrained, can induce various flavor-changing neutral-current (FCNC) productions for the top quark at the large hadron collider (LHC). In this work we assume the presence of the B-violating couplings and examine their contributions to the FCNC productions proceeding through the parton processes cg{yields}t, gg{yields}tc, cg{yields}t{gamma}, cg{yields}tZ and cg{yields}th. We find that all these processes can be greatly enhanced relative to the R-parity preserving predictions. In the parameter space allowed by current experiments, all the production channels except cg{yields}th can reach the 3{sigma} sensitivity, in contrast to the R-parity preserving case in which only cg{yields}t can reach the 3{sigma} sensitivity.

  3. PROMPT PHOTON PRODUCTION IN POLARIZED HADRON COLLISIONS.

    SciTech Connect (OSTI)

    VOGELSANG,W.

    2000-04-25T23:59:59.000Z

    We consider spin asymmetries for prompt photon production in collisions of longitudinally polarized hadrons. This reaction will be a key tool at the BNL-RHIC {rvec p}{rvec p} collider for determining the gluon spin density in a polarized proton. We study the effects of QCD corrections, such as all-order soft-gluon ''threshold'' resummations.

  4. The Next Linear Collider: NLC2001

    SciTech Connect (OSTI)

    D. Burke et al.

    2002-01-14T23:59:59.000Z

    Recent studies in elementary particle physics have made the need for an e{sup +}e{sup -} linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever [1]. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider. A first Zeroth-Order Design Report (ZDR) [2] for a second-generation electron-positron linear collider, the Next Linear Collider (NLC), was published five years ago. The NLC design is based on a high-frequency room-temperature rf accelerator. Its goal is exploration of elementary particle physics at the TeV center-of-mass energy, while learning how to design and build colliders at still higher energies. Many advances in accelerator technologies and improvements in the design of the NLC have been made since 1996. This Report is a brief update of the ZDR.

  5. LARP Long Quadrupole: A "Long" Step Toward an LHC

    ScienceCinema (OSTI)

    Giorgio Ambrosio

    2010-01-08T23:59:59.000Z

    The beginning of the development of Nb3Sn magnets for particle accelerators goes back to the 1960?s. But only very recently has this development begun to face the challenges of fabricating Nb3Sn magnets which can meet the requirements of modern particle accelerators. LARP (the LHC Accelerator Research Program) is leading this effort focusing on long models of the Interaction Region quadrupoles for a possible luminosity upgrade of the Large Hadron Collider. A major milestone in this development is to test, by the end of 2009, 4m-long quadrupole models, which will be the first Nb3Sn accelerator-type magnets approaching the length of real accelerator magnets. The Long Quadrupoles (LQ) are ?Proof-of-Principle? magnets which are to demonstrate that Nb3Sn technology is sufficiently mature for use in high energy particle accelerators. Their design is based on the LARP Technological Quadrupole (TQ) models, under development at FNAL and LBNL, which have design gradients higher than 200 T/m and an aperture of 90 mm. Several challenges must be addressed for the successful fabrication of long Nb3Sn coils and magnets. These challenges and the solutions adopted will be presented together with the main features of the LQ magnets. Several R&D lines are participating to this effort and their contributions will be also presented.

  6. Focusing Strength Measurements of the Main Quadrupoles for the LHC

    E-Print Network [OSTI]

    Smirnov, N; Calvi, M; Deferne, G; Di Marco, J; Sammut, N; Sanfilippo, S

    2006-01-01T23:59:59.000Z

    More than 1100 quadrupole magnets of different types are needed for the Large Hadron Collider (LHC) which is in the construction stage at CERN. The most challenging parameter to measure on these quadrupoles is the integrated gradient (Gdl). An absolute accuracy of 0.1% is needed to control the beta beating. In this paper we briefly describe the whole set of equipment used for Gdl measurements: Automated Scanner system, Single Stretched Wire system and Twin Coils system, concentrating mostly on their absolute accuracies. Most of the possible inherent effects that can introduce systematic errors are discussed along with their preventive methods. In the frame of this qualification some of the magnets were tested with two systems. The results of the intersystem cross-calibrations are presented. In addition, the qualification of the measurement system used at the magnet manufacturer's is based on results of more than 40 quadrupole assemblies tested in cold conditions at CERN and in warm conditions at the vendor si...

  7. The LHCb RICH silica aerogel performance with LHC data

    E-Print Network [OSTI]

    Perego, D L

    2010-01-01T23:59:59.000Z

    In the LHCb detector at the Large Hadron Collider, powerful charged particle identification is performed by Ring Imaging Cherenkov (RICH) technology. In order to cover the full geometric acceptance and the wide momentum range (1-100 GeV/c), two detectors with three Cherenkov radiators have been designed and installed. In the medium (10-40 GeV/c) and high (30-100 GeV/c) momentum range, gas radiators are used (C4F10 and CF4 respectively). In the low momentum range (1 to a few GeV/c) pion/kaon/proton separation will be done with photons produced in solid silica aerogel. A set of 16 tiles, with the large transverse dimensions ever (20x20 cm$^2$) and nominal refractive index 1.03 have been produced. The tiles have excellent optical properties and homogeneity of refractive index within the tile of ~1%. The first data collected at LHC are used to understand the behaviour of the RICH: preliminary results will be presented and discussed on the performance of silica aerogel and of the gas radiators C4F10 and CF4.

  8. Searching for Low Mass Dark Portal at the LHC

    E-Print Network [OSTI]

    Haipeng An; Ran Huo; Lian-Tao Wang

    2012-12-10T23:59:59.000Z

    Light dark matter with mass smaller than about 10 GeV is difficult to probe from direct detection experiments. In order to have the correct thermal relic abundance, the mediator of the interaction between dark matter and the Standard Model (SM) should also be relatively light, $\\sim 10^2$ GeV. If such a light mediator couples to charged leptons, it would already be strongly constrained by direct searches at colliders. In this work, we consider the scenario of a leptophobic light $Z'$ vector boson as the mediator, and study the the prospect of searching for it at the 8 TeV Large Hadron Collider (LHC). To improve the reach in the low mass region, we perform a detailed study of the processes that the $Z'$ is produced in association with jet, photon, $W^\\pm$ and $Z^0$. We show that in the region where the mass of $Z'$ is between 80 and 400 GeV, the constraint from associated production can be comparable or even stronger than the known monojet and dijet constraints. Searches in these channels can be complementary to the monojet search, in particular if the $Z'$ couplings to quarks ($g_{Z'}$) and dark matter ($g_D$) are different. For $g_D < g_{Z'}$, we show that there is a larger region of parameter space which has correct thermal relic abundance and a light $Z'$, $M_{Z'} \\sim 100 $ GeV. This region, which cannot be covered by the mono-jet search, can be covered by the resonance searches described in this paper.

  9. Oasis A New System to Acquire and Display the Analog Signals for LHC

    E-Print Network [OSTI]

    Deghaye, S; Kozar, J; Serrano, J

    2003-01-01T23:59:59.000Z

    To cope with the user requirements for the Large Hadron Collider (LHC) era, a new system has to be developed for the acquisition and display of analog signals in the accelerator domain. OASIS, the Open Analog Signals Information System, extends the capabilities of the existing 'new Analogue observation system' (nAos) in many fronts : new acquisition hardware is supported to provide higher analog bandwidth to the users, a new distributed triggering scheme has been designed for greater flexibility and the software has been completely redesigned with openness in mind to allow easy upgrading and maintainability. This paper describes the architecture chosen to satisfy the new user requirements. The solution involves three tiers and makes use of the J2EE platform to communicate between the GUI and the middle tier. The front-end tier runs on Linux PCs in CompactPCI format, to support fast digitizer modules. A first prototype system, used for the extraction tests from the Super Proton Synchrotron (SPS) to the LHC, is...

  10. Modelling of Quench Limit for Steady State Heat Deposits in LHC Magnets

    E-Print Network [OSTI]

    Bocian, D; Siemko, A

    2008-01-01T23:59:59.000Z

    A quench, the transition of a conductor from the superconducting to the normal conducting state, occurs irreversibly in the accelerator magnets if one of the three parameters: temperature, magnetic field or current density exceeds a critical value. Energy deposited in the superconductor by the particle beams provokes quenches detrimental for the accelerator operation. In particular if particles impacting on the vacuum chamber and their secondary showers depose energy in the magnet coils. The Large Hadron Collider (LHC) nominal beam intensity is 3.2 ldr 10^14 protons. A quench occurs if a fraction of the order of 10^7 protons per second is lost locally. A network model is used to simulate the thermodynamic behaviour of the magnets. The heat flow in the network model was validated with measurements performed in the CERN magnet test facility. A steady state heat flow was introduced in the coil by using the quench heaters implemented in the LHC magnets. The value of the heat source current is determined by the ne...

  11. High Energy Accelerator and Colliding Beam User Group. Progress report, March 1, 1992--October 31, 1992

    SciTech Connect (OSTI)

    Snow, G.A.; Skuja, A.

    1992-05-01T23:59:59.000Z

    This report discusses research in the following areas: the study of e{sup +}e{sup {minus}} interactions; Hadron collider physics at Fermilab; fixed target physics and particle physics of general interest; and, the solenoidal detector collaboration at SSCL.

  12. Simplified SIMPs and the LHC

    E-Print Network [OSTI]

    Daci, Nadir; Lowette, Steven; Tytgat, Michel H G; Zaldivar, Bryan

    2015-01-01T23:59:59.000Z

    The existence of Dark Matter (DM) in the form of Strongly Interacting Massive Particles (SIMPs) may be motivated by astrophysical observations that challenge the classical Cold DM scenario. Other observations greatly constrain, but do not completely exclude, the SIMP alternative. The signature of SIMPs at the LHC may consist of neutral, hadron-like, trackless jets produced in pairs. We show that the absence of charged content can provide a very efficient tool to suppress dijet backgrounds at the LHC, thus enhancing the sensitivity to a potential SIMP signal. We illustrate this using a simplified SIMP model and present a detailed feasibility study based on simulations, including a dedicated detector response parametrization. We evaluate the expected sensitivity to various signal scenarios and tentatively consider the exclusion limits on the SIMP elastic cross section with nucleons.

  13. DIGITAL Visual Fortran Programmer's Guide

    E-Print Network [OSTI]

    accelerator, the LHC, Large Hadron Collider. AlphaGeneration, DEC, DEC Fortran, DIGITAL, OpenVMS, VAX, VAX

  14. Type II Seesaw at LHC: the Roadmap

    E-Print Network [OSTI]

    Alejandra Melfo; Miha Nemevsek; Fabrizio Nesti; Goran Senjanovic; Yue Zhang

    2012-12-22T23:59:59.000Z

    In this Letter we revisit the type-II seesaw mechanism based on the addition of a weak triplet scalar to the standard model. We perform a comprehensive study of its phenomenology at the LHC energies, complete with the electroweak precision constraints. We pay special attention to the doubly-charged component, object of collider searches for a long time, and show how the experimental bound on its mass depends crucially on the particle spectrum of the theory. Our study can be used as a roadmap for future complete LHC studies.

  15. Type II Seesaw at LHC: the Roadmap

    E-Print Network [OSTI]

    Melfo, Alejandra; Nesti, Fabrizio; Senjanovic, Goran; Zhang, Yue

    2012-01-01T23:59:59.000Z

    In this Letter we revisit the type-II seesaw mechanism based on the addition of a weak triplet scalar to the standard model. We perform a comprehensive study of its phenomenology at the LHC energies, complete with the electroweak precision constraints. We pay special attention to the doubly-charged component, object of collider searches for a long time, and show how the experimental bound on its mass depends crucially on the particle spectrum of the theory. Our study can be used as a roadmap for future complete LHC studies.

  16. Estimation of charm production cross section in hadronic interactions at high energies

    E-Print Network [OSTI]

    G. M. Vereshkov; Yu. F. Novoseltsev

    2004-04-24T23:59:59.000Z

    Results of processing experimental data on charm production in hadron-hadron interactions are presented. The analysis is carried out within the frame of phenomenological model of diffraction production and quark statistics based on additive quark model (AQM). In low energy region sqrt s = 20 - 40GeV, the cross sections si_ {pN to c bar cX} (s), si_ {pi N to c bar cX} (s) are fitted by logarithmic function with the parameters connected by relationship of AQM. At collider energies 200, 540, 900, 1800 GeV, the values of si_{bar pp to c bar cX} (s) were obtained by a quark statistics method from the data on diffraction dissociation. It is established, that logarithmic function with universal numerical parameters describes the whole set of low-energy and high-energy data with high accuracy. The expected values of cross sections are si_{pp to c bar cX} = 250 pm 40 mu b and 355 pm 57 mu b at TEVATRON energy sqrt {s} = 1.96 TeV and LHC energy sqrt {s} = 14 TeV accordingly. Opportunities of use of the obtained results for calibration of a flux of "prompt" muons in high-energy component of cosmic rays are discussed.

  17. Jet Charge at the LHC

    E-Print Network [OSTI]

    David Krohn; Tongyan Lin; Matthew D. Schwartz; Wouter J. Waalewijn

    2013-06-14T23:59:59.000Z

    Knowing the charge of the parton initiating a light-quark jet could be extremely useful both for testing aspects of the Standard Model and for characterizing potential beyond-the-Standard-Model signals. We show that despite the complications of hadronization and out-of-jet radiation such as pile-up, a weighted sum of the charges of a jet's constituents can be used at the LHC to distinguish among jets with different charges. Potential applications include measuring electroweak quantum numbers of hadronically decaying resonances or supersymmetric particles, as well as Standard Model tests, such as jet charge in dijet events or in hadronically-decaying W bosons in t-tbar events. We develop a systematically improvable method to calculate moments of these charge distributions by combining multi-hadron fragmentation functions with perturbative jet functions and pertubative evolution equations. We show that the dependence on energy and jet size for the average and width of the jet charge can be calculated despite the large experimental uncertainty on fragmentation functions. These calculations can provide a validation tool for data independent of Monte-Carlo fragmentation models.

  18. Direct searches of extra Higgs boson at future colliders

    E-Print Network [OSTI]

    Yokoya, Hiroshi

    2015-01-01T23:59:59.000Z

    We study direct searches of additional Higgs bosons in multi-top-quarks events at the LHC with the collision energy of 14 TeV as well as the International Linear Collider (ILC) with the collision energy of 1 TeV. As a benchmark model, we consider two Higgs doublet models with a softly-broken discrete $Z_2$ symmetry, where the $t\\bar t$ decay mode of additional neutral Higgs bosons can be dominant if their masses are heavy enough. Thus, the multi-top-quarks events become an important probe of the extended Higgs sector at future colliders. We estimate the discovery reach at the LHC and the ILC, and find that the search at the ILC can survey the parameter regions where the LHC cannot cover.

  19. Black Holes at the LHC: Progress since 2002

    SciTech Connect (OSTI)

    Park, Seong Chan [FRDP, Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of)

    2008-11-23T23:59:59.000Z

    We review the recent noticeable progresses in black hole physics focusing on the up-coming super-collider, the LHC. We discuss the classical formation of black holes by particle collision, the greybody factors for higher dimensional rotating black holes, the deep implications of black hole physics to the 'energy-distance' relation, the security issues of the LHC associated with black hole formation and the newly developed Monte-Carlo generators for black hole events.

  20. Parton-Parton Elastic Scattering and Rapidity Gaps at SSC and LHC Energies

    E-Print Network [OSTI]

    Vittorio Del Duca

    1993-08-02T23:59:59.000Z

    The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at SSC and LHC energies.

  1. Photon collider Higgs factories

    E-Print Network [OSTI]

    V. I. Telnov

    2014-09-19T23:59:59.000Z

    The discovery of the Higgs boson (and still nothing else) have triggered appearance of many proposals of Higgs factories for precision measurement of the Higgs properties. Among them there are several projects of photon colliders (PC) without e+e- in addition to PLC based on e+e- linear colliders ILC and CLIC. In this paper, following a brief discussion of Higgs factories physics program I give an overview of photon colliders based on linear colliders ILC and CLIC, and of the recently proposed photon-collider Higgs factories with no e+e- collision option based on recirculation linacs in ring tunnels.

  2. Testing Minimal Universal Extra Dimensions Using Higgs Boson Searches at the LHC

    E-Print Network [OSTI]

    Genevieve Belanger; Alexander Belyaev; Matthew Brown; Mitsuru Kakizaki; Alexander Pukhov

    2012-12-13T23:59:59.000Z

    Large Hadron Collider (LHC) searches for the SM Higgs boson provide a powerful limit on models involving Universal Extra Dimensions (UED) where the Higgs production is enhanced. We have evaluated all one-loop diagrams for Higgs production from gluon fusion and decay to two photons within "minimal" UED (mUED), independently confirming previous results, and we have evaluated enhancement factors for Higgs boson production and decay over the mUED parameter space. Using these we have derived limits on the parameter space, combining data from both ATLAS and CMS collaborations for the most recent 7 TeV and 8 TeV LHC data. We have performed a rigorous statistical combination of several Higgs boson search channels which is important because mUED signatures from the Higgs boson are not universally enhanced. We have found that 1/R 1000 GeV) around m_h = 118 GeV are left. The latter is likely to be excluded as more data becomes available whereas the region around 125 GeV is where the recently discovered Higgs-like particle was observed and therefore where the exclusion limit is weaker. It is worth stressing that mUED predicts an enhancement for all channels for Higgs production by gluon fusion and decay while the vector boson fusion process WW/ZZ -> h -> AA is generically suppressed and WW/ZZ -> h -> WW*/ZZ* is standard. Therefore, as more 8 TeV LHC data becomes available, the information on individual Higgs boson production and decay processes provided by the CMS and ATLAS experiments can be effectively used to favour mUED or exclude it further.

  3. Search for new charged bosons and dark matter in final states with one lepton and missing transverse energy with the ATLAS detector at the LHC

    E-Print Network [OSTI]

    Bugge, Magnar Kopangen; Read, Alexander Lincoln

    2015-04-30T23:59:59.000Z

    The Standard Model (SM), the current theory of elementary particles and interactions, has been extremely successful in predicting and describing experimental results. The prediction of the electron's anomalous magnetic moment served as an early triumph of quantum electrodynamics, and one success after another has followed, including the discovery of the weak interaction gauge bosons $W^\\pm$ and $Z^0$, and more recently the discovery of the Higgs boson at CERN's Large Hadron Collider (LHC) in 2012. In spite of the success of the theory, though, there are phenomena which it does not explain, such as the dark matter and dark energy making up most of the universe. Extensions of the SM aiming to address its shortcomings typically predict observable deviations from the theory. Although theories predicting significant deviations from the SM in the energy regime so far explored can be immediately excluded, theories that predict deviations at higher, unexplored energies are still viable. Therefore, exploring physics...

  4. Hadronic Radiation Patterns in Vector Boson Fusion Higgs Production

    E-Print Network [OSTI]

    V. A. Khoze; W. J. Stirling; P. H. Williams

    2003-07-23T23:59:59.000Z

    We consider the hadronic radiation patterns for the generic process of bb + 2 forward jet production at the LHC, where the (centrally produced) bb originate either from a Higgs, a Z or from standard QCD production processes. A numerical technique for evaluating the radiation patterns for non-trivial final states is introduced and shown to agree with the standard analytic results for more simple processes. Significant differences between the radiation patterns for the Higgs signal and the background processes are observed and quantified. This suggests that hadronic radiation patterns could be used as an additional diagnostic tool in Higgs searches in this channel at the LHC.

  5. Forward-backward and charge asymmetries at Tevatron and the LHC

    E-Print Network [OSTI]

    Johann H. Kuehn; German Rodrigo

    2014-11-17T23:59:59.000Z

    We provide a qualitative and quantitative unified picture of the charge asymmetry in top quark pair production at hadron colliders in the SM and summarise the most recent experimental measurements.

  6. Particle production sources at LHC energies

    E-Print Network [OSTI]

    Georg Wolschin

    2013-02-18T23:59:59.000Z

    Particle production sources at RHIC and LHC energies are investigated in pseudorapidity space. A nonequilibrium-statistical relativistic diffusion model (RDM) with three sources is applied to the analysis of charged-hadron distributions in AuAu collisions at RHIC energies, in PbPb collisions at the current LHC energy of 2.76 TeV, in pPb at 5.02 TeV, and in pp. The size of the midrapidity source relative to the fragmentation sources in heavy-ion collisions is investigated as function of the incident energy. At LHC energies, the midrapidity value is mostly determined by particle production from gluon-gluon collisions.

  7. Physics at the e+ e- Linear Collider

    E-Print Network [OSTI]

    Moortgat-Pick, G; Battaglia, M; Belanger, G; Fujii, K; Kalinowski, J; Heinemeyer, S; Kiyo, Y; Olive, K; Simon, F; Uwer, P; Wackeroth, D; Zerwas, P M; Arbey, A; Asano, M; Bechtle, P; Bharucha, A; Brau, J; Brummer, F; Choi, S Y; Denner, A; Desch, K; Dittmaier, S; Ellis, J; Ellwanger, U; Englert, C; Freitas, A; Ginzburg, I; Godfrey, S; Greiner, N; Grojean, C; Grunewald, M; Heisig, J; Hocker, A; Kanemura, S; Kawagoe, K; Kogler, R; Krawczyk, M; Kronfeld, A S; Kroseberg, J; Liebler, S; List, J; Mahmoudi, F; Mambrini, Y; Matsumoto, S; Mnich, J; Monig, K; Muhlleitner, M M; Poschl, R; Porod, W; Porto, S; Rolbiecki, K; Schlatter, D; Schmitt, M; Serpico, P; Stanitzki, M; Stål, O; Stefaniak, T; Stockinger, D; Wagner, A; Weiglein, G; Wilson, G W; Zeune, L; Moortgat, F; Xella, S

    2015-01-01T23:59:59.000Z

    A comprehensive review of physics at an e+e- Linear Collider in the energy range of sqrt{s}=92 GeV--3 TeV is presented in view of recent and expected LHC results, experiments from low energy as well as astroparticle physics.The report focuses in particular on Higgs boson, Top quark and electroweak precision physics, but also discusses several models of beyond the Standard Model physics such as Supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analyzed as well.

  8. Physics at the e+ e- Linear Collider

    E-Print Network [OSTI]

    G. Moortgat-Pick; H. Baer; M. Battaglia; G. Belanger; K. Fujii; J. Kalinowski; S. Heinemeyer; Y. Kiyo; K. Olive; F. Simon; P. Uwer; D. Wackeroth; P. M. Zerwas; A. Arbey; M. Asano; P. Bechtle; A. Bharucha; J. Brau; F. Brummer; S. Y. Choi; A. Denner; K. Desch; S. Dittmaier; U. Ellwanger; C. Englert; A. Freitas; I. Ginzburg; S. Godfrey; N. Greiner; C. Grojean; M. Grunewald; J. Heisig; A. Hocker; S. Kanemura; K. Kawagoe; R. Kogler; M. Krawczyk; A. S. Kronfeld; J. Kroseberg; S. Liebler; J. List; F. Mahmoudi; Y. Mambrini; S. Matsumoto; J. Mnich; K. Monig; M. M. Muhlleitner; R. Poschl; W. Porod; S. Porto; K. Rolbiecki; M. Schmitt; P. Serpico; M. Stanitzki; O. Stål; T. Stefaniak; D. Stockinger; G. Weiglein; G. W. Wilson; L. Zeune; F. Moortgat; S. Xella

    2015-04-07T23:59:59.000Z

    A comprehensive review of physics at an e+e- Linear Collider in the energy range of sqrt{s}=92 GeV--3 TeV is presented in view of recent and expected LHC results, experiments from low energy as well as astroparticle physics.The report focuses in particular on Higgs boson, Top quark and electroweak precision physics, but also discusses several models of beyond the Standard Model physics such as Supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analyzed as well.

  9. Hadron physics

    SciTech Connect (OSTI)

    Bunce, G.

    1984-05-30T23:59:59.000Z

    Is all hadronic physics ultimately describable by QCD. Certainly, many disparate phenomena can be understood within the QCD framework. Also certainly, there are important questions which are open, both theoretically (little guidance, as yet) and experimentally, regarding confinement. Are there dibaryons, baryonium, glueballs. In addition, there are experimental results which at present do not have an explanation. This talk, after a short section on QCD successes and difficulties, will emphasize two experimental topics which have recent results - glueball spectroscopy and exclusive reactions at large momentum transfer. Both are experimentally accessible in the AGS/LAMPF II/AGS II/TRIUMF II/SIN II energy domain.

  10. Challenges for highest energy circular colliders

    E-Print Network [OSTI]

    Benedikt, M; Wenninger, J; Zimmermann, F

    2014-01-01T23:59:59.000Z

    A new tunnel of 80–100 km circumference could host a 100 TeV centre-of-mass energy-frontier proton collider (FCC-hh/VHE-LHC), with a circular lepton collider (FCCee/TLEP) as potential intermediate step, and a leptonhadron collider (FCC-he) as additional option. FCC-ee, operating at four different energies for precision physics of the Z, W, and Higgs boson and the top quark, represents a significant push in terms of technology and design parameters. Pertinent R&D efforts include the RF system, topup injection scheme, optics design for arcs and final focus, effects of beamstrahlung, beam polarization, energy calibration, and power consumption. FCC-hh faces other challenges, such as high-field magnet design, machine protection and effective handling of large synchrotron radiation power in a superconducting machine. All these issues are being addressed by a global FCC collaboration. A parallel design study in China prepares for a similar, but smaller collider, called CepC/SppC.

  11. JET PRUNING: Looking for New (BSM) Physics at the LHC with Jets

    E-Print Network [OSTI]

    Ellis, Steve

    JET PRUNING: Looking for New (BSM) Physics at the LHC with Jets US ATLAS Hadronic Final State Forum will be about hadrons (jets). Theory and Experiment must work together to make the most of the data. Big Picture in SINGLE jets ­ bumps in mass distributions · Consider Recombination (kT) jets natural substructure

  12. area lhc tunnel: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Keith 2006-01-01 9 A High Luminosity e+e- Collider in the LHC tunnel to study the Higgs Boson HEP - Experiment (arXiv) Summary: We consider the possibility of a 120x120 GeV e+e-...

  13. Factorization at the LHC: From PDFs to Initial State Jets

    E-Print Network [OSTI]

    Iain W. Stewart; Frank J. Tackmann; Wouter J. Waalewijn

    2010-05-26T23:59:59.000Z

    We study proton-(anti)proton collisions at the LHC or Tevatron in the presence of experimental restrictions on the hadronic final state and for generic parton momentum fractions. At the scale Q of the hard interaction, factorization does not yield standard parton distribution functions (PDFs) for the initial state. The measurement restricting the hadronic final state introduces a new scale \\mu_B Xl+l- where X is restricted to have no central jets. We comment on the extension to cases where the hadronic final state contains a certain number of isolated central jets.

  14. Synchrotron-Radiation Photon Distribution for Highest Energy Circular Colliders

    E-Print Network [OSTI]

    Maury Cuna, GHI; Dugan, G; Zimmermann, F

    2013-01-01T23:59:59.000Z

    At high energies, beam-induced synchrotron radiation is an important source of heating, beam-related vacuum pressure increase, and primary photoelectrons, which can give rise to an electron cloud. The photon distribution along the beam pipe wall is a key input to codes such as ECLOUD and PyECLOUD, which model the electron cloud build-up. For future high-energy colliders, like TLEP or SHE-LHC, photon stops and antechambers are considered in order to facilitate cooling and vacuum pressure control. We use the Synrad3D code developed at Cornell to simulate the photon distribution for the LHC.

  15. Synchrotron-Radiation Photon Distributions for Highest Energy Circular Colliders

    E-Print Network [OSTI]

    Maury Cuna, G H I; Dugan, G; Zimmermann, F

    2013-01-01T23:59:59.000Z

    At high energies, beam-induced synchrotron radiation is an important source of heating, beam-related vacuum pressure increase, and primary photoelectrons, which can give rise to an electron cloud. The photon distribution along the beam pipe wall is a key input to codes such as ECLOUD and PyECLOUD, which model the electron cloud build-up. For future high-energy colliders, like TLEP or SHE-LHC, photon stops and antechambers are considered in order to facilitate cooling and vacuum pressure control. We use the Synrad3D code developed at Cornell to simulate the photon distribution for the LHC.

  16. Measurement of MW+ - MW- at LHC

    E-Print Network [OSTI]

    F. Fayette; M. W. Krasny; W. Placzek; A. Siodmok

    2009-06-17T23:59:59.000Z

    This paper is the second of the series of papers proposing dedicated strategies for precision measurements of the Standard Model parameters at the LHC. The common feature of these strategies is their robustness with respect to the systematic measurement and modeling error sources. Their impact on the precision of the measured parameters is reduced using dedicated observables and dedicated measurement procedures which exploit flexibilities of the collider and detector running modes. In the present paper we focus our attention on the measurement of the charge asymmetry of the W-boson mass. This measurement is of primordial importance for the LHC experimental program, both as a direct test of the charge-sign-independent coupling of the W-bosons to the matter particles and as a necessary first step towards the precision measurement of the charge-averaged W-boson mass. We propose and evaluate the LHC-specific strategy to measure the mass difference between the positively and negatively charged W-bosons, MW+ - MW-. We show that its present precision can be improved at the LHC by a factor of 20. We argue that such a precision is beyond the reach of the standard measurement and calibration methods imported to the LHC from the Tevatron program.

  17. Elastic nucleon scattering at small angles at LHC energies

    E-Print Network [OSTI]

    S. V. Goloskokov; S. P. Kuleshov; O. V. Selyugin

    1997-07-02T23:59:59.000Z

    Predictions of the elastic proton-proton cross sections at energies of LHC are calculate on the base of the high energy dynamical model. The growth of $ds/dt$ at fixed transfer momenta are shown. The form of eikonal of elastic hadron scattering at super high energies is discussed.

  18. Jet and Leading Hadron Production in High-energy Heavy-ion Collisions

    E-Print Network [OSTI]

    Xin-Nian Wang

    2005-10-31T23:59:59.000Z

    Jet tomography has become a powerful tool for the study of properties of dense matter in high-energy heavy-ion collisions. I will discuss recent progresses in the phenomenological study of jet quenching, including momentum, colliding energy and nuclear size dependence of single hadron suppression, modification of dihadron correlations and the soft hadron distribution associated with a quenched jet.

  19. Analytical Representation of the Longitudinal Hadronic Shower Development

    E-Print Network [OSTI]

    Y. A. Kulchitsky; V. B. Vinogradov

    1999-03-12T23:59:59.000Z

    The analytical representation of the longitudinal hadronic shower development from the face of a calorimeter is presented and compared with experimental data. The suggested formula is particularly useful at designing, testing and calibration of huge calorimeter complex like in ATLAS at LHC.

  20. Analytical representation of the longitudinal hadronic shower development

    E-Print Network [OSTI]

    Kulchitskii, Yu A

    1998-01-01T23:59:59.000Z

    The analytical representation of the longitudinal hadronic shower development from the face of a calorimeter is presented and compared with experimental data. The suggested formula is particularly useful at designing, testing and calibration of huge calorimeter complex like in ATLAS at LHC.

  1. W, Z and photon production at the LHC

    E-Print Network [OSTI]

    Masahiro Kuze; on behalf of ATLAS; CMS Collaborations

    2014-10-24T23:59:59.000Z

    Recent results on $W$, $Z$ and photon production at the Large Hadron Collider are presented. Inclusive $W$ and $Z$/$\\gamma^*$ production, their production in association with jets and heavy flavors, and prompt photon, $\\gamma\\gamma$ and $\\gamma$+jets production are discussed.

  2. Les Houches 2013: Physics at TeV Colliders: New Physics Working Group Report

    E-Print Network [OSTI]

    G. Brooijmans; R. Contino; B. Fuks; F. Moortgat; P. Richardson; S. Sekmen; A. Weiler; A. Alloul; A. Arbey; J. Baglio; D. Barducci; A. J. Barr; L. Basso; M. Battaglia; G. Bélanger; A. Belyaev; J. Bernon; A. Bharucha; O. Bondu; F. Boudjema; E. Boos; M. Buchkremer; V. Bunichev; G. Cacciapaglia; G. Chalons; E. Conte; M. J. Dolan; A. Deandrea; K. De Causmaecker; A. Djouadi; B. Dumont; J. Ellis; C. Englert; A. Falkowski; S. Fichet; T. Flacke; A. Gaz; M. Ghezzi; R. Godbole; A. Goudelis; M. Gouzevitch; D. Greco; R. Grober; C. Grojean; D. Guadagnoli; J. F. Gunion; B. Herrmann; J. Kalinowski; J. H. Kim; S. Kraml; M. E. Krauss; S. Kulkarni; S. J. Lee; S. H. Lim; D. Liu; F. Mahmoudi; Y. Maravin; A. Massironi; L. Mitzka; K. Mohan; G. Moreau; M. M. Mühlleitner; D. T. Nhung; B. O'Leary; A. Oliveira; L. Panizzi; D. Pappadopulo; S. Pataraia; W. Porod; A. Pukhov; F. Riva; J. Rojo; R. Rosenfeld; J. Ruiz-Álvarez; H. Rzehak; V. Sanz; D. Sengupta; M. Spannowsky; M. Spira; J. Streicher; N. Strobbe; A. Thamm; M. Thomas; R. Torre; W. Waltenberger; K. Walz; A. Wilcock; A. Wulzer; F. Würthwein; C. Wymant

    2014-05-07T23:59:59.000Z

    We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 3--21 June, 2013). Our report includes new computational tool developments, studies of the implications of the Higgs boson discovery on new physics, important signatures for searches for natural new physics at the LHC, new studies of flavour aspects of new physics, and assessments of the interplay between direct dark matter searches and the LHC.

  3. Interactions of hadrons in the CALICE silicon tungsten electromagnetic calorimeter

    E-Print Network [OSTI]

    Roman Pöschl; for the CALICE Collaboration

    2012-03-07T23:59:59.000Z

    The CALICE collaboration develops prototypes for highly granular calorimeters for detectors at a future linear electron positron collider. The highly granular electromagnetic calorimeter prototype was tested in particle beams. We present the study of the interactions of hadrons in this prototype.

  4. High Energy Colliders as Tools to Understand the Early Universe

    SciTech Connect (OSTI)

    Tait, Tim (ANL) [ANL

    2008-08-16T23:59:59.000Z

    Cosmological observations have reached a new era of precision, and reveal many interesting and puzzling features of the Universe. I will briefly review two of the most exciting mysteries: the nature of the dark components of the Universe, and the origin of the asymmetry between matter and anti-matter. I will argue that our best hope of unraveling these questions will need to combine information from the heavens with measurements in the lab at high energy particle accelerators. The end of run II of the Tevatron, the up-coming Large Hadron Collider and proposed International Linear Collider all have great potential to help us answer these questions in the near future.

  5. Detectors for Linear Colliders: Physics Requirements and Experimental Conditions (1/4)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    How is the anticipated physics program of a future e+e- collider shaping the R&D; for new detectors in collider particle physics ? This presentation will review the main physics requirements and experimental conditions comparing to LHC and LEP. In particular, I shall discuss how e+e- experimentation is expected to change moving from LEP-2 up to multi-TeV energies.

  6. Operational considerations on the stability of colliding beams

    E-Print Network [OSTI]

    Buffat, X; Pieloni, T

    2014-01-01T23:59:59.000Z

    While well studied in the absence of beam-beam and while colliding head-on, the stability of the LHC beams can be very critical in intermediate steps. During the squeeze, the long-range beam-beam interaction becomes a critical component of the beam's dynamics. Also, while the transverse separation at the interaction points is collapsed, the beam-beam forces change drastically, possibly deteriorating the beam's stability. Finally, during luminosity production, the configuration of the LHC in 2012 included few bunches without head-on collision in any of the interaction points having different stability properties. Stability diagrams are being evaluated numerically in these configurations in an attempt to explain instabilities observed in these phases during the 2012 proton run of the LHC.

  7. Updated measurements of hadronic B decays at CDF

    SciTech Connect (OSTI)

    Morello, Michael J.

    2012-01-01T23:59:59.000Z

    The CDF experiment at the Tevatron p{bar p} collider established that extensive and detailed exploration of the b-quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from e{sup +}e{sup -} colliders. This provides a rich, and highly rewarding program that has currently reached full maturity. In the following I report some recent results on hadronic decays: the evidence for the charmless annihilation decay mode B{sub s}{sup 0} {yields} {pi}{sup +}{pi}{sup -}, and the first reconstruction in hadron collisions of the suppressed decays B{sup -} {yields} D({yields} K{sup +}{pi}{sup 0})K{sup -} and B{sup -} {yields} D({yields} K{sup +} {pi}{sup -}){pi}{sup -}.

  8. The 125 GeV Higgs signal at the LHC in the CP Violating MSSM

    E-Print Network [OSTI]

    Amit Chakraborty; Biswaranjan Das; J. Lorenzo Diaz-Cruz; Dilip Kumar Ghosh; Stefano Moretti; P. Poulose

    2014-08-15T23:59:59.000Z

    The ATLAS and CMS collaborations have observed independently at the Large Hadron Collider (LHC) a new Higgs-like particle with a mass $M_h \\sim$ 125 GeV and properties similar to that predicted by the Standard Model (SM). Although the measurements indicate that this Higgs-like boson is compatible with the SM hypothesis, however due to large uncertainties in some of the Higgs detection channels, one still has the possibility of testing this object as being a candidate for some Beyond the SM (BSM) physics scenarios, for example, the Minimal Supersymmetric Standard Model (MSSM), in the CP-conserving version (CPC-MSSM). In this paper, we evaluate the modifications of these CPC-MSSM results when CP-violating (CPV) phases are turned on explicitly, leading to the CP-violating MSSM (CPV-MSSM). We investigate the role of the CPV phases in (some of) the soft Supersymmetry (SUSY) terms on both the mass of the lightest Higgs boson $h_1$, and the rates for the processes $gg \\rightarrow h_1 \\rightarrow \\gamma \\gamma$, $gg \\rightarrow h_1 \\rightarrow ZZ^*\\rightarrow 4l$, $gg \\rightarrow h_1 \\rightarrow WW^*\\rightarrow l \

  9. Testing nuclear parton distributions with pA collisions at the LHC

    E-Print Network [OSTI]

    Paloma Quiroga-Arias; Jose Guilherme Milhano; Urs Achin Wiedemann

    2010-02-12T23:59:59.000Z

    Global perturbative QCD analyses, based on large data sets from electron-proton and hadron collider experiments, provide tight constraints on the parton distribution function (PDF) in the proton. The extension of these analyses to nuclear parton distributions (nPDF) has attracted much interest in recent years. nPDFs are needed as benchmarks for the characterization of hot QCD matter in nucleus-nucleus collisions, and attract further interest since they may show novel signatures of non-linear density-dependent QCD evolution. However, it is not known from first principles whether the factorization of long-range phenomena into process-independent parton distribution, which underlies global PDF extractions for the proton, extends to nuclear effects. As a consequence, assessing the reliability of nPDFs for benchmark calculations goes beyond testing the numerical accuracy of their extraction and requires phenomenological tests of the factorization assumption. Here we argue that a proton-nucleus collision program at the LHC would provide a set of measurements allowing for unprecedented tests of the factorization assumption underlying global nPDF fits.

  10. Testing collinear factorization and nuclear parton distributions with pA collisions at the LHC

    E-Print Network [OSTI]

    Paloma Quiroga-Arias; Jose Guilherme Milhano; Urs Achim Wiedemann

    2010-10-07T23:59:59.000Z

    Global perturbative QCD analyses, based on large data sets from electron-proton and hadron collider experiments, provide tight constraints on the parton distribution function (PDF) in the proton. The extension of these analyses to nuclear parton distributions (nPDF) has attracted much interest in recent years. nPDFs are needed as benchmarks for the characterization of hot QCD matter in nucleus-nucleus collisions, and attract further interest since they may show novel signatures of non- linear density-dependent QCD evolution. However, it is not known from first principles whether the factorization of long-range phenomena into process-independent parton distribution, which underlies global PDF extractions for the proton, extends to nuclear effects. As a consequence, assessing the reliability of nPDFs for benchmark calculations goes beyond testing the numerical accuracy of their extraction and requires phenomenological tests of the factorization assumption. Here we argue that a proton-nucleus collision program at the LHC would provide a set of measurements allowing for unprecedented tests of the factorization assumption underlying global nPDF fits.

  11. There is no explosion risk associated with superfluid Helium in the LHC cooling system

    E-Print Network [OSTI]

    Fairbairn, Malcolm

    2008-01-01T23:59:59.000Z

    We evaluate speculation about the possibility of a dangerous release of energy within the liquid Helium of the Large Hadron Collider (LHC) cryogenic system due to the occurrence of a "Bose-Nova". Bose-Novae are radial bursts of rapidly moving atoms which can occur when a Bose-Einstein Condensate (BEC) undergoes a collapse due the interatomic potential being deliberately made attractive using a magnetic field close to the Feshbach resonance. Liquid 4He has a monatomic structure with s-wave electrons, zero nuclear spin, no hyperfine splitting, and as a consequence no Feshbach resonance which would allow one to change its normally repulsive interactions to be attractive. Because of this, a Bose-Nova style collapse of 4He is impossible. Additional speculations concerning cold fusion during these events are easily dismissed using the usual arguments about the Coulomb barrier at low temperatures, and are not needed to explain the Bose-Einstein condensate Bose-Nova phenomenon. We conclude that that there is no physi...

  12. There is no explosion risk associated with superfluid Helium in the LHC cooling system

    E-Print Network [OSTI]

    Malcolm Fairbairn; Bob McElrath

    2008-09-23T23:59:59.000Z

    We evaluate speculation about the possibility of a dangerous release of energy within the liquid Helium of the Large Hadron Collider (LHC) cryogenic system due to the occurrence of a "Bose-Nova". Bose-Novae are radial bursts of rapidly moving atoms which can occur when a Bose-Einstein Condensate (BEC) undergoes a collapse due the interatomic potential being deliberately made attractive using a magnetic field close to the Feshbach resonance. Liquid 4He has a monatomic structure with s-wave electrons, zero nuclear spin, no hyperfine splitting, and as a consequence no Feshbach resonance which would allow one to change its normally repulsive interactions to be attractive. Because of this, a Bose-Nova style collapse of 4He is impossible. Additional speculations concerning cold fusion during these events are easily dismissed using the usual arguments about the Coulomb barrier at low temperatures, and are not needed to explain the Bose-Einstein condensate Bose-Nova phenomenon. We conclude that that there is no physics whatsoever which suggests that Helium could undergo any kind of unforeseen catastrophic explosion.

  13. Development of reconstruction algorithms for inelastic processes studies in the TOTEM experiment at LHC

    E-Print Network [OSTI]

    Berretti, Mirko; Latino, Giuseppe

    The TOTEM experiment at the Large Hadron Collider (LHC) is designed and optimized to measure the total pp cross section at a center of mass energy of E = 14 TeV with a precision of about 1÷2 %, to study the nuclear elastic pp cross section over a wide range of the squared four-momentum transfer (10^{-3} GeV^2 < |t| < 10 GeV^2) and to perform a comprehensive physics program on diffractive dissociation processes, partially in cooperation with the CMS experiment. Based on the “luminosity independent method”, the evaluation of the total cross section with such a small error will in particular require simultaneous measurement of the pp elastic scattering cross section d\\sigma/dt down to |t| ~10^{-3} GeV^2 (to be extrapolated to t = 0) as well as of the pp inelastic interaction rate, with a large coverage in the forward region. The TOTEM physics programme will be accomplished by using three different types of detectors: elastically scattered protons will be detected by Roman Pots detectors (based on sili...

  14. Hadron-hadron and hadron-nuclei collisions at high energies

    E-Print Network [OSTI]

    G. Giacomelli; R. Giacomelli

    2000-11-15T23:59:59.000Z

    A brief review is made of the present situation of hadron-hadron and hadron-nuclei total elastic and inelastic cross sections at high energies

  15. Seesaw at LHC through Left - Right Symmetry

    E-Print Network [OSTI]

    Goran Senjanovic

    2011-03-16T23:59:59.000Z

    I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of L-R symmetric theories, which led originally to neutrino mass and the seesaw mechanism. A W_R gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. Moreover, LHC can measure the masses of the right-handed neutrinos and the right-handed leptonic mixing matrix, which could in turn be used to predict the rates for neutrinoless double decay and lepton flavor violating violating processes. The LR scale at the LHC energies offers great hope of observing these low energy processes in the present and upcoming experiments.

  16. Radiation zeros in weak boson production processes at hadron colliders

    E-Print Network [OSTI]

    F. Mamedov

    2001-07-31T23:59:59.000Z

    The Standard Model amplitudes for processes where one or more gauge bosons are emitted exhibit zeros in the angular distributions. The theoretical and experimental aspects of these radiation amplitude zeros are reviewed and some recent results are discussed. In particular, the zeros of the $WZ\\gamma$ and $WZZ$ production amplitudes are analyzed. It is briefly explained how radiation zeros can be used to test the SM.

  17. Phenomenological aspects of new physics at high energy hadron colliders

    E-Print Network [OSTI]

    Papaefstathiou, Andreas

    2011-07-12T23:59:59.000Z

    things move and nothing remains still.’ – Heracletus of Ephesus ******** Dedicated to my family, for their love and support. vii Acknowledgements I will begin by thanking my supervisor, Professor Bryan Webber, for his guidance, en- couragement and support...

  18. Establishing the Mirage Mediation Model at the Large Hadron Collider 

    E-Print Network [OSTI]

    Wang, Kechen

    2012-10-19T23:59:59.000Z

    ................................................................................... 21 Figure 4 The Slope of the Visible Transverse Momentum of the Lower Energy Tau PT ?slope Distribution of Benchmark Point.................... 22 Figure 5 The Effective Mass M eff Distribution of Benchmark Point... to the SUSY breaking soft terms. This is also the conversion used in event generator ISAJET [14]), (iii) tan? (the ratio of the vacuum expectation values of the up-type and down-type Higgs, /), (iv) sign(?) (? is the biliear Higgs coupling constant...

  19. Searching for Top Squarks at the Large Hadron Collider 

    E-Print Network [OSTI]

    Wang, Kechen

    2014-08-01T23:59:59.000Z

    decay into a top quark plus the second or third lightest neutralino (called X ?_2^0, X ?_3^0), and the second or third lightest neutralino can decay into 2 leptons plus the lightest neutralino via an intermediate slepton (“light selpton” case) or Z boson...

  20. Detecting exotic heavy leptons at the large hadron collider.

    E-Print Network [OSTI]

    Allanach, B C; Harris, Chris M; Parker, Michael A; Richardson, P; Webber, Bryan R

    the cuts actually slightly increases with mass due to the longer time delays. 0.01 0.1 1 10 100 1000 100 200 300 400 500 600 700 800 900 1000 Cr os s se ct io n (fb ) Mass of heavy lepton (GeV) Before applying cuts After applying cuts Figure 5: Cross...

  1. Searching for Top Squarks at the Large Hadron Collider

    E-Print Network [OSTI]

    Wang, Kechen

    2014-08-01T23:59:59.000Z

    decay into a top quark plus the second or third lightest neutralino (called X ?_2^0, X ?_3^0), and the second or third lightest neutralino can decay into 2 leptons plus the lightest neutralino via an intermediate slepton (“light selpton” case) or Z boson...

  2. Establishing the Mirage Mediation Model at the Large Hadron Collider

    E-Print Network [OSTI]

    Wang, Kechen

    2012-10-19T23:59:59.000Z

    ................................................................................... 21 Figure 4 The Slope of the Visible Transverse Momentum of the Lower Energy Tau PT ?slope Distribution of Benchmark Point.................... 22 Figure 5 The Effective Mass M eff Distribution of Benchmark Point... to the SUSY breaking soft terms. This is also the conversion used in event generator ISAJET [14]), (iii) tan? (the ratio of the vacuum expectation values of the up-type and down-type Higgs, /), (iv) sign(?) (? is the biliear Higgs coupling constant...

  3. Hadron Collider Physics XII 511 June 1997, Stony Brook, NY

    E-Print Network [OSTI]

    Fermilab

    that cover different ranges of pseudorapidity, out to j = 4:2. D0 features a uniform design of depleted uranium and liquid argon calorimetry. The segmentation in j \\Gamma OE is 0:1 \\Theta 0:1, but the third

  4. First Beam for Large Hadron Collider | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 1112011 Strategic Plan| Departmentof OhioFirst Annual Post Competition Accountability ReportBeam

  5. ORNL group leads calorimeter upgrade for Large Hadron Collider experiment |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for Renewable Energy:Nanowire3627Homeland SecurityJonathan Mbah andORNLornl.gov group

  6. Measurements of the Higgs boson mass and width in the four-lepton final state and electron reconstruction in the CMS experiment at the LHC

    E-Print Network [OSTI]

    Dalchenko, Mykhailo; Charlot, Claude

    This thesis document reports measurements of the mass and width of the new boson re- cently discovered at the Large Hadron Collider (LHC), candidating to be the Standard Model Higgs boson. The analysis uses proton-proton collision data recorded by the Compact Muon Solenoid (CMS) detector at the LHC, corresponding to integrated luminosities of $5.1~fb^{?1}$ at $7~$TeV center of mass energy and $19.7~fb^{?1}$ at $8~$TeV center of mass energy. Set of events selecting Higgs boson via the $H\\to ZZ$ decay channel, where both $Z$ bosons decay to electron or muon lepton pairs, is used for the Higgs boson properties measurements. A precise measurement of its mass has been performed and gives $125.6\\pm0.4\\mbox{(stat)}\\pm0.2\\mbox{(syst)}~$GeV. Constraints on the Higgs boson width were established using its off-shell production and decay to a pair of $Z$ bosons, where one $Z$ boson decays to an electron or muon pair, and the other to an electron, muon, or neutrino pair. The obtained result is an upper limit on the Hi...

  7. A boost for the EW SUSY hunt: monojet-like search for compressed sleptons at LHC14 with 100 fb^-1

    E-Print Network [OSTI]

    Alan Barr; James Scoville

    2015-01-27T23:59:59.000Z

    Current Large Hadron Collider (LHC) analyses are blind to compressed supersymmetry (SUSY) models with sleptons near the lightest super partner (LSP) in mass: $m_{\\tilde{l}} - m_{\\tilde{\\chi}_1^0} \\equiv \\Delta m \\lesssim 60$ GeV. We present a search sensitive to the very compressed range $3~\\text{GeV} 100$ GeV). The sleptons recoil against the jet boosting them and their decay products, making the leptons detectable and providing substantial missing transverse momentum. We use the kinematic variable $m_{\\rm T 2}$ along with a different-flavor control region to reduce the large standard model backgrounds and control systematic uncertainty. We find the analysis should allow LHC14 with $100~\\text{fb}^{-1}$ to search for degenerate left-handed selectrons and smuons in the compressed region up to $m_{\\tilde{l}_L} \\lesssim 150$ GeV. In addition, it should be sensitive to $m_{\\tilde{l}_L} \\lesssim 110$ GeV for the very challenging case of auto-concealed SUSY, in which left-handed sleptons decay to the Kaluza-Klein tower of a modulino LSP which lives in $d=6$ extra dimensions. In both the compressed spectrum and auto-concealed SUSY scenarios this analysis will need more data to improve on LEP2 limits for right-handed sleptons due to their smaller cross sections.

  8. Study of Higgs boson production and its b-bbar decay in gamma-gamma processes in proton-nucleus collisions at the LHC

    E-Print Network [OSTI]

    David d'Enterria; Jean-Philippe Lansberg

    2010-01-11T23:59:59.000Z

    We explore for the first time the possibilities to measure an intermediate-mass (mH = 115-140 GeV/c^2) Standard-Model Higgs boson in electromagnetic proton-lead (pPb) interactions at the CERN Large Hadron Collider (LHC) via its b-bbar decay. Using equivalent Weizsaecker-Williams photon fluxes and Higgs effective field theory for the coupling gamma-gamma --> H, we obtain a leading-order cross section of the order of 0.3 pb for exclusive Higgs production in elastic (pPb --> gamma-gamma --> p H Pb) and semielastic (pPb --> gamma-gamma --> Pb H X) processes at sqrt(s) = 8.8 TeV. After applying various kinematics cuts to remove the main backgrounds (gamma-gamma --> b-bbar and misidentified gamma-gamma-->q-qbar events), we find that a Higgs boson with mH = 120 GeV/c^2 could be observed in the b-bbar channel with a 3sigma-significance integrating 300 pb^-1 with an upgraded pA luminosity of 10^31 cm^-2s^-1. We also provide for the first time semielastic Higgs cross sections, along with elastic t-tbar cross sections, for electromagnetic pp, pA and AA collisions at the LHC.

  9. Top physics at LHC with ttbar events

    E-Print Network [OSTI]

    F. Hubaut

    2006-05-10T23:59:59.000Z

    The new CERN proton-proton collider, the LHC, is about to start in 2007 its data taking. Millions of top quarks will be available out of these data, allowing to perform a wide range of precision measurements and searches for new physics. An overview of the planned top physics program accessible with ttbar events is given for the ATLAS and CMS experiments. A particular emphasis is put on the precision measurements of the top mass, top polarization and searches for new physics in top production and decay.

  10. Transverse-Momentum and Pseudorapidity Distributions of Charged Hadrons in pp Collisions at [sqrt] s=7 TeV

    E-Print Network [OSTI]

    Paus, Christoph M. E.

    Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at [sqrt]s=7??TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is ...

  11. Cryogenic Silicon Microstrip Detector Modules for LHC

    E-Print Network [OSTI]

    Perea-Solano, B

    2004-01-01T23:59:59.000Z

    CERN is presently constructing the LHC, which will produce collisions of 7 TeV protons in 4 interaction points at a design luminosity of 1034 cm-2 s-1. The radiation dose resulting from the operation at high luminosity will cause a serious deterioration of the silicon tracker performance. The state-of-art silicon microstrip detectors can tolerate a fluence of about 3 1014 cm-2 of hadrons or charged leptons. This is insufficient, however, for long-term operation in the central parts of the LHC trackers, in particular after the possible luminosity upgrade of the LHC. By operating the detectors at cryogenic temperatures the radiation hardness can be improved by a factor 10. This work proposes a cryogenic microstrip detector module concept which has the features required for the microstrip trackers of the upgraded LHC experiments at CERN. The module can hold an edgeless sensor, being a good candidate for improved luminosity and total cross-section measurements in the ATLAS, CMS and TOTEM experiments. The design o...

  12. Top production at the LHC

    E-Print Network [OSTI]

    Kanzaki, Junichi; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    Measurements of the inclusive top quark production cross sections in proton-proton collisions with the ATLAS and CMS detectors at the Large Hadron Collider are presented. The measurements of the precise pair production cross section are performed for di-lepton, semi-leptonic and hadronic final states. Differential measurements of the top transverse momentum and kinematic properties of the top-anti-top pair are also discussed. The results, unfolded to particle and parton level, are compared to recent Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers and NLO QCD calculations. For single top-quark productions cross sections are measured for t-channel, s-channel and W-boson associated production processes. The single top-quark and anti-top total production cross sections, their ratio, as well as a measurement of the inclusive production cross section is presented. All measurements are compared to theoretical calculations and the CKM matrix element |Vtb| is determined.

  13. Top quark physics in hadron collisions

    E-Print Network [OSTI]

    Wolfgang Wagner

    2007-08-03T23:59:59.000Z

    The top quark is the heaviest elementary particle observed to date. Its large mass makes the top quark an ideal laboratory to test predictions of perturbation theory concerning heavy quark production at hadron colliders. The top quark is also a powerful probe for new phenomena beyond the Standard Model of particle physics. In addition, the top quark mass is a crucial parameter for scrutinizing the Standard Model in electroweak precision tests and for predicting the mass of the yet unobserved Higgs boson. Ten years after the discovery of the top quark at the Fermilab Tevatron top quark physics has entered an era where detailed measurements of top quark properties are undertaken. In this review article an introduction to the phenomenology of top quark production in hadron collisions is given, the lessons learned in Tevatron Run I are summarized, and first Run II results are discussed. A brief outlook to the possibilities of top quark research a the Large Hadron Collider, currently under construction at CERN, is included.

  14. High energy hadron-hadron collisions

    SciTech Connect (OSTI)

    Chou, T.T.

    1991-12-01T23:59:59.000Z

    Results of a study on high energy collision with the geometrical model are summarized in three parts: (1) the elastic hadron-hadron collision, (2) the inelastic hadron-hadron collision, and (3) the e{sup +}e{sup {minus}} annihilation. More recent studies are highlighted below. For elastic scattering, a modified form for the hadronic matter form factor of the proton was proposed which remains to be dipole in form but contains an energy-dependent range parameter. This new expression of the opacity function fits the elastic {bar p}p scattering very well from the ISR to S{bar p}pS energies. Extrapolation of this theory also yielded results in good agreement with the {bar p}p differential cross section measured at the Tevatron. For inelastic hadron-hadron collisions, we have made a systematic investigation of the single-particle momentum spectra in the entire S{bar p}pS energy region. Results are useful for the extrapolation of angular distribution to the higher SSC energies. In e{sup +}e{sup {minus}} annihilation, a detailed analysis of all available experimental multiplicity data from PETRA to LEP energies has been performed. We discovered that the cluster size of emitted hadrons increases steadily with energy and is close to 2 as we predicted.

  15. Photon collider at TESLA

    E-Print Network [OSTI]

    Valery Telnov

    2001-03-06T23:59:59.000Z

    High energy photon colliders (gamma-gamma, gamma-electron) based on backward Compton scattering of laser light is a very natural addition to e+e- linear colliders. In this report we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case the gamma-gamma luminosity luminosity in the high energy part of spectrum can reach (1/3)L_{e+e-}. Typical cross sections of interesting processes in gamma-gamma collisions are higher than those in e+e- collisions by about one order of magnitude, so the number of events in gamma-gamma collisions will be more than that in e+e- collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is ``an optical storage ring (optical trap)'' with diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based at TESLA, its possible parameters and existing problems.

  16. Top quark mass measurements at the LHC

    E-Print Network [OSTI]

    Fuster, Juan; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    The latest measurements of the top quark mass using the ATLAS and CMS experiments at the LHC are presented. The discussion includes the results obtained using the conventional methods (Template/Ideogram) and those derived from the so called alternative methods. Results from the conventional methods using the various top final states (lepton+jets, di-lepton and full hadronic) are reviewed. Determinations using the inclusive ttbar production, the ttbar production with an additional jet and the lepton-b-jet invariant mass distribution are also discussed.

  17. Illuminating Dark Photons with High-Energy Colliders

    E-Print Network [OSTI]

    David Curtin; Rouven Essig; Stefania Gori; Jessie Shelton

    2015-02-27T23:59:59.000Z

    High-energy colliders offer a unique sensitivity to dark photons, the mediators of a broken dark U(1) gauge theory that kinetically mixes with the Standard Model (SM) hypercharge. Dark photons can be detected in the exotic decay of the 125 GeV Higgs boson, h -> Z Z_D -> 4l, and in Drell-Yan events, pp -> Z_D -> ll. If the dark U(1) is broken by a hidden-sector Higgs mechanism, then mixing between the dark and SM Higgs bosons also allows the exotic decay h -> Z_D Z_D -> 4l. We show that the 14 TeV LHC and a 100 TeV proton-proton collider provide powerful probes of both exotic Higgs decay channels. In the case of kinetic mixing alone, direct Drell-Yan production offers the best sensitivity to Z_D, and can probe epsilon >~ 9 x 10^(-4) (4 x 10^(-4)) at the HL-LHC (100 TeV pp collider). The exotic Higgs decay h -> Z Z_D offers slightly weaker sensitivity, but both measurements are necessary to distinguish the kinetically mixed dark photon from other scenarios. If Higgs mixing is also present, then the decay h -> Z_D Z_D can allow sensitivity to the Z_D for epsilon >~ 10^(-9) - 10^(-6) (10^(-10) - 10^(-7)) for the mass range 2 m_mu updating previous work in the literature. Electroweak precision measurements at LEP, Tevatron, and the LHC exclude epsilon as low as 3 x 10^(-2). Sensitivity can be improved by up to a factor of ~2 with HL-LHC data, and an additional factor of ~4 with ILC/GigaZ data.

  18. Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report

    E-Print Network [OSTI]

    J. Butterworth; G. Dissertori; S. Dittmaier; D. de Florian; N. Glover; K. Hamilton; J. Huston; M. Kado; A. Korytov; F. Krauss; G. Soyez; J. R. Andersen; S. Badger; L. Barzè; J. Bellm; F. U. Bernlochner; A. Buckley; J. Butterworth; N. Chanon; M. Chiesa; A. Cooper-Sarkar; L. Cieri; G. Cullen; H. van Deurzen; G. Dissertori; S. Dittmaier; D. de Florian; S. Forte; R. Frederix; B. Fuks; J. Gao; M. V. Garzelli; T. Gehrmann; E. Gerwick; S. Gieseke; D. Gillberg; E. W. N. Glover; N. Greiner; K. Hamilton; T. Hapola; H. B. Hartanto; G. Heinrich; A. Huss; J. Huston; B. Jäger; M. Kado; A. Kardos; U. Klein; F. Krauss; A. Kruse; L. Lönnblad; G. Luisoni; Daniel Maître; P. Mastrolia; O. Mattelaer; J. Mazzitelli; E. Mirabella; P. Monni; G. Montagna; M. Moretti; P. Nadolsky; P. Nason; O. Nicrosini; C. Oleari; G. Ossola; S. Padhi; T. Peraro; F. Piccinini; S. Plätzer; S. Prestel; J. Pumplin; K. Rabbertz; Voica Radescu; L. Reina; C. Reuschle; J. Rojo; M. Schönherr; J. M. Smillie; J. F. von Soden-Fraunhofen; G. Soyez; R. Thorne; F. Tramontano; Z. Trocsanyi; D. Wackeroth; J. Winter; C-P. Yuan; V. Yundin; K. Zapp

    2014-05-05T23:59:59.000Z

    This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.

  19. First observation of beam-beam interactions in high intensity collisions at the LHC

    E-Print Network [OSTI]

    Arduini, G; Jowett, J; Laface, E; Meddahi, M; Schmidt, F

    2010-01-01T23:59:59.000Z

    For the rst time bunches were collided in the LHC with close to nominal parameters and so experienced head-on beam-beam eects comparable to those expected with the nominal LHC parameters. Among other things, this provided an opportunity to test the procedure of separating beams at IP2 to reduce the luminosity and pile-up in the ALICE experiment. We report on the observations made during these runs and related tests.

  20. Stochastic Cooling in Muon Colliders

    E-Print Network [OSTI]

    Barletta, W.A.

    2008-01-01T23:59:59.000Z

    Research Division Stochastic Cooling in Muon Colliders W.A.AC03-76SFOOO98. STOCHASTIC COOLING IN MUON COLLIDERS Williamcan consider the stochastic cooling option as more than a

  1. The ATLAS Tile Calorimeter and its upgrades for the high luminosity LHC

    E-Print Network [OSTI]

    Smirnov, Yuri; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    The Tile Calorimeter (TileCal) of the ATLAS experiment at the LHC is the hadronic calorimeter designed for energy reconstruction of hadrons, jets, tau-particles and missing transverse energy. A summary of performance results for TileCal using pp collisions from the LHC Run I will be presented. For Run 2, which will start this summer, the expected effects of increasing pile-up with rising luminosity will be discussed. For the high luminosity era a major upgrade of the TileCal electronics is planned, and the ongoing developments for on- and off-detector systems, together with expected performance characteristics, will be described.

  2. LHC CLEANING EFFICIENCYWITH IMPERFECTIONS

    E-Print Network [OSTI]

    Bracco, C; Redaelli, S; Weiler, T

    2009-01-01T23:59:59.000Z

    The performance reach of the LHC depends on the magnitude of beam losses and the achievable cleaning efficiency of its collimation system. The ideal performance reach for the nominal Phase 1 collimation system is reviewed. However, unavoidable imperfections affect any accelerator and can further deteriorate the collimation performance. Multiple static machine and collimator imperfections were included in the LHC tracking simulations. Error models for collimator jaw flatness, collimator setup accuracy, the LHC orbit and the LHC aperture were set up, based to the maximum extent possible on measurements and results of experimental beam tests. It is shown that combined “realistic” imperfections can reduce the LHC cleaning efficiency by about a factor 11 on average.

  3. Shooting String Holography of Jet Quenching at RHIC and LHC

    E-Print Network [OSTI]

    Andrej Ficnar; Steven S. Gubser; Miklos Gyulassy

    2014-11-07T23:59:59.000Z

    We derive a new formula for jet energy loss using finite endpoint momentum shooting strings initial conditions in SYM plasmas to overcome the difficulties of previous falling string holographic scenarios. We apply the new formula to compute the nuclear modification factor RAA and the elliptic flow parameter v2 of light hadrons at RHIC and LHC. We show furthermore that Gauss-Bonnet quadratic curvature corrections to the AdS5 geometry improve the agreement with the recent data.

  4. Energy Dependent Growth of Nucleon and Inclusive Charged Hadron Distributions

    E-Print Network [OSTI]

    Hongmin Wang; Zhao-Yu Hou; Xian-Jing Sun

    2015-01-06T23:59:59.000Z

    In the Color Glass Condensate formalism, charged hadron p_{T} distributions in p+p collisions are studied by considering an energy-dependent broadening of nucleon's density distribution. Then, in the Glasma flux tube picture, the n-particle multiplicity distributions at different pseudo-rapidity ranges are investigated. Both of the theoretical results show good agreement with the recent experimental data from ALICE and CMS at \\sqrt{s}=0.9, 2.36, 7 TeV. The predictive results for p_{T} and multiplicity distributions in p+p and p+Pb collisions at the Large Hadron Collider are also given in this paper.

  5. CMS physics highlights in the LHC Run 1

    E-Print Network [OSTI]

    David d'Enterria for the CMS Collaboration

    2015-05-18T23:59:59.000Z

    The main physics results obtained by the CMS experiment during the first three years of operation of the CERN Large Hadron Collider (2010--2013, aka. Run 1) are summarized. The advances in our understanding of the fundamental particles and their interactions are succinctly reviewed under the following physics topics: (i) Quantum Chromodynamics, (ii) Quark Gluon Plasma, (iii) Electroweak interaction, (iv) Top quark, (v) Higgs boson, (vi) Flavour, (vii) Supersymmetry, (viii) Dark Matter, and (ix) other searches of physics beyond the Standard Model.

  6. Inclusive Higgs Boson Searches in Four-Lepton Final States at the LHC

    E-Print Network [OSTI]

    Evelyne Delmeire

    2007-05-15T23:59:59.000Z

    The inclusive search for the Standard Model Higgs boson in four-lepton final states with the ATLAS and CMS detectors at the LHC pp collider is presented. The discussion focusses on the H-> ZZ^(*)->4l+X decay mode for a Higgs boson in the mass range 120 ~Higgs boson properties is also given.

  7. Hadron 07 Oct 2007 1 Christoph Grab

    E-Print Network [OSTI]

    Collisions HadronHadron SpectroscopySpectroscopy inin epep CollisionsCollisions Introduction Light quark

  8. Centrality dependence of charged hadron and strange hadron elliptic flow from root s(NN)=200 GeVAu+Au collisions 

    E-Print Network [OSTI]

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Braidot, E.; Brandin, A. V.; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sanchez, M. Calderon de la Barca; Callner, J.; Catu, O.; Cebra, D.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; De Moura, M. M.; Dedovich, T. G.; DePhillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. -R Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, Carl A.; Gaillard, L.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, R.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Hughes, E. W.; Humanic, T. J.; Lgo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kumar, A.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; LaPointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C. -H; LeVine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, Saskia; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Poskanzer, A. M.; Potekhin, M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Qattan, I. A.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Relyea, D.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Schweda, K.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X. -H; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Z.; Surrow, B.; Symons, T. J. M.; de Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Tram, V. N.; Tratmer, A. L.; Trentalange, S.; Tribble, Robert E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van der Kolk, N.; van Leeuwen, M.; Molen, A. M. Vander; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, J. C.

    2008-01-01T23:59:59.000Z

    We present STAR results on the elliptic flow upsilon(2) Of charged hadrons, strange and multistrange particles from,root s(NN) = 200 GeV Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). The detailed study of the centrality...

  9. Collider Phenomenology with Split-UED

    SciTech Connect (OSTI)

    Kong, Kyoungchul; /SLAC; Park, Seong Chan; /Tokyo U., IPMU; Rizzo, Thomas G.; /SLAC

    2011-12-15T23:59:59.000Z

    We investigate the collider implications of Split Universal Extra Dimensions. The non-vanishing fermion mass in the bulk, which is consistent with the KK-parity, largely modifies the phenomenology of Minimal Universal Extra Dimensions. We scrutinize the behavior of couplings and study the discovery reach of the Tevatron and the LHC for level-2 Kaluza-Klein modes in the dilepton channel, which would indicates the presence of the extra dimensions. Observation of large event rates for dilepton resonances can result from a nontrivial fermion mass profile along the extra dimensions, which, in turn, may corroborate extra dimensional explanation for the observation of the positron excess in cosmic rays. The Minimal Universal Extra Dimensions scenario has received great attention. Recently non-vanishing bulk fermion masses have been introduced without spoiling the virtue of KK-parity. The fermion profiles are no longer simple sine/cosine functions and depend upon the specific values of bulk parameters. The profiles of fermions are split along the extra dimensions while the wave functions of the bosons remain the same as in UED. A simple introduction of a KK-parity conserving bulk fermion mass has significant influences on collider aspects as well as astrophysical implications of UED. For instance, the DM annihilation fraction into certain SM fermion pairs is either enhanced or reduced (compared to the MUED case) so that one can perhaps explain the PAMELA positron excess while suppressing the anti-proton flux. In this paper, we have concentrated on collider phenomenology of Split Universal Extra Dimensions. We have revisited the KK decomposition in detail and analyzed wave function overlaps to compute relevant couplings for collider studies. We have discussed general collider implication for level-1 KK modes and level-2 KK with non-zero bulk mass and have computed LHC reach for the EW level-2 KK bosons, {gamma}{sub 2} and Z{sub 2}, in the dilepton channel. The LHC should able to cover the large parameter space (up to M{sub V{sub 2}} {approx} 1.5 TeV for {mu}L {ge} 1) even with early data assuming {approx}100 pb{sup -1} or less. The existence of double resonances is one essential feature arising from extra dimensional models. Whether or not one can see double resonances depends both on how degenerate the two resonances are and on the mass resolution of the detector. The very high P{sub T} from the decay makes resolution in dimuon channel worse than in dielectron final state. This is because one can reconstruct electron from ECAL but muon momentum reconstruction relies on its track, which is barely curved in this case. Further indication for SUED might be the discovery of W'-like signature of mass close to Z{sub 2}. The MUED predicts a somewhat lower event rate due to 1-loop suppressed coupling of level-2 bosons to SM fermion pair, while it exists at tree level in SUED. Therefore in UED, one has to rely on indirect production of level-2 bosons, whose collider study requires complete knowledge of the model: the mass spectrum and all the couplings. On the other hand, in the large {mu} limit of SUED, the dependence on mass spectrum is diminished since level-2 KK bosons decay only into SM fermion pairs. This allows us to estimate the signal rate from their direct production, so that they can be discovered at the early phase of the LHC. The indirect production mechanism only increases production cross sections, improving our results. Once a discovery has been made, one should try to reconstruct events and do further measurements such as spin and coupling determination, with more accumulated data, which might discriminate KK resonances from other Z' models. The coupling measurement is directly related to the determination of the bulk masses. A challenging issue might be the existence of two resonances which are rather close to each other.

  10. Colliding Nuclei at High Energy

    ScienceCinema (OSTI)

    Brookhaven Lab

    2010-01-08T23:59:59.000Z

    Physicist Peter Steinberg explains what happens when atomic nucleii travelling at close to the speed of light smash together in Brookhaven Lab's Relativistic Heavy Ion Collider (RHIC).

  11. RHIC | Relativistic Heavy Ion Collider

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photo of LINAC The Relativistic Heavy Ion Collider (RHIC) is a world-class particle accelerator at Brookhaven National Laboratory where physicists are exploring the most...

  12. Jet energy scale setting with "photon+Jet" events at LHC energies. Generalities, selection rules

    E-Print Network [OSTI]

    D. V. Bandourin; V. F. Konoplianikov; N. B. Skachkov

    2000-12-14T23:59:59.000Z

    "photon+Jet" events, based on the q~q-> g+photon and qg-> q+photon subprocesses, are proposed for jet energy scale setting and hadron calorimeter calibration at LHC energies. General features and selection criteria of "photon+Jet" events that would provide a good photon Pt - jet Pt balance are described. CMS detector geometry is taken as the basement.

  13. JET PRUNING: Looking for New (BSM) Physics at the LHC with Jets

    E-Print Network [OSTI]

    Ellis, Steve

    JET PRUNING: Looking for New (BSM) Physics at the LHC with Jets LPC Fermilab 5/18/09 For the next) detectors · operating at high energy and high luminosity · most of the data will be about hadrons (jets of (QCD) jets, including masses · Search for BSM physics in SINGLE jets ­ bumps in mass distributions

  14. JET PRUNING: Looking for New (BSM) Physics at the LHC with Jets

    E-Print Network [OSTI]

    Ellis, Steve

    JET PRUNING: Looking for New (BSM) Physics at the LHC with Jets UC Berkeley 4/20/09 For the next) detectors · operating at high energy and high luminosity · most of the data will be about hadrons (jets Walsh & Chris Vermilion 0903.5081 #12;Outline · Brief review of jets · Searching for BSM physics

  15. Jet-hadron correlations in STAR

    E-Print Network [OSTI]

    Alice Ohlson; for the STAR Collaboration

    2011-06-29T23:59:59.000Z

    In recent years, the study of dihadron correlations has been one of the primary methods used to investigate the propagation and modification of hard-scattered partons through the QGP. Due to recent advances in jet-finding algorithms, it is now possible to use reconstructed jets in these correlation studies, extending the kinematic reach compared to dihadron analyses. The results of the jet-hadron correlation analysis indicate a broadening and softening of jets that interact with the medium. Jet-hadron correlations can also be used to assess the systematics of other jet-like correlation analyses, such as 2+1 correlations. It is shown that the jets selected in 2+1 correlations are relatively unmodified. Future work will include an analysis of jet-hadron correlations with respect to the event plane to measure the pathlength dependence of parton energy loss. The first steps in this analysis indicate that complications arise when calculating the event plane in the presence of a jet as well as in calculating jet v2. The data analyzed were collected by the STAR detector in sqrt(s_NN) = 200 GeV Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC).

  16. 2014 8 22 4:00PM-5:00PM Title: "Exploration of the Higgs boson and the Physics case for the Large Hadron Electron

    E-Print Network [OSTI]

    Wang, Yayu

    2014 8 22 4:00PM-5:00PM Title: "Exploration of the Higgs boson and the Physics case for the Large Hadron Electron Collider" Abstract: With the discovery of a Higgs boson at the Large Hadron) Prof. Mellado is an expert on the Higgs boson ­ a sub-atomic particle that is thought to give matter

  17. First measurement of hadronic event shapes in pp collisions at ?s = 7 TeV

    E-Print Network [OSTI]

    CMS Collaboration

    Hadronic event shapes have been measured in proton–proton collisions at ?s =7 TeV, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 pb-1. Event-shape ...

  18. alterungsstudien und studium: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Large Hadron Collider (LHC). One of its detector-systems, the Transition Radiation Detector (TRD), is a gas detector designed for electron identification and charged particle...

  19. audi s8 maserati: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    physics topics at the Large Hadron Collider (LHC), for instance searches for muonic Higgs boson decays or new phenomena, or measurements of the standard model (SM) processes like...

  20. atlas experimental area: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Large Hadron Collider (LHC). ATLAS is a multi-purpose detector built to search the Higgs boson, look 12 Distributed processing and analysis of ATLAS experimental data CERN...

  1. The Electron-Ion Collider

    E-Print Network [OSTI]

    V. Guzey

    2009-07-23T23:59:59.000Z

    The future Electron-Ion Collider (EIC) is a proposed new facility to collide high-energy electrons with beams of polarized protons/light nuclei and unpolarized nuclei. We overview the goals of the project and key measurements at the EIC. We also briefly comment on recent developments of the project.

  2. Positrons for linear colliders

    SciTech Connect (OSTI)

    Ecklund, S.

    1987-11-01T23:59:59.000Z

    The requirements of a positron source for a linear collider are briefly reviewed, followed by methods of positron production and production of photons by electromagnetic cascade showers. Cross sections for the electromagnetic cascade shower processes of positron-electron pair production and Compton scattering are compared. A program used for Monte Carlo analysis of electromagnetic cascades is briefly discussed, and positron distributions obtained from several runs of the program are discussed. Photons from synchrotron radiation and from channeling are also mentioned briefly, as well as positron collection, transverse focusing techniques, and longitudinal capture. Computer ray tracing is then briefly discussed, followed by space-charge effects and thermal heating and stress due to showers. (LEW)

  3. Nuclear modification factor for light and heavy flavors within pQCD and recent data from the LHC

    E-Print Network [OSTI]

    B. G. Zakharov

    2012-10-15T23:59:59.000Z

    We examine the flavor dependence of the nuclear modification factor $R_{AA}$ in the pQCD calculations at LHC energies. The computations are performed accounting for radiative and collisional parton energy loss with running coupling constant. Our results show that the recent LHC data on the $R_{AA}$ for charged hadrons, D-mesons and non-photonic electrons agree reasonably with the pQCD picture of the parton energy loss with the dominating contribution from the radiative mechanism.

  4. Mean pt scaling with m/nq at the LHC: Absence of (hydro) flow in small systems?

    E-Print Network [OSTI]

    Ortiz, Antonio

    2015-01-01T23:59:59.000Z

    In this work, a study of the average transverse momentum (pT) as a function of the mid-rapidity charged hadron multiplicity (Nch) and hadron mass (m) in p-Pb and Pb-Pb collisions at the LHC is presented. For the events producing low Nch, the average pT is found to scale with the reduced hadron mass, i.e., mass divided by the number of quark constituents (m/nq), this scaling also holds for minimum bias pp collisions at RHIC and LHC energies. The scaling is broken in high multiplicity p-Pb and Pb-Pb collisions, namely, for dNch/deta hydro calculations, where a universal scaling with the hadron mass (and not with m/nq) is predicted for all the multiplicity event classes. Only the 0-60% Pb-Pb collisions behave as expected from hydro.

  5. Mean pt scaling with m/nq at the LHC: Absence of (hydro) flow in small systems?

    E-Print Network [OSTI]

    Antonio Ortiz

    2015-06-01T23:59:59.000Z

    In this work, a study of the average transverse momentum (pT) as a function of the mid-rapidity charged hadron multiplicity (Nch) and hadron mass (m) in p-Pb and Pb-Pb collisions at the LHC is presented. For the events producing low Nch, the average pT is found to scale with the reduced hadron mass, i.e., mass divided by the number of quark constituents (m/nq), this scaling also holds for minimum bias pp collisions at RHIC and LHC energies. The scaling is broken in high multiplicity p-Pb and Pb-Pb collisions, namely, for dNch/deta hydro calculations, where a universal scaling with the hadron mass (and not with m/nq) is predicted for all the multiplicity event classes. Only the 0-60% Pb-Pb collisions behave as expected from hydro.

  6. MSSM Electroweak Baryogenesis and LHC Data

    SciTech Connect (OSTI)

    Carena, Marcela; Nardini, Germano; Quiros, Mariano; Wagner, Carlos E.M.

    2013-02-01T23:59:59.000Z

    Electroweak baryogenesis is an attractive scenario for the generation of the baryon asymmetry of the universe as its realization depends on the presence at the weak scale of new particles which may be searched for at high energy colliders. In the MSSM it may only be realized in the presence of light stops, and with moderate or small mixing between the left- and right-handed components. Consistency with the observed Higgs mass around 125 GeV demands the heavier stop mass to be much larger than the weak scale. Moreover the lighter stop leads to an increase of the gluon-gluon fusion Higgs production cross section which seems to be in contradiction with indications from current LHC data. We show that this tension may be considerably relaxed in the presence of a light neutralino with a mass lower than about 60 GeV, satisfying all present experimental constraints. In such a case the Higgs may have a significant invisible decay width and the stop decays through a three or four body decay channel, including a bottom quark and the lightest neutralino in the final state. All these properties make this scenario testable at a high luminosity LHC.

  7. The Search for Higgs particles at high-energy colliders: Past, Present and Future

    E-Print Network [OSTI]

    A. Djouadi

    2002-05-22T23:59:59.000Z

    I briefly review the Higgs sector in the Standard Model and its minimal Supersymmetric extension, the MSSM. After summarizing the properties of the Higgs bosons and the present experimental constraints, I will discuss the prospects for discovering these particle at the upgraded Tevatron, the LHC and a high-energy $e^+e^-$ linear collider. The possibility of studying the properties of the Higgs particles will be then summarized.

  8. Towards hadronic shower timing with CALICE Analog Hadron Calorimeter, Calorimetry for High Energy Frontier

    E-Print Network [OSTI]

    Ramilli, M

    2015-01-01T23:59:59.000Z

    Towards hadronic shower timing with CALICE Analog Hadron Calorimeter, Calorimetry for High Energy Frontier

  9. Discovering colorons at the early stage LHC

    SciTech Connect (OSTI)

    Dicus, Duane A. [Center for Particles and Fields and Texas Cosmology Center, University of Texas, Austin, Texas 78712 (United States); Kao, Chung; Sayre, Joshua [Homer L. Dodge Department of Physics and Astronomy and Oklahoma Center for High Energy Physics, University of Oklahoma, Norman, Oklahoma 73019 (United States); Nandi, S. [Department of Physics and Oklahoma Center for High Energy Physics, Oklahoma State University, Stillwater, Oklahoma 74078 (United States)

    2011-05-01T23:59:59.000Z

    Prospects are investigated for the discovery of massive hypergluons using data from the early runs of the Large Hadron Collider. A center of mass energy of 7 TeV and an integrated luminosity of 1 fb{sup -1} or 5 fb{sup -1} are assumed. A phenomenological Lagrangian is adopted to evaluate the cross section of a pair of colored vector bosons (colorons, {rho}-tilde) decaying into four colored scalar resonances (hyperpions, {pi}-tilde), which then decay into eight gluons. The dominant eight-jet background from the production of 8g, 7g1q, 6g2q, and 5g3q is included. We find an abundance of signal events and that realistic cuts reduce the background enough to establish a 5{sigma} signal for the coloron mass of up to 733 GeV with 1 fb{sup -1} or 833 GeV with 5 fb{sup -1}.

  10. Final Report - The Decline and Fall of the Superconducting Super Collider

    SciTech Connect (OSTI)

    RIORDAN, MICHAEL

    2011-11-29T23:59:59.000Z

    In October 1993 the US Congress terminated the Superconducting Super Collider — at the time the largest pure-science project ever attempted, with a total cost estimated to exceed $10 billion. It was a stunning loss for the US highenergy physics community, which until that moment had perched for decades at the pinnacle of American science. Ever since 1993, this once-dominant scientific community has been in gradual decline. With the 2010 startup of research on the CERN Large Hadron Collider and the 2011 shutdown of the Fermilab Tevatron, world leadership in elementary-particle physics has crossed the Atlantic and returned to Europe.

  11. The LHC Higgs Boson Discovery: Implications for Finite Unified Theories

    E-Print Network [OSTI]

    S. Heinemeyer; M. Mondragon; G. Zoupanos

    2014-12-18T23:59:59.000Z

    Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all-loop orders, based on the principle of reduction of couplings, and therefore are provided with a large predictive power. We confront the predictions of an SU(5) FUT with the top and bottom quark masses and other low-energy experimental constraints, resulting in a relatively heavy SUSY spectrum, naturally consistent with the non-observation of those particles at the LHC. The light Higgs boson mass is automatically predicted in the range compatible with the Higgs discovery at the LHC. Requiring a light Higgs-boson mass in the precise range of M_h = 125.6 +- 2.1 GeV favors the lower part of the allowed spectrum, resulting in clear predictions for the discovery potential at current and future pp, as well as future e+e- colliders.

  12. EIS-0138: Superconducting Super Collider

    Broader source: Energy.gov [DOE]

    The U.S. Department of Energy developed this EIS to analyze the potential environmental impacts of constructing the Superconducting Super Collider, a large proton accelerator, at each of seven alternative locations.

  13. Spin physics and TMD studies at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

    E-Print Network [OSTI]

    J. P. Lansberg; M. Anselmino; R. Arnaldi; S. J. Brodsky; V. Chambert; W. den Dunnen; J. P. Didelez; B. Genolini; E. G. Ferreiro; F. Fleuret; Y. Gao; C. Hadjidakis; I. Hrvinacova; C. Lorce; L. Massacrier; R. Mikkelsen; C. Pisano; A. Rakotozafindrabe; P. Rosier; I. Schienbein; M. Schlegel; E. Scomparin; B. Trzeciak; U. I. Uggerhoj; R. Ulrich; Z. Yang

    2014-10-08T23:59:59.000Z

    We report on the opportunities for spin physics and Transverse-Momentum Dependent distribution (TMD) studies at a future multi-purpose fixed-target experiment using the proton or lead ion LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic fixed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER@LHC using typical targets would surpass that of RHIC by more that 3 orders of magnitude in a similar energy region. In unpolarised proton-proton collisions, AFTER@LHC allows for measurements of TMDs such as the Boer-Mulders quark distributions, the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using the polarisation of hydrogen and nuclear targets, one can measure transverse single-spin asymmetries of quark and gluon sensitive probes, such as, respectively, Drell-Yan pair and quarkonium production. The fixed-target mode has the advantage to allow for measurements in the target-rapidity region, namely at large x^uparrow in the polarised nucleon. Overall, this allows for an ambitious spin program which we outline here.

  14. Head-on beam-beam collisions with high intensities and long range beam-beam studies in the LHC

    E-Print Network [OSTI]

    Albert, M; Assmann, R; Buffat, X; Calaga, R; Cornelis, K; Fitterer, M; Giachino, R; Herr, W; Miyamoto, R; Norman, L; Papotti, G; Pieloni, T; Ponce, L; Redaelli, S; Schaumann, M; Trad, G; Wollmann, D

    2011-01-01T23:59:59.000Z

    In two experiments we studied possible limitations due to the beam-beam effects in the LHC. In the first experiment we collided high intensity bunches head-on to explore the region for high luminosity collisions. In the second test we reduced the crossing angle in the presence of long range encounters to increase their effects.

  15. Assessing Risk in Costing High-energy Accelerators: from Existing Projects to the Future Linear Collider

    E-Print Network [OSTI]

    Lebrun, Philippe

    2010-01-01T23:59:59.000Z

    High-energy accelerators are large projects funded by public money, developed over the years and constructed via major industrial contracts both in advanced technology and in more conventional domains such as civil engineering and infrastructure, for which they often constitute one-of markets. Assessing their cost, as well as the risk and uncertainty associated with this assessment is therefore an essential part of project preparation and a justified requirement by the funding agencies. Stemming from the experience with large circular colliders at CERN, LEP and LHC, as well as with the Main Injector, the Tevatron Collider Experiments and Accelerator Upgrades, and the NOvA Experiment at Fermilab, we discuss sources of cost variance and derive cost risk assessment methods applicable to the future linear collider, through its two technical approaches for ILC and CLIC. We also address disparities in cost risk assessment imposed by regional differences in regulations, procedures and practices.

  16. Observations of beam-beam effects at high intensities in the LHC

    E-Print Network [OSTI]

    Herr, W; Laface, E; Papotti, G; Pieloni, T; Alemany-Fernandez, R; Giachino, R; Schaumann, M

    2011-01-01T23:59:59.000Z

    First observations with colliding beams in the LHC with bunch intensities close to nominal and above are reported. In 2010 the LHC initially operated with few bunches spaced around the circumference. Beam-beam tune shifts exceeding significantly the design value have been observed. In a later stage crossing angles were introduced around the experiments to allow the collisions of bunch trains. We report the first experience with head-on as well as long range interactions of high intensity bunches and discuss the possible performance reach

  17. Central Diffractive Processes at the Tevatron, RHIC and LHC

    SciTech Connect (OSTI)

    Harland-Lang, L. A.; Stirling, W. J. [Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE (United Kingdom); Khoze, V. A. [Department of Physics and IPPP, University of Durham, DH1 3LE (United Kingdom); Ryskin, M. G. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg, 188300 (Russian Federation)

    2011-07-15T23:59:59.000Z

    Central exclusive production (CEP) processes in high-energy hadron collisions offer a very promising framework for studying both novel aspects of QCD and new physics signals. We report on the results of a theoretical study of the CEP of heavy quarkonia ({chi} and {eta}) at the Tevatron, RHIC and LHC (see for details [1]-[3]). These processes provide important information on the physics of bound states and can probe the current ideas and methods of QCD, such as effective field theories and lattice QCD.

  18. LHC beam behaviour

    E-Print Network [OSTI]

    Herr, W

    2010-01-01T23:59:59.000Z

    An attempt is made to extract information on the LHC beam behaviour and dynamics from the observations made during the first runs in 2009. Although no systematic studies have been made, some basic properties can be established and in particular the observations in the presence of two beams and in collision are studied. They are analyzed in view of the foreseen runs at higher energy and possible improvements are proposed.

  19. LHC Newsletter, March 2013

    E-Print Network [OSTI]

    2013-03-01T23:59:59.000Z

    became a voice, often in comic or satirical fashion, through which Hughes could comment on international relations, current events and the everyday concerns of the African American community. Charlotte Pierce-Baker What: "The Fragile Life: A...Langston Hughes Center Newsletter March 2013 Hello Everyone, This is the e-newsletter for the Langston Hughes Center (LHC). The Langston Hughes Center (formerly the Langston Hughes Resource Center, founded in 1998) is an academic...

  20. Electron reconstruction in simulated Pb+Pb events in CMS

    E-Print Network [OSTI]

    Chen, Yi, S.B. Massachusetts Institute of Technology

    2008-01-01T23:59:59.000Z

    Introduction: The Large Hadron Collider (LHC) located at Geneva, Switzerland, will be the biggest particle accelerator in the world. There are a number of detectors on the LHC ring. The LHCb detector is aimed to study ...

  1. Hadron Physics at the Charm and Bottom Thresholds and Other Novel QCD Physics Topics at the NICA Accelerator Facility

    SciTech Connect (OSTI)

    Brodsky, Stanley J.; /SLAC

    2012-06-20T23:59:59.000Z

    The NICA collider project at the Joint Institute for Nuclear Research in Dubna will have the capability of colliding protons, polarized deuterons, and nuclei at an effective nucleon-nucleon center-of mass energy in the range {radical}s{sub NN} = 4 to 11 GeV. I briefly survey a number of novel hadron physics processes which can be investigated at the NICA collider. The topics include the formation of exotic heavy quark resonances near the charm and bottom thresholds, intrinsic strangeness, charm, and bottom phenomena, hidden-color degrees of freedom in nuclei, color transparency, single-spin asymmetries, the RHIC baryon anomaly, and non-universal antishadowing.

  2. Designing and recasting LHC analyses with MadAnalysis 5

    E-Print Network [OSTI]

    Eric Conte; Béranger Dumont; Benjamin Fuks; Chris Wymant

    2014-10-10T23:59:59.000Z

    We present an extension of the expert mode of the MadAnalysis 5 program dedicated to the design or reinterpretation of high-energy physics collider analyses. We detail the predefined classes, functions and methods available to the user and emphasize the most recent developments. The latter include the possible definition of multiple sub-analyses and a novel user-friendly treatment for the selection criteria. We illustrate this approach by two concrete examples: a CMS search for supersymmetric partners of the top quark and a phenomenological analysis targeting hadronically decaying monotop systems.

  3. Delay Tolerant Bulk Data Transfers on the Internet Nikolaos Laoutaris

    E-Print Network [OSTI]

    Sundaram, Ravi

    basis. Ex- amples include pushing scientific data from particle accel- erators/colliders to laboratories, CERN's Large Hadron Collider (LHC) is producing daily 27 Tbytes of particle colli- sion data that need

  4. Delay Tolerant Bulk Data Transfers on the Internet Nikolaos Laoutaris

    E-Print Network [OSTI]

    Smaragdakis, Georgios

    basis. Ex­ amples include pushing scientific data from particle accel­ erators/colliders to laboratories, CERN's Large Hadron Collider (LHC) is producing daily 27 Tbytes of particle colli­ sion data that need

  5. DelayTolerant Bulk Data Transfers on the Internet NIKOLAOS LAOUTARIS + GEORGIOS SMARAGDAKIS # RADE STANOJEVIC +

    E-Print Network [OSTI]

    Smaragdakis, Georgios

    from particle acceler­ ators/colliders to laboratories around the world, synchronizing data, CERN's Large Hadron Collider (LHC) is producing daily 27 Tbytes of particle collision data that need

  6. Charmed hadron production at low transverse momentum in Au+Au collisions at RHIC

    E-Print Network [OSTI]

    B. I. Abelev

    2014-04-25T23:59:59.000Z

    We report measurements of charmed hadron production from hadronic ($D^{0}\\rightarrow K\\pi$) and semileptonic ($\\mu$ and $e$) decays in 200 GeV Au+Au collisions at RHIC. Analysis of the spectra indicates that charmed hadrons have a different radial flow pattern from light or multi-strange hadrons. Charm cross sections at mid-rapidity are extracted by combining the three independent measurements, covering the transverse momentum range that contributes to $\\sim$90% of the integrated cross section. The cross sections scale with number of binary collisions of the initial nucleons, a signature of charm production exclusively at the initial impact of colliding heavy ions. The implications for charm quark interaction and thermalization in the strongly interacting matter are discussed.

  7. Comparison of photon colliders based on e-e- and e+e- beams

    E-Print Network [OSTI]

    V. I. Telnov

    2005-07-15T23:59:59.000Z

    At photon colliders gamma-gamma, gamma-electron high energy photons are produced by Compton scattering of laser light off the high energy electrons (or positrons) at a linear collider. At first sight, photon colliders based on e-e- or e+e- primary beams have similar properties and therefore for convenience one can use e+e- beams both for e+e- and gamma-gamma modes of operation. Below we compare these options and show that e-e- beams are much better (mandatory) because in the e+e- case low energy background gamma-gamma to hadrons is much higher and e+e- annihilation reactions present a very serious background for gamma-gamma processes.

  8. Muon Collider Task Force Report

    SciTech Connect (OSTI)

    Ankenbrandt, C.; Alexahin, Y.; Balbekov, V.; Barzi, E.; Bhat, C.; Broemmelsiek, D.; Bross, A.; Burov, A.; Drozhdin, A.; Finley, D.; Geer, S.; /Fermilab /Argonne /Brookhaven /Jefferson Lab /LBL, Berkeley /MUONS Inc., Batavia /UCLA /UC, Riverside /Mississippi U.

    2007-12-01T23:59:59.000Z

    Muon Colliders offer a possible long term path to lepton-lepton collisions at center-of-mass energies {radical}s {ge} 1 TeV. In October 2006 the Muon Collider Task Force (MCTF) proposed a program of advanced accelerator R&D aimed at developing the Muon Collider concept. The proposed R&D program was motivated by progress on Muon Collider design in general, and in particular, by new ideas that have emerged on muon cooling channel design. The scope of the proposed MCTF R&D program includes muon collider design studies, helical cooling channel design and simulation, high temperature superconducting solenoid studies, an experimental program using beams to test cooling channel RF cavities and a 6D cooling demonstration channel. The first year of MCTF activities are summarized in this report together with a brief description of the anticipated FY08 R&D activities. In its first year the MCTF has made progress on (1) Muon Collider ring studies, (2) 6D cooling channel design and simulation studies with an emphasis on the HCC scheme, (3) beam preparations for the first HPRF cavity beam test, (4) preparations for an HCC four-coil test, (5) further development of the MANX experiment ideas and studies of the muon beam possibilities at Fermilab, (6) studies of how to integrate RF into an HCC in preparation for a component development program, and (7) HTS conductor and magnet studies to prepare for an evaluation of the prospects for of an HTS high-field solenoid build for a muon cooling channel.

  9. Search for Light Higgs Boson at LHC via Production Through Weak Boson Fusion

    E-Print Network [OSTI]

    K. Mazumdar

    2003-08-29T23:59:59.000Z

    The LHC potential for observing a light Higgs boson produced through Weak Boson Fusion mode, ${\\rm qq}\\to {\\rm qqH}$, is presented. For non-hadronic decays modes of the Higgs boson the process is identified with a final state containing two energetic forward-backward jets, separated with a large rapidity and a hadronically quiet central region. The use of these properties, combined with special features of some of the decay modes enhances the potential of an early discovery of a light Higgs boson both in the Standard Model and beyond. The recent studies done in the context of CMS experiment are discussed.

  10. Hadron Spectroscopy with COMPASS

    E-Print Network [OSTI]

    Boris Grube; for the COMPASS Collaboration

    2011-08-29T23:59:59.000Z

    COMPASS is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron aimed at studying the structure and spectrum of hadrons. One primary goal is the search for new hadronic states, in particular spin-exotic mesons and glueballs. We present recent results of partial-wave analyses of (3\\pi)^- and \\pi^-\\eta' final states based on a large data set of diffractive dissociation of a 190 GeV/c \\pi^- beam on a proton target in the squared four-momentum-transfer range 0.1 < t' < 1 (GeV/c)^2. We also show first results from a partial-wave analysis of diffractive dissociation of K^- into K^-\\pi^+\\pi^- final states are presented.

  11. Report of Snowmass 2001 Working Group E2 : Electron-positron Colliders from the $?$ to the Z

    E-Print Network [OSTI]

    Z. Zhao; G. Eigen; G. Burdman; W. Marciano; D. Hitlin; M. Mandelkern; A. Soffer; D. Cassel; L. Gibbons; K. Moenig; J. Butler; P. Kasper; R. Kutschke; P. Mackenzie; S. Pordes; R. Ray; T. Sen; D. Bettoni; R. Calabrese; C. Bloise; D. Kaplan; N. Katayama; Y. Okada; Y. Ohnishi; H. Yamamoto; A. Gritsan; S. Dytman; J. Lee; I. Shipsey; Y. Maravin; F. J. Decker; G. Hiller; P. Kim; D. Leith; S. Petrak; S. Robertson; A. Roodman; J. Seeman; M. Artuso; S. Stone; X. Lou; M. Luke; W. Johns

    2002-01-30T23:59:59.000Z

    We report on the status and plans of experiments now running or proposed for electron-positron colliders at energies between the $\\phi$ and the Z. The $e^{+}e^{-}$ B and charm factories we considered were PEP-II/BABAR, KEKB/Belle, superKEK, SuperBABAR, and CESR-c/CLEO-c. We reviewed the programs at the $\\phi$ factory at Frascati and the proposed PEP-N facility at Stanford Linear Accelerator Center. We studied the prospects for B physics with a dedicated linear collider Z factory, associated with the TESLA high energy linear collider. In all cases, we compared the physics reach of these facilities with that of alternative experiments at hadron colliders or fixed target facilities.

  12. Commissioning of CMS and early standard model measurements with jets, missing transverse energy and photons at the LHC

    E-Print Network [OSTI]

    T. Christiansen

    2008-05-13T23:59:59.000Z

    We report on the status and history of the CMS commissioning, together with selected results from cosmic-ray muon data. The second part focuses on strategies for optimizing the reconstruction of jets, missing transverse energy and photons for early standard model measurements at ATLAS and CMS with the first collision data from the Large Hadron Collider at CERN.

  13. Top Physics at the LHC

    E-Print Network [OSTI]

    P. de Jong

    2009-02-27T23:59:59.000Z

    The LHC will be a top quark factory. In this note, the central role of the top quark for LHC physics will be discussed, and an overview will be given of the studies of top quark properties in preparation, with an emphasis on the systematic uncertainties that will dominate most measurements.

  14. Holographic light quark jet quenching at RHIC and LHC via the shooting strings

    E-Print Network [OSTI]

    Andrej Ficnar; Steven S. Gubser; Miklos Gyulassy

    2014-04-03T23:59:59.000Z

    A new shooting string holographic model of jet quenching of light quarks in strongly coupled plasmas is presented to overcome the phenomenological incompatibilities of previous falling string holographic scenarios that emerged when confronted with the recent LHC data. This model is based on strings with finite momentum endpoints that start close to the horizon and lose energy as they approach the boundary. This framework is applied to compute the nuclear modification factor RAA of light hadrons at RHIC and LHC, showing that this model improves greatly the comparison with the recent light hadron suppression data. The effects of the Gauss-Bonnet quadratic curvature corrections to the AdS5 geometry further improve the agreement with the data.

  15. Physics at high energy photon photon colliders

    SciTech Connect (OSTI)

    Chanowitz, M.S.

    1994-06-01T23:59:59.000Z

    I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking.

  16. Jet Production Studies at Colliders

    E-Print Network [OSTI]

    Robert Hirosky

    2013-05-02T23:59:59.000Z

    An overview of jet production, measurement techniques, and recent physics results from colliders is presented. Analyses utilizing jets and boson plus jets final states are included and implications of the data are discussed. The results presented here are a snapshot of those available at the time of the PIC 2012 conference in September 2012.

  17. Colliding axisymmetric pp-waves

    E-Print Network [OSTI]

    B. V. Ivanov

    1997-10-21T23:59:59.000Z

    An exact solution is found describing the collision of axisymmetric pp-waves with M=0. They are impulsive in character and their coordinate singularities become point curvature singularities at the boundaries of the interaction region. The solution is conformally flat. Concrete examples are given, involving an ultrarelativistic black hole against a burst of pure radiation or two colliding beam- like waves.

  18. From Neutrino Factory to Muon Collider

    SciTech Connect (OSTI)

    Geer, S.; /Fermilab

    2010-01-01T23:59:59.000Z

    Both Muon Colliders and Neutrino Factories require a muon source capable of producing and capturing {Omicron}(10{sup 21}) muons/year. This paper reviews the similarities and differences between Neutrino Factory and Muon Collider accelerator complexes, the ongoing R&D needed for a Muon Collider that goes beyond Neutrino Factory R&D, and some thoughts about how a Neutrino Factory on the CERN site might eventually be upgraded to a Muon Collider.

  19. High energy hadron-hadron collisions. [Dept. of Physics and Astronomy, Univ. of Georgia, Athens, Georgia

    SciTech Connect (OSTI)

    Chou, T.T.

    1992-01-01T23:59:59.000Z

    Results of a study on high energy collisions with the geometrical model are summarized in three parts: (1) the elastic hadron-hadron collision, (2) the inelastic hadron-hadron collision, and (3) e[sup +]e[sup [minus

  20. LHC - a "Why" Facility

    ScienceCinema (OSTI)

    Gordon Kane

    2010-01-08T23:59:59.000Z

    The Standard Models of particle physics and cosmology describe the world we see, and how it works, very well. But we want to understand (not just accommodate) much more ? how does the Higgs mechanism work, what is the dark matter, why is the universe matter and not antimatter, why is parity violated, why are the particles (quarks and leptons) what they are, and why are the forces that act on them to make our world what they are, and more. Today is an exciting time to be doing particle physics ? on the experimental side we have data coming from LHC and dark matter experiments that will provide clues to these questions, and on the theoretical side we have a framework (string theory) that addresses all these ?why? questions. LHC data will not qualitatively improve our description ? rather, it may provide the data that will allow us to learn about the dark matter, the Higgs physics, the matter asymmetry, etc, to test underlying theories such as string theory, and begin to answer the ?why? questions. Supersymmetry is the best motivated discovery, and it would also open a window to the underlying theory near the Planck scale.

  1. Energy dependence of hadron spectra and multiplicities in p+p interactions

    E-Print Network [OSTI]

    Pu?awski, Szymon

    2015-01-01T23:59:59.000Z

    The NA61/SHINE experiment at the CERN SPS aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. In order to reach these goals measurements of hadron production properties are performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a function of collision energy and size of the colliding nuclei. Inclusive spectra of identified hadrons in p+p interactions at the SPS energies are presented as a function of transverse momentum, transverse mass and rapidity. The results are compared with the world data and theoretical models.

  2. Muon Collider Physics at Very High Energies

    E-Print Network [OSTI]

    M. S. Berger

    2000-01-03T23:59:59.000Z

    Muon colliders might greatly extend the energy frontier of collider physics. One can contemplate circular colliders with center-of-mass energies in excess of 10 TeV. Some physics issues that might be relevant at such a machine are discussed.

  3. ATLAS Jet Trigger Update for the LHC Run II

    E-Print Network [OSTI]

    Tavares Delgado, Ademar; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    The CERN Large Hadron Collider is the biggest and most powerful particle collider ever built. It produces up to 40 million proton-proton collisions per second at unprecedented energies to explore the fundamental laws and properties of Nature. The ATLAS experiment is one of the detectors that analyses and records these collisions. It generates dozens of GB/s of data that has to be reduced before it can be permanently stored, the event selection is made by the ATLAS trigger system, which reduces the data volume by a factor of 10^5 . The trigger system has to be highly configurable in order to adapt to changing running conditions and maximize the physics output whilst keeping the output rate under control. A particularly interesting pattern generated during collisions consists of a collimated spray of particles, known as a hadronic jet. To retain the interesting jets and efficiently reject the overwhelming background, optimal jet energy resolution is needed. Therefore the Jet trigger software requires CPU-intens...

  4. Hadron Spectroscopy in COMPASS

    E-Print Network [OSTI]

    Boris Grube; for the COMPASS Collaboration

    2013-01-31T23:59:59.000Z

    The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. In the naive Constituent Quark Model (CQM) mesons are bound states of quarks and antiquarks. QCD, however, predict the existence of hadrons beyond the CQM with exotic properties interpreted as excited glue (hybrids) or even pure gluonic bound states (glueballs). One main goal of COMPASS is to search for these states. Particularly interesting are so called spin-exotic mesons which have J^{PC} quantum numbers forbidden for ordinary q\\bar{q} states. Its large acceptance, high resolution, and high-rate capability make the COMPASS experiment an excellent device to study the spectrum of light-quark mesons in diffractive and central production reactions up to masses of about 2.5 GeV. COMPASS is able to measure final states with charged as well as neutral particles, so that resonances can be studied in different reactions and decay channels. During 2008 and 2009 COMPASS acquired large data samples using negative and positive secondary hadron beams on lH_2, Ni, and Pb targets. The presented overview of the first results from this data set focuses in particular on the search for spin-exotic mesons in diffractively produced \\pi^-\\pi^+\\pi^-, \\eta\\pi, \\eta'\\pi, and \\pi^-\\pi^+\\pi^-\\pi^+\\pi^- final states and the analysis of central-production of \\pi^+\\pi^- pairs in order to study glueball candidates in the scalar sector.

  5. High energy hadron-hadron collisions. Annual progress report

    SciTech Connect (OSTI)

    Chou, T.T.

    1991-12-01T23:59:59.000Z

    Results of a study on high energy collision with the geometrical model are summarized in three parts: (1) the elastic hadron-hadron collision, (2) the inelastic hadron-hadron collision, and (3) the e{sup +}e{sup {minus}} annihilation. More recent studies are highlighted below. For elastic scattering, a modified form for the hadronic matter form factor of the proton was proposed which remains to be dipole in form but contains an energy-dependent range parameter. This new expression of the opacity function fits the elastic {bar p}p scattering very well from the ISR to S{bar p}pS energies. Extrapolation of this theory also yielded results in good agreement with the {bar p}p differential cross section measured at the Tevatron. For inelastic hadron-hadron collisions, we have made a systematic investigation of the single-particle momentum spectra in the entire S{bar p}pS energy region. Results are useful for the extrapolation of angular distribution to the higher SSC energies. In e{sup +}e{sup {minus}} annihilation, a detailed analysis of all available experimental multiplicity data from PETRA to LEP energies has been performed. We discovered that the cluster size of emitted hadrons increases steadily with energy and is close to 2 as we predicted.

  6. High energy hadron-hadron collisions. Annual progress report

    SciTech Connect (OSTI)

    Chou, T.T.

    1992-12-31T23:59:59.000Z

    Results of a study on high energy collisions with the geometrical model are summarized in three parts: (1) the elastic hadron-hadron collision, (2) the inelastic hadron-hadron collision, and (3) e{sup +}e{sup {minus}} annihilation. For elastic scattering, a modified form for the hadronic matter form factor of the proton was proposed which is still dipole in form but contains an energy--dependent range parameter. This new expression of the opacity function fits the elastic {bar p}p scattering very well from the ISR to S{bar p}pS energies. Extrapolation of this theory also yielded results {bar p}p in good agreement with the {bar p}p differential cross section measured at the Tevatron. For inelastic hadron-hadron collisions, we have made a systematic investigation of the single-particle momentum spectra in the entire S{bar p}pS energy region. Results are useful for the extrapolation of angular distribution to the higher SSC energies. In e{sup +}e{sup {minus}} annihilation, a detailed analysis of all available experimental multiplicity data from PETRA to LEP energies has been performed. The cluster size of emitted hadrons increases gradually with energy. Aside from high-energy collisions, the giant fullerene molecules were studied and precise algebraic eigenvalue expressions of the Hueckel problem for carbon-240 were obtained.

  7. Minijet transverse energy production in the next-to-leading order in hadron and nuclear collisions

    E-Print Network [OSTI]

    A. V. Leonidov; D. M. Ostrovsky

    1998-11-23T23:59:59.000Z

    The transverse energy flow generated by minijets in hadron and nuclear collisions into a given rapidity window in the central region is calculated in the next-to-leading (NLO) order in QCD at RHIC and LHC energies. The NLO transverse energy production in pp collisions cross sections are larger than the LO ones by the factors of K_{RHIC} ~ 1.9 and K_{LHC} ~ 2.1 at RHIC and LHC energies correspondingly. These results were then used to calculate transverse energy spectrum in nuclear collisions in a Glauber geometrical model. We show that accounting for NLO corrections in the elementary pp collisions leads to a substantial broadening of the E_{perp} distribution for the nuclear ones, while its form remains practically unchanged.

  8. Operational Experience and First Results with a Highly Granular Tungsten Analog Hadron Calorimeter

    E-Print Network [OSTI]

    Frank Simon; for the CALICE Collaboration

    2011-11-22T23:59:59.000Z

    Precision physics at future multi-TeV lepton colliders such as CLIC requires excellent jet energy resolution. The detectors need deep calorimeter systems to limit the energy leakage also for very highly energetic particles and jets. At the same time, compact physical dimensions are mandatory to permit the installation of the complete calorimeter system inside high-field solenoidal magnets. This requires very dense absorbers, making tungsten a natural choice for hadron calorimeters at such a future collider. To study the performance of such a calorimeter, a physics prototype with tungsten absorbers and scintillator tiles with SiPM readout as active elements has been constructed and has been tested in particle beams at CERN over a wide energy range from 1 GeV to 300 GeV. We report on the construction and on the operational experience obtained with muon, electron and hadron beams.

  9. High energy hadron-hadron collisions. Final report

    SciTech Connect (OSTI)

    Chou, T.T.

    1995-08-01T23:59:59.000Z

    This project of studying high energy collision phenomena with the geometrical model has been undertaken and developed by this investigator and collaborators since 1967. Instead of basing conjectures on mathematical extrapolations from some ad hoc theories, this approach was to scrutinize first the general features of the phenomena before going into specific details. This particular method has proved successful in correlating experimental data, suggesting experiments, predicting new phenomena and guiding future experimental studies. In the following, important results of the geometrical model obtained with the support of the DOE grant are summarized in three parts: the elastic hadron-hadron scattering, the inelastic hadron-hadron collision, and the hadronic production in e{sup +}e{sup {minus}} annihilation. The fourth part of this report outlines the results of other topics of investigation. To avoid repetition, only the main physical ideas and essential experimental evidences are presented, leaving out detailed discussions which can be found in the literature and previous reports.

  10. LHC Higgs Boson searches

    E-Print Network [OSTI]

    William Murray

    2012-01-22T23:59:59.000Z

    A summary of the Higgs boson searches by the ATLAS and CMS collabrations using 1 f b-1 of LHC data is presented, concentrating on the Standard Model Higgs boson. Both experiments have the sensitivity to exclude at 95% CL a Standard Model Higgs boson in most of the Higgs boson mass region between about 130 GeV and 400 GeV. The observed data allow the exclusion of a Higgs Boson of mass 155 GeV to 190 GeV and 295 GeV to 450 GeV (ATLAS) and 149 GeV to 206 GeV and 300 GeV to 440 GeV (CMS). The lower limits are not as constraining as might be expected due to an excess in both experiments of order 2-3{\\sigma} which could be related to a low mass Higgs boson or to a statistical fluctuation.

  11. Strange particle production in hadronic Z{sup 0} decays

    SciTech Connect (OSTI)

    Baird, K.G. III

    1996-04-01T23:59:59.000Z

    A study has been made of neutral strange baryons and pseudoscalar mesons produced in hadronic decays of the weak gauge boson V. The experiment was performed at the Stanford Linear Accelerator Center, which has the unique capability of colliding highly polarized electrons with unpolarized positrons. Overall production rates and spectra of the K{sup 0} and the {Lambda}{sup 0} (+{Lambda}{sup 0}) were measured and compared with other experiments as well as with Quantum Chromodynamics calculations. The combination of the small, stable beam spots produced by the SLAC Linear Collider (SLC) and the precision vertexing capabilities of the SLC Large Detector (SLD) permitted the separation of the hadronic events into three quark flavor-enriched samples. An unfolding was performed to obtain flavor-pure samples, and for the first time measurements were made of K{sup 0} and {Lambda}{sup 0} (+{Lambda}{sup 0}) production rates and spectra in uds, c, and b quark events at the Z{sup 0} pole. This measurement revealed significant production differences. Utilizing the large quark production asymmetry due to the polarized electron beam, high-purity quark and antiquark jet samples were obtained. The first measurement of production differences of the {Lambda}{sup 0} baryon in quark and antiquark jets was performed, which provided clear evidence for a leading particle effect at high momenta.

  12. Left-Right Symmetry: from LHC to Neutrinoless Double Beta Decay

    E-Print Network [OSTI]

    Vladimir Tello; Miha Nemevsek; Fabrizio Nesti; Goran Senjanovi?; Francesco Vissani

    2011-03-29T23:59:59.000Z

    The Large Hadron Collider has a potential to probe the scale of left-right symmetry restoration and the associated lepton number violation. Moreover, it offers hope of measuring the right-handed leptonic mixing matrix. We show how this, together with constraints from lepton flavor violating processes, can be used to make predictions for neutrinoless double beta decay. We illustrate this deep connection in the case of the type-II seesaw.

  13. Left-Right Symmetry: From the LHC to Neutrinoless Double Beta Decay

    SciTech Connect (OSTI)

    Tello, Vladimir [SISSA, Trieste (Italy); Nemevsek, Miha [ICTP, Trieste (Italy); Jozef Stefan Institute, Ljubljana (Slovenia); Nesti, Fabrizio [Universita di Ferrara, Ferrara (Italy); Senjanovic, Goran [ICTP, Trieste (Italy); Vissani, Francesco [LNGS, INFN, Assergi (Italy)

    2011-04-15T23:59:59.000Z

    The Large Hadron Collider has the potential to probe the scale of left-right symmetry restoration and the associated lepton number violation. Moreover, it offers the hope of measuring the right-handed leptonic mixing matrix. We show how this, together with constraints from lepton flavor violating processes, can be used to make predictions for neutrinoless double beta decay. We illustrate this connection in the case of the type-II seesaw.

  14. Heavy-quark probes of the quark-gluon plasma and interpretation of recent data taken at the BNL Relativistic Heavy Ion Collider 

    E-Print Network [OSTI]

    van Hees, H.; Greco, V.; Rapp, Ralf.

    2006-01-01T23:59:59.000Z

    strongly interacting QGP (sQGP), as well as parton coalescence, can play an essential role in the interpretation of recent data from the BNL Relativistic Heavy-Ion Collider (RHIC), and thus illuminate the nature of the sQGP and its hadronization. Our main...

  15. Performance of the Large Scale Prototypes of the CALICE Tile Hadron Calorimeter

    E-Print Network [OSTI]

    Reinecke, M

    2015-01-01T23:59:59.000Z

    The concept of a tile hadron calorimeter (HCAL) for the International Linear Collider (ILC) has been developed. A major aspect is the improvement of the jet energy resolution by measuring details of the shower development and combining them with the data of the tracking chamber (particle flow). The concept utilizes scintillating tiles that are read out by novel Silicon Photomultipliers (SiPMs) and takes into account all design aspects that are demanded by the intended operation

  16. Proton structure at the LHC 

    E-Print Network [OSTI]

    Hartland, Nathan Philip

    2014-11-27T23:59:59.000Z

    A determination of Parton Distribution Functions (PDFs) from a global fit to a dataset including measurements from the LHC has been performed for the first time. The determinations have been performed according to the ...

  17. L'Aventure du LHC

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    Cette présentation s?adressera principalement aux personnes qui ont construit le LHC. La construction du LHC fut longue et difficile. De nombreux problèmes sont apparus en cours de route. Tous ont été résolus grâce au dévouement et à l?engagement du personnel et des collaborateurs. Je reviendrai sur les coups durs et les réussites qui ont marqués ces 15 dernières années et je vous montrerai combien cette machine, le fruit de vos efforts, est extraordinaire.

  18. Momentum space dipole amplitude for DIS and inclusive hadron production

    SciTech Connect (OSTI)

    Basso, E. A.; Gay Ducati, M. B. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 - Porto Alegre, RS (Brazil); De Oliveira, E. G. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05314-970 Sao Paulo, SP (Brazil)

    2013-03-25T23:59:59.000Z

    We show how the AGBS model, originally developed for deep inelastic scattering applied to HERA data on the proton structure function, can also describe the RHIC data on single inclusive hadron yield for d+Au and p+p collisions through a new simultaneous fit. The single inclusive hadron production is modeled through the color glass condensate, which uses the quark(and gluon) condensate amplitudes in momentum space. The AGBS model is also a momentum space model based on the asymptotic solutions of the BK equation, although a different definition of the Fourier transform is used. This description entirely in transverse momentum of both processes arises for the first time. The small difference between the simultaneous fit and the one for HERA data alone suggests that the AGBS model describes very well both kind of processes and thus emerges as a good tool to investigate the inclusive hadron production data. We use this model for predictions at LHC energies, which agree quite well with available experimental data.

  19. Le LHC, un tunnel cosmique

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d?autres termes, qu?est-ce que le LHC peut nous apporter dans la connaissance de l?Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l?univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l?Univers ? La matière noire est-elle détectable au LHC ? L?énergie noire ? Pourquoi l?antimatière accumulée au CERN est-elle si rare dans l?Univers ? Et si le CERN a bâti sa réputation sur l?exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l?évolution cosmique ? Depuis une trentaine d?années, notre compréhension de l?univers dans ses plus grandes dimensions et l?appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

  20. TLEP: A High-Performance Circular e+e- Collider to Study the Higgs Boson

    E-Print Network [OSTI]

    Koratzinos, M; Aleksan, R; Brunner, O; Butterworth, A; Janot, P; Jensen, E; Osborne, J; Zimmermann, F; Ellis, J R; Zanetti, M

    2013-01-01T23:59:59.000Z

    The recent discovery of a light Higgs boson has opened up considerable interest in circular e+e- Higgs factories around the world. We report on the progress of the "TLEP" concept since last year. TLEP is an e+e- circular collider capable of very high luminosities in a wide centre-of-mass (ECM) spectrum from 90 to 350 GeV. TLEP could be housed in a new 80 to 100 km tunnel in the Geneva region. The design can be adapted to different ring circumference (e.g. 'LEP3' in the 27 km LHC tunnel). TLEP is an ideal complementary machine to the LHC thanks to high luminosity, exquisite determination of ECM and the possibility of four interaction points, both for precision measurements of the Higgs boson properties and for precision tests of the closure of the Standard Model from the Z pole to the top threshold. Presented at IPAC'13 Shanghai, 12-17 May 2013

  1. TLEP: A high-Performance Circular $e^{+}e^{-}$ Collider to Study the Higgs Boson

    E-Print Network [OSTI]

    Koratzinos, M; Aleksan, R; Brunner, O; Butterworth, A; Janot, P; Jensen, E; Osborne, J; Zimmermann, F; Ellis, J R; Zanetti, M

    2013-01-01T23:59:59.000Z

    The recent discovery of a light Higgs boson has opened up considerable interest in circular $e^+e^-$ Higgs factories around the world. We report on the progress of the TLEP concept since last year. TLEP is an $e^+e^-$ circular collider capable of very high luminosities in a wide centre-of-mass (ECM) spectrum from 90 to 350 GeV. TLEP could be housed in a new 80 to 100 km tunnel in the Geneva region. The design can be adapted to different ring circumference (e.g. LEP3 in the 27 km LHC tunnel). TLEP is an ideal complementary machine to the LHC thanks to high luminosity, exquisite determination of ECM and the possibility of four interaction points, both for precision measurements of the Higgs boson properties and for precision tests of the closure of the Standard Model from the Z pole to the top threshold.

  2. Isolating Wt production at the LHC

    E-Print Network [OSTI]

    Chris D. White; Stefano Frixione; Eric Laenen; Fabio Maltoni

    2009-11-20T23:59:59.000Z

    We address the issue of single top production in association with a W boson at the Large Hadron Collider, in particular how to obtain an accurate description in the face of the top pair production background given that the two processes interfere with each other. We stress the advantages of an MC@NLO description, and find that for cuts used to isolate the signal, it makes sense to consider Wt as a well-defined production process in that the interference with top pair production is small, and the cross-section of the former is above the scale variation uncertainty associated with the latter. We also consider the case where both Wt and top pair production are backgrounds to a third process (Higgs boson production followed by decay to a W boson pair), and find in this context that interference issues can also be neglected. We discuss the generalization of our results to other situations, aided by a comparison between the MC@NLO approach and a calculation of the WWbb final state matched to a parton shower.

  3. Charmonium absorption and charmed hadron production in hadronic reactions 

    E-Print Network [OSTI]

    Liu, Wei

    2005-02-17T23:59:59.000Z

    for understanding charm production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC), where a quark-gluon plasma is expected to be formed during the initial hot dense stage....

  4. The influence of net-quarks on the yields and rapidity spectra of identified hadrons

    E-Print Network [OSTI]

    Jun Song; Feng-lan Shao; Qu-bing Xie; Yun-fei Wang; De-ming Wei

    2008-02-21T23:59:59.000Z

    Within a quark combination model, we study systematically the yields and rapidity spectra of various hadrons in central Au+Au collisions at $\\sqrt{s_{NN}}= 200$ GeV. We find that considering the difference in rapidity between net-quarks and newborn quarks, the data of multiplicities, rapidity distributions for $\\pi^{\\pm}$, $K^{\\pm}$, $p(\\bar{p})$ and, in particular the ratios of charged antihadron to hadron as a function of rapidity, can be well described. The effect of net-quarks on various hadrons is analysed, and the rapidity distributions for $K^{0}_{s}$, $\\Lambda(\\bar{\\Lambda})$, $\\Sigma^{+}(\\bar{\\Sigma}^{_-})$, $\\mathrm{\\Xi^{-}}$ ($\\mathrm{\\bar{\\Xi}^{_+}}$) and $\\mathrm{\\Omega^{-}}(\\mathrm{\\bar{\\Omega}}^{_+})$ are predicted. We discuss the rapidity distribution of net-baryon, and find that it reflects exactly the energy loss of colliding nuclei.

  5. International Workshop on Linear Colliders 2010

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat  IWLC2010 is hosted by CERN

  6. Harmonic potential and hadron spectroscopy

    E-Print Network [OSTI]

    Rafael Tumanyan

    2009-05-28T23:59:59.000Z

    The quark-gluon sea in the hadrons is considered as periodically correlated. Energy levels of Shrodinger equation with harmonic potential is used for describing of the spectrum of hadron masses. In the considered cases the effective potential operating on each particle of ensemble, under certain conditions becomes square-law on displacement from a equilibrium point. It can become an explanation of popularity of oscillator potential for the description of a spectrum of masses of elementary particles. The analysis shows that levels of periodic potential better agreed to the spectrum of hadron masses, than levels of other potentials used for an explanation of a spectrum of masses.

  7. Muon Colliders and Neutrino Factories

    E-Print Network [OSTI]

    Daniel M. Kaplan; for the MAP; MICE Collaborations

    2014-12-10T23:59:59.000Z

    Muon colliders and neutrino factories are attractive options for future facilities aimed at achieving the highest lepton-antilepton collision energies and precision measurements of Higgs boson and neutrino mixing matrix parameters. The facility performance and cost depend on how well a beam of muons can be cooled. Recent progress in muon cooling design studies and prototype tests nourishes the hope that such facilities could be built starting in the coming decade. The status of the key technologies and their various demonstration experiments is summarized. Prospects "post-P5" are also discussed.

  8. Muon Colliders and Neutrino Factories

    E-Print Network [OSTI]

    Kaplan, Daniel M

    2014-01-01T23:59:59.000Z

    Muon colliders and neutrino factories are attractive options for future facilities aimed at achieving the highest lepton-antilepton collision energies and precision measurements of Higgs boson and neutrino mixing matrix parameters. The facility performance and cost depend on how well a beam of muons can be cooled. Recent progress in muon cooling design studies and prototype tests nourishes the hope that such facilities could be built starting in the coming decade. The status of the key technologies and their various demonstration experiments is summarized. Prospects "post-P5" are also discussed.

  9. US LHC Accelerator Project Baseline Change Request BCR Number 58

    E-Print Network [OSTI]

    Large Hadron Collider Program

    to correspond to the current LHC installation schedule, constrained by the U.S. LHC Project end-of-project

  10. Siting the International Linear Collider at Hanford

    SciTech Connect (OSTI)

    Kouzes, Richard T.; Asner, David M.; Brodzinski, Ronald L.; Fast, James E.; Miley, Harry S.

    2012-03-15T23:59:59.000Z

    Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facilityl.

  11. Siting the International Linear Collider at Hanford

    SciTech Connect (OSTI)

    Kouzes, Richard T.; Asner, David M.; Brodzinski, Ronald L.; Fast, James E.; Miley, Harry S.

    2012-05-01T23:59:59.000Z

    Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facility.

  12. Studies of Transverse-Momentum-Dependent distributions with A Fixed-Target ExpeRiment using the LHC beams (AFTER@LHC)

    E-Print Network [OSTI]

    L. Massacrier; M. Anselmino; R. Arnaldi; S. J. Brodsky; V. Chambert; W. den Dunnen; J. P. Didelez; B. Genolini; E. G. Ferreiro; F. Fleuret; Y. Gao; C. Hadjidakis; I. Hrivnacova; J. P. Lansberg; C. Lorcé; R. Mikkelsen; C. Pisano; A. Rakotozafindrabe; P. Rosier; I. Schienbein; M. Schlegel; E. Scomparin; B. Trzeciak; U. I. Uggerhoj; R. Ulrich; Z. Yang

    2015-02-03T23:59:59.000Z

    We report on the studies of Transverse-Momentum-Dependent distributions (TMDs) at a future fixed-target experiment --AFTER@LHC-- using the $p^+$ or Pb ion LHC beams, which would be the most energetic fixed-target experiment ever performed. AFTER@LHC opens new domains of particle and nuclear physics by complementing collider-mode experiments, in particular those of RHIC and the EIC projects. Both with an extracted beam by a bent crystal or with an internal gas target, the luminosity achieved by AFTER@LHC surpasses that of RHIC by up to 3 orders of magnitude. With an unpolarised target, it allows for measurements of TMDs such as the Boer-Mulders quark distributions and the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using polarised targets, one can access the quark and gluon Sivers TMDs through single transverse-spin asymmetries in Drell-Yan and quarkonium production. In terms of kinematics, the fixed-target mode combined with a detector covering $\\eta_{\\rm lab} \\in [1,5]$ allows one to measure these asymmetries at large $x^\\uparrow$ in the polarised nucleon.

  13. Stochastic cooling in muon colliders

    SciTech Connect (OSTI)

    Barletta, W.A.; Sessler, A.M.

    1993-09-01T23:59:59.000Z

    Analysis of muon production techniques for high energy colliders indicates the need for rapid and effective beam cooling in order that one achieve luminosities > 10{sup 30} cm{sup {minus}2}s{sup {minus}1} as required for high energy physics experiments. This paper considers stochastic cooling to increase the phase space density of the muons in the collider. Even at muon energies greater than 100 GeV, the number of muons per bunch must be limited to {approximately}10{sup 3} for the cooling rate to be less than the muon lifetime. With such a small number of muons per bunch, the final beam emittance implied by the luminosity requirement is well below the thermodynamic limit for beam electronics at practical temperatures. Rapid bunch stacking after the cooling process can raise the number of muons per bunch to a level consistent with both the luminosity goals and with practical temperatures for the stochastic cooling electronics. A major advantage of our stochastic cooling/stacking scheme over scenarios that employ only ionization cooling is that the power on the production target can be reduced below 1 MW.

  14. LHC constraints on gauge boson couplings to dark matter

    E-Print Network [OSTI]

    Crivellin, Andreas; Hibbs, Anthony

    2015-01-01T23:59:59.000Z

    Collider searches for energetic particles recoiling against missing transverse energy allow to place strong bounds on the interactions between dark matter (DM) and standard model particles. In this article we update and extend LHC constraints on effective dimension-7 operators involving DM and electroweak gauge bosons. A concise comparison of the sensitivity of the mono-photon, mono-W, mono-Z, mono-W/Z, invisible Higgs-boson decays in the vector boson fusion mode and the mono-jet channel is presented. Depending on the parameter choices, either the mono-photon or the mono-jet data provide the most stringent bounds at the moment. We furthermore explore the potential of improving the current 8 TeV limits at 14 TeV. Future strategies capable of disentangling the effects of the different effective operators involving electroweak gauge bosons are discussed as well.

  15. 27. Accelerator physics of colliders 1 27. ACCELERATOR PHYSICS OF COLLIDERS

    E-Print Network [OSTI]

    's facilities, and end with some remarks on future possibilities. 27.2. Beam Dynamics The first concern of beam27. Accelerator physics of colliders 1 27. ACCELERATOR PHYSICS OF COLLIDERS Revised July 2011 by D × L (t)dt. (27.1) Today's colliders all employ bunched beams. If two bunches containing n1 and n2

  16. 25. Accelerator physics of colliders 1 25. ACCELERATOR PHYSICS OF COLLIDERS

    E-Print Network [OSTI]

    's facilities, and end with some remarks on future possibilities. 25.2. Beam Dynamics The first concern of beam25. Accelerator physics of colliders 1 25. ACCELERATOR PHYSICS OF COLLIDERS Revised July 2011 by D × L (t)dt. (25.1) Today's colliders all employ bunched beams. If two bunches containing n1 and n2

  17. Pre-Town Meeting on Spin Physics at an Electron-Ion Collider

    E-Print Network [OSTI]

    Elke-Caroline Aschenauer; Ian Balitsky; Leslie Bland; Stanley J. Brodsky; Matthias Burkardt; Volker Burkert; Jian-Ping Chen; Abhay Deshpande; Markus Diehl; Leonard Gamberg; Matthias Grosse Perdekamp; Jin Huang; Charles Hyde; Xiangdong Ji; Xiaodong Jiang; Zhong-Bo Kang; Valery Kubarovsky; John Lajoie; Keh-Fei Liu; Ming Liu; Simonetta Liuti; Wally Melnitchouk; Piet Mulders; Alexei Prokudin; Andrey Tarasov; Jian-Wei Qiu; Anatoly Radyushkin; David Richards; Ernst Sichtermann; Marco Stratmann; Werner Vogelsang; Feng Yuan

    2014-10-31T23:59:59.000Z

    A polarized $ep/eA$ collider (Electron--Ion Collider, or EIC), with polarized proton and light-ion beams and unpolarized heavy-ion beams with a variable center--of--mass energy $\\sqrt{s} \\sim 20$ to $\\sim100$~GeV (upgradable to $\\sim 150$ GeV) and a luminosity up to $\\sim 10^{34} \\, \\textrm{cm}^{-2} \\textrm{s}^{-1}$, would be uniquely suited to address several outstanding questions of Quantum Chromodynamics, and thereby lead to new qualitative and quantitative information on the microscopic structure of hadrons and nuclei. During this meeting at Jefferson Lab we addressed recent theoretical and experimental developments in the spin and the three--dimensional structure of the nucleon (sea quark and gluon spatial distributions, orbital motion, polarization, and their correlations). This mini--review contains a short update on progress in these areas since the EIC White paper~\\cite{Accardi:2012qut}.

  18. Jet physics at HERA, Tevatron and LHC

    E-Print Network [OSTI]

    C. Royon

    2008-11-10T23:59:59.000Z

    In this short report, we discuss the Jet Physics results and perspectives at HERA, Tevatron and LHC.

  19. First Measurement of Bose-Einstein Correlations in Proton-Proton Collisions at [sqrt] s=0.9 and 2.36 TeV at the LHC

    E-Print Network [OSTI]

    Paus, Christoph M. E.

    Bose-Einstein correlations have been measured using samples of proton-proton collisions at 0.9 and 2.36 TeV center-of-mass energies, recorded by the CMS experiment at the CERN Large Hadron Collider. The signal is observed ...

  20. Top-quark mass measurements: Alternative techniques (LHC + Tevatron)

    E-Print Network [OSTI]

    Stefanie Adomeit

    2014-11-28T23:59:59.000Z

    Measurements of the top-quark mass employing alternative techniques are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at the LHC. The alternative methods presented include measurements using the lifetime of $B$-hadrons, the transverse momentum of charged leptons and the endpoints of kinematic distributions in top quark anti-quark pair ($t\\bar{t}$) final states. The extraction of the top-quark pole mass from the $t\\bar{t}$ production cross-section and the normalized differential $t\\bar{t}$ + 1-jet cross-section are discussed as well as the top-quark mass extraction using fixed-order QCD predictions at detector level. Finally, a measurement of the top-quark mass using events enhanced in single top t-channel production is presented.

  1. Readiness of the ATLAS Tile Calorimeter for LHC collisions

    E-Print Network [OSTI]

    The ATLAS Collaboration

    2010-11-19T23:59:59.000Z

    The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration systems are presented, as well as the validation of the timing and energy calibration carried out with minimum ionising cosmic ray muons data. The calibration systems' precision is well below the design of 1%. The determination of the global energy scale was performed with an uncertainty of 4%.

  2. Experimental studies of di-jet survival and surface emission bias in Au plus Au collisions via angular correlations with respect to back-to-back leading hadrons 

    E-Print Network [OSTI]

    Agakishiev, H.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Alekseev, I.; Alford, J.; Anderson, B. D.; Anson, C. D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Beavis, D. R.; Behera, N. K.; Bellwied, R.; Betancourt, M. J.; Betts, R. R.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bridgeman, A.; Brovko, S. G.; Bruna, E.; Bueltmann, S.; Bunzarov, I.; Burton, T. P.; Cai, X. Z.; Caines, H.; Sanchez, M. Calderon de la Barca; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, P.; Codrington, M. J. M.; Corliss, R.; Cramer, J. G.; Crawford, H. J.; Dash, S.; Leyva, A. Davila; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Derevschikov, A. A.; Derradi de Souza, R.; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Efimov, L. G.; Elnimr, M.; Engelage, J.; Eppley, G.; Estienne, M.; Eun, L.; Evdokimov, O.; Fatemi, R.; Fedorisin, J.; Fersch, R. G.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, Carl A.; Gangadharan, D. R.; Geromitsos, A.; Geurts, F.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O. G.; Grosnick, D.; Guertin, S. M.; Gupta, A.; Guryn, W.; Haag, B.; Hajkova, O.; Hamed, A.; Han, L-X; Harris, J. W.; Hays-Wehle, J. P.; Heinz, M.; Heppelmann, S.; Hirsch, A.; Hjort, E.; Hoffmann, G. W.; Hofman, D. J.; Huang, B.; Huang, H. Z.; Humanic, T. J.; Huo, L.; Igo, G.; Jacobs, P.; Jacobs, W. W.; Jena, C.; Jin, F.; Joseph, J.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kettler, D.; Kikola, D. P.; Kiryluk, J.; Kisiel, A.; Kizka, V.; Klein, S. R.; Knospe, A. G.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Koroleva, L.; Korsch, W.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Krueger, K.; Krus, M.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Leight, W.; LeVine, M. J.; Li, C.; Li, L.; Li, N.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Lukashov, E. V.; Luo, X.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; Matulenko, Yu A.; McDonald, D.; McShane, T. S.; Meschanin, A.; Milner, R.; Minaev, N. G.; Mioduszewski, Saskia; Mischke, A.; Mitrovski, M. K.; Mohammed, Y.; Mohanty, B.; Mondal, M. M.; Morozov, B.; Morozov, D. A.; Munhoz, M. G.; Mustafa, M. K.; Naglis, M.; Nandi, B. K.; Nayak, T. K.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pei, H.; Peitzmann, T.; Perkins, C.; Peryt, W.; Phatak, S. C.; Pile, P.; Planinic, M.; Ploskon, M. A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Powell, C. B.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Redwine, R.; Reed, R.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Ruan, L.; Rusnak, J.; Sahoo, N. R.; Sakai, S.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmitz, N.; Schuster, T. R.; Seele, J.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Staszak, D.; Steadman, S. G.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szanto de Toledo, A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarini, L. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trainor, T. A.; Tram, V. N.; Trentalange, S.; Tribble, Robert E.; Tribedy, P.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Q.; Wang, X. L.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Witzke, W.

    2011-01-01T23:59:59.000Z

    We report first results from an analysis based on a new multi-hadron correlation technique, exploring jet-medium interactions and di-jet surface emission bias at the BNL Relativistic Heavy Ion Collider (RHIC). Pairs of back-to-back high...

  3. The Multi-Purpose Detector for NICA heavy-Ion Collider at JINR

    SciTech Connect (OSTI)

    Rogachevsky, O. V., E-mail: rogachevsky@jinr.ru [JINR, Veksler and Baldin Laboratory on High Energy Physics (Russian Federation)

    2012-05-15T23:59:59.000Z

    The Multi-Purpose Detector (MPD) is designed to study heavy-ion collisions at the Nuclotron-based heavy Ion Collider fAcility (NICA) at JINR, Dubna. Its main components located inside a superconducting solenoid are a tracking system composed of a silicon microstrip vertex detector followed by a large volume time-projection chamber, a time-of-flight system for particle identification and a barrel electromagnetic calorimeter. A zero degree hadron calorimeter is designed specifically to measure the energy of spectators. In this paper, all parts of the apparatus are described and their tracking and particle identification parameters are discussed in some detail.

  4. Diffusion of $?_c$ in hot hadronic medium and its impact on $?_c/D$ ratio

    E-Print Network [OSTI]

    Sabyasachi Ghosh; Santosh K. Das; Vincenzo Greco; Sourav Sarkar; Jan-e Alam

    2014-09-19T23:59:59.000Z

    The drag and diffusion coefficients of the $\\Lambda_c(2286$ MeV) have been evaluated in the hadronic medium which is expected to be formed in the later stages of the evolving fire ball produced in heavy ion collisions at RHIC and LHC energies. The interactions between the $\\Lambda_c$ and the hadrons in the medium have been derived from an effective hadronic Lagrangian as well as from the scattering lengths, obtained in the framework of heavy baryon chiral perturbation theory (HB$\\chi$PT). In both the approaches, the magnitude of the transport coefficients are turn out to be significant. A larger value is obtained in the former approach with respect to the latter. Significant values of the coefficients indicate substantial amount of interaction of the $\\Lambda_c$ with the hadronic thermal bath. Furthermore, the transport coefficients of the $\\Lambda_c$ is found to be different from the transport coefficients of $D$ meson. Present study indicates that the hadronic medium has a significant impact on the $\\Lambda_c/D$ ratio in heavy ion collisions.

  5. Jet energy scale setting with "photon+Jet" events at LHC energies. Event rates, Pt structure of jet

    E-Print Network [OSTI]

    D. V. Bandourin; V. F. Konoplianikov; N. B. Skachkov

    2000-12-15T23:59:59.000Z

    In this paper the study of "photon+Jet" events is continued, aimed at jet energy scale setting and hadron calorimeter calibration at LHC energies. The event number distribution over Pt and pseudorapidity eta in the barrel region of the photon is presented. The features of "photon+Jet" events in CMS detector |eta|<1.4 are exposed. Pt structure of the region in the eta-phi space inside and beyond jet is also shown.

  6. Mutual colliding impact fast ignition

    SciTech Connect (OSTI)

    Winterberg, Friedwardt, E-mail: winterbe@unr.edu [Department of Physics, College of Science, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557-0220 (United States)

    2014-09-15T23:59:59.000Z

    It is proposed to apply the well established colliding beam technology of high energy physics to the fast hot spot ignition of a highly compressed DT (deuterium-tritium) target igniting a larger D (deuterium) burn, by accelerating a small amount of solid deuterium, and likewise a small amount of tritium, making a head-on collision in the center of the target, projecting them through conical ducts situated at the opposite side of the target and converging in its center. In their head-on collision, the relative collision velocity is 5/3 times larger compared to the collision velocity of a stationary target. The two pieces have for this reason to be accelerated to a smaller velocity than would otherwise be needed to reach upon impact the same temperature. Since the velocity distribution of the two head-on colliding projectiles is with its two velocity peaks non-Maxwellian, the maximum cross section velocity product turns out to be substantially larger than the maximum if averaged over a Maxwellian. The D and T projectiles would have to be accelerated with two sabots driven by powerful particle or laser beams, permitting a rather large acceleration length. With the substantially larger cross section-velocity product by virtue of the non-Maxwellian velocity distribution, a further advantage is that the head-on collision produces a large magnetic field by the thermomagnetic Nernst effect, enhancing propagating burn. With this concept, the ignition of the neutron-less hydrogen-boron (HB{sup 11}) reaction might even be possible in a heterogeneous assembly of the hydrogen and the boron to reduce the bremsstrahlung-losses, resembling the heterogeneous assembly in a graphite-natural uranium reactor, there to reduce the neutron losses.

  7. RHIC and LHC jet suppression in non-central collisions

    E-Print Network [OSTI]

    Magdalena Djordjevic; Marko Djordjevic; Bojana Blagojevic

    2014-06-25T23:59:59.000Z

    Understanding properties of QCD matter created in ultra-relativistic heavy-ion collisions is a major goal of RHIC and LHC experiments. An excellent tool to study these properties is jet suppression of light and heavy flavor observables. Utilizing this tool requires accurate suppression predictions for different experiments, probes and experimental conditions, and their unbiased comparison with experimental data. With this goal, we here extend our dynamical energy loss formalism towards generating predictions for non-central collisions; the formalism takes into account both radiative and collisional energy loss, dynamical (as opposed to static) scattering centers, finite magnetic mass, running coupling and uses no free parameters in comparison with experimental data. Specifically, we here generate predictions for all available centrality ranges, for both LHC and RHIC experiments, and for four different probes (charged hadrons, neutral pions, D mesons and non-prompt $J/\\psi$). We obtain a very good agreement with all available non-central data, and also generate predictions for suppression measurements that will soon become available. Finally, we discuss implications of the obtained good agreement with experimental data with different medium models that are currently considered.

  8. The history of the LHC

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    Abstract: From the civil engineering, to the manufacturing of the various magnet types, each building block of this extraordinary machine required ambitious leaps in innovation. This lecture will review the history of the LHC project, focusing on the many challenges -- scientific, technological, managerial -- that had to be met during the various phases of R&D;, industrialization, construction, installation and commissioning.

  9. Search for SUSY at LHC

    E-Print Network [OSTI]

    Dova, MT; The ATLAS collaboration

    2012-01-01T23:59:59.000Z

    This is a talk on Search for SUSY at LHC (ATLAS + CMS) to be presented at SILAFAE2012 (IX Simposio Latinoamericano de Fisica de Altas Energías) to be held in Sao Paulo, Brazil (10-14 December) . The content of the slides is mainly with results presented at SUSY2012 with a few updates from HCP results.

  10. LHC Network Measurement Joe Metzger

    E-Print Network [OSTI]

    1 LHC Network Measurement Joe Metzger Nov 6 2007 LHCOPN Meeting at CERN Energy Sciences Network & Capacity RRDMA Input Errors & Output Drops PS-SNMPMA Done ?? Beta Aug 1, Package Sep 1 Visualize perf On-demand AMI MA & Scheduler Hades Owamp MP Beta Sep 15, Package Oct 1 October Done Archive perf

  11. BRAHMS (Broad Range Hadron Magnetic Spectrometer) Figures and Data Archive

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    The BRAHMS experiment was designed to measure charged hadrons over a wide range of rapidity and transverse momentum to study the reaction mechanisms of the relativistic heavy ion reactions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the properties of the highly excited nuclear matter formed in these reactions. The experiment took its first data during the RHIC 2000 year run and completed data taking in June 2006. The BRAHMS archive makes publications available and also makes data and figures from those publications available as separate items. See also the complete list of publications, multimedia presentations, and related papers at http://www4.rcf.bnl.gov/brahms/WWW/publications.html

  12. Scaling patterns for the suppression of charged hadron yields in Pb+Pb collisions at Root_s = 2.76 TeV: Constraints on transport coefficients

    E-Print Network [OSTI]

    Roy A. Lacey; N. N. Ajitanand; J. M. Alexander; J. Jia; A. Taranenko

    2012-02-24T23:59:59.000Z

    Suppression measurements for charged hadrons are used to investigate the path length (L) and transverse momentum (p_T) dependent jet quenching patterns of the hot and dense QCD medium produced in Pb+Pb collisions at Root_s =2.76 TeV at the LHC. The observed scaling patterns, which are similar to those observed for Au+Au collisions at Root_s = 0.20 TeV at RHIC, show the trends predicted for jet-medium interactions dominated by radiative energy loss. They also allow a simple estimate of the transport coefficient $\\hat{q}$, which suggests that the medium produced in LHC collisions is somewhat less opaque than that produced at RHIC, if the same parton-medium coupling strength is assumed. The higher temperature produced in LHC collisions could reduce the parton-medium coupling strength to give identical values for $\\hat{q}$ in LHC and RHIC collisions.

  13. Supergravity gauge theories strike back: There is no crisis for SUSY but a new collider may be required for discovery

    E-Print Network [OSTI]

    Baer, Howard; Savoy, Michael

    2015-01-01T23:59:59.000Z

    More than 30 years ago, Arnowitt-Chamseddine-Nath (ACN) and others established the compelling framework of supergravity gauge theories (SUGRA) as a picture for the next step in beyond the Standard Model physics. We review the current SUGRA scenario in light of recent data from LHC8 collider searches and the Higgs boson discovery. While many SUSY and non-SUSY scenarios are highly disfavored or even excluded by LHC, the essential SUGRA scenario remains intact and as compelling as ever. For naturalness, some non-universality between matter and Higgs sector soft terms is required along with substantial trilinear soft terms. SUSY models with radiatively-driven naturalness (RNS) are found with high scale fine-tuning at a modest ~10%. In this case, natural SUSY might be discovered at LHC13 but could also easily elude sparticle search endeavors. A linear e^+e^- collider with \\sqrt{s}>2m(higgsino) is needed to provide the definitive search for the required light higgsino states which are the hallmark of natural SUSY. ...

  14. No-Scale F-SU(5) in the Light of LHC, Planck and XENON

    E-Print Network [OSTI]

    Tianjun Li; James A. Maxin; Dimitri V. Nanopoulos; Joel W. Walker

    2013-09-17T23:59:59.000Z

    We take stock of the No-Scale F-SU(5) model's experimental status and prospects in the light of results from LHC, Planck, and XENON100. Given that no conclusive evidence for light Supersymmetry (SUSY) has emerged from the 7, 8 TeV collider searches, the present work is focused on exploring and clarifying the precise nature of the high-mass cutoff enforced on this model at the point where the stau and neutralino mass degeneracy becomes so tight that cold dark matter relic density observations cannot be satisfied. This hard upper boundary on the model's mass scale constitutes a top-down theoretical mandate for a comparatively light (and testable) SUSY spectrum which does not excessively stress natural resolution of the gauge hierarchy problem. The overlap between the resulting model boundaries and the expected sensitivities of the future 14 TeV LHC and XENON 1-Ton direct detection SUSY / dark matter experiments is described.

  15. Supersymmetry and dark matter post LHC8: Why we may expect both axion and WIMP detection

    SciTech Connect (OSTI)

    Baer, Howard [Dep't of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2014-01-01T23:59:59.000Z

    In the post-LHC8 era, it is perceived that what is left of SUSY model parameter space is highly finetuned in the EW sector (EWFT). We discuss how conventional measures overestimate EWFT in SUSY theory. Radiatively-driven natural SUSY (RNS) models maintain the SUSY GUT paradigm with low EWFT at 10% level, but are characterized by light higgsinos ~100–300 GeV and a thermal underabundance of WIMP dark matter. Implementing the SUSY DFSZ solution to the strong CP problem explains the small ? parameter but indicates dark matter should be comprised mainly of axions with a small admixture of higgsino-like WIMPs. While RNS might escape LHC14 searches, we would expect ultimately direct detection of both WIMPs and axions. An e?e? collider with ?(s)~500–600 GeV should provide a thorough search for the predicted light higgsinos.

  16. Systematic Analysis of Frontier Energy Collider Data

    E-Print Network [OSTI]

    Bruce Knuteson

    2005-04-23T23:59:59.000Z

    Ignorance of the form new physics will take suggests the importance of systematically analyzing all data collected at the energy frontier, with the goal of maximizing the chance for discovery both before and after the turn on of the LHC.

  17. Comments on "Wall-plug (AC) power consumption of a very high energy e+/e- storage ring collider" by Marc Ross

    E-Print Network [OSTI]

    Blondel, A; Butterworth, A; Janot, P; Zimmermann, F; Aleksan, R; Azzi, P; Ellis, J; Klute, M; Zanetti, M

    2013-01-01T23:59:59.000Z

    The paper arXiv:1308.0735 questions some of the technical assumptions made by the TLEP Steering Group when estimating in arXiv:1305.6498 the power requirement for the very high energy e+e- storage ring collider TLEP. We show that our assumptions are based solidly on CERN experience with LEP and the LHC, as well accelerators elsewhere, and confirm our earlier baseline estimate of the TLEP power consumption.

  18. VNI version 4.1. Simulation of high-energy particle collisions in QCD: Space-time evolution of e{sup +}e{sup {minus}}...A + B collisions with parton-cascades, cluster-hadronization, final-state hadron cascades

    SciTech Connect (OSTI)

    Geiger, K.; Longacre, R. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.; Srivastava, D.K. [Variable Energy Cyclotron Centre, Calcutta (India)

    1999-02-01T23:59:59.000Z

    VNI is a general-purpose Monte-Carlo event-generator, which includes the simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It uses the real-time evolution of parton cascades in conjunction with a self-consistent hadronization scheme, as well as the development of hadron cascades after hadronization. The causal evolution from a specific initial state (determined by the colliding beam particles) is followed by the time-development of the phase-space densities of partons, pre-hadronic parton clusters, and final-state hadrons, in position-space, momentum-space and color-space. The parton-evolution is described in terms of a space-time generalization of the familiar momentum-space description of multiple (semi)hard interactions in QCD, involving 2 {r_arrow} 2 parton collisions, 2 {r_arrow} 1 parton fusion processes, and 1 {r_arrow} 2 radiation processes. The formation of color-singlet pre-hadronic clusters and their decays into hadrons, on the other hand, is treated by using a spatial criterion motivated by confinement and a non-perturbative model for hadronization. Finally, the cascading of produced prehadronic clusters and of hadrons includes a multitude of 2 {r_arrow} n processes, and is modeled in parallel to the parton cascade description. This paper gives a brief review of the physics underlying VNI, as well as a detailed description of the program itself. The latter program description emphasizes easy-to-use pragmatism and explains how to use the program (including simple examples), annotates input and control parameters, and discusses output data provided by it.

  19. Collider searches and cosmology in the MSSM with heavy scalars

    SciTech Connect (OSTI)

    Carena, Marcela; /Fermilab; Freitas, A.; /Zurich U.

    2006-08-01T23:59:59.000Z

    In a variety of supersymmetric extensions of the Standard Model, the scalar partners of the quarks and leptons are predicted to be very heavy and beyond the reach of next-generation colliders. For instance, the realization of electroweak baryogenesis in supersymmetry requires new sources of CP-violation, which can only be naturally accommodated with electric dipole moment constraints if the first and second generation scalar fermions are beyond the TeV scale. Also in focus-point supersymmetry and split supersymmetry the scalar fermions are very heavy. In this work, the phenomenology of scenarios with electroweak baryogenesis and in the focus point region at the LHC and ILC is studied, which becomes challenging due to the presence of heavy scalar fermions. Implications for the analysis of baryogenesis and dark matter are deduced. It is found that precision measurements of superpartner properties allow an accurate determination of the dark matter relic density in both scenarios, while important but only incomplete information about the baryogenesis mechanism can be obtained.

  20. Calculation of associated production of a top quark and a W ? at the LHC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cao, Qing-Hong; Berger, Edmond L.; Yu, Jiang-Hao; Yuan, C.-P.

    2011-11-01T23:59:59.000Z

    We investigate collider signatures of a top-philic W' model, in which the W' boson couples only to the third-generation quarks of the standard model. The main discovery channel for this W' is through associated production of the W' and top quark, yielding a top-quark pair plus an extra bottom-quark jet as a signal. We do a full simulation of the signal and relevant backgrounds. We develop a method of analysis that allows us to conclude that discovery of the W' is promising at the LHC despite large standard model backgrounds. Bottom-quark tagging of the extra jet is key to suppressing the backgrounds.

  1. Scaling of elliptic flow, recombination, and sequential freeze-out of hadrons in heavy-ion collisions 

    E-Print Network [OSTI]

    He, Min; Fries, Rainer J.; Rapp, Ralf.

    2010-01-01T23:59:59.000Z

    partons deconfine and chiral symmetry is restored [1]. One major finding by the experimental program at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Labora- tory is the large azimuthal anisotropy of hadron transverse- momentum (p..., Texas A&M University, College Station, Texas 77843, USA 2RIKEN/BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA (Received 9 June 2010; revised manuscript received 31 August 2010; published 21 September 2010) The scaling...

  2. Tsallis fits to pT spectra and multiple hard scattering in pp collisions at the LHC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wong, Cheuk-Yin; Wilk, Grzegorz

    2013-06-01T23:59:59.000Z

    Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arise from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/pnT at high pT, the power indices n for hadrons are systematically greater than those for jets, for which n?4–5.

  3. Tsallis fits to pT spectra and multiple hard scattering in pp collisions at the LHC

    SciTech Connect (OSTI)

    Wong, Cheuk-Yin; Wilk, Grzegorz

    2013-06-01T23:59:59.000Z

    Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arise from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/pnT at high pT, the power indices n for hadrons are systematically greater than those for jets, for which n?4–5.

  4. Linear Collider LHC Subpanel | U.S. DOE Office of Science (SC)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5Let us countLighting SignLiisaLin Wang

  5. Effective Yukawa couplings and flavor-changing Higgs boson decays at linear colliders

    SciTech Connect (OSTI)

    Gabrielli, E. [CERN, PH-TH, CH-1211 Geneva 23 (Switzerland); Mele, B. [INFN, Sezione di Roma, c/o Dipartimento di Fisica, Universita di Roma 'La Sapienza', Piazzale A. Moro 2, I-00185 Rome (Italy)

    2011-04-01T23:59:59.000Z

    We analyze the advantages of a linear-collider program for testing a recent theoretical proposal where the Higgs boson Yukawa couplings are radiatively generated, keeping unchanged the standard-model mechanism for electroweak-gauge-symmetry breaking. Fermion masses arise at a large energy scale through an unknown mechanism, and the standard model at the electroweak scale is regarded as an effective field theory. In this scenario, Higgs boson decays into photons and electroweak gauge-boson pairs are considerably enhanced for a light Higgs boson, which makes a signal observation at the LHC straightforward. On the other hand, the clean environment of a linear collider is required to directly probe the radiative fermionic sector of the Higgs boson couplings. Also, we show that the flavor-changing Higgs boson decays are dramatically enhanced with respect to the standard model. In particular, we find a measurable branching ratio in the range (10{sup -4}-10{sup -3}) for the decay H{yields}bs for a Higgs boson lighter than 140 GeV, depending on the high-energy scale where Yukawa couplings vanish. We present a detailed analysis of the Higgs boson production cross sections at linear colliders for interesting decay signatures, as well as branching-ratio correlations for different flavor-conserving/nonconserving fermionic decays.

  6. Test facilities for future linear colliders

    SciTech Connect (OSTI)

    Ruth, R.D.

    1995-12-01T23:59:59.000Z

    During the past several years there has been a tremendous amount of progress on Linear Collider technology world wide. This research has led to the construction of the test facilities described in this report. Some of the facilities will be complete as early as the end of 1996, while others will be finishing up around the end 1997. Even now there are extensive tests ongoing for the enabling technologies for all of the test facilities. At the same time the Linear Collider designs are quite mature now and the SLC is providing the key experience base that can only come from a working collider. All this taken together indicates that the technology and accelerator physics will be ready for a future Linear Collider project to begin in the last half of the 1990s.

  7. Superconducting solenoids for the Muon collider

    E-Print Network [OSTI]

    Green, M.A.

    2011-01-01T23:59:59.000Z

    muon collider has superconducting solenoids as an integralLBNL-44303 SCMAG-690 Superconducting Solenoids for the MuonDE-AC03-76SFOOO98. J Superconducting Solenoids for the Muon

  8. Distinguishing spins in supersymmetric and universal extra dimension models at the large hadron collider.

    E-Print Network [OSTI]

    Smillie, Jennifer M; Webber, Bryan R

    lepton with the same helicity as the quark (process 1) will be emitted preferentially at large values of the angle ?? between its direction and that of the quark in the ?˜02 rest frame, with angular distribution (neglecting all SM particle masses) dP SUSY... distribution dP0 d cos ?? = 3 2(2 + y) (sin2 ?? + y cos2 ??) (4.2) where y = m2l?/m 2 Z? . The transverse decay distribution for ±ve helicity is dP± d cos ?? = 3 4(2 + y) [(1± cos ??)2 + y sin2 ??] . (4.3) The angular distributions for the two fundamental...

  9. Synchrotron radiation and beam tube vacuum in a Very Large Hadron Collider; Stage 1 VLHC

    E-Print Network [OSTI]

    Pivi, M.; Turner, W.C.

    2001-01-01T23:59:59.000Z

    Synchrotron Radiation and Beam Tube Vacuum in a Very Large94720 Abstract Synchrotron radiation induced photodesorptionvacuum. The synchrotron radiation power in the Stage 1 VLHC,

  10. The 100,000 amp dc power supply for a staged hadron collider superferric magnet

    SciTech Connect (OSTI)

    Hays, Steven L.; Claypool, Bradley; Foster, G.William; /Fermilab

    2005-09-01T23:59:59.000Z

    A 1.5 volt 100,000 amp DC switcher power supply was developed for testing a superferric magnet string at FNAL. This supply was used during testing as both the ramping supply and holding supply powering a single magnet load with a total load resistance of 0.7{micro} Ohms. The supply consists of ten paralleled switcher cells, powered by a 400 volt/600 Amp DC power supply. Each cell consists of an IGBT H-bridge driving a step-down transformer at a switching frequency of 2 kHz. The transformer has an effective turns ratio of 224:1. The secondary consists of 32 parallel single-turn full wave rectifier windings. The rectification is done with 64 Shottky diodes. Each cell is rated at 1.5 volts/10,000 amps. During this test each cell was operated as a constant power source without load current or field feedback. This paper will describe the design of the switcher cell and control system used during testing. We will also describe the next level of improvements to the current feedback system to improve the ramp control.

  11. Precision SM Shapes Assessing the state of the art for Z & h spectra at hadron colliders

    E-Print Network [OSTI]

    Huston, Joey

    , Melnikov, Mrenna, Nadolsky, Skands, Moretti, Magnea, Balazs, Ferrag, Bartalini, Zametti, Kauer, Krasny.2/6.3) Moretti (HERWIG w/ Higgs + jet real correction) Magnea Balazs Ferrag Bartalini Zametti Kauer Krasny

  12. Development of a small angle hadron calorimeter prototype for the Collider Detector at Fermilab

    E-Print Network [OSTI]

    Thane, John Mark

    1989-01-01T23:59:59.000Z

    that very little shower development would occur within our calorimeter resulting in an almost fiat longitudinal shower profile. At the M'Test beam site at FNAL, we set the calorimeter halves up so that all four chambers would intercept the same particie... of the shower development in a total absorption calorimeter. The histograms in Figure 10 show the longitudinal development of the hsdronic shower as seen by the calorimeter. In Table 2, we look at the efficiency measured in the test beam ss the ratio...

  13. U.S. scientists celebrate the restart of the Large Hadron Collider...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A highlight of the LHCs first run, which began in 2009, was the discovery of the Higgs boson, the last in the suite of elementary particles that make up scientists best picture...

  14. A Large Hadron Electron Collider at CERN | OSTI, US Dept of Energy...

    Office of Scientific and Technical Information (OSTI)

    Resources U.S. Science Information - Science.gov Global Science Information - WorldWideScience.org - Energy Technology Data Exchange - International Nuclear Information System...

  15. Addendum to Distinguishing Spins in Decay Chains at the Large Hadron Collider.

    E-Print Network [OSTI]

    Athanasiou, Christiana; Lester, Christopher G; Smillie, Jennifer M; Webber, Bryan R

    208 FVFS 313 184 14 ? 13077 35 FSFV 436 236 15 12957 ? 39 SFVF 89 126 134 38 42 ? Table 1: The number of events needed to disfavour the column model with respect to the row model by a factor of 0.001, assuming the data to come from the row model... @hep.phy.cam.ac.uk Abstract: We extend our earlier study of spin correlations in the decay chain D ? Cq, C ? Blnear, B ? Alfar, where A,B,C,D are new particles with known masses but undetermined spins, lnear and lfar are opposite-sign same-flavour charged leptons and A...

  16. June 30, 2008: US portion of Large Hadron Collider completed | Department

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page onYouTube YouTube Note: Since the.pdfBreaking ofOil & Gas » MethaneJohnson ControlsJoyce Yang5 - 2011 2013of

  17. U.S. scientists celebrate the restart of the Large Hadron Collider |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence may bediesel

  18. SCIENCE ON SATURDAY- "The Large Hadron Collider: big science for big

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Scienceand Requirements RecentlyElectronicResourcesjobs Running jobsS2.Tour" |questions"

  19. Fermilab | Newsroom | Fermilab/U.S. experts on the Large Hadron Collider

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC) Environmental Assessments (EA)Budget » FYU.S. DOEFigureTip ofTheGraphic

  20. Hadronic rescattering effects on multi-strange hadrons in high-energy nuclear collisions

    E-Print Network [OSTI]

    Takeuchi, Shiori; Hirano, Tetsufumi; Huovinen, Pasi; Nara, Yasushi

    2015-01-01T23:59:59.000Z

    We study the effects of hadronic rescattering on hadron distributions in high-energy nuclear collisions by using an integrated dynamical approach. This approach is based on a hybrid model combining (3+1)-dimensional ideal hydrodynamics for the quark gluon plasma (QGP), and a transport model for the hadron resonance gas. Since the hadron distributions are the result of the entire expansion history of the system, understanding the QGP properties requires investigating how rescattering during the hadronic stage affects the final distributions of hadrons. We include multi-strange hadrons in our study, and quantify the effects of hadronic rescattering on their mean transverse momenta and elliptic flow. We find that multi-strange hadrons scatter less during the hadronic stage than non-strange particles, and thus their distributions reflect the properties of the system in an earlier stage than the distributions of non-strange particles.

  1. Diffractive heavy quark production in AA collisions at the LHC at NLO

    SciTech Connect (OSTI)

    Machado, M. M.; Ducati, M. B. Gay; Machado, M. V. T. [High Energy Physics Phenomenology Group, GFPAE, IF-UFRGS, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

    2011-07-15T23:59:59.000Z

    The single and double diffractive cross sections for heavy quarks production are evaluated at NLO accuracy for hadronic and heavy ion collisions at the LHC. Diffractive charm and bottom production is the main subject of this work, providing predictions for CaCa, PbPb and pPb collisions. The hard diffraction formalism is considered using the Ingelman-Schlein model where a recent parametrization for the Pomeron structure function (DPDF) is applied. Absorptive corrections are taken into account as well. The diffractive ratios are estimated and theoretical uncertainties are discussed. Comparison with competing production channels is also presented.

  2. Multidimensional Hadron Attenuation Gevorg Karyan

    E-Print Network [OSTI]

    aspects of the hadronization process. 50th International Winter Meeting on Nuclear Physics - Bormio2012 the nuclear medium, losing it's energy by emiting a gluon. The time (length) is needed for this prop- agation of this process, nuclei with different mass (size) can be used. The experimen- tal observable is the nuclear

  3. CERN2005014 DESYPROC2005001

    E-Print Network [OSTI]

    Yost, Scott

    Hadron Collider (LHC), which will collide protons with a centre-of-mass energy of 14 Te in the TeV energy scale, such as supersymmetry or extra dimen- sions. Besides these goals, the LHC will also to the workshop: ­ To identify and prioritize those measurements to be made at HERA which have an impact

  4. Elliptic Flow from a Hybrid CGC, Full 3D Hydro and Hadronic Cascade Model

    E-Print Network [OSTI]

    Tetsufumi Hirano; Ulrich W. Heinz; Dmitri Kharzeev; Roy Lacey; Yasushi Nara

    2007-03-27T23:59:59.000Z

    We investigate the robustness of the discovery of the perfect fluid through comparison of hydrodynamic calculations with the elliptic flow coefficient v_2 at midrapidity in Au+Au collisions at sqrt{s_{NN}}=200 GeV. Employing the Glauber model for initial entropy density distributions, the centrality dependence of v_2 is reasonably reproduced by using an ideal fluid description of the early QGP stage followed by a hadronic cascade in the late hadronic stage. On the other hand, initial conditions based on the Colour Glass Condensate model are found to generate larger elliptic flow due to larger initial eccentricity epsilon. We further predict v_2/epsilon at a fixed impact parameter as a function of collision energy sqrt{s_{NN}} up to the LHC energy.

  5. QCD and hard diffraction at the LHC

    SciTech Connect (OSTI)

    Albrow, Michael G.; /Fermilab

    2005-09-01T23:59:59.000Z

    As an introduction to QCD at the LHC the author gives an overview of QCD at the Tevatron, emphasizing the high Q{sup 2} frontier which will be taken over by the LHC. After describing briefly the LHC detectors the author discusses high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. The author introduces the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

  6. US LHC Accelerator Research Program For the BNL-FNAL-LBNL LHC Accelerator Collaboration

    E-Print Network [OSTI]

    Large Hadron Collider Program

    instruments that will improve the operation of the LHC and help us perform accelerator physics experiments science. · Perform accelerator physics studies and advanced magnet R&D that will result in the IR designsUS LHC Accelerator Research Program Jim Strait For the BNL-FNAL-LBNL LHC Accelerator Collaboration

  7. Calculation method for safe ?* in the LHC

    E-Print Network [OSTI]

    Bruce, R; Herr, W; Wollmann, D

    2011-01-01T23:59:59.000Z

    One way of increasing the peak luminosity in the LHC is to decrease the beam size at the interaction points by squeezing to smaller values of ?*. The LHC is now in a regime where safety and stability determines the limit on ?*, as opposed to traditional optics limits. In this paper, we derive a calculation model to determine the safe ?*-values based on collimator settings and operational stability of the LHC. This model was used to calculate the settings for the LHC run in 2011. It was found that ?* could be decreased from 3.5 m to 1.5 m, which has now successfully been put into operation.

  8. LHC end-of-year jamboree

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    A review of the accelerator performance and of the experimental results, at the end of the 2010 run of the LHC

  9. Research and Development for a Free-Running Readout System for the ATLAS LAr Calorimeters at the High Luminosity LHC

    E-Print Network [OSTI]

    Hils, Maximilian; The ATLAS collaboration

    2015-01-01T23:59:59.000Z

    The ATLAS Liquid Argon (LAr) Calorimeters were designed and built to measure electromagnetic and hadronic energy in proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to $10^{34} \\text{cm}^{-2} \\text{s}^{-1}$. The High Luminosity LHC (HL-LHC) programme is now developed for up to 5-7 times the design luminosity, with the goal of accumulating an integrated luminosity of $3000~\\text{fb}^{-1}$. In the HL-LHC phase, the increased radiation levels require a replacement of the front-end electronics of the LAr Calorimeters. Furthermore, the ATLAS trigger system is foreseen to increase the trigger accept rate by a factor 10 to 1 MHz and the trigger latency by a factor of 20 which requires a larger data volume to be buffered. Therefore, the LAr Calorimeter read-out will be exchanged with a new front-end and a high bandwidth back-end system for receiving data from all 186.000 channels at 40 MHz LHC bunch-crossing frequency and for off-detector buffering...

  10. Double hadron leptoproduction in the nuclear medium

    E-Print Network [OSTI]

    Airapetian, A; Akopov, Z; Amarian, M; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Belostotskii, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Borysenko, A; Brüll, A; Bryzgalov, V; Capiluppi, M; Capitani, G P; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; Demey, M; De Nardo, L; De Sanctis, E; Devitsin, E G; Diefenthaler, M; Di Nezza, P; Dreschler, J; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Funel, A; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Gavrilov, G; Karibian, V; Giordano, F; Grebenyuk, O; Gregor, I M; Griffioen, K; Guler, H; Hadjidakis, C; Hartig, M; Hasch, D; Hasegawa, T; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Hristova, I; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Keri, T; Kinney, E; Kiselev, A; Kobayashi, T; Kopytin, M; Korotkov, V; Kozlov, V; Krauss, B; Kravchenko, P; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Lenisa, P; Liebing, P; Linden-Levy, L A; Lorenzon, W; Lü, J; Lu, S; Ma, B Q; Maiheu, B; Makins, N C R; Mao, Y; Marianski, B; Marukyan, H; Masoli, F; Mexner, V; Meyners, N; Michler, T; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Murray, M; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Negodaev, M; Nowak, Wolf-Dieter; Ohsuga, H; Osborne, A; Perez-Benito, R; Pickert, N; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanjiev, I; Savin, I; Schäfer, A; Schnell, G; Schüler, K P; Seele, J; Seidl, R; Seitz, B; Shearer, C; Shibata, T A; Shutov, V; Sinram, K; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Streit, J; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Van Haarlem, Y; Veretennikov, D; Vikhrov, V; Vogel, C; Wang, S; Ye, Y; Ye, Z; Yen, S; Zihlmann, B; Zupranski, P

    2006-01-01T23:59:59.000Z

    First measurement of double-hadron production in deep-inelastic scattering has been measured with the HERMES spectrometer at HERA using a 27.6 GeV positron beam with deuterium, nitrogen, krypton and xenon targets. The influence of the nuclear medium on the ratio of double-hadron to single-hadron yields has been investigated. Nuclear effects are clearly observed but with substantially smaller magnitude and reduced $A$-dependence compared to previously measured single-hadron multiplicity ratios. The data are in fair agreement with models based on partonic or pre-hadronic energy loss, while they seem to rule out a pure absorptive treatment of the final state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

  11. Z'-induced Invisible Right-handed Sneutrino Decays at the LHC

    E-Print Network [OSTI]

    Abdallah, W; Khalil, S; Moretti, S

    2015-01-01T23:59:59.000Z

    The invisible signals of right-handed sneutrino decays originating from a Z' are analysed at the Large Hadron Collider. The possibility of accessing these events helps disentangling the B-L extension of Minimal Supersymmetric Standard Model from more popular scenarios of Supersymmetry. We assess the scope of the CERN machine in establishing the aforementioned signatures when accompanied by mono-jet, single-photon or Z-radiation probes through sophisticated signal-to-background simulations carried out in presence of parton shower, hadronisation as well as detector effects. We find substantial sensitivity to all such signals for standard luminosities at Run 2.

  12. Wesley Smith, U. Wisconsin, January 11, 2007 Aspen Winter Conference: Experimental QCD -1 QCD results from collidersQCD results from collidersQCD results from colliders

    E-Print Network [OSTI]

    Wesley Smith, U. Wisconsin, January 11, 2007 Aspen Winter Conference: Experimental QCD - 1 QCD results from collidersQCD results from collidersQCD results from colliders 2007 Aspen Winter Conference This talk is available on: http://www.hep.wisc.edu/wsmith/files/exp_qcd_smith_aspen07.pdf #12;Wesley Smith

  13. Hadronic shift in pionic hydrogen

    E-Print Network [OSTI]

    M. Hennebach; D. F. Anagnostopoulos; A. Dax; H. Fuhrmann; D. Gotta; A. Gruber; A. Hirtl; P. Indelicato; Y. -W. Liu; B. Manil; V. E. Markushin; A. J. Rusi el Hassani; L. M. Simons; M. Trassinelli; J. Zmeskal

    2014-12-17T23:59:59.000Z

    The hadronic shift in pionic hydrogen has been redetermined to be $\\epsilon_{1s}=7.086\\,\\pm\\,0.007(stat)\\,\\pm\\,0.006(sys)$\\,eV by X-ray spectroscopy of ground state transitions applying various energy calibration schemes. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institut by using the cyclotron trap and an ultimate-resolution Bragg spectrometer with bent crystals.

  14. Hadronic Resonances from Lattice QCD

    SciTech Connect (OSTI)

    John Bulava; Robert Edwards; George Fleming; K. Jimmy Juge; Adam C. Lichtl; Nilmani Mathur; Colin Morningstar; David Richards; Stephen J. Wallace

    2007-06-16T23:59:59.000Z

    The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non-perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.

  15. Hadronic Resonances from Lattice QCD

    SciTech Connect (OSTI)

    Lichtl, Adam C. [RBRC, Brookhaven National Laboratory, Upton, NY 11973 (United States); Bulava, John; Morningstar, Colin [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Edwards, Robert; Mathur, Nilmani; Richards, David [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Fleming, George [Yale University, New Haven, CT 06520 (United States); Juge, K. Jimmy [Department of Physics, University of the Pacific, Stockton, CA 95211 (United States); Wallace, Stephen J. [University of Maryland, College Park, MD 20742 (United States)

    2007-10-26T23:59:59.000Z

    The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non-perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.

  16. The COMPASS Hadron Spectroscopy Programme

    E-Print Network [OSTI]

    A. Austregesilo; for the COMPASS collaboration

    2012-07-05T23:59:59.000Z

    COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and the dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle identification and calorimetry and is therefore ideal to access a broad range of different final states. Following the promising observation of a spin-exotic resonance during an earlier pilot run, COMPASS focused on light-quark hadron spectroscopy during the years 2008 and 2009. A data set, world leading in terms of statistics and resolution, has been collected with a 190GeV/c hadron beam impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and glueball candidates formed in both diffractive dissociation and central production are presently studied. Since the beam composition includes protons, the excited baryon spectrum is also accessible. Furthermore, Primakoff reactions have the potential to determine radiative widths of the resonances and to probe chiral perturbation theory. An overview of the ongoing analyses will be presented. In particular, the employed partial wave analysis techniques will be illustrated and recent results will be shown for a selection of final states.

  17. The Nonperturbative Structure of Hadrons

    E-Print Network [OSTI]

    T. J. Hobbs

    2014-08-23T23:59:59.000Z

    In this thesis we explore a diverse array of issues that strike at the inherently nonperturbative structure of hadrons at momenta below the QCD confinement scale. In so doing, we mainly seek a better control over the partonic substructure of strongly-interacting matter, especially as this relates to the nonperturbative effects that both motivate and complicate experiments --- particularly DIS; among others, such considerations entail sub-leading corrections in $Q^2$, dynamical higher twist effects, and hadron mass corrections. We also present novel calculations of several examples of flavor symmetry violation, which also originates in the long-distance properties of QCD at low energy. Moreover, we outline a recently developed model, framed as a hadronic effective theory amenable to QCD global analysis, which provides new insights into the possibility of nonperturbative heavy quarks in the nucleon. This model can be extended to the scale of the lighter mesons, and we assess the accessibility of the structure function of the interacting pion in the resulting framework.

  18. Science Requirements and Conceptual Design for a Polarized Medium Energy Electron-Ion Collider at Jlab

    SciTech Connect (OSTI)

    Abeyratne, S; Ahmed, S; Barber, D; Bisognano, J; Bogacz, A; Castilla, A; Chevtsov, P; Corneliussen, S; Deconinck, W; Degtiarenko, P; Delayen, J; Derbenev, Ya; DeSilva, S; Douglas, D; Dudnikov, V; Ent, R; Erdelyi, B; Evtushenko, P; Fujii, Yu; Filatov, Yury; Gaskell, D; Geng, R; Guzey, V; Horn, T; Hutton, A; Hyde, C; Johnson, R; Kim, Y; Klein, F; Kondratenko, A; Kondratenko, M; Krafft, G; Li, R; Lin, F; Manikonda, S; Marhauser, F; McKeown, R; Morozov, V; Dadel-Turonski, P; Nissen, E; Ostroumov, P; Pivi, M; Pilat, F; Poelker, M; Prokudin, A; Rimmer, R; Satogata, T; Sayed, H; Spata, M; Sullivan, M; Tennant, C; Terzic, B; Tiefenback, M; Wang, M; Wang, S; Weiss, C; Yunn, B

    2012-08-01T23:59:59.000Z

    Researchers have envisioned an electron-ion collider with ion species up to heavy ions, high polarization of electrons and light ions, and a well-matched center-of-mass energy range as an ideal gluon microscope to explore new frontiers of nuclear science. In its most recent Long Range Plan, the Nuclear Science Advisory Committee (NSAC) of the US Department of Energy and the National Science Foundation endorsed such a collider in the form of a 'half-recommendation.' As a response to this science need, Jefferson Lab and its user community have been engaged in feasibility studies of a medium energy polarized electron-ion collider (MEIC), cost-effectively utilizing Jefferson Lab's already existing Continuous Electron Beam Accelerator Facility (CEBAF). In close collaboration, this community of nuclear physicists and accelerator scientists has rigorously explored the science case and design concept for this envisioned grand instrument of science. An electron-ion collider embodies the vision of reaching the next frontier in Quantum Chromodynamics - understanding the behavior of hadrons as complex bound states of quarks and gluons. Whereas the 12 GeV Upgrade of CEBAF will map the valence-quark components of the nucleon and nuclear wave functions in detail, an electron-ion collider will determine the largely unknown role sea quarks play and for the first time study the glue that binds all atomic nuclei. The MEIC will allow nuclear scientists to map the spin and spatial structure of quarks and gluons in nucleons, to discover the collective effects of gluons in nuclei, and to understand the emergence of hadrons from quarks and gluons. The proposed electron-ion collider at Jefferson Lab will collide a highly polarized electron beam originating from the CEBAF recirculating superconducting radiofrequency (SRF) linear accelerator (linac) with highly polarized light-ion beams or unpolarized light- to heavy-ion beams from a new ion accelerator and storage complex. Since the very beginning, the design studies at Jefferson Lab have focused on achieving high collider performance, particularly ultrahigh luminosities up to 10{sup 34} cm{sup -2}s{sup -1} per detector with large acceptance, while maintaining high polarization for both the electron and light-ion beams. These are the two key performance requirements of a future electron-ion collider facility as articulated by the NSAC Long Range Plan. In MEIC, a new ion complex is designed specifically to deliver ion beams that match the high bunch repetition and highly polarized electron beam from CEBAF. During the last two years, both development of the science case and optimization of the machine design point toward a medium-energy electron-ion collider as the topmost goal for Jefferson Lab. The MEIC, with relatively compact collider rings, can deliver a luminosity above 10{sup 34} cm{sup -2}s{sup -1} at a center-of-mass energy up to 65 GeV. It offers an electron energy up to 11 GeV, a proton energy up to 100 GeV, and corresponding energies per nucleon for heavy ions with the same magnetic rigidity. This design choice balances the scope of the science program, collider capabilities, accelerator technology innovation, and total project cost. An energy upgrade could be implemented in the future by adding two large collider rings housed in another large tunnel to push the center-of-mass energy up to or exceeding 140 GeV. After careful consideration of an alternative electron energy recovery linac on ion storage ring approach, a ring-ring collider scenario at high bunch repetition frequency was found to offer fully competitive performance while eliminating the uncertainties of challenging R&D on ampere-class polarized electron sources and many-pass energy-recovery linacs (ERLs). The essential new elements of an MEIC facility at Jefferson Lab are an electron storage ring and an entirely new, modern ion acceleration and storage complex. For the high-current electron collider ring, the upgraded 12 GeV CEBAF SRF linac will serve as a full-energy injector, and, if needed, provide top

  19. 2009 Linear Collider Workshop of the Americas

    SciTech Connect (OSTI)

    Seidel, Sally

    2009-09-29T23:59:59.000Z

    The 2009 Linear Collider Workshop of the Americas was held on the campus of the University of New Mexico from 29 September to 3 October, 2009. This was a joint meeting of the American Linear Collider Physics Group and the ILC Global Design Effort. Two hundred fifty people attended. The number of scientific contributions was 333. The complete agenda, with links to all of the presentations, is available at physics.unm.edu/LCWA09/. The meeting brought together international experts as well as junior scientists, to discuss the physics potential of the linear collider and advances in detector technology. The validation of detector designs was announced, and the detector design groups planned the next phase of the effort. Detector R&D teams reported on progress on many topics including calorimetry and tracking. Recent accelerator design considerations were discussed in a special session for experimentalists and theorists.

  20. The Tsallis Distribution in Proton-Proton Collisions at $\\sqrt{s}$ = 0.9 TeV at the LHC

    E-Print Network [OSTI]

    J. Cleymans; D. Worku

    2011-10-25T23:59:59.000Z

    The Tsallis distribution has been used recently to fit the transverse momentum distributions of identified particles by the STAR and PHENIX collaborations at the Relativistic Heavy Ion Collider and by the ALICE and CMS collaborations at the Large Hadron Collider. Theoretical issues are clarified concerning the thermodynamic consistency of the Tsallis distribution in the particular case of relativistic high energy quantum distributions. An improved form is proposed for describing the transverse momentum distribution and fits are presented together with estimates of the parameter $q$ and the temperature $T$.