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Sample records for hadron collider lhc

  1. LHC: The Large Hadron Collider

    SciTech Connect (OSTI)

    Lincoln, Don

    2015-03-04

    The Large Hadron Collider (or LHC) is the world’s most powerful particle accelerator. In 2012, scientists used data taken by it to discover the Higgs boson, before pausing operations for upgrades and improvements. In the spring of 2015, the LHC will return to operations with 163% the energy it had before and with three times as many collisions per second. It’s essentially a new and improved version of itself. In this video, Fermilab’s Dr. Don Lincoln explains both some of the absolutely amazing scientific and engineering properties of this modern scientific wonder.

  2. v{sub 4} from ideal and viscous hydrodynamic simulations of nuclear collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC)

    SciTech Connect (OSTI)

    Luzum, Matthew; Gombeaud, Clement; Ollitrault, Jean-Yves

    2010-05-15

    We compute v{sub 4}/(v{sub 2}){sup 2} in ideal and viscous hydrodynamics. We investigate its sensitivity to details of the hydrodynamic model and compare the results to experimental data from the BNL Relativistic Heavy Ion Collider (RHIC). Whereas v{sub 2} has a significant sensitivity only to initial eccentricity and viscosity while being insensitive to freeze-out temperature, we find that v{sub 4}/(v{sub 2}){sup 2} is quite insensitive to initial eccentricity. On the other hand, it can still be sensitive to shear viscosity in addition to freeze-out temperature, although viscous effects do not universally increase v{sub 4}/(v{sub 2}){sup 2} as originally predicted. Consistent with data, we find no dependence on particle species. We also make a prediction for v{sub 4}/(v{sub 2}){sup 2} in heavy ion collisions at the CERN Large Hadron Collider (LHC).

  3. Tomography of quark gluon plasma at energies available at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC)

    SciTech Connect (OSTI)

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

    2009-04-15

    Using the recently published model [Gossiaux and Aichelin, Phys. Rev. C 78, 014904 (2008)] for the collisional energy loss of heavy quarks 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 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 such as anti-de Sitter/conformal field theory (AdS/CFT)

  4. Beam collimation at hadron colliders

    SciTech Connect (OSTI)

    Nikolai V. Mokhov

    2003-08-12

    Operational and accidental beam losses in hadron colliders can have a serious impact on machine and detector performance, resulting in effects ranging from minor to catastrophic. Principles and realization are described for a reliable beam collimation system required to sustain favorable background conditions in the collider detectors, provide quench stability of superconducting magnets, minimize irradiation of accelerator equipment, maintain operational reliability over the life of the machine, and reduce the impact of radiation on personnel and the environment. Based on detailed Monte-Carlo simulations, such a system has been designed and incorporated in the Tevatron collider. Its performance, comparison to measurements and possible ways to further improve the collimation efficiency are described in detail. Specifics of the collimation systems designed for the SSC, LHC, VLHC, and HERA colliders are discussed.

  5. June 30, 2008: US portion of Large Hadron Collider completed

    Broader source: Energy.gov [DOE]

    June 30, 2008The Department and the National Science Foundation announce that the U.S. contribution to the Large Hadron Collider (LHC) has been completed on budget and ahead of schedule. The LHC,...

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

    Energy Savers [EERE]

    Beam for Large Hadron Collider First Beam for Large Hadron Collider September 10, 2008 - 3:20pm Addthis WASHINGTON, DC - An international collaboration of scientists today sent the first beam of protons zooming at nearly the speed of light around the world's most powerful particle accelerator-the Large Hadron Collider (LHC)-located at the CERN laboratory near Geneva, Switzerland. The U.S. Department of Energy (DOE) and the National Science Foundation (NSF) invested a total $531 million in the

  7. Director's colloquium March 18 large hadron collider

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

    Director's colloquium large hadron collider Director's colloquium March 18 large hadron collider Lyndon Evans of CERN will talk about the most complex scientific instrument ever ...

  8. Photoproduction of {rho}{sup 0} mesons in ultraperipheral heavy ion collisions at energies available at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC)

    SciTech Connect (OSTI)

    Goncalves, V. P.; Machado, M. V. T.

    2009-11-15

    We investigate the photoproduction of {rho} mesons in ultraperipheral heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and CERN Large Hadron Collider (LHC) energies in the dipole approach and within two phenomenological models based on the color glass condensate (CGC) formalism. We estimate the integrated cross section and rapidity distribution for meson production and compare our predictions with the data from the STAR Collaboration. In particular, we demonstrate that the total cross section at RHIC is strongly dependent on the energy behavior of the dipole-target cross section at low energies, which is not well determined in the dipole approach. In contrast, the predictions at midrapidities at RHIC and in the full rapidity at LHC are under theoretical control and can be used to test QCD dynamics at high energies.

  9. A large hadron electron collider at CERN

    SciTech Connect (OSTI)

    Abelleira Fernandez, J. L.

    2015-04-06

    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 eletron-ion physics. The LHeC is designed to run synchronously with the LHC in the twenties and to achieve an integrated luminosity of O(100)fb1. 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. A large hadron electron collider at CERN

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

    Abelleira Fernandez, J. L.

    2015-04-06

    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 eletron-ion physics. The LHeC is designed to run synchronously withmore » 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.« less

  11. A large hadron electron collider at CERN

    SciTech Connect (OSTI)

    Abelleira Fernandez, J. L.

    2015-04-06

    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 eletron-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.

  12. Vector meson production in coherent hadronic interactions: Update on predictions for energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Goncalves, V. P.; Machado, M. V. T.

    2011-07-15

    In this Rapid Communication we update our predictions for the photoproduction of vector mesons in coherent pp and AA collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies using the color dipole approach and the Color Glass Condensate formalism. In particular, we present our predictions for the first run of the LHC at half energy and for the rapidity dependence of the ratio between the J/{Psi} and {rho} cross sections at RHIC energies.

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

    SciTech Connect (OSTI)

    Binoth, T.; Gleisberg, T.; Karg, S.; Kauer, N.; Sanguinetti, G.

    2010-05-26

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

    SciTech Connect (OSTI)

    2010-06-21

    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.

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

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  16. Non-Large Hadron Collider Physics Program at CERN (Conference...

    Office of Scientific and Technical Information (OSTI)

    Non-Large Hadron Collider Physics Program at CERN Citation Details In-Document Search Title: Non-Large Hadron Collider Physics Program at CERN You are accessing a document from...

  17. SEARCHING FOR HIGGS BOSONS AND NEW PHYSICS AT HADRON COLLIDERS

    SciTech Connect (OSTI)

    Chung Kao

    2007-09-05

    The objectives of research activities in particle theory are predicting the production cross section and decay branching fractions of Higgs bosons and new particles at hadron colliders, developing techniques and computer software to discover these particles and to measure their properties, and searching for new phenomena and new interactions at the Fermilab Tevatron and the CERN Large Hadron Collider. The results of our project could lead to the discovery of Higgs bosons, new particles, and signatures for new physics, or we will be able to set meaningful limits on important parameters in particle physics. We investigated the the prospects for the discovery at the CERN Large Hadron Collider of Higgs bosons and supersymmetric particles. Promising results are found for the CP-odd pseudoscalar ($A^0$) and the heavier CP-even scalar ($H^0$) Higgs bosons with masses up to 800 GeV. Furthermore, we study properties of the lightest neutralino ($\\chi^0$) and calculate its cosmological relic density in a supersymmetric $U(1)'$ model as well as the muon anomalous magnetic moment $a_\\mu = (g_\\mu - 2)/2$ in a supersymmetric $U(1)'$ model. We found that there are regions of the parameter space that can explain the experimental deviation of $a_\\mu$ from the Standard Model calculation and yield an acceptable cold dark matter relic density without conflict with collider experimental constraints. % Recently, we presented a complete next-to-leading order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion ($b\\bar{b} \\to hh$) at the CERN Large Hadron Collider (LHC) in the Standard Model and the minimal supersymmetric model. We plan to predict the Higgs pair production rate and to study the trilinear coupling among the Higgs bosons. % In addition, we have made significant contributions in B physics, single top production, charged Higgs search at the Fermilab as well as in grid computing for both D0 and ATLAS.

  18. Triphoton production at hadron colliders

    SciTech Connect (OSTI)

    Campbell, John M.; Williams, Ciaran

    2014-06-01

    We present next-to-leading order predictions for the production of triphoton final states at the LHC and the Tevatron. Our results include the effect of photon fragmentation for the first time and we are able to quantify the impact of different isolation prescriptions. We find that calculations accounting for fragmentation effects at leading order, and those employing a smooth cone isolation where no fragmentation contribution is required, are in reasonable agreement with one another. However, larger differences in the predicted rates arise when higher order corrections to the fragmentation functions are included. In addition we present full analytic results for the $\\gamma\\gamma\\gamma$ and $\\gamma\\gamma+$jet one-loop amplitudes. These amplitudes, which are particularly compact, may be useful to future higher-order calculations. Our results are available in the Monte Carlo code MCFM.

  19. Strange quark suppression and strange hadron production in pp collisions at energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Long Haiyan; Feng Shengqin; Zhou Daimei; Yan Yuliang; Ma Hailiang; Sa Benhao

    2011-09-15

    The parton and hadron cascade model PACIAE based on PYTHIA is utilized to systematically investigate strange particle production in pp collisions at energies available at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC). Globally speaking, the PACIAE results of the strange particle rapidity density at midrapidity and the transverse momentum distribution are better than those of PYTHIA (default) in comparison with STAR and ALICE experimental data. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism of strange quark suppression, added in the PACIAE model. The K/{pi} ratios as a function of reaction energy in pp collisions from CERN Super Proton Synchrotron (SPS) to LHC energies are also analyzed in this paper.

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

    SciTech Connect (OSTI)

    Huitu, Katri; Rai, Santosh Kumar; Khalil, Shaaban; Okada, Hiroshi

    2008-10-31

    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.

  1. Accelerator physics and technology challenges of very high energy hadron colliders

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

    Shiltsev, Vladimir D.

    2015-08-20

    High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton–proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This article briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

  2. SCIENCE ON SATURDAY- "The Large Hadron Collider: big science...

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

    January 5, 2013, 9:30am Science On Saturday MBG Auditorium SCIENCE ON SATURDAY- "The Large Hadron Collider: big science for big questions" Professor James Olsen Department of ...

  3. ALCF helps tackle the Large Hadron Collider's big data challenge...

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

    ALCF helps tackle the Large Hadron Collider's big data challenge Author: Jim Collins November 3, 2015 Facebook Twitter LinkedIn Google E-mail Printer-friendly version Argonne ...

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

    SciTech Connect (OSTI)

    Quigg, Chris; /Fermilab /CERN

    2007-02-01

    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?

  5. First Beam Measurements with the LHC Synchrotron Light Monitors...

    Office of Scientific and Technical Information (OSTI)

    Title: First Beam Measurements with the LHC Synchrotron Light Monitors The continuous monitoring of the transverse sizes of the beams in the Large Hadron Collider (LHC) relies on ...

  6. Azimuthally sensitive femtoscopy in hydrodynamics with statistical hadronization from the BNL Relativistic Heavy Ion Collider to the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Kisiel, Adam; Broniowski, Wojciech; Florkowski, Wojciech; Chojnacki, Mikolaj

    2009-01-15

    Azimuthally sensitive femtoscopy for heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) is explored within the approach consisting of the hydrodynamics of perfect fluid followed by statistical hadronization. It is found that for the RHIC initial conditions, employing the Gaussian shape of the initial energy density, the very same framework that reproduces the standard soft observables [including the transverse-momentum spectra, the elliptic flow, and the azimuthally averaged Hanbury-Brown-Twiss (HBT) radii] leads to a proper description of the azimuthally sensitive femtoscopic observables; we find that the azimuthal variation of the side and out HBT radii as well as out-side cross term are very well reproduced for all centralities. Concerning the dependence of the femtoscopic parameters on k{sub T} we find that it is very well reproduced. The model is then extrapolated to the LHC energy. We predict the overall moderate growth of the HBT radii and the decrease of their azimuthal oscillations. Such effects are naturally caused by longer evolution times. In addition, we discuss in detail the space-time patterns of particle emission. We show that they are quite complex and argue that the overall shape seen by the femtoscopic methods cannot be easily disentangled on the basis of simple-minded arguments.

  7. Linear Collider LHC Subpanel | U.S. DOE Office of Science (SC...

    Office of Science (SC) Website

    Subpanel on the Linear Collider and the Large Hadron Collider High Energy Physics Advisory Panel (HEPAP) HEPAP Home Meetings 2015 HEPAP Membership ChargesReports Charter .pdf file ...

  8. TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS

    SciTech Connect (OSTI)

    Jabeen, Shabnam

    2013-10-20

    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.

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

    SciTech Connect (OSTI)

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

    2010-09-07

    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 {sup 197}Au{sup 79}+ 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 {sup 208}Pb+{sup 82+} beams in the LHC at injection and collision energy. For this machine, the two methods agree well.

  10. Single and multiple intrabeam scattering in hadron colliders

    SciTech Connect (OSTI)

    Lebedev, V.; /Fermilab

    2005-01-01

    Single and multiple intra-beam scattering are usually considered separately. Such separation works well for electron-positron colliders but usually yields only coarse description in the case of hadron colliders. Boltzmann type integro-differential equation is used to describe evolution of longitudinal distribution due to IBS. The finite size of the longitudinal potential well, its non-linearity and x-y coupling are taken into account. The model predictions for longitudinal and transverse distributions are compared to the experimental measurements.

  11. 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.

  12. Radio Frequency Noise Effects on the CERN Large Hadron Collider Beam Diffusion

    SciTech Connect (OSTI)

    Mastoridis, T.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; Rivetta, C.; Fox, J.D.; /SLAC

    2012-04-30

    Radio frequency (rf) accelerating system noise can have a detrimental impact on the Large Hadron Collider (LHC) performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and rf station dynamics with the bunch length growth. Measurements were conducted at LHC to determine the performance limiting rf components and validate the formalism through studies of the beam diffusion dependence on rf noise. As a result, a noise threshold was established for acceptable performance which provides the foundation for beam diffusion estimates for higher energies and intensities. Measurements were also conducted to determine the low level rf noise spectrum and its major contributions, as well as to validate models and simulations of this system.

  13. Higgs friends and counterfeits at hadron colliders

    SciTech Connect (OSTI)

    Fox, Patrick J.; Tucker-Smith, David; Weiner, Neal; /New York U., CCPP /New York U. /Princeton, Inst. Advanced Study

    2011-04-01

    We consider the possibility of 'Higgs counterfeits' - scalars that can be produced with cross sections comparable to the SM Higgs, and which decay with identical relative observable branching ratios, but which are nonetheless not responsible for electroweak symmetry breaking. We also consider a related scenario involving 'Higgs friends,' fields similarly produced through gg fusion processes, which would be discovered through diboson channels WW,ZZ,{gamma}{gamma}, or even {gamma}Z, potentially with larger cross sections times branching ratios than for the Higgs. The discovery of either a Higgs friend or a Higgs counterfeit, rather than directly pointing towards the origin of the weak scale, would indicate the presence of new colored fields necessary for the sizable production cross section (and possibly new colorless but electroweakly charged states as well, in the case of the diboson decays of a Higgs friend). These particles could easily be confused for an ordinary Higgs, perhaps with an additional generation to explain the different cross section, and we emphasize the importance of vector boson fusion as a channel to distinguish a Higgs counterfeit from a true Higgs. Such fields would naturally be expected in scenarios with 'effective Z's,' where heavy states charged under the SM produce effective charges for SM fields under a new gauge force. We discuss the prospects for discovery of Higgs counterfeits, Higgs friends, and associated charged fields at the LHC.

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

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  15. 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.

    2012-12-21

    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.

  16. Natural h{yields}4g in supersymmetric models and R-hadrons at the LHC

    SciTech Connect (OSTI)

    Luty, Markus A.; Phalen, Daniel J.; Pierce, Aaron

    2011-04-01

    We construct a simple and natural supersymmetric model where the dominant Higgs decay is h{yields}aa followed by a{yields}gg. In this case m{sub h}LHC. If these particles are stable on collider time scales, they will appear as R-hadrons, a signal visible in early LHC running. A smoking-gun signal that the stable colored particles are mediators of h{yields}4j is R-hadron production in association with an a. We show that this signal with a{yields}{gamma}{gamma} is observable at the LHC with as little as 10 fb{sup -1} of integrated luminosity. Observation of R-hadrons plus missing energy would show that the superpartner of the R-hadron is R-parity odd, and therefore not an ordinary quark or gluon.

  17. The PDF4LHC report on PDFs and LHC data: results from Run I and...

    Office of Scientific and Technical Information (OSTI)

    Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson characterization and precision Standard Model measurements to New Physics...

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

    SciTech Connect (OSTI)

    Berger, C.F.; Bern, Z.; Dixon, Lance J.; Cordero, F.Febres; Forde, D.; Gleisberg, T.; Ita, H.; Kosower, D.A.; Maitre, D.

    2010-09-14

    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.

  19. 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.

    2011-12-09

    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.

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

    SciTech Connect (OSTI)

    Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd; Aguilo, Ernest; Ahsan, Mahsana; Alexeev, Guennadi D.; Alkhazov, Georgiy D.; Alton, Andrew K.; /Michigan U. /Augustana Coll., Sioux Falls /Northeastern U.

    2009-07-01

    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.

  1. Dijet asymmetry at the energies available at the CERN Large Hadron Collider

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | DOE PAGES Dijet asymmetry at the energies available at the CERN Large Hadron Collider « Prev Next » Title: Dijet asymmetry at the energies available at the CERN Large Hadron Collider Authors: Young, Clint ; Schenke, Björn ; Jeon, Sangyong ; Gale, Charles Publication Date: 2011-08-15 OSTI Identifier: 1100553 Type: Publisher's Accepted Manuscript Journal Name: Physical Review C Additional Journal Information: Journal Volume: 84; Journal Issue: 2; Journal ID: ISSN

  2. Dijet asymmetry at the energies available at the CERN Large Hadron Collider

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Dijet asymmetry at the energies available at the CERN Large Hadron Collider Citation Details In-Document Search Title: Dijet asymmetry at the energies available at the CERN Large Hadron Collider Authors: Young, Clint ; Schenke, Björn ; Jeon, Sangyong ; Gale, Charles Publication Date: 2011-08-15 OSTI Identifier: 1100553 Type: Publisher's Accepted Manuscript Journal Name: Physical Review C Additional Journal Information: Journal Volume: 84; Journal Issue:

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

    SciTech Connect (OSTI)

    Bruce, R.; et al.,

    2013-11-21

    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.

  4. The Very Large Hadron Collider: The farthest energy frontier...

    Office of Scientific and Technical Information (OSTI)

    cost more than what is presently politically acceptable. This talk summarizes the strategies of collider design including staged deployment, comparison with electron-positron...

  5. The Very Large Hadron Collider: The farthest energy frontier...

    Office of Scientific and Technical Information (OSTI)

    would cost more than what is presently politically acceptable. This talk summarizes the strategies of collider design including staged deployment, comparison with...

  6. The fate of long-lived superparticles with hadronic decays after LHC Run 1

    SciTech Connect (OSTI)

    Liu, Zhen; Tweedie, Brock

    2015-06-08

    Supersymmetry searches at the LHC are both highly varied and highly constraining, but the vast majority are focused on cases where the final-stage visible decays are prompt. Scenarios featuring superparticles with detector-scale lifetimes have therefore remained a tantalizing possibility for sub-TeV SUSY, since explicit limits are relatively sparse. Nonetheless, the extremely low backgrounds of the few existing searches for collider-stable and displaced new particles facilitates recastings into powerful long-lived superparticle searches, even for models for which those searches are highly non-optimized. In this paper, we assess the status of such models in the context of baryonic R-parity violation, gauge mediation, and mini-split SUSY. We explore a number of common simplified spectra where hadronic decays can be important, employing recasts of LHC searches that utilize different detector systems and final-state objects. The LSP/NLSP possibilities considered here include generic colored superparticles such as the gluino and light-flavor squarks, as well as the lighter stop and the quasi-degenerate Higgsino multiplet motivated by naturalness. We find that complementary coverage over large swaths of mass and lifetime is achievable by superimposing limits, particularly from CMSs tracker-based displaced dijet search and heavy stable charged particle searches. Adding in prompt searches, we find many cases where a range of sparticle masses is now excluded from zero lifetime to infinite lifetime with no gaps. In other cases, the displaced searches furnish the only extant limits at any lifetime.

  7. The fate of long-lived superparticles with hadronic decays after LHC Run 1

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

    Liu, Zhen; Tweedie, Brock

    2015-06-08

    Supersymmetry searches at the LHC are both highly varied and highly constraining, but the vast majority are focused on cases where the final-stage visible decays are prompt. Scenarios featuring superparticles with detector-scale lifetimes have therefore remained a tantalizing possibility for sub-TeV SUSY, since explicit limits are relatively sparse. Nonetheless, the extremely low backgrounds of the few existing searches for collider-stable and displaced new particles facilitates recastings into powerful long-lived superparticle searches, even for models for which those searches are highly non-optimized. In this paper, we assess the status of such models in the context of baryonic R-parity violation, gauge mediation,more »and mini-split SUSY. We then explore a number of common simplified spectra where hadronic decays can be important, employing recasts of LHC searches that utilize different detector systems and final-state objects. The LSP/NLSP possibilities considered here include generic colored superparticles such as the gluino and light-flavor squarks, as well as the lighter stop and the quasi-degenerate Higgsino multiplet motivated by naturalness. We find that complementary coverage over large swaths of mass and lifetime is achievable by superimposing limits, particularly from CMS’s tracker-based displaced dijet search and heavy stable charged particle searches. By adding in prompt searches, we find many cases where a range of sparticle masses is now excluded from zero lifetime to infinite lifetime with no gaps. In other cases, the displaced searches furnish the only extant limits at any lifetime.« less

  8. The fate of long-lived superparticles with hadronic decays after LHC Run 1

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

    Liu, Zhen; Tweedie, Brock

    2015-06-08

    Supersymmetry searches at the LHC are both highly varied and highly constraining, but the vast majority are focused on cases where the final-stage visible decays are prompt. Scenarios featuring superparticles with detector-scale lifetimes have therefore remained a tantalizing possibility for sub-TeV SUSY, since explicit limits are relatively sparse. Nonetheless, the extremely low backgrounds of the few existing searches for collider-stable and displaced new particles facilitates recastings into powerful long-lived superparticle searches, even for models for which those searches are highly non-optimized. In this paper, we assess the status of such models in the context of baryonic R-parity violation, gauge mediation,moreand mini-split SUSY. We explore a number of common simplified spectra where hadronic decays can be important, employing recasts of LHC searches that utilize different detector systems and final-state objects. The LSP/NLSP possibilities considered here include generic colored superparticles such as the gluino and light-flavor squarks, as well as the lighter stop and the quasi-degenerate Higgsino multiplet motivated by naturalness. We find that complementary coverage over large swaths of mass and lifetime is achievable by superimposing limits, particularly from CMSs tracker-based displaced dijet search and heavy stable charged particle searches. Adding in prompt searches, we find many cases where a range of sparticle masses is now excluded from zero lifetime to infinite lifetime with no gaps. In other cases, the displaced searches furnish the only extant limits at any lifetime.less

  9. Jet vetoes for Higgs boson production at future hadron colliders (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Jet vetoes for Higgs boson production at future hadron colliders Citation Details In-Document Search Title: Jet vetoes for Higgs boson production at future hadron colliders Authors: Boughezal, Radja ; Focke, Christfried ; Li, Ye ; Liu, Xiaohui Publication Date: 2014-09-02 OSTI Identifier: 1180233 Grant/Contract Number: AC02- 06CH11357; FG02-08ER4153; AC02-05CH11231; AC02-06CH11357; AC02-76SF00515; FG02-95ER40896 Type: Publisher's Accepted Manuscript Journal Name:

  10. 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

    2012-03-20

    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.

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

    SciTech Connect (OSTI)

    2010-01-20

    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.

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

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  13. Updated Workflows Enhance New LHC Era

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

    A view inside the liquid-argon calorimeter endcap. Photo Credit: The ATLAS Experiment at CERN, atlas.ch After a massive upgrade, the Large Hadron Collider (LHC)-the world's most ...

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

    SciTech Connect (OSTI)

    Yost, Scott A

    2014-04-02

    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.

  15. Color sextet scalars at the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Chen, C.-R.; Klemm, William; Rentala, Vikram; Wang Kai

    2009-03-01

    Taking a phenomenological approach, we study a color sextet scalar at the LHC. We focus on the QCD production of a color sextet pair {phi}{sub 6}{phi}{sub 6} through gg fusion and qq annihilation. Its unique coupling to {psi}{sup c}{psi} allows the color sextet scalar to decay into same-sign diquark states, such as {phi}{sub 6}{yields}tt/tt*. We propose a new reconstruction in the multijet plus same-sign dilepton with missing transverse energy samples (bb+l{sup {+-}}l{sup {+-}}+Ee{sub T}+Nj, N{>=}6) to search for on-shell tttt final states from sextet scalar pair production. Thanks to the large QCD production, the search covers the sextet mass range up to 1 TeV for 100 fb{sup -1} integrated luminosity.

  16. Particle Physics after the Higgs-Boson Discovery: Opportunities for the Large Hadron Collider

    SciTech Connect (OSTI)

    Quigg, Chris

    2015-08-24

    The first run of the Large Hadron Collider at CERN brought the discovery of the Higgs boson, an apparently elementary scalar particle with a mass of 125 GeV, the avatar of the mechanism that hides the electroweak symmetry. Then, a new round of experimentation is beginning, with the energy of the protonproton colliding beams raised to 6.5 TeV per beam, from 4 TeV at the end of the first run. I summarize what we have learned about the Higgs boson, and calls attention to some issues that will be among our central concerns in the near future.

  17. Particle Physics after the Higgs-Boson Discovery: Opportunities for the Large Hadron Collider

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

    Quigg, Chris

    2015-08-24

    The first run of the Large Hadron Collider at CERN brought the discovery of the Higgs boson, an apparently elementary scalar particle with a mass of 125 GeV, the avatar of the mechanism that hides the electroweak symmetry. Then, a new round of experimentation is beginning, with the energy of the proton–proton colliding beams raised to 6.5 TeV per beam, from 4 TeV at the end of the first run. I summarize what we have learned about the Higgs boson, and calls attention to some issues that will be among our central concerns in the near future.

  18. PHOBOS in the LHC era

    SciTech Connect (OSTI)

    Steinberg, Peter

    2015-01-15

    The PHOBOS experiment ran at the RHIC collider from 2000 to 2005, under the leadership of Wit Busza. These proceedings summarize selected PHOBOS results, highlighting their continuing relevance amidst the wealth of new results from the lead–lead program at the Large Hadron Collider (LHC)

  19. SCIENCE ON SATURDAY- "The Large Hadron Collider: big science for big

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

    questions" | Princeton Plasma Physics Lab January 5, 2013, 9:30am Science On Saturday MBG Auditorium SCIENCE ON SATURDAY- "The Large Hadron Collider: big science for big questions" Professor James Olsen Department of Physics, Princeton University Science on Saturday is a series of lectures given by scientists, mathematicians, and other professionals involved in cutting-edge research. Held on Saturday mornings throughout winter, the lectures are geared toward high school

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

    SciTech Connect (OSTI)

    Jung, Chang Kee; Douglas, Michaek; Hobbs, John; McGrew, Clark; Rijssenbeek, Michael

    2013-07-29

    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.

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

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  2. Integrated analysis of particle interactions at hadron colliders Report of research activities in 2010-2015

    SciTech Connect (OSTI)

    Nadolsky, Pavel M.

    2015-08-31

    The report summarizes research activities of the project ”Integrated analysis of particle interactions” at Southern Methodist University, funded by 2010 DOE Early Career Research Award DE-SC0003870. The goal of the project is to provide state-of-the-art predictions in quantum chromodynamics in order to achieve objectives of the LHC program for studies of electroweak symmetry breaking and new physics searches. We published 19 journal papers focusing on in-depth studies of proton structure and integration of advanced calculations from different areas of particle phenomenology: multi-loop calculations, accurate long-distance hadronic functions, and precise numerical programs. Methods for factorization of QCD cross sections were advanced in order to develop new generations of CTEQ parton distribution functions (PDFs), CT10 and CT14. These distributions provide the core theoretical input for multi-loop perturbative calculations by LHC experimental collaborations. A novel ”PDF meta-analysis” technique was invented to streamline applications of PDFs in numerous LHC simulations and to combine PDFs from various groups using multivariate stochastic sampling of PDF parameters. The meta-analysis will help to bring the LHC perturbative calculations to the new level of accuracy, while reducing computational efforts. The work on parton distributions was complemented by development of advanced perturbative techniques to predict observables dependent on several momentum scales, including production of massive quarks and transverse momentum resummation at the next-to-next-to-leading order in QCD.

  3. Fermilab | Science | Particle Physics | Fermilab and the LHC

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

    Fermilab and the LHC photo The Large Hadron Collider is the largest, most powerful particle accelerator in the world. It steers beams of particles on a collision course around a ...

  4. The LHC Experiments

    SciTech Connect (OSTI)

    Lincoln, Don

    2015-03-11

    The Large Hadron Collider or LHC is the world’s biggest particle accelerator, but it can only get particles moving very quickly. To make measurements, scientists must employ particle detectors. There are four big detectors at the LHC: ALICE, ATLAS, CMS, and LHCb. In this video, Fermilab’s Dr. Don Lincoln introduces us to these detectors and gives us an idea of each one’s capabilities.

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

    SciTech Connect (OSTI)

    Cao Qinghong; Khalil, Shaaban; Ma, Ernest; Okada, Hiroshi

    2011-04-01

    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.

  6. K (transverse) jet algorithms in hadron colliders: The D0 experience

    SciTech Connect (OSTI)

    V. Daniel Elvira

    2002-12-05

    D0 has implemented and studied a k{sub {perpendicular}} jet algorithm for the first time in a hadron collider. The authors have submitted two physics results for publication: the subjet multiplicity in quark and gluon jets and the central inclusive jet cross section measurements. A third result, a measurement of thrust distributions in jet events, is underway. A combination of measurements using several types of algorithms and samples taken at different center-of-mass energies is desirable to understand and distinguish with higher accuracy between instrumentation and physics effects.

  7. 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.

    2012-02-22

    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.

  8. Search for a light fermiophobic Higgs boson produced via gluon fusion at hadron colliders

    SciTech Connect (OSTI)

    Arhrib, Abdesslam; Benbrik, Rachid; Guedes, R. B.; Santos, R.

    2008-10-01

    In this study, we propose new Higgs production mechanisms with multiphoton final states in the fermiophobic limit of the two Higgs doublet model. The processes are: gg{yields}hh, gg{yields}Hh followed by H{yields}hh and gg{yields}Ah followed by A{yields}hZ. In the fermiophobic limit, gg{yields}hh and gg{yields}Ah{yields}hhZ would give rise to 4{gamma} signature while gg{yields}Hh{yields}hhh can give a 6{gamma} final state. We show that both the Fermilab Tevatron and CERN's Large Hadron Collider can probe a substantial slice of the parameter space in this fermiophobic scenario of the two Higgs doublet model. If observed the above processes can give some information on the triple Higgs couplings involved.

  9. Higgs self-coupling measurements at a 100 TeV hadron collider

    SciTech Connect (OSTI)

    Barr, Alan J.; Dolan, Matthew J.; Englert, Christoph; Ferreira de Lima, Enoque Danilo; Spannowsky, Michael

    2015-02-03

    An important physics goal of a possible next-generation high-energy hadron collider will be precision characterisation of the Higgs sector and electroweak symmetry breaking. A crucial part of understanding the nature of electroweak symmetry breaking is measuring the Higgs self-interactions. We study dihiggs production in proton-proton collisions at 100 TeV centre of mass energy in order to estimate the sensitivity such a machine would have to variations in the trilinear Higgs coupling around the Standard Model expectation. We focus on the bb¯γγ final state, including possible enhancements in sensitivity by exploiting dihiggs recoils against a hard jet. In conclusion, we find that it should be possible to measure the trilinear self-coupling with 40% accuracy given 3/ab and 12% with 30/ab of data.

  10. Supersymmetry At LHC

    SciTech Connect (OSTI)

    Khalil, Shaaban

    2008-04-21

    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.

  11. High throughput lessons from the LHC experience.Johnston.TNC2013

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

    This is true for the two largest experiments at the Large Hadron Collider (LHC) at CERN - ATLAS and CMS - and for the climate science community. In the near future, experiments ...

  12. Higgs boson pair production in new physics models at hadron, lepton, and photon colliders

    SciTech Connect (OSTI)

    Asakawa, Eri; Harada, Daisuke; Okada, Yasuhiro; Kanemura, Shinya; Tsumura, Koji

    2010-12-01

    We study Higgs boson pair production processes at future hadron and lepton colliders including the photon collision option in several new physics models; i.e., the two-Higgs-doublet model, the scalar leptoquark model, the sequential fourth generation fermion model and the vectorlike quark model. Cross sections for these processes can deviate significantly from the standard model predictions due to the one-loop correction to the triple Higgs boson coupling constant. For the one-loop induced processes such as gg{yields}hh and {gamma}{gamma}{yields}hh, where h is the (lightest) Higgs boson and g and {gamma} respectively represent a gluon and a photon, the cross sections can also be affected by new physics particles via additional one-loop diagrams. In the two-Higgs-doublet model and scalar leptoquark models, cross sections of e{sup +}e{sup -}{yields}hhZ and {gamma}{gamma}{yields}hh can be enhanced due to the nondecoupling effect in the one-loop corrections to the triple Higgs boson coupling constant. In the sequential fourth generation fermion model, the cross section for gg{yields}hh becomes very large because of the loop effect of the fermions. In the vectorlike quark model, effects are small because the theory has decoupling property. Measurements of the Higgs boson pair production processes can be useful to explore new physics through the determination of the Higgs potential.

  13. Production of b-quark jets at the large Hadron Collider in the parton-reggeization approach

    SciTech Connect (OSTI)

    Saleev, V. A. Shipilova, A. V.

    2013-11-15

    The inclusive hadroproduction of b-quark jets and bb-bar-quark dijets at the Large Hadron Collider is considered by using the hypothesis of gluon Reggeization in t-channel exchanges at high energies. Experimental data obtained by the ATLAS Collaboration are described well within all of the presented kinematical regions for single b-quark jets and bb-bar-quark dijets without resort to any free parameters.

  14. Updated Workflows Enhance New LHC Era

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

    Updated Workflows Enhance New LHC Era Updated Workflows Enhance New LHC Era New Software Helps Physics Maximize Next-Gen Supercomputing Architectures February 22, 2016 Linda Vu, +1 510 495 2402, lvu@lbl.gov ATLAS A view inside the liquid-argon calorimeter endcap. Photo Credit: The ATLAS Experiment at CERN, atlas.ch After a massive upgrade, the Large Hadron Collider (LHC)-the world's most powerful particle collider-is now smashing particles at an unprecedented 13 tera-electron-volts (TeV), nearly

  15. Single and double photonuclear excitations in Pb+Pb collisions at {radical}(s{sub NN})=2.76 TeV at the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Djuvsland, Oystein; Nystrand, Joakim

    2011-04-15

    Cross sections are calculated for single and double photon exchange in ultraperipheral Pb+Pb collisions at the CERN Large Hadron Collider. The particle production is simulated with the DPMJET event generator. Large cross sections are found for particle production around midrapidity, making these processes an important background to hadronic nuclear interactions at both the trigger and analysis levels.

  16. Tevatron-for-LHC Report of the QCD Working Group

    SciTech Connect (OSTI)

    Albrow, Michael G.; Begel, M.; Bourilkov, D.; Campanelli, M.; Chlebana, F.; De Roeck, A.; Dittmann, J.R.; Ellis, S.D.; Field, B.; Field, R.; Gallinaro, M.; /Fermilab /Rochester U. /Florida U. /Geneva U. /CERN /Baylor U. /Washington U., Seattle /Florida State U. /Rockefeller U. /Prague, Tech. U. /Michigan State U.

    2006-10-01

    The experiments at Run 2 of the Tevatron have each accumulated over 1 fb{sup -1} of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focused on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.

  17. Technicolor corrections to bb{yields}W{sup {+-}{pi}}{sub t}{sup {+-}}at the CERN Large Hadron Collider

    SciTech Connect (OSTI)

    Huang Jinshu; Pan, Qunna; Song, Taiping; Lu, Gongru

    2010-07-01

    In this paper we calculate the technicolor correction to the production of a charged top pion in association with a W boson via bb annihilation at the CERN Large Hadron Collider in the context of the topcolor assisted technicolor model. We find that the cross section of pp{yields}bb{yields}W{sup {+-}{pi}}{sub t}{sup {+-}}at the tree level can reach a few hundred femtobarns for reasonable ranges of the parameters, roughly corresponding to the result of the process pp{yields}bb{yields}W{sup {+-}H{+-}}in the minimal supersymmetric standard model; the relative corrections arising from the one-loop diagrams are about a few percent to two dozen percent, and they will increase the cross section at the tree level. As a comparison, we also discuss the size of the hadron cross section via the other subprocess gg{yields}W{sup {+-}{pi}}{sub t}{sup {+-}.}

  18. 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)

    2009-08-28

    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.

  19. Catching Collisions in the LHC

    SciTech Connect (OSTI)

    Fruguiele, Claudia; Hirschauer, Jim

    2015-06-16

    Now that the Large Hadron Collider has officially turned back on for its second run, within every proton collision could emerge the next new discovery in particle physics. Learn how the detectors on the Compact Muon Solenoid, or CMS, experiment capture and track particles as they are expelled from a collision. Talking us through these collisions are Claudia Fruguiele and Jim Hirschauer of Fermi National Accelerator Laboratory, the largest U.S. institution collaborating on the LHC.

  20. Les Houches Guidebook to Monte Carlo generators for hadron collider physics

    SciTech Connect (OSTI)

    Dobbs, M.A

    2004-08-24

    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.

  1. Selected experimental results from heavy-ion collisions at LHC

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

    Singh, Ranbir; Kumar, Lokesh; Netrakanti, Pawan Kumar; Mohanty, Bedangadas

    2013-01-01

    We review a subset of experimental results from the heavy-ion collisions at the Large Hadron Collider (LHC) facility at CERN. Excellent consistency is observed across all the experiments at the LHC (at center of mass energysNN=2.76 TeV) for the measurements such as charged particle multiplicity density, azimuthal anisotropy coefficients, and nuclear modification factor of charged hadrons. Comparison to similar measurements from the Relativistic Heavy Ion Collider (RHIC) at lower energy (sNN=200 GeV) suggests that the system formed at LHC has a higher energy density and larger system size and lives for a longer time. These measurements aremore »compared to model calculations to obtain physical insights on the properties of matter created at the RHIC and LHC.« less

  2. Klystron switching power supplies for the Internation Linear Collider

    SciTech Connect (OSTI)

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

    2009-12-01

    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.

  3. CERN and LHC - their place in global science

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  4. 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)

    2009-10-01

    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.

  5. Indications of Conical Emission of Charged Hadrons at the BNL Relativistic Heavy Ion Collider

    SciTech Connect (OSTI)

    Abelev, B. I.; Barannikova, O.; Betts, R. R.; Callner, J.; Garcia-Solis, E.; Hofman, D. J.; Hollis, R. S.; Iordanova, A.; Suarez, M. C.; Aggarwal, M. M.; Bhati, A. K.; Kumar, L.; Pruthi, N. K.; Ahammed, Z.; Chattopadhyay, S.; Dutta Mazumdar, M. R.; Ganti, M. S.; Ghosh, P.; Mohanty, B.; Nayak, T. K.

    2009-02-06

    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}.

  6. Indications of conical emission of charged hadrons at the BNL relativistic heavy ion collider.

    SciTech Connect (OSTI)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Krueger, K.; Spinka, H. M.; Underwood, D. G.; High Energy Physics; Univ. of Illinois; Panjab Univ.; Variable Energy Cyclotron Centre; Kent State Univ.; Particle Physic Lab.; STAR Collaboration

    2009-01-01

    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.

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

    SciTech Connect (OSTI)

    STAR Coll

    2009-02-09

    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}}.

  8. RF system models for the CERN Large Hadron Collider with application to longitudinal dynamics

    SciTech Connect (OSTI)

    Mastorides, T.; Rivetta, C.; Fox, J.D.; Winkle, D.Van; Baudrenghien, P.; /CERN

    2011-03-03

    The LHC RF station-beam interaction strongly influences the longitudinal beam dynamics, both single bunch and collective effects. Non-linearities and noise generated within the Radio Frequency (RF) accelerating system interact with the beam and contribute to beam motion and longitudinal emittance blowup. Thus, the noise power spectrum of the RF accelerating voltage strongly affects the longitudinal beam distribution. Furthermore, the coupled-bunch instabilities are also directly affected by the RF components and the configuration of the Low Level RF (LLRF) feedback loops. In this work we present a formalism relating the longitudinal beam dynamics with the RF system configurations, an estimation of collective effects stability margins, and an evaluation of longitudinal sensitivity to various LLRF parameters and configurations.

  9. Reliability of Beam Loss Monitor Systems for the Large Hadron Collider

    SciTech Connect (OSTI)

    Guaglio, G.; Dehning, B.; Santoni, C.

    2005-06-08

    The increase of beam energy and beam intensity, together with the use of super conducting magnets, opens new failure scenarios and brings new criticalities for the whole accelerator protection system. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system, and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses at 7 TeV and assisted by the Fast Beam Current Decay Monitors at 450 GeV. At medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standard databases. All the data has been processed by reliability software (Isograph). The analysis spaces from the components data to the system configuration.

  10. Jet energy loss, photon production, and photon-hadron correlations at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)

    SciTech Connect (OSTI)

    Qin Guangyou; Ruppert, Joerg; Gale, Charles; Jeon, Sangyong; Moore, Guy D.

    2009-11-15

    Jet energy loss, photon production, and photon-hadron correlations are studied together at high transverse momentum in relativistic heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) energies. The modification of hard jets traversing a hot and dense nuclear medium is evaluated by consistently taking into account induced gluon radiation and elastic collisions. The production of high-transverse-momentum photons in Au+Au collisions at RHIC is calculated by incorporating a complete set of photon-production channels. Comparison with experimental photon production and photon-hadron correlation data is performed, using a (3+1)-dimensional relativistic hydrodynamic description of the thermalized medium created in these collisions. Our results demonstrate that the interaction between the hard jets and the soft medium is important for the study of photon production and of photon-hadron correlation at RHIC.

  11. Radiative return capabilities of a high-energy, high-luminositye+e-collider

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

    Karliner, Marek; Low, Matthew; Rosner, Jonathan L.; Wang, Lian-Tao

    2015-08-14

    An electron-positron collider operating at a center-of-mass energy ECM 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 ECM = 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.

  12. A study on dual readout crystal calorimeter for hadron and jet energy measurement at a future lepton collider

    SciTech Connect (OSTI)

    Yeh, G.P.; /Fermilab

    2010-01-01

    Studies of requirements and specifications of crystals are necessary to develop a new generation of crystals for dual readout crystal hadron or total absorption calorimeter. This is a short and basic study of the characteristics and hadron energy measurement of PbWO4 and BGO crystals for scintillation and Cerenkov Dual Readout hadron calorimeter.

  13. Higher order mode filter design for double quarter wave crab cavity for the LHC high luminosity upgrade

    SciTech Connect (OSTI)

    Xiao, B.; Belomestnykh, S.; Ben-Zvi, I.; Burt, G.; Calaga, R.; Capatina, O.; Hall, B.; Jones, T.; Skaritka, J.; Verdu-Andres, S.; Wu, Q.

    2015-05-03

    A Double Quarter Wave Crab Cavity (DQWCC) was designed for the Large Hadron Collider (LHC) luminosity upgrade. A compact Higher Order Mode (HOM) filter with wide stop band at the deflecting mode is developed for this cavity. Multiphysics finite element simulation results are presented. The integration of this design to the cavity cryomodule is described.

  14. LHC RF System Time-Domain Simulation

    SciTech Connect (OSTI)

    Mastorides, T.; Rivetta, C.

    2010-09-14

    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.

  15. Higgs production and decay from TeV scale black holes at the LHC (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Higgs production and decay from TeV scale black holes at the LHC Citation Details In-Document Search Title: Higgs production and decay from TeV scale black holes at the LHC We perform a detailed study of the Higgs production and decay, when Higgs is emitted from the black holes produced in proton-proton collisions at the Large Hadron Collider. We show that black hole production can significantly enhance the signal for the Higgs search at the LHC. We evaluate

  16. First Experiences with LHC Grid Computing and Distributed Analysis

    SciTech Connect (OSTI)

    Fisk, Ian

    2010-12-01

    In this presentation the experiences of the LHC experiments using grid computing were presented with a focus on experience with distributed analysis. After many years of development, preparation, exercises, and validation the LHC (Large Hadron Collider) experiments are in operations. The computing infrastructure has been heavily utilized in the first 6 months of data collection. The general experience of exploiting the grid infrastructure for organized processing and preparation is described, as well as the successes employing the infrastructure for distributed analysis. At the end the expected evolution and future plans are outlined.

  17. Impact of parton distribution function and {alpha}{sub s} uncertainties on Higgs boson production in gluon fusion at hadron colliders

    SciTech Connect (OSTI)

    Demartin, Federico; Mariani, Elisa [Dipartimento di Fisica, Universita di Milano, Via Celoria 16, I-20133 Milano (Italy); Forte, Stefano; Vicini, Alessandro [Dipartimento di Fisica, Universita di Milano, Via Celoria 16, I-20133 Milano (Italy); INFN, Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Rojo, Juan [INFN, Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy)

    2010-07-01

    We present a systematic study of uncertainties due to parton distributions (PDFs) and the strong coupling on the gluon-fusion production cross section of the standard model Higgs at the Tevatron and LHC colliders. We compare procedures and results when three recent sets of PDFs are used, CTEQ6.6, MSTW08, and NNPDF1.2, and we discuss specifically the way PDF and strong coupling uncertainties are combined. We find that results obtained from different PDF sets are in reasonable agreement if a common value of the strong coupling is adopted. We show that the addition in quadrature of PDF and {alpha}{sub s} uncertainties provides an adequate approximation to the full result with exact error propagation. We discuss a simple recipe to determine a conservative PDF+{alpha}{sub s} uncertainty from available global parton sets, and we use it to estimate this uncertainty on the given process to be about 10% at the Tevatron and 5% at the LHC for a light Higgs.

  18. Dijet asymmetry at the energies available at the CERN Large Hadron...

    Office of Scientific and Technical Information (OSTI)

    Dijet asymmetry at the energies available at the CERN Large Hadron Collider Prev Next Title: Dijet asymmetry at the energies available at the CERN Large Hadron Collider ...

  19. The PDF4LHC report on PDFs and LHC data: Results from Run I and preparation for Run II

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

    Rojo, Juan; Accardi, Alberto; Ball, Richard D.; Cooper-Sarkar, Amanda; de Roeck, Albert; Farry, Stephen; Ferrando, James; Forte, Stefano; Gao, Jun; Harland-Lang, Lucian; et al

    2015-09-16

    The accurate determination of Parton Distribution Functions (PDFs) of the proton is an essential ingredient of the Large Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson characterization and precision Standard Model measurements to New Physics searches. A major recent development in modern PDF analyses has been to exploit the wealth of new information contained in precision measurements from the LHC Run I, as well as progress in tools and methods to include these data in PDF fits. In this report we summarize the information that PDF-sensitive measurements at the LHC have provided somore » far, and review the prospects for further constraining PDFs with data from the recently started Run II. As a result, this document aims to provide useful input to the LHC collaborations to prioritize their PDF-sensitive measurements at Run II, as well as a comprehensive reference for the PDF-fitting collaborations.« less

  20. Measurement of identified charged hadron spectra in proton-proton collisions using the Inner Tracking System of the ALICE experiment at the LHC

    SciTech Connect (OSTI)

    Biolcati, Emanuele

    2011-05-23

    The measurement of the identified charged hadron p{sub t} spectra using the ITS energy loss signal in the pp data at {radical}(s) = 900 GeV collected by the ALICE experiment at LHC will be discussed. It is performed using the Inner Tracking System (ITS) in stand-alone mode, both for track reconstruction and particle identification, allowing one to detect low momentum particles with p{sub t} below 200 MeV/c. A second method using the tracks reconstructed by both the ITS and the Time Projection Chamber (TPC) has also been developed. The obtained results will be compared with the ones obtained from the TPC and from the Time Of Flight detector and used to extract the mean p{sub t} value.

  1. Shadowing effects on J/ψ and Υ production at energies available at the CERN Large Hadron Collider

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

    Vogt, R.

    2015-09-17

    Proton-nucleus collisions have been used as a intermediate baseline for the determination of cold medium effects. They lie between proton-proton collisions in vacuum and nucleus-nucleus collisions which are expected to be dominated by hot matter effects. Modifications of the quark densities in nuclei relative to those of the proton are well established although those of the gluons in the nucleus are not well understood. We focus on the effect of these on quarkonium production in proton-lead collisions at the LHC at a center of mass energy of 5.02 TeV.

  2. Development of Large Area Gas Electron Multiplier Detector and Its Application to a Digital Hadron Calorimeter for Future Collider Experiments

    SciTech Connect (OSTI)

    Yu, Jaehoon; White, Andrew

    2014-09-25

    The UTA High Energy Physics Group conducted generic detector development based on large area, very thin and high sensitivity gas detector using gas electron multiplier (GEM) technology. This is in preparation for a use as a sensitive medium for sampling calorimeters in future collider experiments at the Energy Frontier as well as part of the tracking detector in Intensity Frontier experiments. We also have been monitoring the long term behavior of one of the prototype detectors (30cmx30cm) read out by the SLAC-developed 13-bit KPiX analog chip over three years and have made presentations of results at various APS meetings. While the important next step was the development of large area (1m x 1m) GEM planes, we also have looked into opportunities of applying this technology to precision tracking detectors to significantly improve the performance of the Range Stack detector for CP violation experiments and to provide an amplification layer for the liquid Argon Time Projection Chamber in the LBNE experiment. We have jointly developed 33cmx100cm large GEM foils with the CERN gas detector development group to construct 33cm x100cm unit chambers. Three of these unit chambers will be put together to form a 1m x 1m detector plane. Following characterization of one 33cmx100cm unit chamber prototype, a total of five 1m x 1m planes will be constructed and inserted into an existing 1m3 RPC DHCAL stack to test the performance of the new GEM DHCAL in particle beams. The large area GEM detector we planned to develop in this proposal not only gives an important option to DHCAL for future collider experiments but also the potential to expand its use to Intensity Frontier and Cosmic Frontier experiments as high efficiency, high amplification anode planes for liquid Argon time projection chambers. Finally, thanks to its sensitivity to X-rays and other neutral radiations and its light-weight characteristics, the large area GEM has a great potential for the use in medical imaging and homeland security, as well as satellite based astronomy experiments.

  3. Cryogenic test of double quarter wave crab cavity for the LHC High luminosity upgrade

    SciTech Connect (OSTI)

    Xiao, B.; Alberty, L.; Belomestnykh, S.; Ben-Zvi, I.; Calaga, R.; Cullen, C.; Capatina, O.; Hammons, L.; Li, Z.; Marques, C.; Skaritka, J.; Verdu-Andres, S.; Wu, Q.

    2015-05-03

    A Proof-of-Principle (PoP) Double Quarter Wave Crab Cavity (DQWCC) was designed and fabricated for the Large Hadron Collider (LHC) luminosity upgrade. A vertical cryogenic test has been done at Brookhaven National Lab (BNL). The cavity achieved 4.5 MV deflecting voltage with a quality factor above 3×109. We report the test results of this design.

  4. Probing top-Z dipole moments at the LHC and ILC

    SciTech Connect (OSTI)

    Röntsch, Raoul; Schulze, Markus

    2015-08-11

    We investigate the weak electric and magnetic dipole moments of top quark-Z boson interactions at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). Their vanishingly small magnitude in the Standard Model makes these couplings ideal for probing New Physics interactions and for exploring the role of top quarks in electroweak symmetry breaking. In our analysis, we consider the production of two top quarks in association with a Z boson at the LHC, and top quark pairs mediated by neutral gauge bosons at the ILC. These processes yield direct sensitivity to top quark-Z boson interactions and complement indirect constraints from electroweak precision data. Our computation is accurate to next-to-leading order in QCD, we include the full decay chain of top quarks and the Z boson, and account for theoretical uncertainties in our constraints. Furthermore, we find that LHC experiments will soon be able to probe weak dipole moments for the first time.

  5. Comparison of LHC and ILC Capabilities for Higgs Boson Coupling...

    Office of Scientific and Technical Information (OSTI)

    I estimate the accuracies on Higgs boson coupling constants that experiments at the Large Hadron Collider and the International Linear Collider are capable of reaching over the ...

  6. Summary of the Mini BNL/LARP/CARE-HHH Workshop on Crab Cavities for the LHC (LHC-CC08)

    SciTech Connect (OSTI)

    Ben-Zvi,I.; Calaga, R.; Zimmermann, F.

    2008-05-01

    The first mini-workshop on crab compensation for the LHC luminosity upgrade (LHC-CC08) was held February 24-25, 2008 at the Brookhaven National Laboratory. A total of 35 participants from 3 continents and 15 institutions from around the world participated to discuss the exciting prospect of a crab scheme for the LHC. If realized it will be the first demonstration in hadron colliders. The workshop is organized by joint collaboration of BNL, US-LARP and CARE-HHH. The enormous interest in the subject of crab cavities for the international linear collider and future light sources has resulted in a large international collaboration to exchange aspects of synergy and expertise. A central repository for this exchange of information documenting the latest design effort for LHC crab cavities is consolidated in a wiki page: https://twiki.cern.ch/twiki/bin/view/Main/LHCCrabCavities. The main goal of this workshop was to define a road-map for a prototype crab cavity to be installed in the LHC and to discuss the associated R&D and beam dynamics challenges. The diverse subject of implementing the crab scheme resulted in a scientific program with a wide range of subtopics which were divided into 8 sessions. Each session was given a list of fundamental questions to be addressed and used as a guideline to steer the discussions.

  7. Radiative return capabilities of a high-energy, high-luminositye+e-collider

    SciTech Connect (OSTI)

    Karliner, Marek; Low, Matthew; Rosner, Jonathan L.; Wang, Lian-Tao

    2015-08-14

    An electron-positron collider operating at a center-of-mass energy ECM 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 ECM = 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.

  8. LHC Physics Potential versus Energy

    SciTech Connect (OSTI)

    Quigg, Chris; /Fermilab

    2009-08-01

    Parton luminosities are convenient for estimating how the physics potential of Large Hadron Collider experiments depends on the energy of the proton beams. I present parton luminosities, ratios of parton luminosities, and contours of fixed parton luminosity for gg, u{bar d}, and qq interactions over the energy range relevant to the Large Hadron Collider, along with example analyses for specific processes.

  9. 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.

    2009-07-01

    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.

  10. Probing New Physics with Jets at the LHC

    ScienceCinema (OSTI)

    Harris, Robert

    2009-09-01

    The Large Hadron Collider at CERN has the potential to make a major discovery as early as 2008 from simple measurements of events with two high energy jets. This talk will present the jet trigger and analysis plans of the CMS collaboration, which were produced at the LHC Physics Center at Fermilab. Plans to search the two jet channel for generic signals of new particles and forces will be discussed. I will present the anticipated sensitivity of the CMS experiment to a variety of models of new physics, including quark compositeness, technicolor, superstrings, extra dimensions and grand unification.

  11. COLLOQUIUM: Fundamental Physics and the LHC: A Progress Report | Princeton

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

    Plasma Physics Lab 17, 2013, 4:15pm to 5:30pm Colloquia MBG Auditorium COLLOQUIUM: Fundamental Physics and the LHC: A Progress Report Professor Nima Arkani-Hamed The Institute for Advanced Study Presentation: PDF icon WC17APR2013_NAHamed.pdf Last July's discovery of the Higgs particle at the Large Hadron Collider was a triumph for both experiment and theory in fundamental physics. But the Higgs also introduces major conceptual paradoxes that strongly suggest we are missing essential new

  12. Hadron Colliders Working Group Report

    SciTech Connect (OSTI)

    S. Peggs and M.J. Syphers

    2001-11-08

    The ''point design'' studied this year shows that a staged VLHC (40, {approx} 200 TeV) is feasible, with no insurmountable challenges. Further work can provide a more optimized design, by studying various alternative field strengths (e.g., superferric magnets for Stage 1) for improvements to vacuum, wall impedance, and other major performance parameters. It may be that a ''single-stage'' scenario for accessing higher energies sooner is the correct approach. A next-step design study should be considered to look at the two cases near to and complementary to the 2001 VLHC Design Study. The effectiveness of photon stops and their engineering design need to be addressed in the near future to truly determine if these devices can lead this effort to even higher luminosities and energies. The superbunch approach should continue to be studied, as well as IR designs, new instrumentation and diagnostics, and beam dynamics issues. Finally, a well organized VLHC-motivated beam studies effort should become part of the national program.

  13. International linear collider reference design report

    SciTech Connect (OSTI)

    Aarons, G.

    2007-06-22

    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.

  14. The Interplay Between Collider Searches For Supersymmetric Higgs Bosons and Direct Dark Matter Experiments

    SciTech Connect (OSTI)

    Carena, Marcela; Hooper, Dan; Vallinotto, Alberto; /Fermilab /Chicago U. /Paris, Inst. Astrophys.

    2006-11-01

    In this article, we explore the interplay between searches for supersymmetric particles and Higgs bosons at hadron colliders (the Tevatron and the LHC) and direct dark matter searches (such as CDMS, ZEPLIN, XENON, EDELWEISS, CRESST, WARP and others). We focus on collider searches for heavy MSSM Higgs bosons (A, H, H{sup {+-}}) and how the prospects for these searches are impacted by direct dark matter limits and vice versa. We find that the prospects of these two experimental programs are highly interrelated. A positive detection of A, H or H{sup {+-}} at the Tevatron would dramatically enhance the prospects for a near future direct discovery of neutralino dark matter. Similarly, a positive direct detection of neutralino dark matter would enhance the prospects of discovering heavy MSSM Higgs bosons at the Tevatron or the LHC. Combining the information obtained from both types of experimental searches will enable us to learn more about the nature of supersymmetry.

  15. Steady State Heat Deposits Modeling in the Nb3Sn Quadrupole Magnets for the Upgrade of the LHC Inner Triplet

    SciTech Connect (OSTI)

    Bocian, D.; Ambrosio, G.; Felice, H.; Barzi, E.; Bossert, R.; Caspi, S.; Chlachidze, G.; Dietderich, D.; Feher, S.; Ferracin, P.; Hafalia, R.; /Fermilab /Lawrence Berkeley Lab /Brookhaven

    2011-09-01

    In hadron colliders such as the LHC, the energy deposited in the superconductors by the particles lost from the beams or coming from the collision debris may provoke quenches detrimental to the accelerator operation. In previous papers, a Network Model has been used to study the thermodynamic behavior of magnet coils and to calculate the quench levels in the LHC magnets for expected beam loss profiles. This model was subsequently used for thermal analysis and design optimization of Nb{sub 3}Sn quadrupole magnets, which LARP (US LHC Accelerator Research Program) is developing for possible use in the LHC luminosity upgrade. For these new magnets, the heat transport efficiency from the coil to the helium bath needs to be determined and optimized. In this paper the study of helium cooling channels and the heat evacuation scheme are presented and discussed.

  16. Beam-machine Interaction at the CERN LHC

    SciTech Connect (OSTI)

    Boccone, V.; Bruce, R.; Brugger, M.; Calviani, M.; Cerutti, F. Esposito, L.S.; Ferrari, A.; Lechner, A.; Mereghetti, A.; Nowak, E.; Shetty, N.V.; Skordis, E.; Versaci, R.; Vlachoudis, V.

    2014-06-15

    The radiation field generated by a high energy and intensity accelerator is of concern in terms of element functionality threat, component damage, electronics reliability, and material activation, but also provides signatures that allow actual operating conditions to be monitored. The shower initiated by an energetic hadron involves many different physical processes, down to slow neutron interactions and fragment de-excitation, which need to be accurately described for design purposes and to interpret operation events. The experience with the transport and interaction Monte Carlo code FLUKA at the Large Hadron Collider (LHC), operating at CERN with 4 TeV proton beams (and equivalent magnetic rigidity Pb beams) and approaching nominal luminosity and energy, is presented. Design, operation and upgrade challenges are reviewed in the context of beam-machine interaction account and relevant benchmarking examples based on radiation monitor measurements are shown.

  17. Physics validation studies for muon collider detector background simulations

    SciTech Connect (OSTI)

    Morris, Aaron Owen; /Northern Illinois U.

    2011-07-01

    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.

  18. General-purpose event generators for LHC physics

    SciTech Connect (OSTI)

    Buckley, Andy; Butterworth, Jonathan; Gieseke, Stefan; Grellscheid, David; Hoche, Stefan; Hoeth, Hendrik; Krauss, Frank; Lonnblad, Leif; Nurse, Emily; Richardson, Peter; Schumann, Steffen; Seymour, Michael H.; Sjostrand, Torbjorn; Skands, Peter; Webber, Bryan; /Cambridge U.

    2011-03-03

    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.

  19. Collider effects of unparticle interactions in multiphoton signals

    SciTech Connect (OSTI)

    Aliev, T. M.; Frank, Mariana; Turan, Ismail

    2009-12-01

    A new model of physics, with a hidden conformal sector which manifests itself as an unparticle coupling to standard model particles effectively through higher dimensional operators, predicts strong collider signals due to unparticle self-interactions. We perform a complete analysis of the most spectacular of these signals at the hadron collider, pp(p){yields}{gamma}{gamma}{gamma}{gamma} and {gamma}{gamma}gg. These processes can go through the three-point unparticle self-interactions as well as through some s and t channel diagrams with one and/or two unparticle exchanges. We study the contributions of individual diagrams classified with respect to the number of unparticle exchanges and discuss their effect on the cross sections at the Tevatron and the LHC. We also restrict the Tevatron bound on the unknown coefficient of the three-point unparticle correlator. With the availability of data from the Tevatron, and the advent of the data emerging from the LHC, these interactions can provide a clear and strong indication of unparticle physics and distinguish this model from other beyond the standard model scenarios.

  20. Automated next-to-leading order predictions for new physics at the LHC: The case of colored scalar pair production

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

    Degrande, Céline; Fuks, Benjamin; Hirschi, Valentin; Proudom, Josselin; Shao, Hua -Sheng

    2015-05-05

    We present for the first time the full automation of collider predictions matched with parton showers at the next-to-leading accuracy in QCD within nontrivial extensions of the standard model. The sole inputs required from the user are the model Lagrangian and the process of interest. As an application of the above, we explore scenarios beyond the standard model where new colored scalar particles can be pair produced in hadron collisions. Using simplified models to describe the new field interactions with the standard model, we present precision predictions for the LHC within the MadGraph5_aMC@NLO framework.

  1. The standard model and colliders

    SciTech Connect (OSTI)

    Hinchliffe, I.

    1987-03-01

    Some topics in the standard model of strong and electroweak interactions are discussed, as well as how these topics are relevant for the high energy colliders which will become operational in the next few years. The radiative corrections in the Glashow-Weinberg-Salam model are discussed, stressing how these corrections may be measured at LEP and the SLC. CP violation is discussed briefly, followed by a discussion of the Higgs boson and the searches which are relevant to hadron colliders are then discussed. Some of the problems which the standard model does not solve are discussed, and the energy ranges accessible to the new colliders are indicated. (LEW)

  2. First Beam Measurements with the LHC Synchrotron Light Monitors

    SciTech Connect (OSTI)

    Lefevre, Thibaut; Bravin, Enrico; Burtin, Gerard; Guerrero, Ana; Jeff, Adam; Rabiller, Aurelie; Roncarolo, Federico; Fisher, Alan; /SLAC

    2012-07-13

    The continuous monitoring of the transverse sizes of the beams in the Large Hadron Collider (LHC) relies on the use of synchrotron radiation and intensified video cameras. Depending on the beam energy, different synchrotron light sources must be used. A dedicated superconducting undulator has been built for low beam energies (450 GeV to 1.5 TeV), while edge and centre radiation from a beam-separation dipole magnet are used respectively for intermediate and high energies (up to 7 TeV). The emitted visible photons are collected using a retractable mirror, which sends the light into an optical system adapted for acquisition using intensified CCD cameras. This paper presents the design of the imaging system, and compares the expected light intensity with measurements and the calculated spatial resolution with a cross calibration performed with the wire scanners. Upgrades and future plans are also discussed.

  3. Probing top-Z dipole moments at the LHC and ILC

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

    Röntsch, Raoul; Schulze, Markus

    2015-08-11

    We investigate the weak electric and magnetic dipole moments of top quark-Z boson interactions at the Large Hadron Collider (LHC) and the International Linear Collider (ILC). Their vanishingly small magnitude in the Standard Model makes these couplings ideal for probing New Physics interactions and for exploring the role of top quarks in electroweak symmetry breaking. In our analysis, we consider the production of two top quarks in association with a Z boson at the LHC, and top quark pairs mediated by neutral gauge bosons at the ILC. These processes yield direct sensitivity to top quark-Z boson interactions and complement indirectmore » constraints from electroweak precision data. Our computation is accurate to next-to-leading order in QCD, we include the full decay chain of top quarks and the Z boson, and account for theoretical uncertainties in our constraints. Furthermore, we find that LHC experiments will soon be able to probe weak dipole moments for the first time.« less

  4. 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

    2008-02-25

    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.

  5. Baseline review of the U.S. LHC Accelerator project

    SciTech Connect (OSTI)

    1998-02-01

    The Department of Energy (DOE) Review of the U.S. Large Hadron Collider (LHC) Accelerator project was conducted February 23--26, 1998, at the request of Dr. John R. O`Fallon, Director, Division of High Energy Physics, Office of Energy Research, U.S. DOE. This is the first review of the U.S. LHC Accelerator project. Overall, the Committee found that the U.S. LHC Accelerator project effort is off to a good start and that the proposed scope is very conservative for the funding available. The Committee recommends that the project be initially baselined at a total cost of $110 million, with a scheduled completion data of 2005. The U.S. LHC Accelerator project will supply high technology superconducting magnets for the interaction regions (IRs) and the radio frequency (rf) straight section of the LHC intersecting storage rings. In addition, the project provides the cryogenic support interface boxes to service the magnets and radiation absorbers to protect the IR dipoles and the inner triplet quadrupoles. US scientists will provide support in analyzing some of the detailed aspects of accelerator physics in the two rings. The three laboratories participating in this project are Brookhaven National Laboratory, Fermi National Accelerator Laboratory (Fermilab), and Lawrence Berkeley National Laboratory. The Committee was very impressed by the technical capabilities of the US LHC Accelerator project team. Cost estimates for each subsystem of the US LHC Accelerator project were presented to the Review Committee, with a total cost including contingency of $110 million (then year dollars). The cost estimates were deemed to be conservative. A re-examination of the funding profile, costs, and schedules on a centralized project basis should lead to an increased list of deliverables. The Committee concluded that the proposed scope of US deliverables to CERN can be readily accomplished with the $110 million total cost baseline for the project. The current deliverables should serve as the baseline scope with the firm expectation that additional scope will be restored to the baseline as the project moves forward. The Committee supports the FY 1998 work plan and scope of deliverables but strongly recommends the reevaluation of costs and schedules with the goal of producing a plan for restoring the US deliverables to CERN. This plan should provide precise dates when scope decisions must be made.

  6. An updated analysis of Inert Higgs Doublet Model in light of the recent results from LUX, PLANCK, AMS-02 and LHC

    SciTech Connect (OSTI)

    Arhrib, Abdesslam; Tsai, Yue-Lin Sming; Yuan, Tzu-Chiang; Yuan, Qiang E-mail: yue-lin.tsai@ipmu.jp E-mail: tcyuan@phys.sinica.edu.tw

    2014-06-01

    In light of the recent discovery by the ATLAS and CMS experiments at the Large Hadron Collider (LHC) of a Higgs-like particle with a narrow mass range of 125126 GeV, we perform an updated analysis on one of the popular scalar dark matter models, the Inert Higgs Doublet Model (IHDM). We take into account in our likelihood analysis of various experimental constraints, including recent relic density measurement, dark matter direct and indirect detection constraints as well as the latest collider constraints on the invisible decay width of the Higgs boson and monojet search at the LHC. It is shown that if the invisible decay of the standard model Higgs boson is open, LHC as well as direct detection experiments like LUX and XENON100 could put stringent limits on the Higgs boson couplings to dark matter. We find that the most favoured parameter space for IHDM corresponds to dark matter with a mass less than 100 GeV or so. In particular, the best-fit points are at the dark matter mass around 70 GeV where the invisible Higgs decay to dark matter is closed. Scalar dark matter in the higher mass range of 0.54 TeV is also explored in our study. Projected sensitivities for the future experiments of monojet at LHC-14, XENON1T and AMS-02 one year antiproton flux are shown to put further constraints on the existing parameter space of IHDM.

  7. Higgs Hunting at the Large Hadron Collider

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

    ... with exactly 4 leptons There are 11 channels due to lepton flavor Leptons with large transverse momentum can be identified and measured very precisely so also the Higgs ...

  8. 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.

    2009-03-01

    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.

  9. Muon Collider Progress: Accelerators

    SciTech Connect (OSTI)

    Zisman, Michael S.

    2011-09-10

    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 10{sup 34} cm{sup 2}s{sup 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.

  10. March

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

    Director's colloquium March 18 large hadron collider Lyndon Evans of CERN will talk about the most complex scientific instrument ever built-the Large Hadron Collider (LHC). - 310...

  11. Fermilab Today

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

    LHC arrives at the next energy frontier Data collection has officially begun at the Large Hadron Collider. Photo: Maximilien Brice, CERN On Wednesday the Large Hadron Collider ...

  12. Muon Collider

    SciTech Connect (OSTI)

    Palmer, R.

    2009-10-19

    Parameters are given of muon colliders with center of mass energies of 1.5 and 3 TeV. Pion production is from protons on a mercury target. Capture, decay, and phase rotation yields bunch trains of both muon signs. Six dimensional cooling reduces the emittances until the trains are merged into single bunches, one of each sign. Further cooling in 6 dimensions is then applied, followed by final transverse cooling in 50 T solenoids. After acceleration the muons enter the collider ring. Ongoing R&D is discussed.

  13. Operational results from the LHC luminosity monitors

    SciTech Connect (OSTI)

    Miyamoto, R.; Ratti, A.; Matis, H.S.; Stezelberger, T.; Turner, W.C.; Yaver, H.; Bravin, E.

    2011-03-28

    The luminosity monitors for the high luminosity regions in the LHC have been operating to monitor and optimize the luminosity since 2009. The device is a gas ionization chamber inside the neutral particle absorber 140 m from the interaction point and monitors showers produced by high energy neutral particles from the collisions. It has the ability to resolve the bunch-by-bunch luminosity as well as to survive the extreme level of radiation in the nominal LHC operation. We present operational results of the device during proton and lead ion operations in 2010 and make comparisons with measurements of experiments. The Large Hadron Collider (LHC) at CERN can accelerate proton and lead ion beams to 7 TeV and 547 TeV and produce collisions of these particles. Luminosity measures performance of the LHC and is particularly important for experiments in high luminosity interaction points (IPs), ATLAS (IP1) and CMS (IP5). To monitor and optimize the luminosities of these IPs, BRAN (Beam RAte Neutral) detectors [1, 2] have been installed and operating since the beginning of the 2009 operation [3]. A neutral particle absorber (TAN) protects the D2 separation dipole from high energy forward neutral particles produced in the collisions [4]. These neutral particles produce electromagnetic and hadronic showers inside the TAN and their energy flux is proportional to the collision rate and hence to the luminosity. The BRAN detector is an Argon gas ionization chamber installed inside the TANs on both sides of the IP1 and IP5 and monitors the relative changes in the luminosity by detecting the ionization due to these showers. When the number of collisions per bunch crossing (multiplicity) is small, the shower rate inside the TAN is also proportional to the luminosity. Hence, the detector is designed to operate by measuring either the shower rate (counting mode for low and intermediate luminosities) or the average shower flux (pulse height mode for high luminosities). The detector is also designed (1) to survive the extreme level of radiation ({approx}1 GGy in the nominal condition), (2) to resolve the shower from each bunch crossing (40 MHz in the nominal condition) and measure the bunch-by-bunch luminosities, and (3) to have four independent square shaped channels, each occupying a quadrant, making the detector sensitive to the crossing angle [1, 2]. During the proton operation in 2010, the beam energy was 3.5 TeV and the multiplicity did not exceed four. Because the counting mode is still effective in such a condition [5], the BRAN were operated in the counting mode in 2010. This paper presents operational results of the BRANs during the operation in 2010 (mainly the proton operation) and makes comparisons with measurements of the experiments. The luminosity optimization is discussed in detail in [6] and so this paper focuses on measurements during the normal operation.

  14. QCD and Hadron Physics

    SciTech Connect (OSTI)

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

    2015-02-26

    This White Paper 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. The meeting was held in coordination with the Town Meeting on Phases of QCD and included a full day of joint plenary sessions of the two meetings. The goals of the meeting were to report and highlight progress in hadron physics in the seven years since the 2007 Long Range Plan (LRP07), and present a vision for the future by identifying the key questions and plausible paths to solutions which should define the next decade. The introductory summary details the recommendations and their supporting rationales, as determined at the Town Meeting on QCD and Hadron Physics, and the endorsements that were voted upon. The larger document is organized as follows. Section 2 highlights major progress since the 2007 LRP. It is followed, in Section 3, by a brief overview of the physics program planned for the immediate future. Finally, Section 4 provides an overview of the physics motivations and goals associated with the next QCD frontier: the Electron-Ion-Collider.

  15. Hadron interactions

    SciTech Connect (OSTI)

    K. Orginos

    2011-12-01

    In this talk I am reviewing recent calculations of properties of multi-hadron systems in lattice QCD. In particular, I am reviewing results of elastic scattering phase shifts in meson-meson, meson-baryon and baryon-baryon systems, as well as discussing results indicating possible existence of bound states in two baryon systems. Finally, calculations of properties of systems with more than two hadrons are presented.

  16. Tevatron instrumentation: boosting collider performance

    SciTech Connect (OSTI)

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

    2006-05-01

    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.

  17. Muon Colliders: The Next Frontier

    ScienceCinema (OSTI)

    Tourun, Yagmur [Illinois Institute of Technology, Chicago, Illinois, United States

    2010-01-08

    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.

  18. hhjj production at the LHC

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

    Dolan, Matthew J.; Englert, Christoph; Greiner, Nicolas; Nordstrom, Karl; Spannowsky, Michael

    2015-08-25

    The search for di-Higgs production at the LHC in order to set limits on the Higgs trilinear coupling and constraints on new physics is one of the main motivations for the LHC high-luminosity phase. Recent experimental analyses suggest that such analyses will only be successful if information from a range of channels is included. We therefore investigate di-Higgs production in association with two hadronic jets and give a detailed discussion of both the gluon- and the weak boson-fusion (WBF) contributions, with a particular emphasis on the phenomenology with modified Higgs trilinear and quartic gauge couplings. We perform a detailed investigationmore » of the full hadronic final state and find that hhjj production should add sensitivity to a di-Higgs search combination at the HL-LHC with 3 ab-1. Since the WBF and GF contributions are sensitive to different sources of physics beyond the Standard Model, we devise search strategies to disentangle and isolate these production modes. In addition, while gluon fusion remains non-negligible in WBF-type selections, sizeable new physics contributions to the latter can still be constrained. As an example of the latter point we investigate the sensitivity that can be obtained for a measurement of the quartic Higgs–gauge boson couplings.« less

  19. Is Particle Physics Ready for the LHC

    ScienceCinema (OSTI)

    Lykken, Joseph

    2009-09-01

    The advent of the Large Hadron Collider in 2007 entails daunting challenges to particle physicists. The first set of challenges will arise from trying to separate new physics from old. The second set of challenges will come in trying to interpret the new discoveries. I will describe a few of the scariest examples.

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

    SciTech Connect (OSTI)

    Cao Junjie; Heng Zhaoxia; Yang Jinmin; Wu Lei

    2009-03-01

    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.

  1. Muon Muon Collider: Feasibility Study

    SciTech Connect (OSTI)

    Gallardo, J.C.; Palmer, R.B.; Tollestrup, A.V.; Sessler, A.M.; Skrinsky, A.N.; 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. ,

    2012-04-05

    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 how to shield the detector and reduce the background are addressed in the Detector Chapter. Polarization of the muons allows many very interesting measurements which are discussed in the Physics Chapter. Unlike the electron collider in which the electron beam is highly polarized and the positron beam unpolarized, both muon beams may be partially polarized. It is necessary to select forward moving muons from the pion's decay and thus reduce the available number of muons and hence the luminosity. The necessary machine technology needed to achieve such a collider is discussed in the Option Chapter; at the moment it is not part of our point design, although such capability would almost certainly be incorporated into an actual device.

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

    ScienceCinema (OSTI)

    Giorgio Ambrosio

    2010-01-08

    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.

  3. High precision predictions for exclusive VH production at the LHC

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

    Li, Ye; Liu, Xiaohui

    2014-06-04

    We present a resummation-improved prediction for pp → VH + 0 jets at the Large Hadron Collider. We focus on highly-boosted final states in the presence of jet veto to suppress the tt¯ background. In this case, conventional fixed-order calculations are plagued by the existence of large Sudakov logarithms αnslogm(pvetoT/Q) for Q ~ mV + mH which lead to unreliable predictions as well as large theoretical uncertainties, and thus limit the accuracy when comparing experimental measurements to the Standard Model. In this work, we show that the resummation of Sudakov logarithms beyond the next-to-next-to-leading-log accuracy, combined with the next-to-next-to-leading ordermore » calculation, reduces the scale uncertainty and stabilizes the perturbative expansion in the region where the vector bosons carry large transverse momentum. Thus, our result improves the precision with which Higgs properties can be determined from LHC measurements using boosted Higgs techniques.« less

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

    SciTech Connect (OSTI)

    Harrison, M.

    2011-04-30

    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.

  5. LHC Computing

    SciTech Connect (OSTI)

    Lincoln, Don

    2015-07-28

    The LHC is the world’s highest energy particle accelerator and scientists use it to record an unprecedented amount of data. This data is recorded in electronic format and it requires an enormous computational infrastructure to convert the raw data into conclusions about the fundamental rules that govern matter. In this video, Fermilab’s Dr. Don Lincoln gives us a sense of just how much data is involved and the incredible computer resources that makes it all possible.

  6. Hadron physics

    SciTech Connect (OSTI)

    Bunce, G.

    1984-05-30

    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.

  7. ESnet4:

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

    ... (updated 20052006) - Magnetic Fusion - Large Hadron Collider (LHC) - Climate Modeling - ... Manage allocations of scarce, shared resources - Authentication to prevent ...

  8. The Next Linear Collider: NLC2001

    SciTech Connect (OSTI)

    D. Burke et al.

    2002-01-14

    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.

  9. LHC Physics Potential vs. Energy: Considerations for the 2011 Run

    SciTech Connect (OSTI)

    Quigg, Chris; /Fermilab /CERN

    2011-02-01

    Parton luminosities are convenient for estimating how the physics potential of Large Hadron Collider experiments depends on the energy of the proton beams. I quantify the advantage of increasing the beam energy from 3.5 TeV to 4 TeV. I present parton luminosities, ratios of parton luminosities, and contours of fixed parton luminosity for gg, u {bar d}, qq, and gq interactions over the energy range relevant to the Large Hadron Collider, along with example analyses for specific processes. This note extends the analysis presented in Ref. [1]. Full-size figures are available as pdf files at lutece.fnal.gov/PartonLum11/.

  10. HEPAP Agenda March 3-4, 2006 | U.S. DOE Office of Science (SC...

    Office of Science (SC) Website

    P-5: Particle Physics Project Prioritization Panel Subpanel NuSAG: Neutrino Scientific Assessment Group Subpanel ILC: International Linear Collider LHC: Large Hadron Collider Last ...

  11. CaseStudyTemplate

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

    Relevant DOEHEP applications include the Large Hadron Collider (LHC), Project X and the International Linear Collider (ILC). Normal conducting (warm) RF cavities and waveguides ...

  12. Rainer Fries

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

    My research is related to the experimental programs at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab and the Large Hadron Collider (LHC) at CERN. Teaching ...

  13. LHC detector upgrades

    SciTech Connect (OSTI)

    Dan Green

    2003-09-15

    The LHC detectors are well into their construction phase. The LHC schedule shows first beam to ATLAS and CMS in 2007. Because the LHC accelerator has begun to plan for a ten fold increase in LHC design luminosity (the SLHC or super LHC) it is none too soon to begin to think about the upgrades which will be required of the present LHC detectors. In particular, the tracking systems of ATLAS and CMS will need to be completely rebuilt. Given the time needed to do the R & D, make prototypes, and construct the new detectors and given the accelerator schedule for the SLHC, work needs to begin rather soon.

  14. LHC luminosity upgrade with large Piwinski angle scheme: a recent look

    SciTech Connect (OSTI)

    Bhat, C.M.; Zimmermann, f.; /CERN

    2011-09-01

    Luminosity upgrade at the LHC collider using longitudinally flat bunches in combination with the large crossing angle (large Piwinski angle scheme) is being studied with renewed interest in recent years. By design, the total beam-beam tune shift at the LHC is less than 0.015 for two interaction points together. But the 2010-11 3.5 TeV collider operation and dedicated studies indicated that the beam-beam tune shift is >0.015 per interaction point. In view of this development we have revisited the requirements for the Large Piwinski Angle scheme at the LHC. In this paper we present a new set of parameters and luminosity calculations for the desired upgrade by investigating: (1) current performance of the LHC injectors, (2) e-cloud issues on nearly flat bunches and (3) realistic beam particle distributions from longitudinal beam dynamics simulations. We also make some remarks on the needed upgrades on the LHC injector accelerators.

  15. High precision predictions for exclusive VH production at the LHC

    SciTech Connect (OSTI)

    Li, Ye; Liu, Xiaohui

    2014-06-04

    We present a resummation-improved prediction for pp → VH + 0 jets at the Large Hadron Collider. We focus on highly-boosted final states in the presence of jet veto to suppress the tt¯ background. In this case, conventional fixed-order calculations are plagued by the existence of large Sudakov logarithms αnslogm(pvetoT/Q) for Q ~ mV + mH which lead to unreliable predictions as well as large theoretical uncertainties, and thus limit the accuracy when comparing experimental measurements to the Standard Model. In this work, we show that the resummation of Sudakov logarithms beyond the next-to-next-to-leading-log accuracy, combined with the next-to-next-to-leading order calculation, reduces the scale uncertainty and stabilizes the perturbative expansion in the region where the vector bosons carry large transverse momentum. Thus, our result improves the precision with which Higgs properties can be determined from LHC measurements using boosted Higgs techniques.

  16. Ion Desorption Stability in Superconducting High Energy Physics Proton Colliders

    SciTech Connect (OSTI)

    Turner, W.C.

    1995-05-29

    In this paper we extend our previous analysis of cold beam tube vacuum in a superconducting proton collider to include ion desorption in addition to thermal desorption and synchrotron radiation induced photodesorption. The new ion desorption terms introduce the possibility of vacuum instability. This is similar to the classical room temperature case but now modified by the inclusion of ion desorption coefficients for cryosorbed (physisorbed) molecules which can greatly exceed the coefficients for tightly bound molecules. The sojourn time concept for physisorbed H{sub 2} is generalized to include photodesorption and ion desorption as well as the usually considered thermal desorption. The ion desorption rate is density dependent and divergent so at the onset of instability the sojourn time goes to zero. Experimental data are used to evaluate the H{sub 2} sojourn time for the conditions of the Large Hadron Collider (LHC) and the situation is found to be stable. The sojourn time is dominated by photodesorption for surface density s(H{sub 2}) less than a monolayer and by thermal deposition for s(H{sub 2}) greater than a monolayer. For a few percent of a monolayer, characteristic of a beam screen, the photodesorption rate exceeds ion desorption rate by more than two orders of magnitude. The photodesorption rate corresponds to a sojourn time of approximately 100 sec. The paper next turns to the evaluation of stability margins and inclusion of gases heavier than H{sub 2} (CO, CO{sub 2} and CH{sub 4}), where ion desorption introduces coupling between molecular species. Stability conditions are worked out for a simple cold beam tube, a cold beam tube pumped from the ends and a cold beam tube with a co-axial perforated beam screen. In each case a simple inequality for stability of a single component is replaced by a determinant that must be greater than zero for a gas mixture. The connection with the general theory of feedback stability is made and it is shown that the gains of the diagonal uncoupled feedback loops are first order in the ion desorption coefficients whereas the gains of the off diagonal coupled feedback loops are second and higher order. For this reason it turns out that in practical cases stability is dominated by the uncoupled diagonal elements and the inverse of the largest first order closed loop gain is a useful estimate of the margin of stability. In contrast to the case of a simple cold beam tube, the stability condition for a beam screen does not contain the desorption coefficient for physisorbed molecules, even when the screen temperature is low enough that there is a finite surface density of them on the screen surface. Consequently there does not appear to be any particular advantage to operating the beam screen at high enough temperature to avoid physisorption. Numerical estimates of ion desorption stability are given for a number of cases relevant to LHC and all of the ones likely to be encountered were found to be stable. The most important case, a I % transparency beam screen at {approx}4.2 K, was found to have a stability safety margin of approximately thirty determined by ion desorption of CO. Ion desorption of H{sub 2} is about a factor of eighty less stringent than CO. For these estimates the beam tube surface was assumed to be solvent cleaned but otherwise untreated, for example by a very high temperature vacuum bakeout or by glow discharge cleaning.

  17. A Large Hadron Electron Collider at CERN (Journal Article) |...

    Office of Scientific and Technical Information (OSTI)

    M. ; Brookhaven ; Barber, D. ; Daresbury DESY Liverpool U. ; Bartels, J. ; Hamburg, Tech. U. ; Behnke, O. ; DESY ; Behr, J. ; DESY ; Belyaev, A.S. ; Rutherford...

  18. Dark matter signals in dilepton production at hadron colliders...

    Office of Scientific and Technical Information (OSTI)

    This content will become publicly available on June 7, 2016 Title: Dark matter signals in ... will become publicly available on June 7, 2016 Publisher's Version of Record 10.1103...

  19. Non-Large Hadron Collider Physics Program at CERN (Conference...

    Office of Scientific and Technical Information (OSTI)

    at CERN (AD) is looking at antimatter production and trapping. First trapped anti-hydrogen were reported in 2010. Interdisciplinary team is working in the CLOUD experiment,...

  20. New Perspectives for QCD Physics at the LHC

    SciTech Connect (OSTI)

    Brodsky, Stanley J.; /SLAC /Stanford U. /Southern Denmark U., CP3-Origins

    2011-02-07

    I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as diffractive deep inelastic scattering, The antishadowing of nuclear structure functions is predicted to depend on the flavor quantum numbers of each quark and antiquark. Isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation, even at the LHC. Such 'direct' processes can explain the observed deviations from pQCD predictions of the power-law fall-off of inclusive hadron cross sections as well as the 'baryon anomaly' seen in high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p{sub T} photon plus charm-jet events observed at the Tevatron and imply a large production rate for charm and bottom jets at high p{sub T} at the LHC, as well as a novel mechanism for Higgs and Z{sup 0} production at high x{sub F}. The light-front wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at the amplitude level. The elimination of the renormalization scale ambiguity for the QCD coupling using the scheme-independent BLM method will increase the sensitivity of searches for new physics at the LHC. The implications of 'in-hadron condensates' for the QCD contribution to the cosmological constant are also discussed.

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

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  2. Nonglobal correlations in collider physics

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

    Moult, Ian; Larkoski, Andrew J.

    2016-01-13

    Despite their importance for precision QCD calculations, correlations between in- and out-of-jet regions of phase space have never directly been observed. These so-called non-global effects are present generically whenever a collider physics measurement is not explicitly dependent on radiation throughout the entire phase space. In this paper, we introduce a novel procedure based on mutual information, which allows us to isolate these non-global correlations between measurements made in different regions of phase space. We study this procedure both analytically and in Monte Carlo simulations in the context of observables measured on hadronic final states produced in e+e- collisions, though itmore » is more widely applicable.The procedure exploits the sensitivity of soft radiation at large angles to non-global correlations, and we calculate these correlations through next-to-leading logarithmic accuracy. The bulk of these non-global correlations are found to be described in Monte Carlo simulation. They increase by the inclusion of non-perturbative effects, which we show can be incorporated in our calculation through the use of a model shape function. As a result, this procedure illuminates the source of non-global correlations and has connections more broadly to fundamental quantities in quantum field theory.« less

  3. Accelerator physics in ERL based polarized electron ion collider

    SciTech Connect (OSTI)

    Hao, Yue

    2015-05-03

    This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

  4. Researchers create enormous simulation of proton collisions ...

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

    events with transverse momentum of jets above 2.7 TeV. Such an event sample is expected to be produced by a future hadron collider that surpasses the Large Hadron Collider (LHC). ...

  5. Higgs boson hadronic branching ratios at the ILC (Journal Article) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Higgs boson hadronic branching ratios at the ILC Citation Details In-Document Search Title: Higgs boson hadronic branching ratios at the ILC We present a study of the Higgs boson decay branching ratios to bb, cc, and gluons, one of the cornerstones of the physics program at the International Linear Collider. A standard model Higgs boson of 120 GeV mass, produced in the Higgs-strahlung process at {radical}(s)=250 GeV, was investigated using the full detector simulation and

  6. Shooting string holography of jet quenching at RHIC and LHC

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

    Ficnar, Andrej; Gubser, Steven S.; Gyulassy, Miklos

    2014-10-13

    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 GaussBonnet quadratic curvature corrections to the AdS5 geometry improve the agreement with the recent data.

  7. Erratum to: Constraining couplings of top quarks to the Z boson in $$ t\\overline{t} $$ + Z production at the LHC

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

    Röntsch, Raoul; Schulze, Markus

    2015-09-21

    We study top quark pair production in association with a Z boson at the Large Hadron Collider (LHC) and investigate the prospects of measuring the couplings of top quarks to the Z boson. To date these couplings have not been constrained in direct measurements. Such a determination will be possible for the first time at the LHC. Our calculation improves previous coupling studies through the inclusion of next-to-leading order (NLO) QCD corrections in production and decays of all unstable particles. We treat top quarks in the narrow-width approximation and retain all NLO spin correlations. To determine the sensitivity of amore » coupling measurement we perform a binned log-likelihood ratio test based on normalization and shape information of the angle between the leptons from the Z boson decay. The obtained limits account for statistical uncertainties as well as leading theoretical systematics from residual scale dependence and parton distribution functions. We use current CMS data to place the first direct constraints on the ttbZ couplings. We also consider the upcoming high-energy LHC run and find that with 300 inverse fb of data at an energy of 13 TeV the vector and axial ttbZ couplings can be constrained at the 95% confidence level to C_V=0.24^{+0.39}_{-0.85} and C_A=-0.60^{+0.14}_{-0.18}, where the central values are the Standard Model predictions. This is a reduction of uncertainties by 25% and 42%, respectively, compared to an analysis based on leading-order predictions. We also translate these results into limits on dimension-six operators contributing to the ttbZ interactions beyond the Standard Model.« less

  8. Erratum to: Constraining couplings of top quarks to the Z boson in $ t\\overline{t} $ + Z production at the LHC

    SciTech Connect (OSTI)

    Röntsch, Raoul; Schulze, Markus

    2015-09-21

    We study top quark pair production in association with a Z boson at the Large Hadron Collider (LHC) and investigate the prospects of measuring the couplings of top quarks to the Z boson. To date these couplings have not been constrained in direct measurements. Such a determination will be possible for the first time at the LHC. Our calculation improves previous coupling studies through the inclusion of next-to-leading order (NLO) QCD corrections in production and decays of all unstable particles. We treat top quarks in the narrow-width approximation and retain all NLO spin correlations. To determine the sensitivity of a coupling measurement we perform a binned log-likelihood ratio test based on normalization and shape information of the angle between the leptons from the Z boson decay. The obtained limits account for statistical uncertainties as well as leading theoretical systematics from residual scale dependence and parton distribution functions. We use current CMS data to place the first direct constraints on the ttbZ couplings. We also consider the upcoming high-energy LHC run and find that with 300 inverse fb of data at an energy of 13 TeV the vector and axial ttbZ couplings can be constrained at the 95% confidence level to C_V=0.24^{+0.39}_{-0.85} and C_A=-0.60^{+0.14}_{-0.18}, where the central values are the Standard Model predictions. This is a reduction of uncertainties by 25% and 42%, respectively, compared to an analysis based on leading-order predictions. We also translate these results into limits on dimension-six operators contributing to the ttbZ interactions beyond the Standard Model.

  9. DOE Issues Request for Proposals Seeking a Contractor to Manage...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    the Host Laboratory for U.S. participation in the Large Hadron Collider (LHC) Compact Muon Solenoid detector, construction of certain LHC accelerator components, and the U.S. LHC...

  10. Spin and diffractive physics with a fixed-target experiment at the LHC (AFTER-LHC)

    SciTech Connect (OSTI)

    Lorce, C.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Rosier, P.; Brodsky, S. J.; Ferreiro, E. G.; Fleuret, F.

    2013-04-15

    We report on the spin and diffractive physics at a future multi-purpose f xed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic f xed-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 using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The f xed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

  11. Novel QCD Phenomena at the LHC: The Ridge, Digluon-Initiated Subprocesses, Direct Reactions, Non-Universal Antishadowing, and Forward Higgs Production

    SciTech Connect (OSTI)

    Brodsky, Stanley J.; /SLAC

    2014-10-03

    I discuss a number of novel tests of QCD at the LHC, measurements which can illuminate fundamental features of hadron physics. I also review the “Principle of Maximum Conformality” (PMC) which systematically sets the renormalization scale order-by-order in pQCD, eliminating an unnecessary theoretical uncertainty. The PMC allows LHC experiments to test QCD much more precisely, and the sensitivity of LHC measurements to physics beyond the Standard Model is increased.

  12. The Muon Collider

    SciTech Connect (OSTI)

    Zisman, Michael S.

    2011-01-05

    We describe the scientific motivation for a new type of accelerator, the muon collider. This accelerator would permit an energy-frontier scientific program and yet would fit on the site of an existing laboratory. Such a device is quite challenging, and requires a substantial R&D program. After describing the ingredients of the facility, the ongoing R&D activities of the Muon Accelerator Program are discussed. A possible U.S. scenario that could lead to a muon collider at Fermilab is briefly mentioned.

  13. The Muon Collider

    SciTech Connect (OSTI)

    Zisman, Michael S

    2010-05-17

    We describe the scientific motivation for a new type of accelerator, the muon collider. This accelerator would permit an energy-frontier scientific program and yet would fit on the site of an existing laboratory. Such a device is quite challenging, and requires a substantial R&D program. After describing the ingredients of the facility, the ongoing R&D activities of the Muon Accelerator Program are discussed. A possible U.S. scenario that could lead to a muon collider at Fermilab is briefly mentioned.

  14. Topics in Hadronic Physics

    SciTech Connect (OSTI)

    Alfred Tang

    2002-08-01

    Hadron production cross sections are calculated in the perturbative QCD frame work. Parton distribution functions are obtained from a strip-soliton model. The fragmentation functions are derived from the Lund model of string breaking.

  15. ERL BASED ELECTRON-ION COLLIDER ERHIC.

    SciTech Connect (OSTI)

    LITVINENKO,V.N.; BEN-ZVI,I.; ANDERSON,D.; ET AL.

    2005-05-16

    In this paper we describe eRHIC design based on the RHIC hadron rings and 10-to-20 GeV energy recovery electron linac. RHIC requires a very large tunability range for c.m. energies while maintaining very high luminosity up to 10{sup 34} cm{sup -2} s{sup -1} per nucleon. The designs of this future polarized electron-hadron collider, eRHIC, based on a high current super-conducting energy-recovery linac (ERL) with energy of electrons up to 20 GeV, have a number of specific requirements on the ERL optics. Two of the most attractive features of this scheme are full spin transparency of the ERL at all operational energies and the capability to support up to four interaction points. We present two main layouts of the eRHIC, the expected beam and luminosity parameter, and discuss the potential limitation of its performance. Two of the most attractive features of this scheme are full spin transparency of the ERL at all operational energies and the capability to support up to four interaction points. We present two main layouts of the eRHIC, the expected beam and luminosity parameter, and discuss the potential limitation of its performance.

  16. Symmetry restored in dibosons at the LHC?

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

    Brehmer, Johann; Hewett, JoAnne; Kopp, Joachim; Rizzo, Thomas; Tattersall, Jamie

    2015-10-28

    A number of LHC resonance search channels display an excess in the invariant mass region of 1.8–2.0 TeV. Among them is a 3.4σ excess in the fully hadronic decay of a pair of Standard Model electroweak gauge bosons, in addition to potential signals in the HW and dijet final states. We perform a model-independent cross-section fit to the results of all ATLAS and CMS searches sensitive to these final states. We then interpret these results in the context of the Left-Right Symmetric Model, based on the extended gauge group SU(2)L × SU(2)R × U(1)', and show that a heavy right-handedmore » gauge boson WR can naturally explain the current measurements with just a single coupling gR ~ 0.4. Thus, we discuss a possible connection to dark matter.« less

  17. hhjj production at the LHC

    SciTech Connect (OSTI)

    Dolan, Matthew J.; Englert, Christoph; Greiner, Nicolas; Nordstrom, Karl; Spannowsky, Michael

    2015-08-25

    The search for di-Higgs production at the LHC in order to set limits on the Higgs trilinear coupling and constraints on new physics is one of the main motivations for the LHC high-luminosity phase. Recent experimental analyses suggest that such analyses will only be successful if information from a range of channels is included. We therefore investigate di-Higgs production in association with two hadronic jets and give a detailed discussion of both the gluon- and the weak boson-fusion (WBF) contributions, with a particular emphasis on the phenomenology with modified Higgs trilinear and quartic gauge couplings. We perform a detailed investigation of the full hadronic final state and find that hhjj production should add sensitivity to a di-Higgs search combination at the HL-LHC with 3 ab-1. Since the WBF and GF contributions are sensitive to different sources of physics beyond the Standard Model, we devise search strategies to disentangle and isolate these production modes. In addition, while gluon fusion remains non-negligible in WBF-type selections, sizeable new physics contributions to the latter can still be constrained. As an example of the latter point we investigate the sensitivity that can be obtained for a measurement of the quartic Higgs–gauge boson couplings.

  18. Physics at the e⁺e⁻ linear collider

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

    Moortgat-Picka, G.; Kronfeld, A. S.

    2015-08-14

    A comprehensive review of physics at an e⁺e⁻ linear collider in the energy range of √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 analysed as well.

  19. Physics at the e?e? linear collider

    SciTech Connect (OSTI)

    Moortgat-Picka, G.; Kronfeld, A. S.

    2015-08-14

    A comprehensive review of physics at an e?e? linear collider in the energy range of ?s = 92 GeV3 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 analysed as well.

  20. Fermilab | Newsroom | Press Releases | July 4, 2012: Search for...

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

    that scientists, engineers and students from Fermilab have made to the LHC." Search for Higgs boson at Large Hadron Collider reveals new particle Physicists on experiments at the...

  1. Quark Flavors and Conserved Charges at Finite Density in the...

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

    National Laboratory and at the Large Hadron Collider (LHC) at CERN near Geneva, Switzerland. This project is pursuing a microscopic understanding of the QGP properties near...

  2. ESnet Planning, Status,

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

    ... Sciences (FE) - Magnetic Fusion EnergyITER * High Energy Physics (HEP) - LHC (Large Hadron Collider, CERN), Tevatron (FNAL) * Nuclear Physics (NP) - RHIC (Relativistic Heavy ...

  3. Science DMZ at the University of Florida

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

    in 2008 the High Energy Physics community began operating the Large Hadron Collider (LHC), which produced hundreds of terabytes of data for physicists and students to analyze. ...

  4. Science News

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

    Updated Workflows Enhance New LHC Era February 22, 2016 Researchers working on ATLAS, one of the Large Hadron Collider's largest experiments, are using updated workflow management ...

  5. ESnet Defined: Challenges and Overview Department of Energy...

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

    ... of the network * Example case studies (from 20052006 update) - Magnetic Fusion - Large Hadron Collider (LHC) - Climate Modeling - Spallation Neutron Source 3. Observation of the ...

  6. Our Mission

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

    This growth trend is only accelerating as international scientific collaborations such as the Large Hadron Collider (LHC), Coupled Model Intercomparison Project (CMIP), and ...

  7. Photo of the Week: July 6, 2012 | Department of Energy

    Energy Savers [EERE]

    Fermi National Accelerator Laboratory and Brookhaven National Laboratory are the host laboratories for the U.S. contingents of the Large Hadron Collider (LHC) experiments that ...

  8. National Energy Research Scientific Computing Center

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

    Updated Workflows for New LHC Era Researchers working on ATLAS, one of the Large Hadron Collider's largest experiments, are using updated workflow management tools developed ...

  9. Facility Ops | U.S. DOE Office of Science (SC)

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

    U.S. LHC Operations supports scientists from US universities and national laboratories who participate in the design and construction of the Large Hadron Collider, its startup, and ...

  10. All User Facilities | U.S. DOE Office of Science (SC)

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

    National Accelerator Facility Non-DOE Host Institutions Cadarache, France CERN Large Hadron Collider (LHC) Cerro Pachon mountain, Chile General Atomics Global Network High ...

  11. ILC Electron Source Gets Help from JLab | Jefferson Lab

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

    With the activation of the LHC, or Large Hadron Collider, some particle physicists are now looking forward to the next big machine. For many, that's the International Linear ...

  12. Fermilab Today

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

    Unsubscribe from Fermilab Today From symmetry LHC achieves record-energy collisions The Large Hadron Collider broke its own record again in 13-trillion-electronvolt test ...

  13. The Evolution of Research and Education Networks and their Essential...

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

    ... The ESnet architecture and capacity are driven by DOE's involvement in some of the world's largest science experiments. The Large Hadron Collider (LHC) comes online in 2009, ...

  14. Layout 1

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

    ... easily handling dramatic growth in traffic requirements: around 80 percent growth year over year and 300 per- cent growth with the Large Hadron Collider (LHC) coming online. ...

  15. A general encoding framework for representing network measurement...

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

    International efforts such as the Large Hadron Collider (LHC) project from the European Organization for Nuclear Research (CERN) rely heavily on the underlying Correspondence ...

  16. 24544_FES_ESnet_Cover_final

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

    ... to reach its full potential. A set of data and service challenges, similar to those used in preparation for the Large Hadron Collider (LHC) experiments, should be considered. ...

  17. SC14 DOE Booth Presentations by NERSC, Berkeley Lab Staff

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

    giving researchers at American universities and national laboratories the fastest possible access to scientific data from the Large Hadron Collider (LHC) and other sites in Europe. ...

  18. PFX

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

    ... Fermilab is the host laboratory for US CMS, a collaboration participating in the program of the Large Hadron Collider (LHC) at CERN. Collaborators working at Fermilab from more ...

  19. High Performance Networks for High Impact Science

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

    ... Physics Network HTML hyper text markup language IP Internet Protocol LHC CERN's Large Hadron Collider MICS Mathematical, Information, and Computational Sciences MPLS ...

  20. Fermilab | Science at Fermilab | Experiments & Projects | Energy...

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

    Accelerator & Detector Physics Computing CMS Detector Intensity Frontier Cosmic Frontier Works in Progress Energy Frontier Large Hadron Collider The LHC at CERN, the European ...

  1. Deploying

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

    Fermilab hosts the US Tier-1 center for data storage and analysis of the Large Hadron Collider's (LHC) Compact Muon Solenoid (CMS) experiment. To satisfy operational requirements ...

  2. 'Shifter' Makes Container-based HPC a Breeze

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

    ... So this results in much better utilization of our resources. Gerhardt: With scientists from the Large Hadron Collider's (LHC) ALICE, ATLAS and CMS experiments at CERN, we are ...

  3. User Submitted Research Citations

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

    ... Primary NERSC Repository Used m231 NERSC Resources Used Edison - Cray XC30, HPSS ... The current experimental frontier in HEP is the Large Hadron Collider (LHC), the most ...

  4. Untitled

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

    ... of scientific collaboration are trending toward increased use of network resources. ... http:www.internet2.eduion. 11 Internet2 ION Case Study: Large Hadron Collider (LHC). ...

  5. Broadening

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

    ... workflow system, PANDA 9 , used in the Large Hadron Collider (LHC) ATLAS project. The distributed compute resources and data associated with the computations are centrally managed. ...

  6. User Submitted Research Citations

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

    ... Primary NERSC Repository Used m1643 NERSC Resources Used Edison - Cray XC30, Carver ... The current experimental frontier in HEP is the Large Hadron Collider (LHC), the most ...

  7. Microsoft PowerPoint - NERSC-Science-NUG08

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

    ... e.g., from ESnet Magnetic Fusion Large Hadron Collider (LHC) Climate Modeling ... of NERSC's computational and analysis resources * Single unified namespace makes it ...

  8. On-board Diagnostics

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

    ... Their high energy physics group 16 participates in the Large Hadron Collider (LHC) Compact ... This center houses numerous computing and storage resources for many research ...

  9. Monitoring

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

    ... and facilities together at the Large Hadron Collider4 (LHC) to learn about the ... abnormalities, and saved the time and resources of strained operations staff. 8. ...

  10. Muon Colliders and Neutrino Factories

    SciTech Connect (OSTI)

    Geer, Steve; /Fermilab

    2009-11-01

    Over the past decade, there has been significant progress in developing the concepts and technologies needed to produce, capture, and accelerate {Omicron}(10{sup 21}) muons per year. These developments have paved the way for a new type of neutrino source (neutrino factory) and a new type of very high energy lepton-antilepton collider (muon collider). This article reviews the motivation, design, and research and development for future neutrino factories and muon colliders.

  11. Muon colliders and neutrino factories

    SciTech Connect (OSTI)

    Geer, S.; /Fermilab

    2010-09-01

    Over the last decade there has been significant progress in developing the concepts and technologies needed to produce, capture and accelerate {Omicron}(10{sup 21}) muons/year. This development prepares the way for a new type of neutrino source (Neutrino Factory) and a new type of very high energy lepton-antilepton collider (Muon Collider). This article reviews the motivation, design and R&D for Neutrino Factories and Muon Colliders.

  12. Colliding Nuclei at High Energy

    ScienceCinema (OSTI)

    Brookhaven Lab

    2010-01-08

    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).

  13. Flat bunch creation and acceleration: a possible path for the LHC luminosity upgrade

    SciTech Connect (OSTI)

    Bhat, C.M.; /Fermilab

    2009-05-01

    Increasing the collider luminosity by replacing bunches having Gaussian line-charge distribution with flat bunches, but with same beam-beam tune shift at collision, has been studied widely in recent years. But, creation of 'stable' flat bunches (and their acceleration) using a multiple harmonic RF system has not been fully explored. Here, we review our experience with long flat bunches in the barrier RF buckets at Fermilab.We presentsome preliminary results from beam dynamics simulations and recent beam studies in the LHC injectors to create stable flat bunches using double harmonic RF systems. The results deduced from these studies will be used to model the necessary scheme for luminosity upgrade in the LHC. We have also described a viable (and economical) way for creation and acceleration of flat bunches in the LHC. The flat bunch scheme may have many advantages over the LHC baseline scenario, particularly because of the reduced momentum spread of the bunch for increased intensities.

  14. Reconstruction and identification of $\\tau$ lepton decays to hadrons and $\

    SciTech Connect (OSTI)

    Khachatryan, Vardan

    2015-10-27

    This paper describes the algorithms used by the CMS experiment to reconstruct and identify ?? hadrons + vt decays during Run 1 of the LHC. The performance of the algorithms is studied in proton-proton collisions recorded at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The algorithms achieve an identification efficiency of 5060%, with misidentification rates for quark and gluon jets, electrons, and muons between per mille and per cent levels.

  15. The PDF4LHC report on PDFs and LHC data: results from Run I and...

    Office of Scientific and Technical Information (OSTI)

    The PDF4LHC report on PDFs and LHC data: results from Run I and preparation for Run II Citation Details In-Document Search Title: The PDF4LHC report on PDFs and LHC data: results...

  16. Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC...

    Office of Scientific and Technical Information (OSTI)

    Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC) Citation Details In-Document Search Title: Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC) You...

  17. LHC forward physics

    SciTech Connect (OSTI)

    Cartiglia, N.; Royon, C.

    2015-10-02

    The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.

  18. First Measurement of Hadronic Event Shapes in pp Collisions at sqrt(s)=7 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan; et al.

    2011-05-01

    Hadronic event shapes have been measured in proton-proton collisions at sqrt(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 inverse picobarns. Event-shape distributions, corrected for detector response, are compared with five models of QCD multijet production.

  19. Positrons for linear colliders

    SciTech Connect (OSTI)

    Ecklund, S.

    1987-11-01

    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)

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

    SciTech Connect (OSTI)

    RIORDAN, MICHAEL

    2011-11-29

    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.

  1. SciDAC advances in beam dynamics simulation: from light sources to colliders

    SciTech Connect (OSTI)

    Qiang, Ji; Qiang, J.; Borland, M.; Kabel, A.; Li, R.; Ryne, R.; Stern, E.; Wang, Y.; Wasserman, H.; Zhang, Y.

    2008-06-16

    In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of SciDAC-II accelerator project,"Community Petascale Project for Accelerator Science and Simulation (ComPASS)." Several parallel computational tools for beam dynamics simulation will be described. A number of applications in current and future accelerator facilities, e.g., LCLS, RHIC, Tevatron, LHC, ELIC, are presented.

  2. Hadron Structure from Lattice QCD

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

    1 st order coupled PDE's * Large, sparse, matrix solve per ... * Requires capability resources 3 Analysis Compute ... methods for spectroscopy, hadron & nuclear structure ...

  3. Possibility of observing an MSSM charged Higgs boson in association with a W boson at the LHC

    SciTech Connect (OSTI)

    Hashemi, M.

    2011-03-01

    The possibility of observing associated production of the charged Higgs and W boson in the framework of the minimal supersymmetric standard model (MSSM) at LHC is studied. Both leptonic and hadronic decays of the W boson are studied while the charged Higgs boson is considered to decay to a {tau} lepton and a neutrino. Therefore two search categories are defined based on the leptonic and hadronic final states, i.e., l{tau}+E{sub T}{sup miss} and jj{tau}+E{sub T}{sup miss} where l=e or {mu} and j is a light jet from W decay. The discovery chance of the two categories is evaluated at an integrated luminosity of 300 fb{sup -1} at LHC. It is shown that both leptonic and hadronic final states have the chance of discovery at high tan{beta}. Finally 5{sigma} and 3{sigma} contours are provided for both search categories.

  4. Monte Carlo event generators for hadron-hadron collisions

    SciTech Connect (OSTI)

    Knowles, I.G.; Protopopescu, S.D.

    1993-06-01

    A brief review of Monte Carlo event generators for simulating hadron-hadron collisions is presented. Particular emphasis is placed on comparisons of the approaches used to describe physics elements and identifying their relative merits and weaknesses. This review summarizes a more detailed report.

  5. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... model indeed exists, the energy scale of new physics might be beyond the reach at the Large Hadron Collider (LHC), and the LHC could find only the Higgs boson but nothing else. ...

  6. Beyond the Standard Model Theory

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

    Rajan Gupta (505) 667-7664 Email Bruce Carlsten (505) 667-5657 Email LHC physics at Los Alamos The Large Hadron Collider (LHC) is studying the structure of matter at sub-nucleon ...

  7. perfsonar-roads.dvi

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

    ... Much of the initial perfSONAR deployment effort target- ted the immediate needs of the Large Hadron Collider (LHC) community. The LHC, located at CERN near Geneva Switzerland, will ...

  8. Can WIMP dark matter overcome the nightmare scenario? (Journal...

    Office of Scientific and Technical Information (OSTI)

    Even if new physics beyond the standard model indeed exists, the energy scale of new physics might be beyond the reach at the Large Hadron Collider (LHC), and the LHC could find ...

  9. 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.

  10. Observation of Exclusive Electron-Positron Production in Hadron-Hadron Collisions

    SciTech Connect (OSTI)

    Abulencia, A.; Adelman, J.; Affolder, T.; Akimoto, T.; Albrow, M.G.; Ambrose, D.; Amerio, S.; Amidei, D.; Anastassov, A.; Anikeev, K.; Annovi, A.

    2006-11-01

    We present the first observation of exclusive e{sup +}e{sup -} production in hadron-hadron collisions, using p{bar p} collision data at {radical}s = 1.96 TeV taken by the Run II Collider Detector at Fermilab, and corresponding to an integrated luminosity of 532 pb{sup -1}. We require the absence of any particle signatures in the detector except for an electron and a positron candidate, each with transverse energy E{sub T} > 5 GeV and pseudorapidity |{eta}| < 2. With these criteria, 16 events are observed compared to a background expectation of 1.9 {+-} 0.3 events. These events are consistent in cross section and properties with the QED process p{bar p} {yields} p + e{sup +}e{sup -} + {bar p} through two-photon exchange. The measured cross section is 1.6{sub -0.3}{sup +0.5}(stat) {+-} 0.3(syst) pb. This agrees with the theoretical prediction of 1.71 {+-} 0.01 pb.

  11. LHC - a "Why" Facility

    ScienceCinema (OSTI)

    Gordon Kane

    2010-01-08

    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.

  12. Santa Fe Jets and Heavy Flavor Workshop

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

    With results from the Relativistic Heavy Ion Collider (RHIC) and Large hadron Collider (LHC) proton-proton and heavy ion runs I at hand, this is the opportune time for a focused ...

  13. Jefferson Lab: Research Highlights

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

    ... The first is to build increasingly energetic colliders, such as the Large Hadron Collider (LHC) at CERN, to excite matter into a new form. The second approach is to perform high ...

  14. Jeff Porter

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

    High Energy Nuclear Physics (HENP) experiments: DLS at LBNL, NA49 at CERN, STAR at BNL's Relativistic Heavy Ion Collider (RHIC), and ALICE at the CERN Large Hadron Collider (LHC). ...

  15. Momentum space dipole amplitude for DIS and inclusive hadron production

    SciTech Connect (OSTI)

    Basso, E. A.; Gay Ducati, M. B.; De Oliveira, E. G.

    2013-03-25

    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.

  16. Looking for intrinsic charm in the forward region at BNL RHIC and CERN LHC

    SciTech Connect (OSTI)

    Goncalves, V.; Ullrich, T.; Navarra, F.S.

    2010-04-21

    The complete understanding of the basic constituents of hadrons and the hadronic dynamics at high energies are two of the main challenges for the theory of strong interactions. In particular, the existence of intrinsic heavy quark components in the hadron wave function must be confirmed (or disproved). In this paper we propose a new mechanism for the production of D-mesons at forward rapidities based on the Color Glass Condensate (CGC) formalism and demonstrate that the resulting transverse momentum spectra are strongly dependent on the behavior of the charm distribution at large Bjorken x. Our results show clearly that the hypothesis of intrinsic charm can be tested in pp and p(d)A collisions at RHIC and LHC.

  17. Symmetry restored in dibosons at the LHC?

    SciTech Connect (OSTI)

    Brehmer, Johann; Hewett, JoAnne; Kopp, Joachim; Rizzo, Thomas; Tattersall, Jamie

    2015-10-28

    A number of LHC resonance search channels display an excess in the invariant mass region of 1.8–2.0 TeV. Among them is a 3.4σ excess in the fully hadronic decay of a pair of Standard Model electroweak gauge bosons, in addition to potential signals in the HW and dijet final states. We perform a model-independent cross-section fit to the results of all ATLAS and CMS searches sensitive to these final states. We then interpret these results in the context of the Left-Right Symmetric Model, based on the extended gauge group SU(2)L × SU(2)R × U(1)', and show that a heavy right-handed gauge boson WR can naturally explain the current measurements with just a single coupling gR ~ 0.4. Thus, we discuss a possible connection to dark matter.

  18. Inclusive Production of {rho}{+-}(770) Meson in Hadronic Decays of Z0 Boson

    SciTech Connect (OSTI)

    Beddall, A.; Beddall, A.; Binguel, A.

    2007-04-23

    The inclusive production of the charged vector meson {rho}{+-}(770) in hadronic Z decays is measured with the ALEPH detector at the LEP collider. Decays of {rho}{+-} {yields} {pi}0 + {pi}{+-} are reconstructed for x > 0.05 where x = E{rho}/Ebeam. The results are compared with Monte Carlo model predictions and OPAL measurements. Bose-Einstein effects are found to be important in extracting {rho}{+-}(770) from two pion invariant mass spectra.

  19. The Future of Hadrons: The Nexus of Subatomic Physics

    SciTech Connect (OSTI)

    Quigg, Chris

    2011-09-01

    The author offers brief observations on matters discussed at the XIV International Conference on Hadron Spectroscopy and explore prospects for hadron physics. Quantum chromodynamics (QCD) has been validated as a new law of nature. It is internally consistent up to very high energies, and so could be a complete theory of the strong interactions. Whether QCD is the final answer for the strong interactions is a subject for continuing experimental tests, which are being extended in experimentation at the Large Hadron Collider. Beyond the comparison of perturbative calculations with experiment, it remains critically important to test the confinement hypothesis by searching for free quarks, or for signatures of unconfined color. Sensitive negative searches for quarks continue to be interesting, and the definitive observation of free quarks would be revolutionary. Breakdowns of factorization would compromise the utility of perturbative QCD. Other discoveries that would require small or large revisions to QCD include the observation of new kinds of colored matter beyond quarks and gluons, the discovery that quarks are composite, or evidence that SU(3){sub c} gauge symmetry is the vestige of a larger, spontaneously broken, color symmetry. While probing our underlying theory for weakness or new openings, we have plenty to do to apply QCD to myriad experimental settings, to learn its implications for matter under unusual conditions, and to become more adept at calculating its consequences. New experimental tools provide the means for progress on a very broad front.

  20. 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)

    2011-04-15

    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.

  1. Optimization of dynamic aperture for hadron lattices in eRHIC

    SciTech Connect (OSTI)

    Jing, Yichao; Litvinenko, Vladimir; Trbojevic, Dejan

    2015-05-03

    The potential upgrade of the Relativistic Heavy Ion Collider (RHIC) to an electron ion collider (eRHIC) involves numerous extensive changes to the existing collider complex. The expected very high luminosity is planned to be achieved at eRHIC with the help of squeezing the beta function of the hadron ring at the IP to a few cm, causing a large rise of the natural chromaticities and thus bringing with it challenges for the beam long term stability (Dynamic aperture). We present our effort to expand the DA by carefully tuning the nonlinear magnets thus controlling the size of the footprints in tune space and all lower order resonance driving terms. We show a reasonably large DA through particle tracking over millions of turns of beam revolution.

  2. Hadron particle theory

    SciTech Connect (OSTI)

    Alonso, J.R.

    1995-05-01

    Radiation therapy with ``hadrons`` (protons, neutrons, pions, ions) has accrued a 55-year track record, with by now over 30,000 patients having received treatments with one of these particles. Very good, and in some cases spectacular results are leading to growth in the field in specific well-defined directions. The most noted contributor to success has been the ability to better define and control the radiation field produced with these particles, to increase the dose delivered to the treatment volume while achieving a high degree of sparing of normal tissue. An additional benefit is the highly-ionizing, character of certain beams, leading to creater cell-killing potential for tumor lines that have historically been very resistant to radiation treatments. Until recently these treatments have been delivered in laboratories and research centers whose primary, or original mission was physics research. With maturity in the field has come both the desire to provide beam facilities more accessible to the clinical setting, of a hospital, as well as achieving, highly-efficient, reliable and economical accelerator and beam-delivery systems that can make maximum advantage of the physical characteristics of these particle beams. Considerable work in technology development is now leading, to the implementation of many of these ideas, and a new generation of clinically-oriented facilities is beginning to appear. We will discuss both the physical, clinical and technological considerations that are driving these designs, as well as highlighting, specific examples of new facilities that are either now treating, patients or that will be doing so in the near future.

  3. From Neutrino Factory to Muon Collider

    SciTech Connect (OSTI)

    Geer, S.; /Fermilab

    2010-01-01

    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.

  4. B_c Meson Production Around the Z^0 Peak at a High Luminosity e^+ e^- Collider

    SciTech Connect (OSTI)

    Yang, Zhi; Wu, Xing-Gang; Chen, Gu; Liao, Qi-Li; Zhang, Jia-Wei; /Chongqing U.

    2012-05-22

    Considering the possibility to build an e{sup +}e{sup -} collider at the energies around the Z{sup 0}-boson resonance with a planned luminosity so high as L {proportional_to} 10{sup 34} {approx} 10{sup 36} cm{sup -2}s{sup -1} (super Z-factory), we make a detailed discussion on the (c{bar b})-quarkonium production through e{sup +}e{sup -} {yields} (c{bar b})[n] + b + {bar c} within the framework of non-relativistic QCD. Here [n] stands for the Fock-states |(c{sub b}){sub 1}[{sup 1}S{sub 0}]>, |(c{bar b})8[{sup 1}S{sub 0}]g>, |(c{bar b} ){sub 1}[{sup 3}S{sub 1}]>, |(c{bar b}){sub 8}[{sup 3}S{sub 1}]g>, |(c{bar b}){sub 1}[{sup 1}P{sub 1}]> and |(c{bar b}){sub 1}[{sup 3}P{sub J}]> (with J = (1, 2, 3)) respectively. To simplify the hard-scattering amplitude as much as possible and to derive analytic expressions for the purpose of future events simulation, we adopt the 'improved trace technology' to do our calculation, which deals with the hard scattering amplitude directly at the amplitude level other than the conventional way at the squared-amplitude level. Total cross-section uncertainties caused by the quark masses are predicted by taking m{sub c} = 1.50 {+-} 0.30 GeV and m{sub b} = 4.90 {+-} 0.40 GeV. If all higher (c{bar b})-quarkonium states decay to the ground state B{sub c} (|(c{bar b}){sub 1}[{sup 1}S{sub 0}]>) with 100% efficiency, we obtain {sigma}{sub e{sup +}+e{sup -}{yields}B{sub c}+b+{bar c}} = 5.190{sub -2.419}{sup +6.222} pb, which shows that about 10{sup 5} {approx} 10{sup 7} B{sub c} events per operation year can be accumulated in the super Z-factory. If taking the collider energy runs slightly off the Z{sup 0}-peak, i.e. {radical}S = (1.00 {+-} 0.05)m{sub Z}, the total cross-section shall be lowered by about one-order from its peak value. Such a super Z-factory shall provide another useful platform to study the properties of B{sub c} meson, or even the properties of its excited P-wave states, in addition to its production at the hadronic colliders Tevatron and LHC.

  5. Le LHC, un tunnel cosmique

    ScienceCinema (OSTI)

    None

    2011-10-06

    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

  6. Conventional power sources for colliders

    SciTech Connect (OSTI)

    Allen, M.A.

    1987-07-01

    At SLAC we are developing high peak-power klystrons to explore the limits of use of conventional power sources in future linear colliders. In an experimental tube we have achieved 150 MW at 1 ..mu..sec pulse width at 2856 MHz. In production tubes for SLAC Linear Collider (SLC) we routinely achieve 67 MW at 3.5 ..mu..sec pulse width and 180 pps. Over 200 of the klystrons are in routine operation in SLC. An experimental klystron at 8.568 GHz is presently under construction with a design objective of 30 MW at 1 ..mu..sec. A program is starting on the relativistic klystron whose performance will be analyzed in the exploration of the limits of klystrons at very short pulse widths.

  7. L'Aventure du LHC

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  8. 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

  9. The history of the LHC

    ScienceCinema (OSTI)

    None

    2011-10-06

    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.

  10. The history of the LHC

    SciTech Connect (OSTI)

    2010-05-11

    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.

  11. 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.; Srivastava, D.K.

    1999-02-01

    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.

  12. Gravitino LSP and leptogenesis after the first LHC results

    SciTech Connect (OSTI)

    Heisig, Jan

    2014-04-01

    Supersymmetric scenarios where the lightest superparticle (LSP) is the gravitino are an attractive alternative to the widely studied case of a neutralino LSP. A strong motivation for a gravitino LSP arises from the possibility of achieving higher reheating temperatures and thus potentially allow for thermal leptogenesis. The predictions for the primordial abundances of light elements in the presence of a late decaying next-to-LSP (NSLP) as well as the currently measured dark matter abundance allow us to probe the cosmological viability of such a scenario. Here we consider a gravitino-stau scenario. Utilizing a pMSSM scan we work out the implications of the 7 and 8 TeV LHC results as well as other experimental and theoretical constraints on the highest reheating temperatures that are cosmologically allowed. Our analysis shows that points with T{sub R}?>10{sup 9}GeV survive only in a very particular corner of the SUSY parameter space. Those spectra feature a distinct signature at colliders that could be looked at in the upcoming LHC run.

  13. Inclusive b-hadron production cross section with muons in pp collisions at sqrt(s) = 7 TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan; et al.

    2011-03-01

    A measurement of the b-hadron production cross section in proton-proton collisions at sqrt(s)=7 TeV is presented. The dataset, corresponding to 85 inverse nanobarns, was recorded with the CMS experiment at the LHC using a low-threshold single-muon trigger. Events are selected by the presence of a muon with transverse momentum greater than 6 GeV with respect to the beam direction and pseudorapidity less than 2.1. The transverse momentum of the muon with respect to the closest jet discriminates events containing b hadrons from background. The inclusive b-hadron production cross section is presented as a function of muon transverse momentum and pseudorapidity. The measured total cross section in the kinematic acceptance is sigma(pp to b+X to mu + X') =1.32 +/- 0.01 (stat) +/- 0.30 (syst) +/- 0.15 (lumi) microbarns.

  14. International Workshop on Linear Colliders 2010

    ScienceCinema (OSTI)

    None

    2011-10-06

    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

  15. International Workshop on Linear Colliders 2010

    ScienceCinema (OSTI)

    None

    2011-10-06

    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 SecretariatIWLC2010 is hostedby CERN

  16. International Linear Collider Technical Design Report - Volume...

    Office of Scientific and Technical Information (OSTI)

    Linear Collider Technical Design Report - Volume 2: Physics Baer, Howard; Barklow, Tim; Fujii, Keisuke; Gao, Yuanning; Hoang, Andre; Kanemura, Shinya; List, Jenny; Logan, Heather...

  17. International Linear Collider Technical Design Report - Volume...

    Office of Scientific and Technical Information (OSTI)

    Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical Design Report - Volume 2: Physics You are accessing a ...

  18. The Multi-Purpose Detector for NICA heavy-Ion Collider at JINR

    SciTech Connect (OSTI)

    Rogachevsky, O. V.

    2012-05-15

    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.

  19. Relic neutralino surface at a 100 TeV collider

    SciTech Connect (OSTI)

    Bramante, Joseph; Fox, Patrick J.; Martin, Adam; Ostdiek, Bryan; Plehn, Tilman; Schell, Torben; Takeuchi, Michihisa

    2015-03-11

    We map the parameter space for minimal supersymmetric Standard Model neutralino dark matter which freezes out to the observed relic abundance, in the limit that all superpartners except the neutralinos and charginos are decoupled. In this space of relic neutralinos, we show the dominant dark matter annihilation modes, the mass splittings among the electroweakinos, direct detection rates, and collider cross sections. The mass difference between the dark matter and the next-to-lightest neutral and charged states is typically much less than electroweak gauge boson masses. With these small mass differences, the relic neutralino surface is accessible to a future 100 TeV hadron collider, which can discover interneutralino mass splittings down to 1 GeV and thermal relic dark matter neutralino masses up to 1.5 TeV with a few inverse attobarns of luminosity. This coverage is a direct consequence of the increased collider energy: in the Standard Model events with missing transverse momentum in the TeV range have mostly hard electroweak radiation, distinct from the soft radiation shed in compressed electroweakino decays. As a result, we exploit this kinematic feature in final states including photons and leptons, tailored to the 100 TeV collider environment.

  20. Relic neutralino surface at a 100 TeV collider

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

    Bramante, Joseph; Fox, Patrick J.; Martin, Adam; Ostdiek, Bryan; Plehn, Tilman; Schell, Torben; Takeuchi, Michihisa

    2015-03-11

    We map the parameter space for minimal supersymmetric Standard Model neutralino dark matter which freezes out to the observed relic abundance, in the limit that all superpartners except the neutralinos and charginos are decoupled. In this space of relic neutralinos, we show the dominant dark matter annihilation modes, the mass splittings among the electroweakinos, direct detection rates, and collider cross sections. The mass difference between the dark matter and the next-to-lightest neutral and charged states is typically much less than electroweak gauge boson masses. With these small mass differences, the relic neutralino surface is accessible to a future 100 TeVmore » hadron collider, which can discover interneutralino mass splittings down to 1 GeV and thermal relic dark matter neutralino masses up to 1.5 TeV with a few inverse attobarns of luminosity. This coverage is a direct consequence of the increased collider energy: in the Standard Model events with missing transverse momentum in the TeV range have mostly hard electroweak radiation, distinct from the soft radiation shed in compressed electroweakino decays. As a result, we exploit this kinematic feature in final states including photons and leptons, tailored to the 100 TeV collider environment.« less

  1. Research and Development of Future Muon Collider

    SciTech Connect (OSTI)

    Yonehara, K.; /Fermilab

    2012-05-01

    Muon collider is a considerable candidate of the next generation high-energy lepton collider machine. A novel accelerator technology must be developed to overcome several intrinsic issues of muon acceleration. Recent research and development of critical beam elements for a muon accelerator, especially muon beam phase space ionization cooling channel, are reviewed in this paper.

  2. Photoproduction of Vector Mesons at LHC and the Nuclear Gluon Distribution

    SciTech Connect (OSTI)

    Griep, M. T.; Goncalves, V. P.; Ayala Filho, A. L.

    2010-11-12

    A systematic measurement of the nuclear gluon distribution is of fundamental interest in understanding the parton structure of nuclei and to determine the initial conditions of the quark gluon plasma (QGP) predicted to be formed in central heavy ion collisions. At the moment the behavior of this distribution is completely undetermined by the fixed target experiments, with a possible improvement in the future electron-nucleus colliders. However, as the date of construction and start of operation of these colliders is still in debate, we need to obtain alternative searches to estimate the medium effects in the nuclear gluon distribution. An alternative is the study of the vector meson production in ultraperipheral heavy ion collisions at RHIC and LHC in order to constrain the nuclear medium effects present in the nuclear gluon distribution. In this contribution we present our main results for the J/{Psi} photoproduction.

  3. LHC crab-cavity aspects and strategy

    SciTech Connect (OSTI)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-05-23

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  4. LHC end-of-year jamboree

    ScienceCinema (OSTI)

    None

    2011-10-06

    A review of the accelerator performance and of the experimental results, at the end of the 2010 run of the LHC

  5. Timeline of Events: 2008 | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    8 Timeline of Events: 2008 June 30, 2008: US portion of Large Hadron Collider completed June 30, 2008: US portion of Large Hadron Collider completed The Department and the National Science Foundation announce that the U.S. contribution to the Large Hadron Collider (LHC) has been completed on budget and ahead of schedule. Read more February 20, 2008: Navy shoots down NASA satellite February 20, 2008: Navy shoots down NASA satellite The Navy successfully shoots down with a missile an errant

  6. A search for jet handedness in hadronic Z{sup 0} decays

    SciTech Connect (OSTI)

    Hasegawa, Yoji

    1995-03-01

    Transport of polarization through hadronization process is one of the fundamental interest in Quantum Chromodynamics which is a theory of strong interactions. In the low energy region where the hadronization occurs, QCD calculations are difficult, therefore at present the transport can be investigated experimentally. In this study the authors have searched for signatures of polarization of quarks and antiquarks in hadronic jets from Z{sup 0} {yields} q{bar q} decays. The polarization of quarks and antiquark produced by Z{sup 0} decays are predicted by the Standard Model of elementary particle physics. The authors defined several quantities depending on {open_quotes}jet handedness{close_quotes} methods and studied the correlation between the predicted polarization and the quantities. The signal was estimated by analyzing power which represents degree of the polarization transport through the hadronization process. The Z{sup 0} decays were measured by SLC Large Detector and the polarized electron beam provided by SLAC Linear Collider was useful for this study. The data from the 1993 run showed no signature of the transport of quark and antiquark polarization. Upper limits on magnitude of the analyzing power were set in the range 0.05-0.15 depending on the methods.

  7. New Detector Technologies for the LHC Experiments: Prospects, Strategies

    Office of Scientific and Technical Information (OSTI)

    and Technologies for the HL-LHC Upgrades (Conference) | SciTech Connect New Detector Technologies for the LHC Experiments: Prospects, Strategies and Technologies for the HL-LHC Upgrades Citation Details In-Document Search Title: New Detector Technologies for the LHC Experiments: Prospects, Strategies and Technologies for the HL-LHC Upgrades We review the prospects, strategies and technologies for the High Luminosity (HL-LHC) upgrades of the ATLAS and CMS detectors, in the light of a very

  8. Heavy flavor production from photons and hadrons

    SciTech Connect (OSTI)

    Heusch, C.A.

    1982-01-01

    The present state of the production and observation of hadrons containing heavy quarks or antiquarks as valence constituents, in reactions initiated by real and (space-like) virtual photon or by hadron beams is discussed. Heavy flavor production in e/sup +/e/sup -/ annihilation, which is well covered in a number of recent review papers is not discussed, and similarly, neutrino production is omitted due to the different (flavor-changing) mechanisms that are involved in those reactions. Heavy flavors from spacelike photons, heavy flavors from real photons, and heavy flavors from hadron-hadron collisions are discussed. (WHK)

  9. Hadronization measurements in cold nuclear matter

    SciTech Connect (OSTI)

    Dupre, Raphael

    2015-05-01

    Hadronization is the non-perturbative process of QCD by which partons become hadrons. It has been studied at high energies through various processes, we focus here on the experiments of lepto-production of hadrons in cold nuclear matter. By studying the dependence of observables to the atomic number of the target, these experimentscan give information on the dynamic of the hadronization at the femtometer scale. In particular, we will present preliminary results from JLab Hall B (CLAS collaboration), which give unprecedented statistical precision. Then, we will present results of a phenomenological study showing how HERMES data can be described with pure energyloss models.

  10. Systematics of quarkonium production at the LHC and double parton...

    Office of Scientific and Technical Information (OSTI)

    Systematics of quarkonium production at the LHC and double parton fragmentation Citation Details In-Document Search Title: Systematics of quarkonium production at the LHC and ...

  11. QCD Factorization for heavy quarkonium production at collider...

    Office of Scientific and Technical Information (OSTI)

    Title: QCD Factorization for heavy quarkonium production at collider energies In this talk, I briefly review several models of the heavy quarkonium production at collider energies, ...

  12. Updates to the International Linear Collider Damping Rings Baseline...

    Office of Scientific and Technical Information (OSTI)

    Updates to the International Linear Collider Damping Rings Baseline Design Citation Details In-Document Search Title: Updates to the International Linear Collider Damping Rings...

  13. Top quark anomalous couplings at the International Linear Collider...

    Office of Scientific and Technical Information (OSTI)

    Top quark anomalous couplings at the International Linear Collider Citation Details In-Document Search Title: Top quark anomalous couplings at the International Linear Collider ...

  14. Physics Case for the International Linear Collider (Technical...

    Office of Scientific and Technical Information (OSTI)

    Collider We summarize the physics case for the International Linear Collider (ILC). We review the key motivations for the ILC presented in the literature, updating the projected...

  15. Proton-Nucleus Scattering Approximations and Implications for LHC Crystal Collimation

    SciTech Connect (OSTI)

    Noble, Robert; ,

    2010-06-07

    In particle accelerators, scattered protons with energies close to the incident particles may travel considerable distances with the beam before impacting on accelerator components downstream. To analyze such problems, angular deflection and energy loss of scattered particles are the main quantities to be simulated since these lead to changes in the beam's phase space distribution and particle loss. Simple approximations for nuclear scattering processes causing limited energy loss to high-energy protons traversing matter are developed which are suitable for rapid estimates and reduced-description Monte Carlo simulations. The implications for proton loss in the Large Hadron Collider due to nuclear scattering on collimation crystals are discussed.

  16. Compensatable muon collider calorimeter with manageable backgrounds

    DOE Patents [OSTI]

    Raja, Rajendran

    2015-02-17

    A method and system for reducing background noise in a particle collider, comprises identifying an interaction point among a plurality of particles within a particle collider associated with a detector element, defining a trigger start time for each of the pixels as the time taken for light to travel from the interaction point to the pixel and a trigger stop time as a selected time after the trigger start time, and collecting only detections that occur between the start trigger time and the stop trigger time in order to thereafter compensate the result from the particle collider to reduce unwanted background detection.

  17. Beamstrahlung spectra in next generation linear colliders

    SciTech Connect (OSTI)

    Barklow, T.; Chen, P. ); Kozanecki, W. )

    1992-04-01

    For the next generation of linear colliders, the energy loss due to beamstrahlung during the collision of the e{sup +}e{sup {minus}} beams is expected to substantially influence the effective center-of-mass energy distribution of the colliding particles. In this paper, we first derive analytical formulae for the electron and photon energy spectra under multiple beamstrahlung processes, and for the e{sup +}e{sup {minus}} and {gamma}{gamma} differential luminosities. We then apply our formulation to various classes of 500 GeV e{sup +}e{sup {minus}} linear collider designs currently under study.

  18. Electron-hadron correlations in pp collisions at {radical}(s) = 2.76TeV with the ALICE experiment

    SciTech Connect (OSTI)

    De Oliveira Filho, Elienos P.; Collaboration: ALICE Collaboration

    2013-03-25

    In this work we are studying the relative beauty to charm production in pp collisions at {radical}(s) = 2.76TeV, through correlations between electrons from heavy-flavour decay and charged hadrons, with the ALICE detector at the LHC. This study represents a baseline for the analysis in heavy-ion collisions where heavy flavour production is a powerful tool to study the Quark Gluon Plasma (QGP).

  19. Novel Perspectives for Hadron Physics

    SciTech Connect (OSTI)

    Brodsky, Stanley J.; /SLAC

    2012-03-09

    I discuss several novel and unexpected aspects of quantum chromodynamics. These include: (a) the nonperturbative origin of intrinsic strange, charm and bottom quarks in the nucleon at large x; the breakdown of pQCD factorization theorems due to the lensing effects of initial- and final-state interactions; (b) important corrections to pQCD scaling for inclusive reactions due to processes in which hadrons are created at high transverse momentum directly in the hard processes and their relation to the baryon anomaly in high-centrality heavy-ion collisions; and (c) the nonuniversality of quark distributions in nuclei. I also discuss some novel theoretical perspectives in QCD: (a) light-front holography - a relativistic color-confining first approximation to QCD based on the AdS/CFT correspondence principle; (b) the principle of maximum conformality - a method which determines the renormalization scale at finite order in perturbation theory yielding scheme independent results; (c) the replacement of quark and gluon vacuum condensates by 'in-hadron condensates' and how this helps to resolve the conflict between QCD vacuum and the cosmological constant.

  20. Effective Yukawa couplings and flavor-changing Higgs boson decays at linear colliders

    SciTech Connect (OSTI)

    Gabrielli, E.; Mele, B.

    2011-04-01

    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.

  1. Di-hadron production at Jefferson Lab

    SciTech Connect (OSTI)

    Anefalos Pereira, Sergio; et. al.,

    2014-10-01

    Semi-inclusive deep inelastic scattering (SIDIS) has been used extensively in recent years as an important testing ground for QCD. Studies so far have concentrated on better determination of parton distribution functions, distinguishing between the quark and antiquark contributions, and understanding the fragmentation of quarks into hadrons. Hadron pair (di-hadron) SIDIS provides information on the nucleon structure and hadronization dynamics that complement single hadron SIDIS. Di-hadrons allow the study of low- and high-twist distribution functions and Dihadron Fragmentation Functions (DiFF). Together with the twist-2 PDFs ( f1, g1, h1), the Higher Twist (HT) e and hL functions are very interesting because they offer insights into the physics of the largely unexplored quark-gluon correlations, which provide access into the dynamics inside hadrons. The CLAS spectrometer, installed in Hall-B at Jefferson Lab, has collected data using the CEBAF 6 GeV longitudinally polarized electron beam on longitudinally polarized solid NH3 targets. Preliminary results on di-hadron beam-, target- and double-spin asymmetries will be presented.

  2. A tevatron collider beauty factory. [Final report, 1980--1992

    SciTech Connect (OSTI)

    Not Available

    1992-12-31

    This document which is labeled a final report consists of several different items. The first is a proposal for a detector to be developed for beauty physics. The detector is proposed for the Fermilab Tevatron, and would be designed to measure mixing reactions, rare decay modes, and even CP violation in hadron collider beauty production. The general outline of the work proposed is given, and an estimate of the time to actually design the detector is presented, along with proposed changes to the Tevatron to accommodate the system. A preliminary report on an experiment to verify a reported observation of a 17 keV neutrino in tritium decay is presented. The present results in the decay spectra actually show a depression below expected levels, which is not consistent with a massive neutrino. Additional interest has been shown in finishing an electrostatic beta spectrometer which was started several years previously. The instrument uses hemispherical electrostatic electric fields to retard electrons emitted in tritium decay, allowing measurement of integral spectra. The design goal has a 5 eV energy resolution, which may be achievable. A new PhD student is pursuing this experiment. Also the report contains a proposal for additional work in the field of non-perturbative quantum field theory by the theoretical group at OU. The work which is proposed will be applied to electroweak and strong interactions, as well as to quantum gravitational phenomena.

  3. Electromagnetic effects on the light hadron spectrum (Conference...

    Office of Scientific and Technical Information (OSTI)

    Electromagnetic effects on the light hadron spectrum Citation Details In-Document Search Title: Electromagnetic effects on the light hadron spectrum You are accessing a document...

  4. The Common Elements of Atomic and Hadronic Physics (Conference...

    Office of Scientific and Technical Information (OSTI)

    The Common Elements of Atomic and Hadronic Physics Citation Details In-Document Search Title: The Common Elements of Atomic and Hadronic Physics Authors: Brodsky, Stanley J. ;...

  5. QCD and Hadron Physics (Conference) | SciTech Connect

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

    Conference: QCD and Hadron Physics Citation Details In-Document Search Title: QCD and Hadron Physics This White Paper presents the recommendations and scientific conclusions from ...

  6. Electromagnetic effects on the light hadron spectrum (Conference...

    Office of Scientific and Technical Information (OSTI)

    Conference: Electromagnetic effects on the light hadron spectrum Citation Details In-Document Search Title: Electromagnetic effects on the light hadron spectrum Authors: Basak, S. ...

  7. Twist-3 fragmentation effects for ALT in light hadron production...

    Office of Scientific and Technical Information (OSTI)

    Twist-3 fragmentation effects for ALT in light hadron production from proton-proton collisions Title: Twist-3 fragmentation effects for ALT in light hadron production from...

  8. Answering Gauguin's Questions in Particle Physics: Where are...

    Office of Scientific and Technical Information (OSTI)

    of space? The Large Hadron Collider (LHC) at the CERN Laboratory in Geneva, Switzerland, where high-energy experiments have now started, will take physics into a new realm...

  9. DOE Launches First Segment of its Next-Generation Nationwide...

    Broader source: Energy.gov (indexed) [DOE]

    ... Among the most ambitious projects to be undertaken by physicists around the globe is a series of experiments at the new Large Hadron Collider (LHC) at CERN, near Geneva, ...

  10. HEPAP Agenda July 6-7, 2006 U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    CERN Council Planning Group Report .pdf file (61KB) G. Wormser 4:40 Discussion 4:50 Large Hadron Collider (LHC) Theory Initiative .pdf file (36KB) J. Bagger 5:00 Adjourn M. Shochet ...

  11. Engineering Division Superconducting

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

    ... Engineering Division HEP Accelerator Dipole 10152014 Joseph V. Minervini 58 * Large Hadron Collider (LHC) at CERN uses NbTi dipoles and quadrupoles operating at 8 T, 2 K ...

  12. U.S. Completes Contribution to World's Most Powerful Particle...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    U.S. Completes Contribution to World's Most Powerful Particle Accelerator June 30, 2008 - 2:15pm Addthis WASHINGTON, DC - The U.S. contribution to the Large Hadron Collider (LHC) ...

  13. Fermilab | Science | Particle Physics | Scientific Computing

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

    Today Fermilab serves as one of two US computing centers that processes and analyzes data from experiments at the Large Hadron Collider. The worldwide LHC computing project is one ...

  14. Searching for Cosmic Accelerators via IceCube

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

    In our universe there are particle accelerators 40 million times more powerful than the Large Hadron Collider (LHC) at CERN. Scientists don't know what these cosmic accelerators ...

  15. Inder\tMonga CTO,\tEnergy\tSciences\tNetwork Deputy,\tScienEfic\tNetworking...

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

    Emerging Design Pa:erns Design Pa:ern 1: Protect your Elephant Flows 2816 13 2816 14 Large Hadron Collider (LHC) InternaEonal Thermonuclear Experimental Reactor (ITER) ...

  16. Fermilab Today

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

    tiny universe hit a growth spurt that used 15 billion times more energy than a collision in the Large Hadron Collider. Scientists can't crank the LHC up that high, not even close. ...

  17. Fermilab Today

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

    ... LHC restarts (low-energy) proton collisions From Discovery News, May 5, 2015 For the first time since the Large Hadron Collider was shut down in 2013 for its two-year hiatus for a ...

  18. William Johnston

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

    During his tenure Johnston led the effort to develop a new network, ESnet4, to accommodate massive scientific data flows of petabytesyear from the Large Hadron Collider (LHC) at ...

  19. Experiences

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

    ... The Large Hadron Collider 1 (LHC), the most well-known high- energy physics collaboration, was a driving force in the deployment of high bandwidth connections in the research and ...

  20. Statement by U.S. Secretary of Energy Steven Chu on the Higgs Particle

    Broader source: Energy.gov [DOE]

    Hundreds of scientists and graduate students from American institutions have played important roles in the search for the Higgs using the Large Hadron Collider (LHC) at the CERN laboratory.

  1. The Origins of the Universe | U.S. DOE Office of Science (SC...

    Office of Science (SC) Website

    ... In addition to RHIC, the Office of Science supports research on the environmental conditions of the Big Bang at the Large Hadron Collider External link (LHC), located at CERN, the ...

  2. Efficient Data Transfer Protocols

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

    Efficient protocols and tools are necessary to move vast amounts of scientific data over high-bandwidth networks in such collaborations. The Large Hadron Collider 1 (LHC), the most ...

  3. ESnet: Advanced Networking for Science

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

    ... operated or being built by the DOE SC, in addition to the Large Hadron Collider (LHC) at CERN (figure 2, p50) and the ITER fusion research project in France (figure 4, p51). ...

  4. Fermilab Today

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

    with CERN on the development of these and other Nb3Sn magnets are enabling the use of this innovative technology for future upgrades of the Large Hadron Collider (LHC). ...

  5. Biological and Environmenal Research Network Requirements Review

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

    ... The Large Hadron Collider (LHC) experiments are in the process of transi oning to this remote IO model-genomics could take advantage of this model as well. 3. Compu ng workflows ...

  6. Microsoft Word - Motivation, Design, Deployment and Evolution...

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

    ... requirements. 1.1 Data Management in High Energy Physics One of the major experiments associated with the Large Hadron Collider program (LHC 4) at CERN is the ATLAS 6 detector. ...

  7. Efficient Wide Area Data Transfer Protocols

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

    ... E cient tools are necessary to move vast amounts of scientific data over high-bandwidth networks in such state- of-the-art collaborations. The Large Hadron Collider 1 (LHC), the ...

  8. User Submitted Research Citations

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

    ... Society 10.1021jacs.5b10354 | NERSC Resources Used: Edison - Cray XC30, Hopper - Cray ... The current experimental frontier in HEP is the Large Hadron Collider (LHC), the most ...

  9. User Submitted Research Citations

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

    ... NERSC Repository: m558 NERSC Resources Used: Edison - Cray XC30, Hopper - Cray XE6 ... The current experimental frontier in HEP is the Large Hadron Collider (LHC), the most ...

  10. HEP-Tsung.pptx

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

    ... 5 years with access to 50X NERSC resources? - Better understanding of the ... The Large Hadron Collider (LHC) at CERN came online in 2008. The construction cost alone for ...

  11. Scientific Data Movement

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

    ... These far reaching networks, designed to offer large amounts ... using existing network resources (i.e. not requiring new ... 1 Internet2 ION Case Study: Large Hadron Collider (LHC). ...

  12. 25420_ESNet_ASCR_Cover_Final2

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

    ... The ability of HPC resources to produce data in the future time frame may be comparable to the ability of current large instruments (for instance, the Large Hadron Collider LHC) ...

  13. Overview of LHC physics results at ICHEP

    ScienceCinema (OSTI)

    None

    2011-04-25

     This month LHC physics day will review the physics results presented by the LHC experiments at the 2010 ICHEP in Paris. The experimental presentations will be preceeded by the bi-weekly LHC accelerator status report.The meeting will be broadcast via EVO (detailed info will appear at the time of the meeting in the "Video Services" item on the left menu bar)For those attending, information on accommodation, access to CERN and laptop registration is available from http://cern.ch/lpcc/visits

  14. Overview of LHC physics results at ICHEP

    SciTech Connect (OSTI)

    2011-02-25

    This month LHC physics day will review the physics results presented by the LHC experiments at the 2010 ICHEP in Paris. The experimental presentations will be preceeded by the bi-weekly LHC accelerator status report.The meeting will be broadcast via EVO (detailed info will appear at the time of the meeting inthe "Video Services" item on the left menu bar)For those attending, information on accommodation, access to CERN and laptop registration is available from http://cern.ch/lpcc/visits

  15. Gluino polarization at the LHC

    SciTech Connect (OSTI)

    Kraemer, M.; Popenda, E.; Spira, M.; Zerwas, P. M.

    2009-09-01

    Gluinos are produced pairwise at the LHC in quark-antiquark and gluon-gluon collisions: qq, gg{yields}g-tildeg-tilde. While the individual polarization of gluinos vanishes in the limit in which the small mass difference between L and R squarks of the first two generations is neglected, nonzero spin-spin correlations are predicted within gluino pairs. If the squark/quark charges in Majorana gluino decays are tagged, the spin correlations have an impact on the energy and angular distributions in reconstructed final states. On the other hand, the gluino polarization in single gluino production in the supersymmetric Compton process gq{yields}g-tildeq-tilde{sub R,L} is predicted to be nonzero, and the polarization affects the final-state distributions in super-Compton events.

  16. 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

    2012-08-01

    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-off refilling. The CEBAF fixed-target nuclear physics program can be simultaneously operated since the filling time of the electron ring is very short. The ion complex for MEIC consists of sources for polarized light ions and unpolarized light to heavy ions, an SRF ion linac with proton energy up to 280 MeV, a 3 GeV prebooster synchrotron, a large booster synchrotron for proton energy up to 20 GeV, and a medium-energy collider ring with energy up to 100 GeV. The ion complex can accelerate other species of ions with corresponding energies at each accelerating stage. There are three collision points planned for MEIC. Two of them are for collisions with medium-energy ions; the third is for low energy ion beams stored in a dedicated low-energy compact storage ring, as a possible follow-on project.

  17. Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC) Citation Details In-Document Search Title: Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC) Authors: Rakotozafindrabe, A. ; /DAPNIA, Saclay ; Anselmino, M. ; /INFN, Turin ; Arnaldi, R. ; /INFN, Turin ; Brodsky, S.J. ; /SLAC ; Chambert, V. ; /Orsay, IPN ; Didelez, J.P. ; /Orsay, IPN ; Ferreiro, E.G. ; /Santiago de Compostela U., IGFAE ; Fleuret, F. ; /Ecole Polytechnique ; Genolini,

  18. The optics of the low energy FFAG cell of the eRHIC collider, using realistic field maps

    SciTech Connect (OSTI)

    Tsoupas, N.; Brooks, S.; Jain, A.; Meot, F.; Mahler, G.; Ptitsyn, V.; Trbojevic, D.; Severance, M.

    2015-07-02

    The proposed electron accelerator of the eRHIC complex [1] will use a 1.32 GeV Energy Recovery Linac (ERL) to accelerate the e-bunches to a top energy of 21.2 GeV before they collide with the hadron bunches. The e-bunches attain the 21.2 GeV energy after passing through the ERL 16 times as they recirculate in two rings which are placed alongside the RHIC hadron accelerator. The two rings [1] are made of periodic cells and each cell is made of one focusing and one defocusing permanent magnet qudrupole. In this paper we present the electromagnetic calculations of the 2D and 3D models of a cell which is comprised of two modified Halbach quadrupoles [4], and the optical properties of the cell.

  19. First Measurement of the Underlying Event Activity at the LHC with $\\sqrt{s} = 0.9$ TeV

    SciTech Connect (OSTI)

    Khachatryan, Vardan; et al.

    2010-11-06

    A measurement of the underlying activity in scattering processes with transverse momentum scale in the GeV region is performed in proton-proton collisions at sqrt(s) = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged hadron production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged hadrons with pseudorapidity eta < 2, p_T > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object.

  20. Freeze-In dark matter with displaced signatures at colliders

    SciTech Connect (OSTI)

    Co, Raymond T.; D’Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

    2015-12-11

    Dark matter, X, may be generated by new physics at the TeV scale during an early matter-dominated (MD) era that ends at temperature T{sub R}≪ TeV. Compared to the conventional radiation-dominated (RD) results, yields from both Freeze-Out and Freeze-In processes are greatly suppressed by dilution from entropy production, making Freeze-Out less plausible while allowing successful Freeze-In with a much larger coupling strength. Freeze-In is typically dominated by the decay of a particle B of the thermal bath, B→X. For a large fraction of the relevant cosmological parameter space, the decay rate required to produce the observed dark matter abundance leads to displaced signals at LHC and future colliders, for any m{sub X} in the range keV colliders. This result applies whether the early MD era arises after conventional inflation, when T{sub R} is the usual reheat temperature, or is a generic MD era with an alternative origin. In the former case, if m{sub X} is sufficiently large to be measured from kinematics, the reheat temperature T{sub R} can be extracted. Our result is independent of the particular particle physics implementation of B→X, and can occur via any operator of dimension less than 8 (4) for a post-inflation (general MD) cosmology. An interesting example is provided by DFS axion theories with TeV-scale supersymmetry and axino dark matter of mass GeV to TeV, which is typically overproduced in a conventional RD cosmology. If B is the higgsino, h-tilde, Higgs, W and Z particles appear at the displaced decays, h-tilde→ha-tilde, Za-tilde and h-tilde{sup ±}→W{sup ±}a-tilde. The scale of axion physics, f, is predicted to be in the range (3×10{sup 8}−10{sup 12}) GeV and, over much of this range, can be extracted from the decay length.

  1. Experimental study of magnetically confined hollow electron beams in the Tevatron as collimators for intense high-energy hadron beams

    SciTech Connect (OSTI)

    Stancari, G.; Annala, G.; Shiltsev, V.; Still, D.; Valishev, A.; Vorobiev, L.; /Fermilab

    2011-03-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable losses. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and tested at Fermilab for this purpose. It was installed in one of the Tevatron electron lenses in the summer of 2010. We present the results of the first experimental tests of the hollow-beam collimation concept on 980-GeV antiproton bunches in the Tevatron.

  2. Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons

    SciTech Connect (OSTI)

    Boer, Daniel; /Groningen, KVI; Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Mulders, Piet J.; /Brussels U., IIHE; Pisano, Cristian; /Cagliari U. /INFN, Cagliari

    2011-02-07

    We show that the unmeasured distribution of linearly polarized gluons inside unpolarized hadrons can be directly probed in jet or heavy quark pair production both in electron-hadron and hadron-hadron collisions. We present expressions for the simplest cos 2{phi} asymmetries and estimate their maximal value in the particular case of electron-hadron collisions. Measurements of the linearly polarized gluon distribution in the proton should be feasible in future EIC or LHeC experiments.

  3. Light-cone quantization and hadron structure

    SciTech Connect (OSTI)

    Brodsky, S.J.

    1996-04-01

    Quantum chromodynamics provides a fundamental description of hadronic and nuclear structure and dynamics in terms of elementary quark and gluon degrees of freedom. In practice, the direct application of QCD to reactions involving the structure of hadrons is extremely complex because of the interplay of nonperturbative effects such as color confinement and multi-quark coherence. In this talk, the author will discuss light-cone quantization and the light-cone Fock expansion as a tractable and consistent representation of relativistic many-body systems and bound states in quantum field theory. The Fock state representation in QCD includes all quantum fluctuations of the hadron wavefunction, including fax off-shell configurations such as intrinsic strangeness and charm and, in the case of nuclei, hidden color. The Fock state components of the hadron with small transverse size, which dominate hard exclusive reactions, have small color dipole moments and thus diminished hadronic interactions. Thus QCD predicts minimal absorptive corrections, i.e., color transparency for quasi-elastic exclusive reactions in nuclear targets at large momentum transfer. In other applications, such as the calculation of the axial, magnetic, and quadrupole moments of light nuclei, the QCD relativistic Fock state description provides new insights which go well beyond the usual assumptions of traditional hadronic and nuclear physics.

  4. Hiding a Heavy Higgs Boson at the 7 TeV LHC

    SciTech Connect (OSTI)

    Bai, Yang; Fan, JiJi; Hewett, JoAnne L.

    2012-03-20

    A heavy Standard Model Higgs boson is not only disfavored by electroweak precision observables but is also excluded by direct searches at the 7 TeV LHC for a wide range of masses. Here, we examine scenarios where a heavy Higgs boson can be made consistent with both the indirect constraints and the direct null searches by adding only one new particle beyond the Standard Model. This new particle should be a weak multiplet in order to have additional contributions to the oblique parameters. If it is a color singlet, we find that a heavy Higgs with an intermediate mass of 200-300 GeV can decay into the new states, suppressing the branching ratios for the standard model modes, and thus hiding a heavy Higgs at the LHC. If the new particle is also charged under QCD, the Higgs production cross section from gluon fusion can be reduced significantly due to the new colored particle one-loop contribution. Current collider constraints on the new particles allow for viable parameter space to exist in order to hide a heavy Higgs boson. We categorize the general signatures of these new particles, identify favored regions of their parameter space and point out that discovering or excluding them at the LHC can provide important indirect information for a heavy Higgs. Finally, for a very heavy Higgs boson, beyond the search limit at the 7 TeV LHC, we discuss three additional scenarios where models would be consistent with electroweak precision tests: including an additional vector-like fermion mixing with the top quark, adding another U(1) gauge boson and modifying triple-gauge boson couplings.

  5. FFAG Designs for Muon Collider Acceleration

    SciTech Connect (OSTI)

    Berg, J. Scott

    2014-01-13

    I estimate FFAG parameters for a muon collider with a 70mm longitudinal emittance. I do not discuss the lower emittance beam for a Higgs factory. I produce some example designs, giving only parameters relevant to estimating cost and performance. The designs would not track well, but the parameters of a good design will be close to those described. I compare these cost estimates to those for a fast-ramping synchrotron and a recirculating linear accelerator. I conclude that FFAGs do not appear to be cost-effective for the large longitudinal emittance in a high-energy muon collider.

  6. Beam instrumentation for the Tevatron Collider

    SciTech Connect (OSTI)

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

    2009-10-01

    The Tevatron in Collider Run II (2001-present) is operating with six times more bunches and 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 future colliders.

  7. Beyond the Standard Model Theory

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

    Beyond the Standard Model Theory Beyond the Standard Model Understanding discoveries at the Energy, Intensity, and Cosmic Frontiers Get Expertise Rajan Gupta (505) 667-7664 Email Bruce Carlsten (505) 667-5657 Email LHC physics at Los Alamos The Large Hadron Collider (LHC) is studying the structure of matter at sub-nucleon distance scales by colliding protons together at high center of mass energy. The LHC has a broad scientific program, performing studies of QCD, heavy quarks, the W and Z

  8. Mixing stops at the LHC

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

    Agrawal, Prateek; Frugiuele, Claudia

    2014-01-01

    We study the phenomenology of a light stop NLSP in the presence of large mixing with either the first or the second generation. R-symmetric models provide a prime setting for this scenario, but our discussion also applies to the MSSM when a significant amount of mixing can be accommodated. In our framework the dominant stop decay is through the flavor violating mode into a light jet and the LSP in an extended region of parameter space. There are currently no limits from ATLAS and CMS in this region. We emulate shape-based hadronic SUSY searches for this topology, and find thatmore » they have potential sensitivity. If the extension of these analyses to this region is robust, we find that these searches can set strong exclusion limits on light stops. If not, then the flavor violating decay mode is challenging and may represent a blind spot in stop searches even at 13 TeV. Thus, an experimental investigation of this scenario is well motivated.« less

  9. Probing the Quark Sea and Gluons: the Electron-Ion Collider Projects

    SciTech Connect (OSTI)

    Rolf Ent

    2012-04-01

    EIC is the generic name for the nuclear science-driven Electron-Ion Collider presently considered in the US. Such an EIC would be the worlds first polarized electron-proton collider, and the worlds first e-A collider. Very little remains known about the dynamical basis of the structure of hadrons and nuclei in terms of the fundamental quarks and gluons of Quantum Chromodynamics (QCD). A large community effort to sharpen a compelling nuclear science case for an EIC occurred during a ten-week program taking place at the Institute for Nuclear Theory (INT) in Seattle from September 13 to November 19, 2010. The critical capabilities of a stage-I EIC are a range in center-of-mass energies from 20 to 70 GeV and variable, full polarization of electrons and light ions (the latter both longitudinal and transverse), ion species up to A=200 or so, multiple interaction regions, and a high luminosity of about 10{sup 34} electron-nucleons per cm{sup 2} and per second. The physics program of such a stage-I EIC encompass inclusive measurements (ep/A{yields}e'+X), which require detection of the scattered lepon and/or the full scattered hadronic debris with high precision, semi-inclusive processes (ep/A{yields}e'+h+X), which require detection in coincidence with the scattered lepton of at least one (current or target region) hadron; and exclusive processes (ep/A{yields}e'+N'/A'+{gamma}/m), which require detection of all particles in the reaction. The main science themes of an EIC are to i) map the spin and spatial structure of quarks and gluons in nucleons, ii) discover the collective effects of gluons in atomic nuclei, and (iii) understand the emergence of hadronic matter from color charge. In addition, there are opportunities at an EIC for fundamental symmetry and nucleon structure measurements using the electroweak probe. To truly make headway to image the sea quarks and gluons in nucleons and nuclei, the EIC needs high luminosity over a range of energies as more exclusive scattering probabilities are small, and any integrated detector/interaction region design needs to provide uniform coverage to detect spectator and diffractive products. This is because e-p and even more e-A colliders have a large fraction of their science related to what happens to the nucleon or ion beams. As a result, the philosophy of integration of complex detectors into an extended interaction region faces challenging constraints. Designs feature crossing angles between the protons or heavy ions during collisions with electrons, to remove potential problems for the detector induced by synchrotron radiation. Designs allocate quite some detector space before the final-focus ion quads, at the cost of luminosity, given that uniform detection coverage is a must for deep exclusive and diffractive processes. The integrated EIC detector/interaction region design at JLab focused on establishing full acceptance for such processes over a wide range of proton energies (20-100 GeV) with well achievable interaction region magnets. The detector design at BNL uses the higher ion beam energies to achieve good detection efficiency for instance for protons following a DVCS reaction, for proton beam energies starting from 100 GeV. Following a recommendation of the 2007 US Nuclear Science Long-Range Planning effort, the DOE Office of Nuclear Physics (DOE/NP) has allocated accelerator R&D funds to lay the foundation for a polarized EIC. BNL, in association with JLab and DOE/NP, has also established a generic detector R&D program to address the scientific requirements for measurements at a future EIC.

  10. Towards a Future Linear Collider and The Linear Collider Studies at CERN

    ScienceCinema (OSTI)

    None

    2011-10-06

    During the week 18-22 October, more than 400 physicists will meet at CERN and in the CICG (International Conference Centre Geneva) to review the global progress towards a future linear collider. The 2010 International Workshop on Linear Colliders will study the physics, detectors and accelerator complex of a linear collider covering both the CLIC and ILC options. Among the topics presented and discussed will be the progress towards the CLIC Conceptual Design Report in 2011, the ILC Technical Design Report in 2012, physics and detector studies linked to these reports, and an increasing numbers of common working group activities. The seminar will give an overview of these topics and also CERN?s linear collider studies, focusing on current activities and initial plans for the period 2011-16. n.b: The Council Chamber is also reserved for this colloquium with a live transmission from the Main Auditorium.

  11. Identification techniques for highly boosted W bosons that decay into hadrons

    SciTech Connect (OSTI)

    Khachatryan, V.

    2014-12-02

    In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMS detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.

  12. Identification techniques for highly boosted W bosons that decay into hadrons

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

    Khachatryan, V.

    2014-12-02

    In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMSmoredetector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.less

  13. Identification techniques for highly boosted W bosons that decay into hadrons

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

    Khachatryan, Vardan

    2014-12-02

    In searches for new physics in the energy regime of the LHC, it is becoming increasingly important to distinguish single-jet objects that originate from the merging of the decay products of W bosons produced with high transverse momenta from jets initiated by single partons. Algorithms are defined to identify such W jets for different signals of interest, using techniques that are also applicable to other decays of bosons to hadrons that result in a single jet, such as those from highly boosted Z and Higgs bosons. The efficiency for tagging W jets is measured in data collected with the CMSmore » detector at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb-1. The performance of W tagging in data is compared with predictions from several Monte Carlo simulators.« less

  14. THEORETICAL STUDIES OF HADRONS AND NUCLEI

    SciTech Connect (OSTI)

    STEPHEN R COTANCH

    2007-03-20

    This report details final research results obtained during the 9 year period from June 1, 1997 through July 15, 2006. The research project, entitled ?Theoretical Studies of Hadrons and Nuclei?, was supported by grant DE-FG02-97ER41048 between North Carolina State University [NCSU] and the U. S. Department of Energy [DOE]. In compliance with grant requirements the Principal Investigator [PI], Professor Stephen R. Cotanch, conducted a theoretical research program investigating hadrons and nuclei and devoted to this program 50% of his time during the academic year and 100% of his time in the summer. Highlights of new, significant research results are briefly summarized in the following three sections corresponding to the respective sub-programs of this project (hadron structure, probing hadrons and hadron systems electromagnetically, and many-body studies). Recent progress is also discussed in a recent renewal/supplemental grant proposal submitted to DOE. Finally, full detailed descriptions of completed work can be found in the publications listed at the end of this report.

  15. First Results of the CMS Experiment at the LHC (Conference) ...

    Office of Scientific and Technical Information (OSTI)

    Search Title: First Results of the CMS Experiment at the LHC The 2010 proton-proton run of LHC has been very successful delivering an integrated luminosity in excess of 45...

  16. Missing energy signatures of dark matter at the LHC (Journal...

    Office of Scientific and Technical Information (OSTI)

    Missing energy signatures of dark matter at the LHC Citation Details In-Document Search Title: Missing energy signatures of dark matter at the LHC Authors: Fox, Patrick J. ; ...

  17. Higgs boson and Z physics at the first muon collider

    SciTech Connect (OSTI)

    Demarteau, M.; Han, T.

    1998-01-01

    The potential for the Higgs boson and Z-pole physics at the first muon collider is summarized, based on the discussions at the ``Workshop on the Physics at the First Muon Collider and at the Front End of a Muon Collider``.

  18. SciDAC Advances in Beam Dynamics Simulation: From Light Sources to Colliders

    SciTech Connect (OSTI)

    Qiang, J.; Borland, M.; Kabel, A.; Li, R.; Ryne, R.; Stern, E.; Wang, Y.; Wasserman, H.; Zhang, Y.; /SLAC

    2011-11-14

    In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities (e.g., LCLS, RHIC, Tevatron, LHC, and ELIC). Particle accelerators are some of most important tools of scientific discovery. They are widely used in high-energy physics, nuclear physics, and other basic and applied sciences to study the interaction of elementary particles, to probe the internal structure of matter, and to generate high-brightness radiation for research in materials science, chemistry, biology, and other fields. Modern accelerators are complex and expensive devices that may be several kilometers long and may consist of thousands of beamline elements. An accelerator may transport trillions of charged particles that interact electromagnetically among themselves, that interact with fields produced by the accelerator components, and that interact with beam-induced fields. Large-scale beam dynamics simulations on massively parallel computers can help provide understanding of these complex physical phenomena, help minimize design cost, and help optimize machine operation. In this paper, we report on beam dynamics simulations in a variety of accelerators ranging from next generation light sources to high-energy ring colliders that have been studied during the first year of the SciDAC-2 accelerator project.

  19. Bulk matter evolution and extraction of jet transport parameters in heavy-ion collisions at energies available at the BNL Relativistic Heavy Ion Collider (RHIC)

    SciTech Connect (OSTI)

    Chen Xiaofang; Greiner, Carsten; Wang Enke; Wang Xinnian; Xu Zhe

    2010-06-15

    Within the picture of jet quenching induced by multiple parton scattering and gluon bremsstrahlung, medium modification of parton fragmentation functions and therefore the suppression of large transverse-momentum hadron spectra are controlled by both the value and the space-time profile of the jet transport parameter along the jet propagation path. Experimental data on single-hadron suppression in high-energy heavy-ion collisions at the Relativistic Heavy Ion Collider energy are analyzed within the higher-twist (HT) approach to the medium-modified fragmentation functions and the next-to-leading order perturbative QCD parton model. Assuming that the jet transport parameter q is proportional to the particle number density in both quark gluon plasma (QGP) and hadronic phase, experimental data on jet quenching in deeply inelastic scattering off nuclear targets can provide guidance on q{sub h} in the hot hadronic matter. One can then study the dependence of the extracted initial value of jet-quenching parameter q{sub 0} at initial time tau{sub 0} on the bulk medium evolution. Effects of transverse expansion, radial flow, phase transition, and nonequilibrium evolution are examined. The extracted values are found to vary from q{sub 0}tau{sub 0}=0.54 GeV{sup 2} in the (1+3)d ideal hydrodynamic model to 0.96 GeV{sup 2} in a cascade model, with the main differences coming from the initial nonequilibrium evolution and the later hadronic evolution. The overall contribution to jet quenching from the hadronic phase, about 22%-44%, is found to be significant. Therefore, a realistic description of the early nonequilibrium parton evolution and later hadronic interaction will be critical for accurate extraction of the jet transport parameter in the strongly interacting QGP phase in high-energy heavy-ion collisions.

  20. Hadronic form factors in kaon photoproduction

    SciTech Connect (OSTI)

    Syukurilla, L. Mart, T.

    2014-09-25

    We have revisited the effect of hadronic form factors in kaon photoproduction process by utilizing an isobaric model developed for kaon photoproduction off the proton. The model is able to reproduce the available experimental data nicely as well as to reveal the origin of the second peak in the total cross section, which was the main source of confusion for decades. Different from our previous study, in the present work we explore the possibility of using different hadronic form factors in each of the K?N vertices. The use of different hadronic form factors, e.g. dipole, Gaussian, and generalized dipole, has been found to produce a more flexible isobar model, which can provide a significant improvement in the model.

  1. Using tevatron magnets for HE-LHC or new ring in LHC tunnel

    SciTech Connect (OSTI)

    Piekarz, Henryk; /Fermilab

    2011-08-01

    Two injector accelerator options for HE-LHC of p{sup +} - p{sup +} collisions at 33 TeV cms energy are briefly outlined. One option is based on the Super-SPS (S-SPS) accelerator in the SPS tunnel, and the other one is based on the LER (Low-Energy-Ring) accelerator in the LHC tunnel. Expectations of performance of the main arc accelerator magnets considered for the construction of the S-SPS and of the LER accelerators are used to tentatively devise some selected properties of these accelerators as potential injectors to HE-LHC.

  2. Charged-particle multiplicity at LHC energies

    ScienceCinema (OSTI)

    None

    2011-10-06

    The talk presents the measurement of the pseudorapidity density and the multiplicity distribution with ALICE at the achieved LHC energies of 0.9 and 2.36 TeV.An overview about multiplicity measurements prior to LHC is given and the related theoretical concepts are briefly discussed.The analysis procedure is presented and the systematic uncertainties are detailed. The applied acceptance corrections and the treatment of diffraction are discussed.The results are compared with model predictions. The validity of KNO scaling in restricted phase space regions is revisited. 

  3. High-energy high-luminosity electron-ion collider eRHIC

    SciTech Connect (OSTI)

    Litvinenko, V.N.; Ben-Zvi, I.; Hammons, L.; Hao, Y.; Webb, S.; et al

    2011-08-09

    In this paper, we describe a future electron-ion collider (EIC), based on the existing Relativistic Heavy Ion Collider (RHIC) hadron facility, with two intersecting superconducting rings, each 3.8 km in circumference. The replacement cost of the RHIC facility is about two billion US dollars, and the eRHIC will fully take advantage and utilize this investment. We plan adding a polarized 5-30 GeV electron beam to collide with variety of species in the existing RHIC accelerator complex, from polarized protons with a top energy of 325 GeV, to heavy fully-striped ions with energies up to 130 GeV/u. Brookhaven's innovative design, is based on one of the RHIC's hadron rings and a multi-pass energy-recovery linac (ERL). Using the ERL as the electron accelerator assures high luminosity in the 10{sup 33}-10{sup 34} cm{sup -2} sec{sup -1} range, and for the natural staging of eRHIC, with the ERL located inside the RHIC tunnel. The eRHIC will provide electron-hadron collisions in up to three interaction regions. We detail the eRHIC's performance in Section 2. Since first paper on eRHIC paper in 2000, its design underwent several iterations. Initially, the main eRHIC option (the so-called ring-ring, RR, design) was based on an electron ring, with the linac-ring (LR) option as a backup. In 2004, we published the detailed 'eRHIC 0th Order Design Report' including a cost-estimate for the RR design. After detailed studies, we found that an LR eRHIC has about a 10-fold higher luminosity than the RR. Since 2007, the LR, with its natural staging strategy and full transparency for polarized electrons, became the main choice for eRHIC. In 2009, we completed technical studies of the design and dynamics for MeRHIC with 3-pass 4 GeV ERL. We learned much from this evaluation, completed a bottom-up cost estimate for this $350M machine, but then shelved the design. In the same year, we turned again to considering the cost-effective, all-in-tunnel six-pass ERL for our design of the high-luminosity eRHIC. In it, electrons from the polarized pre-injector will be accelerated to their top energy by passing six times through two SRF linacs. After colliding with the hadron beam in up to three detectors, the e-beam will be decelerated by the same linacs and dumped. The six-pass magnetic system with small-gap magnets will be installed from the start. We will stage the electron energy from 5 GeV to 30 GeV stepwise by increasing the lengths of the SRF linacs. We discuss details of eRHIC's layout in Section 3. We considered several IR designs for eRHIC. The latest one, with a 10 mrad crossing angle and {beta}* = 5 cm, takes advantage of newly commissioned Nb{sub 3}Sn quadrupoles. Section 4 details the eRHIC lattice and the IR layout. The current eRHIC design focuses on electron-hadron collisions. If justified by the EIC physics, we will add a 30 GeV polarized positron ring with full energy injection from eRHIC ERL. This addition to the eRHIC facility provide for positron-hadron collisions, but at a significantly lower luminosity than those attainable in the electron-hadron mode. As a novel high-luminosity EIC, eRHIC faces many technical challenges, such as generating 50 mA of polarized electron current. eRHIC also will employ coherent electron cooling (CeC) for the hadron beams. Staff at BNL, JLab, and MIT is pursuing vigorously an R&D program for resolving addressing these obstacles. In collaboration with Jlab, BNL plans experimentally to demonstrate CeC at the RHIC. We discuss the structure and the status of the eRHIC R&D in Section 5.

  4. Constraining Inert Triplet dark matter by the LHC and FermiLAT

    SciTech Connect (OSTI)

    Ayazi, Seyed Yaser; Firouzabadi, S. Mahdi E-mail: smmfirouz@yahoo.com

    2014-11-01

    We study collider phenomenology of inert triplet scalar dark matter at the LHC. We discuss possible decay of Higgs boson to dark matter candidate and apply current experimental data for invisible Higgs decay and R{sub ??} to constrain parameter space of our model. We also investigate constraints on dark matter coming from forthcoming measurement, R{sub Z?} and mono-Higgs production. We analytically calculate the annihilation cross section of dark matter candidate into 2? and Z? and then use FermiLAT data to put constraints on parameter space of Inert Triplet Model. We found that this limit can be stronger than the constraints provided by LUX experiment for low mass DM.

  5. Development of GEM-Based Digital Hadron Calorimetry Using the...

    Office of Scientific and Technical Information (OSTI)

    Conference: Development of GEM-Based Digital Hadron Calorimetry Using the SLAC KPiX Chip Citation Details In-Document Search Title: Development of GEM-Based Digital Hadron...

  6. COMMISSIONING OF THE RELATIVISTIC HEAVY ION COLLIDER.

    SciTech Connect (OSTI)

    TRBOJEVIC,D.; AHRENS,L.; BLASKIEWICZ,M.; BRENNAN,M.; BAI,M.; CAMERON,P.; CARDONA,J.; CONNOLLY,R.; ET AL; TSOUPAS,N.; VAN ZEIJTS,J.

    2001-06-18

    This report describes in detail steps performed in bringing the Relativistic Heavy Ion Collider (RHIC) from the commissioning into the operational stage when collisions between 60 bunches of fully striped gold ions, were routinely provided. Corrections of the few power supplies connections by the beam measurements are described. Beam lifetime improvements at injection, along the acceleration are shown. The beam diagnostic results; like Schottky detector, beam profile monitor, beam position monitors, tune meter and others, are shown [1].

  7. Structure and Dynamics of Colliding Plasma Jets

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

    Li, C.; Ryutov, D.; Hu, S.; Rosenberg, M.; Zylstra, A.; Seguin, F.; Frenje, J.; Casey, D.; Gatu Johnson, M.; Manuel, M.; et al

    2013-12-01

    Monoenergetic-proton radiographs of laser-generated, high-Mach-number plasma jets colliding at various angles shed light on the structures and dynamics of these collisions. The observations compare favorably with results from 2D hydrodynamic simulations of multistream plasma jets, and also with results from an analytic treatment of electron flow and magnetic field advection. In collisions of two noncollinear jets, the observed flow structure is similar to the analytic model’s prediction of a characteristic feature with a narrow structure pointing in one direction and a much thicker one pointing in the opposite direction. Spontaneous magnetic fields, largely azimuthal around the colliding jets and generatedmore » by the well-known ∇Te ×∇ne Biermann battery effect near the periphery of the laser spots, are demonstrated to be “frozen in” the plasma (due to high magnetic Reynolds number RM ~5×10⁴) and advected along the jet streamlines of the electron flow. These studies provide novel insight into the interactions and dynamics of colliding plasma jets.« less

  8. Structure and Dynamics of Colliding Plasma Jets

    SciTech Connect (OSTI)

    Li, C.; Ryutov, D.; Hu, S.; Rosenberg, M.; Zylstra, A.; Seguin, F.; Frenje, J.; Casey, D.; Gatu Johnson, M.; Manuel, M.; Rinderknecht, H.; Petrasso, R.; Amendt, P.; Park, H.; Remington, B.; Wilks, S.; Betti, R.; Froula, D.; Knauer, J.; Meyerhofer, D.; Drake, R.; Kuranz, C.; Young, R.; Koenig, M.

    2013-12-01

    Monoenergetic-proton radiographs of laser-generated, high-Mach-number plasma jets colliding at various angles shed light on the structures and dynamics of these collisions. The observations compare favorably with results from 2D hydrodynamic simulations of multistream plasma jets, and also with results from an analytic treatment of electron flow and magnetic field advection. In collisions of two noncollinear jets, the observed flow structure is similar to the analytic models prediction of a characteristic feature with a narrow structure pointing in one direction and a much thicker one pointing in the opposite direction. Spontaneous magnetic fields, largely azimuthal around the colliding jets and generated by the well-known ?Te ?ne Biermann battery effect near the periphery of the laser spots, are demonstrated to be frozen in the plasma (due to high magnetic Reynolds number RM ~510?) and advected along the jet streamlines of the electron flow. These studies provide novel insight into the interactions and dynamics of colliding plasma jets.

  9. Neutrino Factory and Muon Collider Fellow

    SciTech Connect (OSTI)

    Hanson, Gail G.; Snopak, Pavel; Bao, Yu

    2015-03-20

    Muons are fundamental particles like electrons but much more massive. Muon accelerators can provide physics opportunities similar to those of electron accelerators, but because of the larger mass muons lose less energy to radiation, allowing more compact facilities with lower operating costs. The way muon beams are produced makes them too large to fit into the vacuum chamber of a cost-effective accelerator, and the short muon lifetime means that the beams must be reduced in size rather quickly, without losing too many of the muons. This reduction in size is called "cooling." Ionization cooling is a new technique that can accomplish such cooling. Intense muon beams can then be accelerated and injected into a storage ring, where they can be used to produce neutrino beams through their decays or collided with muons of the opposite charge to produce a muon collider, similar to an electron-positron collider. We report on the research carried out at the University of California, Riverside, towards producing such muon accelerators, as part of the Muon Accelerator Program based at Fermilab. Since this research was carried out in a university environment, we were able to involve both undergraduate and graduate students.

  10. First measurement of ADS parameters using $B^- \\to D^0K^-$ decays in hadron collisions

    SciTech Connect (OSTI)

    Garosi, Paola; /Siena U. /INFN, Pisa

    2011-06-01

    Measurements of branching fractions and CP-asymmetries of B{sup -} {yields} D{sup 0}K{sup -} modes allow a theoretically-clean extraction of the CKM angle {gamma}. The method proposed by Atwood, Dunietz and Soni (ADS) makes use of a decay chain where color and Cabibbo suppression interfere, which produces large CP-violating asymmetries. The CDF experiment reports the first measurement at a hadron collider of branching fractions and CP-asymmetries of suppressed B{sup -} {yields} D{sup 0}h{sup -} signals, where h is {pi} or K. Using 5.0 fb{sup -1} of data we found a combined significance exceeding 5{sigma} and we determined the ADS parameters with accuracy comparable with B-factories.

  11. Measurement of the Top Quark Mass in the All-Hadronic Mode at CDF

    SciTech Connect (OSTI)

    Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J.A.; Arisawa, T.; Artikov, A.; /Dubna, JINR /Texas A-M

    2011-12-01

    A measurement of the top quark mass (M{sub top}) in the all-hadronic decay channel is presented. It uses 5.8 fb{sup -1} of p{bar p} data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines M{sub top} and the jet energy scale (JES) calibration. The fit yields a value of M{sub top} = 172.5 {+-} 1.4 (stat) {+-} 1.0 (JES) {+-} 1.1 (syst) GeV/c{sup 2}.

  12. BEAM INSTRUMENTATION FOR HIGH POWER HADRON BEAMS

    SciTech Connect (OSTI)

    Aleksandrov, Alexander V

    2013-01-01

    This presentation will describe developments in the beam diagnostics which support the understanding and operation of high power hadron accelerators. These include the measurement of large dynamic range transverse and longitudinal beam profiles, beam loss detection, and non-interceptive diagnostics.

  13. Hidden sector dark matters and elusive Higgs boson(s) at the LHC

    SciTech Connect (OSTI)

    Ko, P.

    2012-07-27

    We consider two types of hidden sector dark matters (DM's), with and without QCD-like new strong interaction with confinement properties, and their interplays with the Standard Model (SM) Higgs boson. Assuming the hidden sector has only fermions (and gauge bosons in case of strongly interacting hidden sector), we have to introduce a real singlet scalar boson S as a messenger between the SM and the hidden sector dark matters. This singlet scalar will mix with the SM Higgs boson h, and we expect there are two Higgs-like scalar bosons H{sub 1} and H{sub 2}. Imposing all the relevant constraints from collider search bounds on Higgs boson, DM scattering cross section on proton and thermal relic density, we find that one of the two Higgs-like scalar bosons can easily escape the detections at the LHC. Recent results on the Higgs-like new boson with mass around with 125 GeV from the LHC will constrain this class of models, which is left for future study.

  14. Resonance-continuum interference in the di-photon Higgs signal at the LHC

    SciTech Connect (OSTI)

    Dixon, Lance

    2003-02-25

    A low mass Standard Model Higgs boson should be visible at the Large Hadron Collider through its production via gluon-gluon fusion and its decay to two photons. We compute the interference of this resonant process, gg {yields} H {yields} {gamma}{gamma}, with the continuum QCD background, gg {yields} {gamma}{gamma} induced by quark loops. Helicity selection rules suppress the effect, which is dominantly due to the imaginary part of the two-loop gg {yields} {gamma}{gamma} scattering amplitude. The interference is destructive, but only of order 5% in the Standard Model, which is still below the 10-20% present accuracy of the total cross section prediction. We comment on the potential size of such effects in other Higgs models.

  15. Measurement of the hadronic cross section in electron-positron annihilation

    SciTech Connect (OSTI)

    Clearwater, S.

    1983-11-01

    This thesis describes the most precise measurement to date of the ratio R, the hadronic cross section in lowest order electron-positron annihilation to the cross section for muon pair production in lowest order electron-positron annihilation. This experiment is of interest because R is a fundamental parameter that tests in a model independent way the basic assumptions of strong interaction theories. According to the assumptions of one of these theories the value of R is determined simply from the electric charges, spin, and color assignments of the produced quark-pairs. The experiment was carried out with the MAgnetic Calorimeter using collisions of 14.5 GeV electrons and positrons at the 2200m circumference PEP storage ring at SLAC. The MAC detector is one of the best-suited collider detectors for measuring R due to its nearly complete coverage of the full angular range. The data for this experiment were accumulated between February 1982 and April 1983 corresponding to a total event sample of about 40,000 hadronic events. About 5% of the data were taken with 14 GeV beams and the rest of the data were taken with 14.5 GeV beams. A description of particle interactions and experimental considerations is given.

  16. Measurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at s=2.76TeV

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

    Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; et al

    2015-01-07

    The pT-differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at √s = 2.76  TeV in the transverse momentum range 0.5 < pT < 12  GeV/c with the ALICE detector at the LHC. The analysis was performed using minimum bias events and events triggered by the electromagnetic calorimeter. Predictions from perturbative QCD calculations agree with the data within the theoretical and experimental uncertainties.

  17. Breaking of the number-of-constituent-quark scaling for identified-particle elliptic flow as a signal of phase change in low-energy data taken at the BNL Relativistic Heavy Ion Collider (RHIC)

    SciTech Connect (OSTI)

    Tian, J.; Jin, F.; Zhang, S.; Chen, J. H.; Ma, Y. G.; Cai, X. Z.; Ma, G. L.; Zhong, C.

    2009-06-15

    We argue that measurements of identified-particle elliptic flow in a wide energy range could shed light on the possible phase change in high-energy heavy ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC). When the hadronization process is dominated by quark coalescence, the number-of-constituent-quark (NCQ) scaling for the identified-particle elliptic flow can serve as a probe for studying the strong interacting partonic matter. In the upcoming RHIC low-energy runs, the NCQ scaling behavior may be broken because of the change of the effective degrees of freedom of the hot dense matter, which corresponds to the transition from the dominant partonic phase to the dominant hadronic phase. A multiphase transport model is used to present the dependence of NCQ scaling behavior on the different hadronization mechanisms.

  18. QCD Factorization for heavy quarkonium production at collider energies

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect QCD Factorization for heavy quarkonium production at collider energies Citation Details In-Document Search Title: QCD Factorization for heavy quarkonium production at collider energies In this talk, I briefly review several models of the heavy quarkonium production at collider energies, and discuss the status of QCD factorization for these production models. Authors: Qiu Jianwei [1] ; Physics Department, Brookhaven National Laboratory, Upton, New York

  19. International Linear Collider-A Technical Progress Report (Technical

    Office of Scientific and Technical Information (OSTI)

    Report) | SciTech Connect Technical Report: International Linear Collider-A Technical Progress Report Citation Details In-Document Search Title: International Linear Collider-A Technical Progress Report 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

  20. A Fast Monte Carlo Simulation for the International Linear Collider

    Office of Scientific and Technical Information (OSTI)

    Detector (Technical Report) | SciTech Connect A Fast Monte Carlo Simulation for the International Linear Collider Detector Citation Details In-Document Search Title: A Fast Monte Carlo Simulation for the International Linear Collider Detector The following paper contains details concerning the motivation for, implementation and performance of a Java-based fast Monte Carlo simulation for a detector designed to be used in the International Linear Collider. This simulation, presently included

  1. Identification and energy calibration of hadronically decaying tau leptons with the ATLAS experiment in pp collisions at √s = 8 TeV

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

    Aad, G.

    2015-07-02

    This study describes the trigger and offline reconstruction, identification and energy calibration algorithms for hadronic decays of tau leptons employed for the data collected from pp collisions in 2012 with the ATLAS detector at the LHC center-of-mass energy √s=8 TeV. The performance of these algorithms is measured in most cases with Z decays to tau leptons using the full 2012 dataset, corresponding to an integrated luminosity of 20.3 fb–1. An uncertainty on the offline reconstructed tau energy scale of 2–4%, depending on transverse energy and pseudorapidity, is achieved using two independent methods. The offline tau identification efficiency is measured withmore » a precision of 2.5% for hadronically decaying tau leptons with one associated track, and of 4% for the case of three associated tracks, inclusive in pseudorapidity and for a visible transverse energy greater than 20 GeV. For hadronic tau lepton decays selected by offline algorithms, the tau trigger identification efficiency is measured with a precision of 2–8%, depending on the transverse energy. The performance of the tau algorithms, both offline and at the trigger level, is found to be stable with respect to the number of concurrent proton–proton interactions and has supported a variety of physics results using hadronically decaying tau leptons at ATLAS.« less

  2. Identification and energy calibration of hadronically decaying tau leptons with the ATLAS experiment in pp collisions at ?s = 8 TeV

    SciTech Connect (OSTI)

    Aad, G.

    2015-07-02

    This study describes the trigger and offline reconstruction, identification and energy calibration algorithms for hadronic decays of tau leptons employed for the data collected from pp collisions in 2012 with the ATLAS detector at the LHC center-of-mass energy ?s=8 TeV. The performance of these algorithms is measured in most cases with Z decays to tau leptons using the full 2012 dataset, corresponding to an integrated luminosity of 20.3 fb1. An uncertainty on the offline reconstructed tau energy scale of 24%, depending on transverse energy and pseudorapidity, is achieved using two independent methods. The offline tau identification efficiency is measured with a precision of 2.5% for hadronically decaying tau leptons with one associated track, and of 4% for the case of three associated tracks, inclusive in pseudorapidity and for a visible transverse energy greater than 20 GeV. For hadronic tau lepton decays selected by offline algorithms, the tau trigger identification efficiency is measured with a precision of 28%, depending on the transverse energy. The performance of the tau algorithms, both offline and at the trigger level, is found to be stable with respect to the number of concurrent protonproton interactions and has supported a variety of physics results using hadronically decaying tau leptons at ATLAS.

  3. A young person's view of the Superconducting Super Collider

    SciTech Connect (OSTI)

    Moya, A.

    1990-08-01

    This report gives a simple description of the Superconducting Super Collider, how it works, and what it is used for. (LSP)

  4. Far Future Colliders and Required R&D Program

    SciTech Connect (OSTI)

    Shiltsev, V.; /Fermilab

    2012-06-01

    Particle colliders for high energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the collider has progressed immensely, while the beam energy, luminosity, facility size and the cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but its pace of progress has greatly slowed down. In this paper we very briefly review the R&D toward near future colliders and make an attempt to look beyond the current horizon and outline the changes in the paradigm required for the next breakthroughs.

  5. Luminosity goals for a 100-TeV pp collider

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

    Hinchliffe, Ian; Kotwal, Ashutosh; Mangano, Michelangelo L.; Quigg, Chris; Wang, Lian-Tao

    2015-08-20

    We consider diverse examples of science goals that provide a framework to assess luminosity goals for a future 100-TeV proton-proton collider.

  6. Collider Tests of the Little Higgs Model (Journal Article) |...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Collider Tests of the Little Higgs Model The ... Research Org: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US) ...

  7. Luminosity goals for a 100-TeV pp collider

    SciTech Connect (OSTI)

    Hinchliffe, Ian; Kotwal, Ashutosh; Mangano, Michelangelo L.; Quigg, Chris; Wang, Lian-Tao

    2015-04-23

    We consider diverse examples of science goals that provide a framework to assess luminosity goals for a future 100-TeV proton-proton collider.

  8. Gap between jets at the LHC

    SciTech Connect (OSTI)

    Royon, Christophe

    2013-04-15

    We describe a NLL BFKL calculation implemented in the HERWIG MC of the gap between jets cross section, that represent a test of BFKL dynamics. We compare the predictions with recent measurements at the Tevatron and present predictions for the LHC. We also discuss the interesting process of looking for gap between jets in diffractive events when protons are detected in the ATLAS Forward Physics (AFP) detectors.

  9. Status of LHC crab activity simulations and beam studies

    SciTech Connect (OSTI)

    Calaga,R.; Assman, R.; Barranco, J.; Barranco, J.; Calaga, R.; Caspers, F.; Ciapala, E.; De-Maria, R.; Koutchouk, J. P.; Linnecar, T.; Metral, E.; Morita, A.; Solyak, N.; Sun, Y.; Tomas, R.; Tuckmantel, J.; Weiler, T.; Zimmermann, F.

    2009-05-04

    The LHC crab cavity program is advancing rapidly towards a first prototype which is anticipated to be tested during the early stages of the LHC phase I upgrade and commissioning. The general project status and some aspects related to crab optics, collimation, aperture constraints, impedances, noise effects. beam transparency and machine protection critical for a safe and robust operation of LHC beams with crab cavities are addressed here.

  10. Electron Lens for Beam-Beam Compensation at LHC

    SciTech Connect (OSTI)

    Valishev, A.; Shiltsev, V.; /Fermilab

    2009-05-01

    Head-on beam-beam effect may become a major performance limitation for the LHC in some of the upgrade scenarios. Given the vast experience gained from the operation of Tevatron electron lenses, a similar device provides significant potential for mitigation of beam-beam effects at the LHC. In this report we present the results of simulation studies of beam-beam compensation and analyze potential application of electron lense at LHC and RHIC.

  11. From the Proton Synchroton to the Large Hadron Collider - 50 Years of Nobel Memories in High-Energy Physics

    ScienceCinema (OSTI)

    None

    2011-10-06

    The seminars will be held in the Main Auditorium with transmission to : Council Chamber, IT Auditorium, Prévessin BE Auditorium , Kjell Johnssen Auditorium in Building 30, Room 40-S2-A01, and via webcast. Confirmed Speakers include: Prof. Jack Steinberger, Dr. Guenther Plass, Prof. Emilio Picasso, Dr. Steve Myers, Prof. Carlo Rubbia, Prof. Burton Richter, Dr. Lyndon Evans, Prof. Rolf-Dieter Heuer, Prof. Leon Lederman, Prof. Jim Cronin, Prof. Sheldon Glashow, Prof. Jerome Friedman, Prof. Frank Wilczek, Prof. Martinus Veltman, Prof. Gerardus 't Hooft, Prof. David Gross, Prof. Samuel Ting, Prof. Steven Weinberg (via teleconference) --- Contact: Directorate.Office@cern.ch

  12. From the Proton Synchroton to the Large Hadron Collider - 50 Years of Nobel Memories in High-Energy Physics

    ScienceCinema (OSTI)

    None

    2011-10-06

    The seminars will be held in the Main Auditorium with transmission to : Council Chamber, IT Auditorium, Prvessin BE Auditorium , Kjell Johnssen Auditorium in Building 30, Room 40-S2-A01, and via webcast. Confirmed Speakers include: Prof. Jack Steinberger, Dr. Guenther Plass, Prof. Emilio Picasso, Dr. Steve Myers, Prof. Carlo Rubbia, Prof. Burton Richter, Dr. Lyndon Evans, Prof. Rolf-Dieter Heuer, Prof. Leon Lederman, Prof. Jim Cronin, Prof. Sheldon Glashow, Prof. Jerome Friedman, Prof. Frank Wilczek, Prof. Martinus Veltman, Prof. Gerardus 't Hooft, Prof. David Gross, Prof. Samuel Ting, Prof. Steven Weinberg (via teleconference) --- Contact: Directorate.Office@cern.ch

  13. Physics of Ultra-Peripheral Nuclear Collisions

    SciTech Connect (OSTI)

    Bertulani, Carlos A.; Klein, Spencer R.; Nystrand, Joakim

    2005-02-02

    Moving highly-charged ions carry strong electromagnetic fields which act as a field of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as ultra-peripheral collisions (UPC). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a {gamma}p energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the {rho}{sup 0}, transmutation of lead into bismuth and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of ''new physics''.

  14. Diffraction Dissociation at the LHC; Role of the Background

    SciTech Connect (OSTI)

    Jenkovszky, L. L.; Kuprash, O. E.; Magas, V. K.

    2011-07-15

    We discuss two topical problems of diffraction dissociation at the LHC, namely the role of the background and the elastic contribution.

  15. Summary of the LHC Performance Workshop - Chamonix 2010

    ScienceCinema (OSTI)

    None

    2011-10-06

    Summary of the LHC Performance Workshop, held in Chamonix from 25 - 29 January 2010. Steve Myers Chairman Roger Bailey Deputy Chairman Frank Zimmermann Scientific Secretary

  16. Comparison of LHC and ILC Capabilities for Higgs Boson Coupling

    Office of Scientific and Technical Information (OSTI)

    LHC and ILC Capabilities for Higgs Boson Coupling Measurements Peskin, Michael E.; SLAC 43 PARTICLE ACCELERATORS; ACCURACY; BOSONS; COUPLING CONSTANTS; DECOUPLING; FERMIONS;...

  17. Fast timing detectors for forward protons at the LHC

    SciTech Connect (OSTI)

    Albrow, Michael; /Fermilab

    2011-04-01

    The author discusses the development of high precision timing detectors for high momentum protons at the LHC, and their application in studying exclusive Higgs boson production.

  18. Fermilab Joins in a New Era of LHC Exploration

    SciTech Connect (OSTI)

    Lincoln, Don; Albrow, Mike; Sexton- Kennedy, Elizabeth; Vernieri, Caterina; Das, Souvik

    2015-06-03

    U.S. scientists at Fermilab celebrate the official start of LHC Run II and discuss what they hope to find at a higher energy and increased intensity.

  19. EIS-0138-S: Superconducting Super Collider, Supplemental, Waxahatchie, Texas

    Broader source: Energy.gov [DOE]

    The U.S. Department of Energy developed this supplementary statement to analyze the environmental impacts of design modifications to the Superconducting Super Collider that were made following the publication of the Record of Decision that selected Ellis County, Texas, as the location of the laboratory facility. This statement supplements DOE/EIS-0138, Superconducting Super Collider.

  20. Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

    ScienceCinema (OSTI)

    None

    2011-10-06

    Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D; efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

  1. The Brief Life of a Hadron: QCD unquenched

    SciTech Connect (OSTI)

    Pennington, Michael R.

    2015-03-01

    Once upon a time, the picture of hadrons was of mesons made of a quark and an antiquark, and baryons of three quarks. Though hadrons heavier than the ground states inevitably decay by the strong interaction, the successes of the quark model might suggest their decays are a mere perturbation. However, Eef van Beveren, whose career we celebrate here, recognised that decays are an integral part of the life of a hadron. The channels into which they decay are often essential to their very existence. These hold the secrets of strong coupling QCD and teach us the way quarks really build hadrons.

  2. Hadron Spectroscopy from QCD Robert Edwards Jefferson Lab

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

    * Can we predict hadron properties from first principles? ... arxiv:1212.0830 ORNL resources More complicated example: ... 1 st order coupled PDE's * Large, sparse, matrix solve per ...

  3. The pMSSM10 after LHC run 1

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

    de Vries, K. J.; Bagnaschi, E. A.; Buchmueller, O.; Cavanaugh, R.; Citron, M.; De Roeck, A.; Dolan, M. J.; Ellis, J. R.; Flächer, H.; Heinemeyer, S.; et al

    2015-09-01

    We present a frequentist analysis of the parameter space of the pMSSM10, in which the following ten soft SUSY-breaking parameters are specified independently at the mean scalar top mass scale MSUSY ≡ √mmore » $$\\tilde{t}$$1m$$\\tilde{t}$$2 : the gaugino masses M1,2,3 , the first-and second-generation squark masses m$$\\tilde{q}$$1 = m$$\\tilde{q}$$2 , the third-generation squark mass m$$\\tilde{q}$$3, a common slepton mass m$$\\tilde{ℓ}$$ and a common trilinear mixing parameter A , as well as the Higgs mixing parameter μ , the pseudoscalar Higgs mass MA and tanβ , the ratio of the two Higgs vacuum expectation values. We use the MultiNest sampling algorithm with ∼ 1.2 ×109 points to sample the pMSSM10 parameter space. A dedicated study shows that the sensitivities to strongly interacting sparticle masses of ATLAS and CMS searches for jets, leptons + E-slashT signals depend only weakly on many of the other pMSSM10 parameters. With the aid of the Atom and Scorpion codes, we also implement the LHC searches for electroweakly interacting sparticles and light stops, so as to confront the pMSSM10 parameter space with all relevant SUSY searches. In addition, our analysis includes Higgs mass and rate measurements using the HiggsSignals code, SUSY Higgs exclusion bounds, the measurements of BR(Bs→μ+μ-) by LHCb and CMS, other B -physics observables, electroweak precision observables, the cold dark matter density and the XENON100 and LUX searches for spin-independent dark matter scattering, assuming that the cold dark matter is mainly provided by the lightest neutralino χ-tilde10 . We show that the pMSSM10 is able to provide a supersymmetric interpretation of (g-2)μ , unlike the CMSSM, NUHM1 and NUHM2. As a result, we find (omitting Higgs rates) that the minimum χ2=20.5 with 18 degrees of freedom (d.o.f.) in the pMSSM10, corresponding to a χ2 probability of 30.8 %, to be compared with χ2/d.o.f.=32.8/24(31.1/23)(30.3/22) in the CMSSM (NUHM1) (NUHM2). We display the one-dimensional likelihood functions for sparticle masses, and we show that they may be significantly lighter in the pMSSM10 than in the other models, e.g., the gluino may be as light as ∼ 1250 GeV at the 68 % CL, and squarks, stops, electroweak gauginos and sleptons may be much lighter than in the CMSSM, NUHM1 and NUHM2. We discuss the discovery potential of future LHC runs, e+e- colliders and direct detection experiments.« less

  4. The pMSSM10 after LHC run 1

    SciTech Connect (OSTI)

    de Vries, K. J.; Bagnaschi, E. A.; Buchmueller, O.; Cavanaugh, R.; Citron, M.; De Roeck, A.; Dolan, M. J.; Ellis, J. R.; Flächer, H.; Heinemeyer, S.; Isidori, G.; Malik, S.; Marrouche, J.; Santos, D. Martínez; Olive, K. A.; Sakurai, K.; Weiglein, G.

    2015-09-01

    We present a frequentist analysis of the parameter space of the pMSSM10, in which the following ten soft SUSY-breaking parameters are specified independently at the mean scalar top mass scale MSUSY ≡ $\\sqrt{m$\\tilde{t}$1m$\\tilde{t}$2}$ : the gaugino masses M1,2,3 , the first-and second-generation squark masses m$\\tilde{q}$1 = m$\\tilde{q}$2 , the third-generation squark mass m$\\tilde{q}$3, a common slepton mass m$\\tilde{ℓ}$ and a common trilinear mixing parameter A , as well as the Higgs mixing parameter μ , the pseudoscalar Higgs mass MA and tanβ , the ratio of the two Higgs vacuum expectation values. We use the MultiNest sampling algorithm with ∼ 1.2 ×109 points to sample the pMSSM10 parameter space. A dedicated study shows that the sensitivities to strongly interacting sparticle masses of ATLAS and CMS searches for jets, leptons + E-slashT signals depend only weakly on many of the other pMSSM10 parameters. With the aid of the Atom and Scorpion codes, we also implement the LHC searches for electroweakly interacting sparticles and light stops, so as to confront the pMSSM10 parameter space with all relevant SUSY searches. In addition, our analysis includes Higgs mass and rate measurements using the HiggsSignals code, SUSY Higgs exclusion bounds, the measurements of BR(Bs→μ+μ-) by LHCb and CMS, other B -physics observables, electroweak precision observables, the cold dark matter density and the XENON100 and LUX searches for spin-independent dark matter scattering, assuming that the cold dark matter is mainly provided by the lightest neutralino χ-tilde10 . We show that the pMSSM10 is able to provide a supersymmetric interpretation of (g-2)μ , unlike the CMSSM, NUHM1 and NUHM2. As a result, we find (omitting Higgs rates) that the minimum χ2=20.5 with 18 degrees of freedom (d.o.f.) in the pMSSM10, corresponding to a χ2 probability of 30.8 %, to be compared with χ2/d.o.f.=32.8/24(31.1/23)(30.3/22) in the CMSSM (NUHM1) (NUHM2). We display the one-dimensional likelihood functions for sparticle masses, and we show that they may be significantly lighter in the pMSSM10 than in the other models, e.g., the gluino may be as light as ∼ 1250 GeV at the 68 % CL, and squarks, stops, electroweak gauginos and sleptons may be much lighter than in the CMSSM, NUHM1 and NUHM2. We discuss the discovery potential of future LHC runs, e+e- colliders and direct detection experiments.

  5. SiD Linear Collider Detector R&D, DOE Final Report

    SciTech Connect (OSTI)

    Brau, James E.; Demarteau, Marcel

    2015-05-15

    The Department of Energy’s Office of High Energy Physics supported the SiD university detector R&D projects in FY10, FY11, and FY12 with no-cost extensions through February, 2015. The R&D projects were designed to advance the SiD capabilities to address the fundamental questions of particle physics at the International Linear Collider (ILC): • What is the mechanism responsible for electroweak symmetry breaking and the generation of mass? • How do the forces unify? • Does the structure of space-time at small distances show evidence for extra dimensions? • What are the connections between the fundamental particles and forces and cosmology? Silicon detectors are used extensively in SiD and are well-matched to the challenges presented by ILC physics and the ILC machine environment. They are fast, robust against machine-induced background, and capable of very fine segmentation. SiD is based on silicon tracking and silicon-tungsten sampling calorimetry, complemented by powerful pixel vertex detection, and outer hadronic calorimetry and muon detection. Radiation hard forward detectors which can be read out pulse by pulse are required. Advanced calorimetry based on a particle flow algorithm (PFA) provides excellent jet energy resolution. The 5 Tesla solenoid is outside the calorimeter to improve energy resolution. PFA calorimetry requires fine granularity for both electromagnetic and hadronic calorimeters, leading naturally to finely segmented silicon-tungsten electromagnetic calorimetry. Since silicon-tungsten calorimetry is expensive, the detector architecture is compact. Precise tracking is achieved with the large magnetic field and high precision silicon microstrips. An ancillary benefit of the large magnetic field is better control of the e⁺e⁻ pair backgrounds, permitting a smaller radius beampipe and improved impact parameter resolution. Finally, SiD is designed with a cost constraint in mind. Significant advances and new capabilities have been made and are described in this report.

  6. Constraining the viscous freeze-out distribution function with data obtained at the BNL Relativistic Heavy Ion Collider (RHIC)

    SciTech Connect (OSTI)

    Luzum, Matthew; Ollitrault, Jean-Yves

    2010-07-15

    We investigate the form of the viscous correction to the equilibrium distribution function in the context of a Cooper-Frye freeze-out prescription for viscous hydrodynamic simulations of relativistic heavy ion collisions. The standard quadratic ansatz used by all groups for the case of shear viscosity is found to be disfavored by experimental data for v{sub 4}/(v{sub 2}){sup 2} at the Relativistic Heavy Ion Collider and is unlikely to be correct for the hadron resonance gas present at freeze-out. Instead, data for v{sub 2}(p{sub t}) along with v{sub 4}/(v{sub 2}){sup 2} favor a momentum dependence between linear and quadratic.

  7. Supersymmetric Dark Matter after LHC Run 1

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

    Bagnaschi, E. A.; Buchmueller, O.; Cavanaugh, R.; Citron, M.; De Roeck, A.; Dolan, M. J.; Ellis, J. R.; Flacher, H.; Heinemeyer, S.; Isidori, G.; et al

    2015-10-23

    Different mechanisms operate in various regions of the MSSM parameter space to bring the relic density of the lightest neutralino, χ~01, assumed here to be the lightest SUSY particle (LSP) and thus the dark matter (DM) particle, into the range allowed by astrophysics and cosmology. These mechanisms include coannihilation with some nearly degenerate next-to-lightest supersymmetric particle such as the lighter stau τ~1, stop t~1 or chargino χ~±1, resonant annihilation via direct-channel heavy Higgs bosons H / A, the light Higgs boson h or the Z boson, and enhanced annihilation via a larger Higgsino component of the LSP in the focus-pointmore » region. These mechanisms typically select lower-dimensional subspaces in MSSM scenarios such as the CMSSM, NUHM1, NUHM2, and pMSSM10. We analyze how future LHC and direct DM searches can complement each other in the exploration of the different DM mechanisms within these scenarios. We find that the τ~1 coannihilation regions of the CMSSM, NUHM1, NUHM2 can largely be explored at the LHC via searches for /ET events and long-lived charged particles, whereas theirH / A funnel, focus-point and χ~±1 coannihilation regions can largely be explored by the LZ and Darwin DM direct detection experiments. Furthermore, we find that the dominant DM mechanism in our pMSSM10 analysis is χ~±1 coannihilation: parts of its parameter space can be explored by the LHC, and a larger portion by future direct DM searches.« less

  8. Supersymmetric Dark Matter after LHC Run 1

    SciTech Connect (OSTI)

    Bagnaschi, E. A.; Buchmueller, O.; Cavanaugh, R.; Citron, M.; De Roeck, A.; Dolan, M. J.; Ellis, J. R.; Flacher, H.; Heinemeyer, S.; Isidori, G.; Malik, S.; Santos, D. Martinez; Olive, K. A.; Sakurai, K.; de Vries, K. J.; Weiglein, G.

    2015-10-23

    Different mechanisms operate in various regions of the MSSM parameter space to bring the relic density of the lightest neutralino, ?~01, assumed here to be the lightest SUSY particle (LSP) and thus the dark matter (DM) particle, into the range allowed by astrophysics and cosmology. These mechanisms include coannihilation with some nearly degenerate next-to-lightest supersymmetric particle such as the lighter stau ?~1, stop t~1 or chargino ?~1, resonant annihilation via direct-channel heavy Higgs bosons H / A, the light Higgs boson h or the Z boson, and enhanced annihilation via a larger Higgsino component of the LSP in the focus-point region. These mechanisms typically select lower-dimensional subspaces in MSSM scenarios such as the CMSSM, NUHM1, NUHM2, and pMSSM10. We analyze how future LHC and direct DM searches can complement each other in the exploration of the different DM mechanisms within these scenarios. We find that the ?~1 coannihilation regions of the CMSSM, NUHM1, NUHM2 can largely be explored at the LHC via searches for /ET events and long-lived charged particles, whereas theirH / A funnel, focus-point and ?~1 coannihilation regions can largely be explored by the LZ and Darwin DM direct detection experiments. Furthermore, we find that the dominant DM mechanism in our pMSSM10 analysis is ?~1 coannihilation: parts of its parameter space can be explored by the LHC, and a larger portion by future direct DM searches.

  9. The operation of the LHC accelerator complex (1/2)

    ScienceCinema (OSTI)

    None

    2011-10-06

    These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages. o Lecture 1: Wednesday April 7, 10-11am o Lecture 2: Friday April 9, 10-11am The lectures will be webcast, recorded and archived. Coffee will be served before the lectures, starting at 9:45

  10. The operation of the LHC accelerator complex (2/2)

    ScienceCinema (OSTI)

    None

    2011-10-06

    These lectures will give an overview of what happens when the LHC is in running mode. They are aimed at students working on the LHC experiments, but all those who are curious about what happens behind the scenes of the LHC are welcomed. You will learn all you always wanted to know about the LHC, and never had the courage to ask! The only pre-requisite is a basic, college-level, knowledge of EM and of the principles that allow to steer charged beams. Topics covered will include, among others: - the description of the injector chain, from the generation of the protons, to the delivery of bunches to the LHC. - the discussion of the steps required to accelerate the beams in the LHC, to bring them into collision, and to control the luminosity at the interaction points. - the description of the monitoring tools available to the LHC operators, and an explanation of the various plots and panels that can be found on the LHC web pages. o Lecture 1: Wednesday April 7, 10-11am o Lecture 2: Friday April 9, 10-11am The lectures will be webcast, recorded and archived. Coffee will be served before the lectures, starting at 9:45

  11. W/Z + jets production at the tevatron {bar p}p collider (Conference...

    Office of Scientific and Technical Information (OSTI)

    Conference: WZ + jets production at the tevatron bar pp collider Citation Details In-Document Search Title: WZ + jets production at the tevatron bar pp collider You are...

  12. Exotic Leptons. Higgs, Flavor and Collider Phenomenology

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

    Altmannshofer, Wolfgang; Bauer, Martin; Carena, Marcela

    2014-01-15

    We study extensions of the standard model by one generation of vector-like leptons with non-standard hypercharges, which allow for a sizable modification of the h → γγ decay rate for new lepton masses in the 300 GeV-1 TeV range. We also analyze vacuum stability implications for different hypercharges. Effects in h → Zγ are typically much smaller than in h → γγ, but distinct among the considered hypercharge assignments. Non-standard hypercharges constrain or entirely forbid possible mixing operators with standard model leptons. As a consequence, the leading contributions to the experimentally strongly constrained electric dipole moments of standard model fermionsmore » are only generated at the two loop level by the new CP violating sources of the considered setups. Furthermore, we derive the bounds from dipole moments, electro-weak precision observables and lepton flavor violating processes, and discuss their implications. Finally, we examine the production and decay channels of the vector-like leptons at the LHC, and find that signatures with multiple light leptons or taus are already probing interesting regions of parameter space.« less

  13. Future directions in particle and nuclear physics at multi-GeV hadron beam facilities

    SciTech Connect (OSTI)

    Geesaman, D.F. [Argonne National Lab., IL (United States)] [ed.

    1993-11-01

    This report contains papers on the following topics in particle and nuclear physics: hadron dynamics; lepton physics; spin physics; hadron and nuclear spectroscopy; hadronic weak interactions; and Eta physics. These papers have been indexed separately elsewhere.

  14. Governance of the International Linear Collider Project

    SciTech Connect (OSTI)

    Foster, B.; Barish, B.; Delahaye, J.P.; Dosselli, U.; Elsen, E.; Harrison, M.; Mnich, J.; Paterson, J.M.; Richard, F.; Stapnes, S.; Suzuki, A.; Wormser, G.; Yamada, S.; /KEK, Tsukuba

    2012-05-31

    Governance models for the International Linear Collider Project are examined in the light of experience from similar international projects around the world. Recommendations for one path which could be followed to realize the ILC successfully are outlined. The International Linear Collider (ILC) is a unique endeavour in particle physics; fully international from the outset, it has no 'host laboratory' to provide infrastructure and support. The realization of this project therefore presents unique challenges, in scientific, technical and political arenas. This document outlines the main questions that need to be answered if the ILC is to become a reality. It describes the methodology used to harness the wisdom displayed and lessons learned from current and previous large international projects. From this basis, it suggests both general principles and outlines a specific model to realize the ILC. It recognizes that there is no unique model for such a laboratory and that there are often several solutions to a particular problem. Nevertheless it proposes concrete solutions that the authors believe are currently the best choices in order to stimulate discussion and catalyze proposals as to how to bring the ILC project to fruition. The ILC Laboratory would be set up by international treaty and be governed by a strong Council to whom a Director General and an associated Directorate would report. Council would empower the Director General to give strong management to the project. It would take its decisions in a timely manner, giving appropriate weight to the financial contributions of the member states. The ILC Laboratory would be set up for a fixed term, capable of extension by agreement of all the partners. The construction of the machine would be based on a Work Breakdown Structure and value engineering and would have a common cash fund sufficiently large to allow the management flexibility to optimize the project's construction. Appropriate contingency, clearly apportioned at both a national and global level, is essential if the project is to be realised. Finally, models for running costs and decommissioning at the conclusion of the ILC project are proposed. This document represents an interim report of the bodies and individuals studying these questions inside the structure set up and supervised by the International Committee for Future Accelerators (ICFA). It represents a request for comment to the international community in all relevant disciplines, scientific, technical and most importantly, political. Many areas require further study and some, in particular the site selection process, have not yet progressed sufficiently to be addressed in detail in this document. Discussion raised by this document will be vital in framing the final proposals due to be published in 2012 in the Technical Design Report being prepared by the Global Design Effort of the ILC.

  15. Summary of the working group 4: Hadron spectroscopy

    SciTech Connect (OSTI)

    Crowe, K.M.

    1991-03-01

    This report is a summary of the working group 4 on hadron spectroscopy. The topics covered are: physics motivation; design of spectrometer; status of some existing hadron spectrometers; improvements to LASS; and arguments for/against a LASS-like design.

  16. Hadron physics at the new CW electron accelerators

    SciTech Connect (OSTI)

    Burkert, V.D.

    1990-01-01

    Major trends of the physics program related to the study of hadron structure and hadron spectroscopy at the new high current, high duty cycle electron machines are discussed. It is concluded that planned experiments at these machines may have important impact on our understanding of the strong interaction by studying the internal structure and spectroscopy of the nucleon and lower mass hyperon states.

  17. Using analytic continuation for the hadronic vacuum polarization computation

    SciTech Connect (OSTI)

    Feng, Xu; Hashimoto, Shoji; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner Dru B

    2014-11-01

    We present two examples of applications of the analytic continuation method for computing the hadronic vacuum polarization function in space- and time-like momentum regions. These examples are the Adler function and the leading order hadronic contribution to the muon anomalous magnetic moment. We comment on the feasibility of the analytic continuation method and provide an outlook for possible further applications.

  18. Beamstrahlung spectra in next generation linear colliders. Revision

    SciTech Connect (OSTI)

    Barklow, T.; Chen, P.; Kozanecki, W.

    1992-04-01

    For the next generation of linear colliders, the energy loss due to beamstrahlung during the collision of the e{sup +}e{sup {minus}} beams is expected to substantially influence the effective center-of-mass energy distribution of the colliding particles. In this paper, we first derive analytical formulae for the electron and photon energy spectra under multiple beamstrahlung processes, and for the e{sup +}e{sup {minus}} and {gamma}{gamma} differential luminosities. We then apply our formulation to various classes of 500 GeV e{sup +}e{sup {minus}} linear collider designs currently under study.

  19. Top Quark Anomalous Couplings at the International Linear Collider (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Quark Anomalous Couplings at the International Linear Collider Citation Details In-Document Search Title: Top Quark Anomalous Couplings at the International Linear Collider We present a study of the experimental determination of the forward-backward asymmetry in the process e{sup +}e{sup -} {yields} t{bar t} and in the subsequent t {yields} Wb decay, studied in the context of the International Linear Collider. This process probes the elementary couplings of the top

  20. Exotic/charmonium Hadron Spectroscopy at Belle and BaBar (Conference...

    Office of Scientific and Technical Information (OSTI)

    Conference: Exoticcharmonium Hadron Spectroscopy at Belle and BaBar Citation Details In-Document Search Title: Exoticcharmonium Hadron Spectroscopy at Belle and BaBar You are...

  1. Exclusive processes and the fundamental structure of hadrons

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

    Brodsky, Stanley J.

    2015-01-20

    I review the historical development of QCD predictions for exclusive hadronic processes, beginning with constituent counting rules and the quark interchange mechanism, phenomena which gave early validation for the quark structure of hadrons. The subsequent development of pQCD factorization theorems for hard exclusive amplitudes and the development of evolution equations for the hadron distribution amplitudes provided a rigorous framework for calculating hadronic form factors and hard scattering exclusive scattering processes at high momentum transfer. I also give a brief introduction to the field of "light-front holography" and the insights it brings to quark confinement, the behavior of the QCD couplingmore » in the nonperturbative domain, as well as hadron spectroscopy and the dynamics of exclusive processes.« less

  2. Fragmentation and Hadronization in e+e- Collisions

    SciTech Connect (OSTI)

    Muller, David

    2001-11-15

    We present a number of jet fragmentation and hadronization measurements in e{sup +}e{sup -} {yields} Z{sup 0} {yields} hadrons. The L3 collaboration has searched for pointlike color singlet radiation in multi-jet events, limiting any such contribution to rapidity gap events at the few percent level. ALEPH and SLD have measured production rates of a number of identified hadrons, including precise, full-coverage spectra of B hadrons. L3 and SLD have studied charged track and identified hadron production in heavy- and light-flavor events. OPAL has made a pioneering comparison of charged multiplicities between events of the three light flavors, u{bar u}, d{bar d} and s{bar s}.

  3. Exclusive processes and the fundamental structure of hadrons

    SciTech Connect (OSTI)

    Brodsky, Stanley J.

    2015-01-20

    I review the historical development of QCD predictions for exclusive hadronic processes, beginning with constituent counting rules and the quark interchange mechanism, phenomena which gave early validation for the quark structure of hadrons. The subsequent development of pQCD factorization theorems for hard exclusive amplitudes and the development of evolution equations for the hadron distribution amplitudes provided a rigorous framework for calculating hadronic form factors and hard scattering exclusive scattering processes at high momentum transfer. I also give a brief introduction to the field of "light-front holography" and the insights it brings to quark confinement, the behavior of the QCD coupling in the nonperturbative domain, as well as hadron spectroscopy and the dynamics of exclusive processes.

  4. New Methods of Particle Collimation in Colliders

    SciTech Connect (OSTI)

    Stancari, Giulio; /Fermilab

    2011-10-01

    The collimation system is an essential part of the design of any high-power accelerator. Its functions include protection of components from accidental and intentional energy deposition, reduction of backgrounds, and beam diagnostics. Conventional multi-stage systems based on scatterers and absorbers offer robust shielding and efficient collection of losses. Two complementary concepts have been proposed to address some of the limitations of conventional systems: channeling and volume reflection in bent crystals and collimation with hollow electron beams. The main focus of this paper is the hollow electron beam collimator, a novel concept based on the interaction of the circulating beam with a 5-keV, magnetically confined, pulsed hollow electron beam in a 2-m-long section of the ring. The electrons enclose the circulating beam, kicking halo particles transversely and leaving the beam core unperturbed. By acting as a tunable diffusion enhancer and not as a hard aperture limitation, the hollow electron beam collimator extends conventional collimation systems beyond the intensity limits imposed by tolerable losses. The concept was tested experimentally at the Fermilab Tevatron proton-antiproton collider. Results on the collimation of 980-GeV antiprotons are presented, together with prospects for the future.

  5. SSC 50 mm collider dipole cryostat design

    SciTech Connect (OSTI)

    Nicol, T.H.

    1992-04-01

    The cryostat of a Superconducting Super Collider (SSC) dipole magnet consists of all magnet components except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course of their expected operating life. This paper describes the design of the current SSC dipole magnet cryostat and includes discussions on the structural and thermal considerations involved in the development of each of the major systems.

  6. Cryostat design for the Superconducting Super Collider

    SciTech Connect (OSTI)

    Nicol, T.H.

    1990-09-01

    The cryostat of an SSC dipole magnet consists of all magnet components except the cold mass assembly. It serves to support the cold mass accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation (MLI) system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course their 25 year expected life. This paper describes the design of the current SSC collider dipole magnet cryostat and includes discussions on the thermal, structural, and dynamic considerations involved in the development of each of the major systems. 7 refs., 4 figs.

  7. Searches for supersymmetry using the MT2 variable in hadronic events produced in pp collisions at 8 TeV

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

    Khachatryan, V.

    2015-05-15

    Searches for supersymmetry (SUSY) are performed using a sample of hadronic events produced in 8 TeV pp collisions at the CERN LHC. The searches are based on the MT2 variable, which is a measure of the transverse momentum imbalance in an event. The data were collected with the CMS detector and correspond to an integrated luminosity of 19.5 fb?. Two related searches are performed. The first is an inclusive search based on signal regions defined by the value of the MT2 variable, the hadronic energy in the event, the jet multiplicity, and the number of jets identified as originating frommorebottom quarks. The second is a search for a mass peak corresponding to a Higgs boson decaying to a bottom quark-antiquark pair, where the Higgs boson is produced as a decay product of a SUSY particle. For both searches, the principal backgrounds are evaluated with data control samples. No significant excess over the expected number of background events is observed, and exclusion limits on various SUSY models are derived.less

  8. Possible Implication of a Single Nonextensive p_T Distribution for Hadron Production in High-Energy pp Collisions

    SciTech Connect (OSTI)

    Wong, Cheuk-Yin; Wilk, Grzegorz; Cirto, Leonardo J. L.; Tsallis, Constantino

    2015-01-01

    Multiparticle production processes in $pp$ collisions at the central rapidity region are usually considered to be divided into independent "soft" and "hard" components. The first is described by exponential (thermal-like) transverse momentum spectra in the low-$p_T$ region with a scale parameter $T$ associated with the temperature of the hadronizing system. The second is governed by a power-like distributions of transverse momenta with power index $n$ at high-$p_T$ associated with the hard scattering between partons. We show that the hard-scattering integral can be approximated as a nonextensive distribution of a quasi-power-law containing a scale parameter $T$ and a power index $n=1/(q -1)$, where $q$ is the nonextensivity parameter. We demonstrate that the whole region of transverse momenta presently measurable at LHC experiments at central rapidity (in which the observed cross sections varies by $14$ orders of magnitude down to the low $p_T$ region) can be adequately described by a single nonextensive distribution. These results suggest the dominance of the hard-scattering hadron-production process and the approximate validity of a ``no-hair" statistical-mechanical description of the $p_T$ spectra for the whole $p_T$ region at central rapidity for $pp$ collisions at high-energies.

  9. Rf System Requirements for JLabs MEIC Collider Ring

    SciTech Connect (OSTI)

    Wang, Shaoheng; Li, Rui; Rimmer, Robert A.; Wang, Haipeng; Zhang, Yuhong

    2013-06-01

    The Medium-energy Electron Ion Collider (MEIC), proposed by Jefferson Lab, consists of a series of accelerators. At the top energy are the electron and ion collider rings. For the ion ring, it accelerates five long ion bunches to colliding energy and rebunches ions into a train of very short bunches before colliding. A set of low frequency RF system is needed for the long ion bunch energy ramping. Another set of high frequency RF cavities is needed to rebunch ions. For the electron ring, superconducting RF (SRF) cavities are needed to compensate the synchrotron radiation energy loss. The impedance of the SRF cavities must be low enough to keep the high current electron beam stable. The preliminary design requirements of these RF cavities are presented.

  10. Heavy-flavour and quarkonium production in the LHC era: from proton-proton to heavy-ion collisions

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

    Andronic, A.; Arleo, F.; Arnaldi, R.; Beraudo, A.; Bruna, E.; Caffarri, D.; del Valle, Z. C.; Contreras, J. G.; Dahms, T.; Dainese, A.; et al

    2016-02-29

    This report reviews the study of open heavy-flavour and quarkonium production in high-energy hadronic collisions, as tools to investigate fundamental aspects of Quantum Chromodynamics, from the proton and nucleus structure at high energy to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is given to the lessons learnt from LHC Run 1 results, which are reviewed in a global picture with the results from SPS and RHIC at lower energies, as well as to the questions to be addressed in the future. The report covers heavy flavour and quarkonium production in proton-proton, proton-nucleus and nucleus-nucleus collisions. This includes discussionmore » of the effects of hot and cold strongly interacting matter, quarkonium photo-production in nucleus-nucleus collisions and perspectives on the study of heavy flavour and quarkonium with upgrades of existing experiments and new experiments. The report results from the activity of the SaporeGravis network of the I3 Hadron Physics programme of the European Union 7th Framework Programme.« less

  11. Ion polarization in the MEIC figure-8 ion collider ring

    SciTech Connect (OSTI)

    V.S. Morozov, Ya.S. Derbenev, Y. Zhang, P. Chevtsov, A.M. Kondratenko, M.A. Kondratenko, Yu.N. Filatov

    2012-07-01

    The nuclear physics program envisaged at the Medium-energy Electron-Ion Collider (MEIC) currently being developed at the Jefferson Lab calls for collisions of 3-11 GeV/c longitudinally polarized electrons and 20-100 GeV/c, in equivalent proton momentum, longitudinally/ transversely polarized protons/ deuterons/ light ions. We present a scheme that provides the required ion polarization arrangement in the MEIC's ion collider ring.

  12. International Linear Collider Technical Design Report - Volume 2: Physics

    Office of Scientific and Technical Information (OSTI)

    (Technical Report) | SciTech Connect International Linear Collider Technical Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical Design Report - Volume 2: Physics Authors: Baer, Howard ; Barklow, Tim ; Fujii, Keisuke ; Gao, Yuanning ; Hoang, Andre ; Kanemura, Shinya ; List, Jenny ; Logan, Heather E. ; Nomerotski, Andrei ; Perelstein, Maxim ; Peskin, Michael E. ; Poschl, Roman ; Reuter, Jurgen ; Riemann, Sabine ; Savoy-Navarro,

  13. Discrimination of new physics models with the International Linear Collider

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Discrimination of new physics models with the International Linear Collider Citation Details In-Document Search Title: Discrimination of new physics models with the International Linear Collider Authors: Asano, Masaki ; Saito, Tomoyuki ; Suehara, Taikan ; Fujii, Keisuke ; Hundi, R. S. ; Itoh, Hideo ; Matsumoto, Shigeki ; Okada, Nobuchika ; Takubo, Yosuke ; Yamamoto, Hitoshi Publication Date: 2011-12-02 OSTI Identifier: 1098342 Type: Publisher's Accepted

  14. International Linear Collider Technical Design Report - Volume 2: Physics

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

    (Technical Report) | SciTech Connect International Linear Collider Technical Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical Design Report - Volume 2: Physics Authors: Baer, Howard ; Barklow, Tim ; Fujii, Keisuke ; Gao, Yuanning ; Hoang, Andre ; Kanemura, Shinya ; List, Jenny ; Logan, Heather E. ; Nomerotski, Andrei ; Perelstein, Maxim ; Peskin, Michael E. ; Poschl, Roman ; Reuter, Jurgen ; Riemann, Sabine ; Savoy-Navarro,

  15. JLab Supports International Linear Collider Cavity Development Work |

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

    Jefferson Lab Supports International Linear Collider Cavity Development Work NEWPORT NEWS, Va. Feb. 12, 2008 - It's not often that major-league baseball and nuclear physics get to share the limelight, but that's what's happening at the Department of Energy's Jefferson Lab. The baseball connection involves a nine-cell niobium cavity developed by KEK accelerator scientists in Japan as one of several designs being tested for development for the proposed International Linear Collider. JLab is

  16. Top Quark Anomalous Couplings at the International Linear Collider (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Top Quark Anomalous Couplings at the International Linear Collider Citation Details In-Document Search Title: Top Quark Anomalous Couplings at the International Linear Collider × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and

  17. Top quark anomalous couplings at the International Linear Collider (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Top quark anomalous couplings at the International Linear Collider Citation Details In-Document Search Title: Top quark anomalous couplings at the International Linear Collider Authors: Devetak, Erik ; Nomerotski, Andrei ; Peskin, Michael Publication Date: 2011-08-17 OSTI Identifier: 1100572 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal Volume: 84; Journal Issue: 3; Journal ID: ISSN 1550-7998

  18. Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

    SciTech Connect (OSTI)

    ATLAS Collaboration,

    2013-10-01

    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H???, H?ZZ{sup ?}?4? and H?WW{sup ?}?????. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of {radical s}=7 TeV and {radical s}=8 TeV, corresponding to an integrated luminosity of about 25 fb{sup ?1}. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson.

  19. Development of the conventional facilities of the Superconducting Super Collider. Revision 1

    SciTech Connect (OSTI)

    Toohig, T.E.

    1994-02-01

    This report discusses an overview of the construction of facilities at the Superconducting Super Collider.

  20. The NUHM2 after LHC Run 1

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

    Buchmueller, O.; Cavanaugh, R.; Citron, M.; De Roeck, A.; Dolan, M. J.; Ellis, J. R.; Flächer, H.; Heinemeyer, S.; Malik, S.; Marrouche, J.; et al

    2014-12-17

    We make a frequentist analysis of the parameter space of the NUHM2, in which the soft supersymmetry (SUSY)-breaking contributions to the masses of the two Higgs multiplets, m2Hu,d, vary independently from the universal soft SUSY-breaking contributions m20 to the masses of squarks and sleptons. Our analysis uses the MultiNest sampling algorithm with over 4 × 10⁸ points to sample the NUHM2 parameter space. It includes the ATLAS and CMS Higgs mass measurements as well as the ATLAS search for supersymmetric jets + /ET signals using the full LHC Run 1 data, the measurements of BR(Bs→μ⁺μ⁻) by LHCb and CMS togethermore » with other B-physics observables, electroweak precision observables and the XENON100 and LUX searches for spin-independent dark-matter scattering. We find that the preferred regions of the NUHM2 parameter space have negative SUSY-breaking scalar masses squared at the GUT scale for squarks and sleptons, m20 < 0, as well as m2Hu < m2Hd < 0. The tension present in the CMSSM and NUHM1 between the supersymmetric interpretation of (g – 2)μ and the absence to date of SUSY at the LHC is not significantly alleviated in the NUHM2. We find that the minimum χ2 = 32.5 with 21 degrees of freedom (dof) in the NUHM2, to be compared with χ2/dof = 35.0/23 in the CMSSM, and χ2/dof = 32.7/22 in the NUHM1. We find that the one-dimensional likelihood functions for sparticle masses and other observables are similar to those found previously in the CMSSM and NUHM1.« less

  1. Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies

    SciTech Connect (OSTI)

    Konar, Partha; Kong, Kyoungchul; Matchev, Konstantin T.; Park, Myeonghun; /Florida U.

    2012-04-03

    We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M{sub T2} variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint M{sub T2(max)} of the M{sub T2} distribution now gives the mass {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}) of the parent particles as a function of two input children masses {tilde M}{sub c}{sup (a)} and {tilde M}{sub c}{sup (b)}. We propose two methods for an independent determination of the individual children masses M{sub c}{sup (a)} and M{sub c}{sup (b)}. First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}, P{sub UTM}) is independent of P{sub UTM} at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.

  2. Computing the hadronic vacuum polarization function by analytic continuation

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

    Feng, Xu; Hashimoto, Shoji; Hotzel, Grit; Jansen, Karl; Petschlies, Marcus; Renner, Dru B.

    2013-08-29

    We propose a method to compute the hadronic vacuum polarization function on the lattice at continuous values of photon momenta bridging between the spacelike and timelike regions. We provide two independent demonstrations to show that this method leads to the desired hadronic vacuum polarization function in Minkowski spacetime. We present with the example of the leading-order QCD correction to the muon anomalous magnetic moment that this approach can provide a valuable alternative method for calculations of physical quantities where the hadronic vacuum polarization function enters.

  3. First Results of the CMS Experiment at the LHC (Conference) ...

    Office of Scientific and Technical Information (OSTI)

    Technical Information Service, Springfield, VA at www.ntis.gov. The 2010 proton-proton run of LHC has been very successful delivering an integrated luminosity in excess of 45...

  4. New Detector Technologies for the LHC Experiments: Prospects...

    Office of Scientific and Technical Information (OSTI)

    We review the prospects, strategies and technologies for the High Luminosity (HL-LHC) upgrades of the ATLAS and CMS detectors, in the light of a very successful two year-long first ...

  5. Systematics of quarkonium production at the LHC and double parton

    Office of Scientific and Technical Information (OSTI)

    fragmentation (Journal Article) | SciTech Connect Systematics of quarkonium production at the LHC and double parton fragmentation Citation Details In-Document Search Title: Systematics of quarkonium production at the LHC and double parton fragmentation Authors: Fleming, Sean ; Leibovich, Adam K. ; Mehen, Thomas ; Rothstein, Ira Z. Publication Date: 2012-11-06 OSTI Identifier: 1101291 Type: Publisher's Accepted Manuscript Journal Name: Physical Review D Additional Journal Information: Journal

  6. SUSY searches at the LHC with the ATLAS experiment

    ScienceCinema (OSTI)

    None

    2011-04-25

    First ATLAS searches for signals of Supersymmetry in proton-proton collisions at the LHC are presented. These searches are performed in various channels containing different lepton and jet multiplicities in the final states; the full data sample recorded in the 2010 LHC run, corresponding to an integrated luminosity of 35 pb-1, has been analysed. Limits on squarks and gluins are the most stringent to date.

  7. First-Principles Computation of Hadronic Contributions to the Muon

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

    Anomalous Magnetic Moment | Argonne National Laboratory First-Principles Computation of Hadronic Contributions to the Muon Anomalous Magnetic Moment March 16, 2016 11:00AM to 12:00PM Presenter Christoph Lehner, Brookhaven National Laboratory Location Building 362, Room F108 Type Seminar Series HEP Division Seminar Abstract: In order to match the increased precision of the upcoming Fermilab E989 experiment, a more precise determination of hadronic contributions to the muon anomalous magnetic

  8. The Common Elements of Atomic and Hadronic Physics

    SciTech Connect (OSTI)

    Brodsky, Stanley J.

    2015-02-26

    Atomic physics and hadronic physics are both governed by the Yang Mills gauge theory Lagrangian; in fact, Abelian quantum electrodynamics can be regarded as the zero-color limit of quantum chromodynamics. I review a number of areas where the techniques of atomic physics can provide important insight into hadronic eigenstates in QCD. For example, the Dirac-Coulomb equation, which predicts the spectroscopy and structure of hydrogenic atoms, has an analog in hadron physics in the form of frame-independent light-front relativistic equations of motion consistent with light-front holography which give a remarkable first approximation to the spectroscopy, dynamics, and structure of light hadrons. The production of antihydrogen in flight can provide important insight into the dynamics of hadron production in QCD at the amplitude level. The renormalization scale for the running coupling is unambiguously set in QED; an analogous procedure sets the renormalization scales in QCD, leading to scheme-independent scale-fixed predictions. Conversely, many techniques which have been developed for hadron physics, such as scaling laws, evolution equations, the quark-interchange process and light-front quantization have important applicants for atomic physics and photon science, especially in the relativistic domain.

  9. Fermilab | Science | Particle Accelerators | LHC and Future Accelerato...

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

    These accelerators, each with its own specialty, would open new windows into our universe, allowing us to view it from as yet unexplored vantages. Upgrades to the Large Hadron ...

  10. The Muon Collider as a $H/A$ factory

    SciTech Connect (OSTI)

    Eichten, Estia; Martin, Adam

    2014-01-01

    We show that a muon collider is ideally suited for the study of heavy H/A scalars, cousins of the Higgs boson found in two-Higgs doublet models and required in supersymmetric models. The key aspects of H/A are: (1) they are narrow, yet have a width-to-mass ratio far larger than the expected muon collider beam-energy resolution, and (2) the larger muon Yukawa allows efficient s-channel production. We study in detail a representative Natural Supersymmetry model which has a 1.5 Tev H/A with $m_H$- $m_A$ = 10 Gev. The large event rates at resonant peak allow the determination of the individual H and A resonance parameters (including CP) and the decays into electroweakinos provides a wealth of information unavailable to any other present or planned collider.

  11. The Muon Collider as a $H/A$ factory

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

    Eichten, Estia; Martin, Adam; Univ. of Notre Dame, IN

    2013-11-22

    We show that a muon collider is ideally suited for the study of heavy H/A scalars, cousins of the Higgs boson found in two-Higgs doublet models and required in supersymmetric models. The key aspects of H/A are: (1) they are narrow, yet have a width-to-mass ratio far larger than the expected muon collider beam-energy resolution, and (2) the larger muon Yukawa allows efficient s-channel production. We study in detail a representative Natural Supersymmetry model which has a 1.5 Tev H/A with $m_H$- $m_A$ = 10 Gev. The large event rates at resonant peak allow the determination of the individual Hmore » and A resonance parameters (including CP) and the decays into electroweakinos provides a wealth of information unavailable to any other present or planned collider.« less

  12. Update on the MEIC electron collider ring design

    SciTech Connect (OSTI)

    Lin, F.; Derbenev, Ya. S.; Harwood, L.; Hutton, A.; Morozov, V. S.; Pilat, F.; Zhang, Y.; Cai, Y.; Nosochkov, Y. M.; Sullivan, M.; Wang, M-H; Wienands, U.

    2015-07-14

    The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEPII components, such as magnets, power supplies, vacuum system, etc. This has the potential to significantly reduce the cost and engineering effort needed to bring the project to fruition. This paper reports on an electron ring optics design considering the balance of PEP-II hardware parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and electron beam quality in terms of equilibrium emittances.

  13. Power Saving Optimization for Linear Collider Interaction Region Parameters

    SciTech Connect (OSTI)

    Seryi, Andrei; /SLAC

    2009-10-30

    Optimization of Interaction Region parameters of a TeV energy scale linear collider has to take into account constraints defined by phenomena such as beam-beam focusing forces, beamstrahlung radiation, and hour-glass effect. With those constraints, achieving a desired luminosity of about 2E34 would require use of e{sup +}e{sup -} beams with about 10 MW average power. Application of the 'travelling focus' regime may allow the required beam power to be reduced by at least a factor of two, helping reduce the cost of the collider, while keeping the beamstrahlung energy loss reasonably low. The technique is illustrated for the 500 GeV CM parameters of the International Linear Collider. This technique may also in principle allow recycling the e{sup +}e{sup -} beams and/or recuperation of their energy.

  14. Massive Stars in Colliding Wind Systems: the GLAST Perspective

    SciTech Connect (OSTI)

    Reimer, Anita; Reimer, Olaf; /Stanford U., HEPL /KIPAC, Menlo Park

    2011-11-29

    Colliding winds of massive stars in binary systems are considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may constitute a detectable source population for the GLAST observatory. The present work investigates such population study of massive colliding wind systems at high-energy gamma-rays. Based on the recent detailed model (Reimer et al. 2006) for non-thermal photon production in prime candidate systems, we unveil the expected characteristics of this source class in the observables accessible at LAT energies. Combining the broadband emission model with the presently cataloged distribution of such systems and their individual parameters allows us to conclude on the expected maximum number of LAT-detections among massive stars in colliding wind binary systems.

  15. The NUHM? after LHC Run 1

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

    Buchmueller, O.; Cavanaugh, R.; Citron, M.; De Roeck, A.; Dolan, M. J.; Ellis, J. R.; Flcher, H.; Heinemeyer, S.; Malik, S.; Marrouche, J.; et al

    2014-12-17

    We make a frequentist analysis of the parameter space of the NUHM2, in which the soft supersymmetry (SUSY)-breaking contributions to the masses of the two Higgs multiplets, m2Hu,d, vary independently from the universal soft SUSY-breaking contributions m20 to the masses of squarks and sleptons. Our analysis uses the MultiNest sampling algorithm with over 4 10? points to sample the NUHM2 parameter space. It includes the ATLAS and CMS Higgs mass measurements as well as the ATLAS search for supersymmetric jets + /ET signals using the full LHC Run 1 data, the measurements of BR(Bs?????) by LHCb and CMS togethermorewith other B-physics observables, electroweak precision observables and the XENON100 and LUX searches for spin-independent dark-matter scattering. We find that the preferred regions of the NUHM2 parameter space have negative SUSY-breaking scalar masses squared at the GUT scale for squarks and sleptons, m20 2Hu 2Hd 2 = 32.5 with 21 degrees of freedom (dof) in the NUHM2, to be compared with ?2/dof = 35.0/23 in the CMSSM, and ?2/dof = 32.7/22 in the NUHM1. We find that the one-dimensional likelihood functions for sparticle masses and other observables are similar to those found previously in the CMSSM and NUHM1.less

  16. QCD, Tevatron results and LHC prospects

    SciTech Connect (OSTI)

    Elvira, V.Daniel; /Fermilab

    2008-08-01

    We present a summary of the most recent measurements relevant to Quantum Chromodynamics (QCD) delivered by the D0 and CDF Tevatron experiments by May 2008. CDF and D0 are moving toward precision measurements of QCD based on data samples in excess of 1 fb-1. The inclusive jet cross sections have been extended to forward rapidity regions and measured with unprecedented precision following improvements in the jet energy calibration. Results on dijet mass distributions, bbbar dijet production using tracker based triggers, underlying event in dijet and Drell-Yan samples, inclusive photon and diphoton cross sections complete the list of measurements included in this paper. Good agreement with pQCD within errors is observed for jet production measurements. An improved and consistent theoretical description is needed for photon+jets processes. Collisions at the LHC are scheduled for early fall 2008, opening an era of discoveries at the new energy frontier, 5-7 times higher than that of the Tevatron.

  17. Charge recombination in the muon collider cooling channel

    SciTech Connect (OSTI)

    Fernow, R. C.; Palmer, R. B.

    2012-12-21

    The final stage of the ionization cooling channel for the muon collider must transversely recombine the positively and negatively charged bunches into a single beam before the muons can be accelerated. It is particularly important to minimize any emittance growth in this system since no further cooling takes place before the bunches are collided. We have found that emittance growth could be minimized by using symmetric pairs of bent solenoids and careful matching. We show that a practical design can be found that has transmission {approx}99%, emittance growth less than 0.1%, and minimal dispersion in the recombined bunches.

  18. R&D Toward a Neutrino Factory and Muon Collider

    SciTech Connect (OSTI)

    Zisman, Michael S

    2011-03-20

    Significant progress has been made in recent years in R&D towards a neutrino factory and muon collider. The U.S. Muon Accelerator Program (MAP) has been formed recently to expedite the R&D efforts. This paper will review the U.S. MAP R&D programs for a neutrino factory and muon collider. Muon ionization cooling research is the key element of the program. The first muon ionization cooling demonstration experiment, MICE (Muon Ionization Cooling Experiment), is under construction now at RAL (Rutherford Appleton Laboratory) in the UK. The current status of MICE will be described.

  19. Ripple distribution in magnet strings of Super Collider

    SciTech Connect (OSTI)

    Smedley, K. ); Jayasuriya, A. ); Christiansen, C. ); Shafer, R. )

    1994-08-01

    The voltage ripple in the power supplies of the Collider generate ripple current in the magnet coil that, in turn, generates ripple in the magnetic field of dipoles and quadrupoles. The ripple in the magnetic field will be a function of time and space due to the transmission line effect. The work reported in this paper gives a thorough analysis the frequency spectrum and the spatial propagation pattern of the differential mode ripple in the magnet strings for the injection mode and the collider mode.

  20. When Galaxies Collide: Ripples Indicate Recent Impact Close to Home |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy When Galaxies Collide: Ripples Indicate Recent Impact Close to Home When Galaxies Collide: Ripples Indicate Recent Impact Close to Home June 28, 2012 - 11:16am Addthis This is a graphic representation of the Milky Way, the galaxy in which Earth is contained. Scientists know of more than 20 visible satellite galaxies that circle the center of the Milky Way, with masses ranging from one million to one billion solar masses. Occasionally, one of these orbiting galaxies pass

  1. Importance of proper renormalization scale-setting for QCD testing at colliders

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

    Wu, Xing-Gang; Wang, Sheng-Quan; Brodsky, Stanley J.

    2015-12-22

    A primary problem affecting perturbative quantum chromodynamic (pQCD) analyses is the lack of a method for setting the QCD running-coupling renormalization scale such that maximally precise fixed-order predictions for physical observables are obtained. The Principle of Maximum Conformality (PMC) eliminates the ambiguities associated with the conventional renormalization scale-setting procedure, yielding predictions that are independent of the choice of renormalization scheme. The QCD coupling scales and the effective number of quark flavors are set order-by-order in the pQCD series. The PMC has a solid theoretical foundation, satisfying the standard renormalization group invariance condition and all of the self-consistency conditions derived frommore » the renormalization group. The PMC scales at each order are obtained by shifting the arguments of the strong force coupling constant αs to eliminate all non-conformal {βi} terms in the pQCD series. The {βi} terms are determined from renormalization group equations without ambiguity. The correct behavior of the running coupling at each order and at each phase-space point can then be obtained. The PMC reduces in the NC → 0 Abelian limit to the Gell-Mann-Low method. In this brief report, we summarize the results of our recent application of the PMC to a number of collider processes, emphasizing the generality and applicability of this approach. A discussion of hadronic Z decays shows that, by applying the PMC, one can achieve accurate predictions for the total and separate decay widths at each order without scale ambiguities. We also show that, if one employs the PMC to determine the top-quark pair forward-backward asymmetry at the next-to-next-to-leading order level, one obtains a comprehensive, self-consistent pQCD explanation for the Tevatron measurements of the asymmetry. This accounts for the “increasing-decreasing” behavior observed by the D0 collaboration for increasing tt invariant mass. At lower energies, the angular distributions of heavy quarks can be used to obtain a direct determination of the heavy quark potential. A discussion of the angular distributions of massive quarks and leptons is also presented, including the fermionic component of the two-loop corrections to the electromagnetic form factors. These results demonstrate that the application of the PMC systematically eliminates a major theoretical uncertainty for pQCD predictions, thus increasing collider sensitivity to possible new physics beyond the Standard Model.« less

  2. Importance of proper renormalization scale-setting for QCD testing at colliders

    SciTech Connect (OSTI)

    Wu, Xing-Gang; Wang, Sheng-Quan; Brodsky, Stanley J.

    2015-12-22

    A primary problem affecting perturbative quantum chromodynamic (pQCD) analyses is the lack of a method for setting the QCD running-coupling renormalization scale such that maximally precise fixed-order predictions for physical observables are obtained. The Principle of Maximum Conformality (PMC) eliminates the ambiguities associated with the conventional renormalization scale-setting procedure, yielding predictions that are independent of the choice of renormalization scheme. The QCD coupling scales and the effective number of quark flavors are set order-by-order in the pQCD series. The PMC has a solid theoretical foundation, satisfying the standard renormalization group invariance condition and all of the self-consistency conditions derived from the renormalization group. The PMC scales at each order are obtained by shifting the arguments of the strong force coupling constant αs to eliminate all non-conformal {βi} terms in the pQCD series. The {βi} terms are determined from renormalization group equations without ambiguity. The correct behavior of the running coupling at each order and at each phase-space point can then be obtained. The PMC reduces in the NC → 0 Abelian limit to the Gell-Mann-Low method. In this brief report, we summarize the results of our recent application of the PMC to a number of collider processes, emphasizing the generality and applicability of this approach. A discussion of hadronic Z decays shows that, by applying the PMC, one can achieve accurate predictions for the total and separate decay widths at each order without scale ambiguities. We also show that, if one employs the PMC to determine the top-quark pair forward-backward asymmetry at the next-to-next-to-leading order level, one obtains a comprehensive, self-consistent pQCD explanation for the Tevatron measurements of the asymmetry. This accounts for the “increasing-decreasing” behavior observed by the D0 collaboration for increasing tt invariant mass. At lower energies, the angular distributions of heavy quarks can be used to obtain a direct determination of the heavy quark potential. A discussion of the angular distributions of massive quarks and leptons is also presented, including the fermionic component of the two-loop corrections to the electromagnetic form factors. These results demonstrate that the application of the PMC systematically eliminates a major theoretical uncertainty for pQCD predictions, thus increasing collider sensitivity to possible new physics beyond the Standard Model.

  3. Supersymmetry Without Prejudice at the LHC

    SciTech Connect (OSTI)

    Conley, John A.; Gainer, James S.; Hewett, JoAnne L.; Le, My Phuong; Rizzo, Thomas G.; /SLAC

    2011-08-19

    The discovery and exploration of Supersymmetry in a model-independent fashion will be a daunting task due to the large number of soft-breaking parameters in the MSSM. In this paper, we explore the capability of the ATLAS detector at the LHC ({radical}s = 14 TeV, 1 fb{sup -1}) to find SUSY within the 19-dimensional pMSSM subspace of the MSSM using their standard transverse missing energy and long-lived particle searches that were essentially designed for mSUGRA. To this end, we employ a set of {approx} 71k previously generated model points in the 19-dimensional parameter space that satisfy all of the existing experimental and theoretical constraints. Employing ATLAS-generated SM backgrounds and following their approach in each of 11 missing energy analyses as closely as possible, we explore all of these 71k model points for a possible SUSY signal. To test our analysis procedure, we first verify that we faithfully reproduce the published ATLAS results for the signal distributions for their benchmark mSUGRA model points. We then show that, requiring all sparticle masses to lie below 1(3) TeV, almost all(two-thirds) of the pMSSM model points are discovered with a significance S > 5 in at least one of these 11 analyses assuming a 50% systematic error on the SM background. If this systematic error can be reduced to only 20% then this parameter space coverage is increased. These results are indicative that the ATLAS SUSY search strategy is robust under a broad class of Supersymmetric models. We then explore in detail the properties of the kinematically accessible model points which remain unobservable by these search analyses in order to ascertain problematic cases which may arise in general SUSY searches.

  4. Searches for third-generation squark production in fully hadronic final states in proton-proton collisions at ?s = 8 TeV

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

    Khachatryan, V.

    2015-06-17

    Searches for third-generation squarks in fully hadronic final states are presented using data samples corresponding to integrated luminosities of 19.4 or 19.7 fb?, collected at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Three mutually exclusive searches are presented, each optimized for a different decay topology. They include a multijet search requiring one fully reconstructed top quark, a dijet search requiring one or two jets originating from b quarks, and a monojet search. No excesses above the standard model expectations are seen, and limits are set on top and bottom squark production in the contextmoreof simplified models of supersymmetry.less

  5. Searches for third-generation squark production in fully hadronic final states in proton-proton collisions at ?s = 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, V.

    2015-06-17

    Searches for third-generation squarks in fully hadronic final states are presented using data samples corresponding to integrated luminosities of 19.4 or 19.7 fb?, collected at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Three mutually exclusive searches are presented, each optimized for a different decay topology. They include a multijet search requiring one fully reconstructed top quark, a dijet search requiring one or two jets originating from b quarks, and a monojet search. No excesses above the standard model expectations are seen, and limits are set on top and bottom squark production in the context of simplified models of supersymmetry.

  6. Identification of boosted, hadronically decaying W bosons and comparisons with ATLAS data taken at √s = 8 TeV

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

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; et al

    2016-03-17

    This paper reports a detailed study of techniques for identifying boosted, hadronically decaying W bosons using 20.3 fb–1 of proton–proton collision data collected by the ATLAS detector at the LHC at a centre-of-mass energy √s = 8 TeV. A range of techniques for optimising the signal jet mass resolution are combined with various jet substructure variables. The results of these studies in Monte Carlo simulations show that a simple pairwise combination of groomed jet mass and one substructure variable can provide a 50 % efficiency for identifying W bosons with transverse momenta larger than 200 GeV while maintaining multijet backgroundmore » efficiencies of 2–4 % for jets with the same transverse momentum. As a result, these signal and background efficiencies are confirmed in data for a selection of tagging techniques.« less

  7. Searches for third-generation squark production in fully hadronic final states in proton-proton collisions at $$ \\sqrt{s} = 8$$ TeV

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

    Khachatryan, Vardan

    2015-06-17

    We searched for third-generation squarks in fully hadronic final states and presented them using data samples corresponding to integrated luminosities of 19.4 or 19.7 fb-1, collected at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Three mutually exclusive searches are presented, each optimized for a different decay topology. They include a multijet search requiring one fully reconstructed top quark, a dijet search requiring one or two jets originating from b quarks, and a monojet search. Furthermore, no excesses above the standard model expectations are seen, and limits are set on top and bottom squark productionmore » in the context of simplified models of supersymmetry.« less

  8. Search for the Production of Gluinos and Squarks with the CDF II Experiment at the Tevatron Collider

    SciTech Connect (OSTI)

    De Lorenzo, Gianluca

    2010-05-01

    This thesis reports on two searches for the production of squarks and gluinos, supersymmetric partners of the Standard Model (SM) quarks and gluons, using the CDF detector at the Tevatron {radical}s = 1.96 TeV p{bar p} collider. An inclusive search for squarks and gluinos pair production is performed in events with large E{sub T} and multiple jets in the final state, based on 2 fb{sup -1} of CDF Run II data. The analysis is performed within the framework of minimal supergravity (mSUGRA) and assumes R-parity conservation where sparticles are produced in pairs. The expected signal is characterized by the production of multiple jets of hadrons from the cascade decays of squarks and gluinos and large missing transverse energy E{sub T} from the lightest supersymmetric particles (LSP). The measurements are in good agreement with SM predictions for backgrounds. The results are translated into 95% confidence level (CL) upper limits on production cross sections and squark and gluino masses in a given mSUGRA scenario. An upper limit on the production cross section is placed in the range between 1 pb and 0.1 pb, depending on the gluino and squark masses considered. The result of the search is negative for gluino and squark masses up to 392 GeV/c{sup 2} in the region where gluino and squark masses are close to each other, gluino masses up to 280 GeV/c{sup 2} regardless of the squark mass, and gluino masses up to 423 GeV=c2 for squark masses below 378 GeV/c{sup 2}. These results are compatible with the latest limits on squark/gluino production obtained by the D0 Collaboration and considerably improve the previous exclusion limits from direct and indirect searches at LEP and the Tevatron. The inclusive search is then extended to a scenario where the pair production of sbottom squarks is dominant. The new search is performed in a generic MSSM scenario with R-parity conservation. A specific SUSY particle mass hierarchy is assumed such that the sbottom decays exclusively as {tilde b}{sub 1} {yields} b{sub {tilde {chi}}{sub 1}{sup 0}}. The expected signal for direct sbottom pair production is characterized by the presence of two jets of hadrons from the hadronization of the bottom quarks and E=T from the two LSPs in the final state. The events are selected with large E{sub T} and two energetic jets in the final state, and at least one jet is required to be associated with a b quark. The measurements are in good agreement with SM predictions for backgrounds. The results are translated into 95% CL exclusion limits on production cross sections and sbottom and neutralino masses in the given MSSM scenario. Cross sections down to 0.1 pb are excluded for the sbottom mass range considered. Sbottom masses up to 230 GeV/c{sup 2} are excluded at 95% CL for neutralino masses below 70 GeV/c{sup 2}. This analysis increases the previous CDF limit by more than 40 GeV/c{sup 2}. The sensitivity of both the inclusive and the exclusive search is dominated by systematic effects and the results of the two analyses can be considered as conclusive for CDF Run II. With the new energy frontier of the newly commissioned Large Hadron Collider in Geneva, the experience from Tevatron will be of crucial importance in the developing of effective strategies to search for SUSY in the next era of particle physics experiments.

  9. Scanning Synchronization of Colliding Bunches for MEIC Project

    SciTech Connect (OSTI)

    Derbenev, Yaroslav S.; Popov, V. P.; Chernousov, Y. D.; Kazakevich, G. M.

    2015-09-01

    Synchronization of colliding beams is one of the major issues of an electron-ion collider (EIC) design because of sensitivity of ion revolution frequency to beam energy. A conventional solution for this trouble is insertion of bent chicanes in the arcs space. In our report we consider a method to provide space coincidence of encountering bunches in the crab-crossing orbits Interaction Region (IR) while repetition rates of two beams do not coincide. The method utilizes pair of fast kickers realizing a bypass for the electron bunches as the way to equalize positions of the colliding bunches at the Interaction Point (IP). A dipole-mode warm or SRF cavities fed by the magnetron transmitters are used as fast kickers, allowing a broad-band phase and amplitude control. The proposed scanning synchronization method implies stabilization of luminosity at a maximum via a feedback loop. This synchronization method is evaluated as perspective for the Medium Energy Electron-Ion collider (MEIC) project of JLab with its very high bunch repetition rate.

  10. Computer protection plan for the Superconducing Super Collider Laboratory

    SciTech Connect (OSTI)

    Hunter, S.

    1992-04-15

    The purpose of this document is to describe the current unclassified computer security program practices, Policies and procedures for the Superconducting Super Collider Laboratory (SSCL). This document includes or references all related policies and procedures currently implemented throughout the SSCL. The document includes security practices which are planned when the facility is fully operational.

  11. PROTON BEAM REQUIREMENTS FOR A NEUTRINO FACTORY AND MUON COLLIDER

    SciTech Connect (OSTI)

    Zisman, Michael S.

    2009-12-11

    Both a Neutrino Factory and a Muon Collider place stringent demands on the proton beam used to generate the desired beam of muons. Here we discuss the advantages and challenges of muon accelerators and the rationale behind the requirements on proton beam energy, intensity, bunch length, and repetition rate. Example proton driver configurations that have been considered in recent years are also briefly indicated.

  12. Superconducting Super Collider Magnet System requirements. Revision A

    SciTech Connect (OSTI)

    1986-10-23

    This report discusses the Superconducting Super Collider magnet system requirements when the following categories: Functions; operational performance requirements; system configuration and essential features; structural requirements; availability/reliability; instrumentation and control requirements; design life; environment; maintenance requirements; interface systems; quality assurance; safety; and applicable codes and standards.

  13. Simulating three-dimensional nonthermal high-energy photon emission in colliding-wind binaries

    SciTech Connect (OSTI)

    Reitberger, K.; Kissmann, R.; Reimer, A.; Reimer, O.

    2014-07-01

    Massive stars in binary systems have long been regarded as potential sources of high-energy ? rays. The emission is principally thought to arise in the region where the stellar winds collide and accelerate relativistic particles which subsequently emit ? rays. On the basis of a three-dimensional distribution function of high-energy particles in the wind collision regionas obtained by a numerical hydrodynamics and particle transport modelwe present the computation of the three-dimensional nonthermal photon emission for a given line of sight. Anisotropic inverse Compton emission is modeled using the target radiation field of both stars. Photons from relativistic bremsstrahlung and neutral pion decay are computed on the basis of local wind plasma densities. We also consider photon-photon opacity effects due to the dense radiation fields of the stars. Results are shown for different stellar separations of a given binary system comprising of a B star and a Wolf-Rayet star. The influence of orbital orientation with respect to the line of sight is also studied by using different orbital viewing angles. For the chosen electron-proton injection ratio of 10{sup 2}, we present the ensuing photon emission in terms of two-dimensional projections maps, spectral energy distributions, and integrated photon flux values in various energy bands. Here, we find a transition from hadron-dominated to lepton-dominated high-energy emission with increasing stellar separations. In addition, we confirm findings from previous analytic modeling that the spectral energy distribution varies significantly with orbital orientation.

  14. Learning How to Count: A High Multiplicity Search for the LHC...

    Office of Scientific and Technical Information (OSTI)

    Learning How to Count: A High Multiplicity Search for the LHC Citation Details In-Document Search Title: Learning How to Count: A High Multiplicity Search for the LHC Authors:...

  15. DESIGN OF A 6 TEV MUON COLLIDER (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    DESIGN OF A 6 TEV MUON COLLIDER Citation Details In-Document Search Title: DESIGN OF A 6 TEV MUON COLLIDER You are accessing a document from the Department of Energy's (DOE)...

  16. DESIGN OF A 6 TEV MUON COLLIDER (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    DESIGN OF A 6 TEV MUON COLLIDER Citation Details In-Document Search Title: DESIGN OF A 6 TEV MUON COLLIDER Authors: Wang, M.-H. ; Nosochkov, Y. ; Cai, Y. ; SLAC ; Palmer, M. ;...

  17. Status of the MEIC ion collider ring design (Conference) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    Status of the MEIC ion collider ring design Citation Details In-Document Search Title: Status of the MEIC ion collider ring design We present an update on the design of the ion...

  18. A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory...

    Office of Scientific and Technical Information (OSTI)

    A Beam Driven Plasma-Wakefield Linear Collider: From Higgs Factory to Multi-TeV Citation Details In-Document Search Title: A Beam Driven Plasma-Wakefield Linear Collider: From...

  19. A Feasibility Study of an e e- Ring Collider for Higgs Factory...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: A Feasibility Study of an e e- Ring Collider for Higgs Factory Citation Details In-Document Search Title: A Feasibility Study of an e e- Ring Collider for Higgs...

  20. Measurements of {phi} meson production in relativistic heavy-ion collisions at the BNL relativistic heavy ion collider (RHIC).

    SciTech Connect (OSTI)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Krueger, K.; Spinka, H.; Underwood, D. G.; High Energy Physics; Univ. of Illinois; Kent State Univ.; Panjab Univ.; Variable Energy Cyclotron Centre; Kent State Univ.; Particle Physics Lab.; STAR Collaboration

    2009-01-01

    We present results for the measurement of {phi} meson production via its charged kaon decay channel {phi} {yields} K{sup +}K{sup -} in Au+Au collisions at {radical}S{sub NN} = 62.4, 130, and 200 GeV, and in p+p and d+Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC). The midrapidity (|y| < 0.5) {phi} meson transverse momentum (p{sub T}) spectra in central Au+Au collisions are found to be well described by a single exponential distribution. On the other hand, the p{sub T} spectra from p+p, d+Au, and peripheral Au+Au collisions show power-law tails at intermediate and high p{sub T} and are described better by Levy distributions. The constant {phi}/K{sup -} yield ratio vs beam species, collision centrality, and colliding energy is in contradiction with expectations from models having kaon coalescence as the dominant mechanism for {phi} production at RHIC. The {Omega}/{phi} yield ratio as a function of p{sub T} is consistent with a model based on the recombination of thermal s quarks up to p{sub T} {approx} 4 GeV/c, but disagrees at higher transverse momenta. The measured nuclear modification factor, R{sub dAu}, for the {phi} meson increases above unity at intermediate p{sub T}, similar to that for pions and protons, while R{sub AA} is suppressed due to the energy loss effect in central Au+Au collisions. Number of constituent quark scaling of both R{sub cp} and v{sub 2} for the {phi} meson with respect to other hadrons in Au+Au collisions at {radical}s{sub NN} = 200 GeV at intermediate p{sub T} is observed. These observations support quark coalescence as being the dominant mechanism of hadronization in the intermediate p{sub T} region at RHIC.

  1. Measurements of {phi} meson production in relativistic heavy-ion collisions at the BNL Relativistic Heavy Ion Collider (RHIC)

    SciTech Connect (OSTI)

    Abelev, B. I.; Barannikova, O.; Betts, R. R.; Callner, J.; Garcia-Solis, E.; Hofman, D. J.; Hollis, R. S.; Iordanova, A.; Suarez, M. C.; Aggarwal, M. M.; Bhati, A. K.; Kumar, L.; Pruthi, N. K.; Ahammed, Z.; Chattopadhyay, S.; Mazumdar, M. R. Dutta; Ganti, M. S.; Ghosh, P.; Mohanty, B.; Nayak, T. K.

    2009-06-15

    We present results for the measurement of {phi} meson production via its charged kaon decay channel {phi}{yields}K{sup +}K{sup -} in Au+Au collisions at {radical}(s{sub NN})=62.4,130, and 200 GeV, and in p+p and d+Au collisions at {radical}(s{sub NN})=200 GeV from the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC). The midrapidity (|y|<0.5) {phi} meson transverse momentum (p{sub T}) spectra in central Au+Au collisions are found to be well described by a single exponential distribution. On the other hand, the p{sub T} spectra from p+p, d+Au, and peripheral Au+Au collisions show power-law tails at intermediate and high p{sub T} and are described better by Levy distributions. The constant {phi}/K{sup -} yield ratio vs beam species, collision centrality, and colliding energy is in contradiction with expectations from models having kaon coalescence as the dominant mechanism for {phi} production at RHIC. The {omega}/{phi} yield ratio as a function of p{sub T} is consistent with a model based on the recombination of thermal s quarks up to p{sub T}{approx}4 GeV/c, but disagrees at higher transverse momenta. The measured nuclear modification factor, R{sub dAu}, for the {phi} meson increases above unity at intermediate p{sub T}, similar to that for pions and protons, while R{sub AA} is suppressed due to the energy loss effect in central Au+Au collisions. Number of constituent quark scaling of both R{sub cp} and v{sub 2} for the {phi} meson with respect to other hadrons in Au+Au collisions at {radical}(s{sub NN})=200 GeV at intermediate p{sub T} is observed. These observations support quark coalescence as being the dominant mechanism of hadronization in the intermediate p{sub T} region at RHIC.

  2. New Tools for Forecasting Old Physics at the LHC

    ScienceCinema (OSTI)

    None

    2011-10-06

    For the LHC to uncover many types of new physics, the "old physics" produced by the Standard Model must be understood very well. For decades, the central theoretical tool for this job was the Feynman diagram expansion. However, Feynman diagrams are just too slow, even on fast computers, to allow adequate precision for complicated LHC events with many jets in the final state. Such events are already visible in the initial LHC data. Over the past few years, alternative methods to Feynman diagrams have come to fruition. These new "on-shell" methods are based on the old principles of unitarity and factorization. They can be much more efficient because they exploit the underlying simplicity of scattering amplitudes, and recycle lower-loop information. I will describe how and why these methods work, and present some of the recent state-of-the-art results that have been obtained with them.

  3. NEUTRON-ENHANCED CALORIMETRY FOR HADRONS (NECH): FINAL REPORT

    SciTech Connect (OSTI)

    Andrew Stroud, Lee Sawyer

    2012-08-31

    We present the results of a project to apply scintillator technology recently developed at Louisiana Tech University to hadronic calorimetry. In particular, we developed a prototype calorimeter module incorporating scintillator embedded with metal oxide nanoparticles as the active layers. These metal oxide nanoparticles of gadolinium oxide, have high cross-sections for interactions with slow neutrons. As a part fo this research project, we have developed a novel method for producing plastic scintillators with metal oxide nanoparticles evenly distributed through the plastic without aggregation.We will test the performance of the calorimeter module in test beam and with a neutron source, in order to measure the response to the neutron component of hadronic showers. We will supplement our detector prototyping activities with detailed studies of the effect of neutron component on the resolution of hadronic energy measurements, particular in the next generation of particle flow calorimeters.

  4. Hadronic nuclear energy: An approach towards green energy

    SciTech Connect (OSTI)

    Das Sarma, Indrani B.

    2015-03-10

    Nuclear energy is undoubtedly the largest energy source capable of meeting the total energy requirements to a large extent in long terms. However the conventional nuclear energy involves production of high level of radioactive wastes which possesses threat, both to the environment and mankind. The modern day demand of clean, cheap and abundant energy gets fulfilled by the novel fuels that have been developed through hadronic mechanics/chemistry. In the present paper, a short review of Hadronic nuclear energy by intermediate controlled nuclear synthesis and particle type like stimulated neutron decay and double beta decay has been presented.

  5. Spectroscopy and Decay of $B$ Hadrons at the Tevatron

    SciTech Connect (OSTI)

    Paulini, Manfred

    2007-02-01

    The authors review recent results on heavy quark physics focusing on Run II measurements of B hadron spectroscopy and decay at the Tevatron. A wealth of new B physics measurements from CDF and D0 has been available. These include the spectroscopy of excited B states (B**, B**{sub s}) and the observation of the {Sigma}{sub b} baryon. The discussion of the decays of B hadrons and measurements of branching fractions focuses on charmless two-body decays of B {yields} h{sup +}h{sup -}. They report several new B{sub s}{sup 0} and {Lambda}{sub b}{sup 0} decay channels.

  6. Detectors for Linear Colliders: Tracking and Vertexing (2/4)

    ScienceCinema (OSTI)

    None

    2011-10-06

    Efficient and precise determination of the flavour of partons in multi-hadron final states is essential to the anticipated LC physics program. This makes tracking in the vicinity of the interaction region of great importance. Tracking extrapolation and momentum resolution are specified by precise physics requirements. The R&D; towards detectors able to meet these specifications will be discussed, together with some of their application beyond particle physics.

  7. Searches for supersymmetry using the M$_{T2}$ variable in hadronic events produced in pp collisions at 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, V.

    2015-05-15

    Searches for supersymmetry (SUSY) are performed using a sample of hadronic events produced in 8 TeV pp collisions at the CERN LHC. The searches are based on the M$_{T2}$ variable, which is a measure of the transverse momentum imbalance in an event. The data were collected with the CMS detector and correspond to an integrated luminosity of 19.5 fb1. Two related searches are performed. The first is an inclusive search based on signal regions defined by the value of the M$_{T2}$ variable, the hadronic energy in the event, the jet multiplicity, and the number of jets identified as originating from bottom quarks. The second is a search for a mass peak corresponding to a Higgs boson decaying to a bottom quark-antiquark pair, where the Higgs boson is produced as a decay product of a SUSY particle. For both searches, the principal backgrounds are evaluated with data control samples. No significant excess over the expected number of background events is observed, and exclusion limits on various SUSY models are derived.

  8. Searches for supersymmetry using the MT2 variable in hadronic events produced in pp collisions at 8 TeV

    SciTech Connect (OSTI)

    Khachatryan, V.

    2015-05-15

    Searches for supersymmetry (SUSY) are performed using a sample of hadronic events produced in 8 TeV pp collisions at the CERN LHC. The searches are based on the MT2 variable, which is a measure of the transverse momentum imbalance in an event. The data were collected with the CMS detector and correspond to an integrated luminosity of 19.5 fb?. Two related searches are performed. The first is an inclusive search based on signal regions defined by the value of the MT2 variable, the hadronic energy in the event, the jet multiplicity, and the number of jets identified as originating from bottom quarks. The second is a search for a mass peak corresponding to a Higgs boson decaying to a bottom quark-antiquark pair, where the Higgs boson is produced as a decay product of a SUSY particle. For both searches, the principal backgrounds are evaluated with data control samples. No significant excess over the expected number of background events is observed, and exclusion limits on various SUSY models are derived.

  9. Searches for supersymmetry using the M$$_{T2}$$ variable in hadronic events produced in pp collisions at 8 TeV

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

    Khachatryan, V.

    2015-05-15

    Searches for supersymmetry (SUSY) are performed using a sample of hadronic events produced in 8 TeV pp collisions at the CERN LHC. The searches are based on the Mmore » $$_{T2}$$ variable, which is a measure of the transverse momentum imbalance in an event. The data were collected with the CMS detector and correspond to an integrated luminosity of 19.5 fb1. Two related searches are performed. The first is an inclusive search based on signal regions defined by the value of the M$$_{T2}$$ variable, the hadronic energy in the event, the jet multiplicity, and the number of jets identified as originating from bottom quarks. The second is a search for a mass peak corresponding to a Higgs boson decaying to a bottom quark-antiquark pair, where the Higgs boson is produced as a decay product of a SUSY particle. For both searches, the principal backgrounds are evaluated with data control samples. No significant excess over the expected number of background events is observed, and exclusion limits on various SUSY models are derived.« less

  10. Averages of B-Hadron, C-Hadron, and tau-lepton properties as of early 2012

    SciTech Connect (OSTI)

    Amhis, Y.; et al.

    2012-07-01

    This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.

  11. Status of the MEIC ion collider ring design (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Status of the MEIC ion collider ring design Citation Details In-Document Search Title: Status of the MEIC ion collider ring design We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab

  12. Update on the MEIC electron collider ring design (Conference) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Update on the MEIC electron collider ring design Citation Details In-Document Search Title: Update on the MEIC electron collider ring design The electron collider ring of the Medium-energy Electron-Ion Collider (MEIC) at Jefferson Lab is designed to accumulate and store a high-current polarized electron beam for collisions with an ion beam. We consider a design of the electron collider ring based on reusing PEP-II components, such as magnets, power supplies, vacuum system, etc. This

  13. Estimates of HE-LHC beam parameters at different injection energies

    SciTech Connect (OSTI)

    Sen, Tanaji; /Fermilab

    2010-11-01

    A future upgrade to the LHC envisions increasing the top energy to 16.5 TeV and upgrading the injectors. There are two proposals to replace the SPS as the injector to the LHC. One calls for a superconducting ring in the SPS tunnel while the other calls for an injector (LER) in the LHC tunnel. In both scenarios, the injection energy to the LHC will increase. In this note we look at some of the consequences of increased injection energy to the beam dynamics in the LHC.

  14. ALICE and The state of matter at LHC

    ScienceCinema (OSTI)

    None

    2011-10-06

    Assembly and installation of ALICE, the LHC heavy ion experiment dedicated to the study of matter at extreme temperature and pressure, is nearing completion and the commissioning of the detector is well under way. A good time to look back, to the making of ALICE, and to look forward, to the first physics with proton and heavy ion beams.

  15. LHC Beam Diffusion Dependence on RF Noise: Models And Measurements

    SciTech Connect (OSTI)

    Mastorides, T.; Rivetta, C.; Fox, J.D.; Van Winkle, D.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; ,

    2010-09-14

    Radio Frequency (RF) accelerating system noise and non-idealities can have detrimental impact on the LHC performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and RF loop dynamics with the bunch length growth [1]. Measurements were conducted at LHC to validate the formalism, determine the performance limiting RF components, and provide the foundation for beam diffusion estimates for higher energies and intensities. A brief summary of these results is presented in this work. During a long store, the relation between the energy lost to synchrotron radiation and the noise injected to the beam by the RF accelerating voltage determines the growth of the bunch energy spread and longitudinal emittance. Since the proton synchrotron radiation in the LHC is very low, the beam diffusion is extremely sensitive to RF perturbations. The theoretical formalism presented in [1], suggests that the noise experienced by the beam depends on the cavity phase noise power spectrum, filtered by the beam transfer function, and aliased due to the periodic sampling of the accelerating voltage signal V{sub c}. Additionally, the dependence of the RF accelerating cavity noise spectrum on the Low Level RF (LLRF) configurations has been predicted using time-domain simulations and models [2]. In this work, initial measurements at the LHC supporting the above theoretical formalism and simulation predictions are presented.

  16. Neutral currents production in LHC for 331 models

    SciTech Connect (OSTI)

    Martinez, R.; Ochoa, F.

    2010-07-29

    A brief review about the production of a Z' resonance in the framework of the 331 models is given. Their signatures at CERN LHC is highlighted by studying the Z' production and decay features, including different final states and one-loop corrections.

  17. Testing the Muon g-2 Anomaly at the LHC

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

    Freitas, Ayres; Lykken, Joseph; Kell, Stefan; Westhoff, Susanne

    2014-05-29

    The long-standing difference between the experimental measurement and the standard-model prediction for the muon's anomalous magnetic moment, $a_{\\mu} = (g_{\\mu}-2)/2$, may be explained by the presence of new weakly interacting particles with masses of a few 100 GeV. Particles of this kind can generally be directly produced at the LHC, and thus they may already be constrained by existing data. In this work, we investigate this connection between $a_{\\mu}$ and the LHC in a model-independent approach, by introducing one or two new fields beyond the standard model with spin and weak isospin up to one. For each case, we identifymore »the preferred parameter space for explaining the discrepancy of a_mu and derive bounds using data from LEP and the 8-TeV LHC run. Furthermore, we estimate how these limits could be improved with the 14-TeV LHC. We find that the 8-TeV results already rule out a subset of our simplified models, while almost all viable scenarios can be tested conclusively with 14-TeV data.« less

  18. Search for squark production in events with jets, hadronically decaying tau leptons and missing transverse energy at s**(1/2) = 1.96-TeV

    SciTech Connect (OSTI)

    Abazov, V.M.; /Dubna, JINR; Abbott, B.; /Oklahoma U.; Abolins, M.; /Michigan State U.; Acharya, B.S.; /Tata Inst.; Adams, M.; /Illinois U., Chicago; Adams, T.; /Florida State U.; Aguilo, E.; /Alberta U. /Simon Fraser U. /York U., Canada /McGill U.; Ahsan, M.; /Kansas State U.; Alexeev, G.D.; /Dubna, JINR; Alkhazov, G.; /St. Petersburg, INP; Alton, A.; /Michigan U. /Northeastern U.

    2009-05-01

    A search for supersymmetric partners of quarks is performed in the topology of multijet events accompanied by at least one tau lepton decaying hadronically and large missing transverse energy. Approximately 1 fb-1 of ppbar collision data from the Fermilab Tevatron Collider at a center of mass energy of 1.96 TeV recorded by the D0 detector is analyzed. Results are combined with the previously published D0 inclusive search for squarks and gluinos. No evidence of physics beyond the standard model is found and lower limits on the squark mass up to 410 GeV are derived in the framework of minimal supergravity with tan(beta)=15, A{sub 0}=-2m{sub 0} and mu<0, in the region where decays to tau leptons dominate. Gaugino masses m{sub 1/2} are excluded up to 172 GeV.

  19. Observation of snake resonances at Relativistic Heavy Ion Collider

    SciTech Connect (OSTI)

    Bai, M.; Ahrens, L.; Alekseev, I.G.; Alessi, J.; et al

    2010-09-27

    The Siberian snakes are powerful tools in preserving polarization in high energy accelerators has been demonstrated at the Brookhaven Relativistic Heavy Ion Collider (RHIC). Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the Siberian snakes also introduce a new set of depolarization resonances, i.e. snake resonances as first discovered by Lee and Tepikian. The intrinsic spin resonances above 100 GeV are about a factor of two stronger than those below 100 GeV which raises the challenge to preserve the polarization up to 250 GeV. In 2009, polarized protons collided for the first time at the RHIC design store energy of 250 GeV. This paper presents the experimental measurements of snake resonances at RHIC. The plan for avoiding these resonances is also presented.

  20. Probing contact interactions at high energy lepton colliders

    SciTech Connect (OSTI)

    Cheung, K.; Godfrey, S.; Hewett, J.A.

    1996-12-01

    Fermion compositeness and other new physics can be signaled by the presence of a strong four-fermion contact interaction. Here the authors present a study of {ell}{ell}qq and {ell}{ell}{ell}{prime}{ell}{prime} contact interactions using the reactions: {ell}{sup +}{ell}{sup {minus}} {r_arrow} {ell}{prime}{sup +} {ell}{prime}{sup {minus}}, b{anti b}, c{anti c} at future e{sup +}e{sup {minus}} linear colliders with {radical}s = 0.5--5 TeV and {mu}{sup +}{mu}{sup {minus}} colliders with {radical}s = 0.5, 4 TeV. They find that very large compositeness scales can be probed at these machines and that the use of polarized beams can unravel their underlying helicity structure.

  1. R&D Toward a Neutrino Factory and Muon Collider

    SciTech Connect (OSTI)

    Zisman, Michael S

    2009-04-29

    There is considerable interest in the use of muon beams to create either an intense source of decay neutrinos aimed at a detector located 3000-7500 km away (a Neutrino Factory), or a Muon Collider that produces high-luminosity collisions at the energy frontier. R&D aimed at producing these facilities has been under way for more than 10 years. This paper will review experimental results from MuCool, MERIT, and MICE and indicate the extent to which they will provide proof-of-principle demonstrations of the key technologies required for a Neutrino Factory or Muon Collider. Progress in constructing components for the MICE experiment will also be described.

  2. Physics and technology of the next linear collider

    SciTech Connect (OSTI)

    1996-06-01

    The authors present the prospects for the next generation of high-energy physics experiments with electron-positron colliding beams. This report summarizes the current status of the design and technological basis of a linear collider of center-of-mass energy 0.5--1.5 TeV, and the opportunities for high-energy physics experiments that this machine is expected to open. The physics goals discussed here are: Standard Model processes and simulation; top quark physics; Higgs boson searches and properties; supersymmetry; anomalous gauge boson couplings; strong WW scattering; new gauge bosons and exotic particles; e{sup {minus}}e{sup {minus}}, e{sup {minus}}{gamma}, and {gamma}{gamma} interactions; and precision tests of QCD.

  3. Progress on muon{sup +}muon{sup {minus}} colliders

    SciTech Connect (OSTI)

    Palmer, R.B.

    1997-05-01

    Advantages and disadvantages of muon colliders are discussed. Recent results of calculations of the radiation hazard from muon decay neutrinos are presented. This is a significant problem for machines with center of mass energy of 4 TeV, but of no consequence for lower energies. Plans are outlined for future theoretical and experimental studies. Besides continued work on the parameters of a 4 TeV collider, studies are now starting on a machine near 100 GeV that could be a factory for the s-channel production of Higgs particles. Proposals are also presented for a demonstration of ionization cooling and of the required targeting, pion capture, and phase rotation rf.

  4. Status of superconducting magnets for the Superconducting Super Collider

    SciTech Connect (OSTI)

    Schermer, R.I.

    1993-09-01

    The arc sections of the High Energy Booster and the two Collider Rings will need more than 10,000, very large, superconducting dipole and quadrupole magnets. Development work on these magnets was carried out at US/DOE laboratories in a program that began in the mid 1980`s. In 1991-1992, the technology was transferred to industry and twenty, full-length, Collider dipoles were successfully fabricated and tested. This program, along with HERA and Tevatron experience, has provided industry a data base to use in formulating detailed designs for the prototypes of the accelerator magnets, with an eye to reducing cost and enhancing producibility. Several model magnets from this latest phase of the industrial program have already been tested. The excessive ramp-rate sensitivity of the magnets is understood and solutions are under investigation.

  5. New timing system for the Stanford Linear Collider

    SciTech Connect (OSTI)

    Paffrath, L.; Bernstein, D.; Kang, H.; Koontz, R.; Leger, G.; Ross, M.; Pierce, W.; Wilmunder, A.

    1984-11-01

    In order to be able to meet the goals of the Stanford Linear Collider, a much more precise timing system had to be implemented. This paper describes the specification and design of this system, and the results obtained from its use on 1/3 of the SLAC linac. The functions of various elements are described, and a programmable delay unit (PDU) is described in detail.

  6. Relativistic Heavy-Ion Collider (RHIC) physics overview

    SciTech Connect (OSTI)

    Ruan, L.J.; Ruan, L.; n /a

    2010-02-08

    The results from data taken during the last several years at the Relativistic Heavy-Ion Collider (RHIC) will be reviewed in the paper. Several selected topics that further our understanding of constituent quark scaling, jet quenching and color screening effect of heavy quarkonia in the hot dense medium will be presented. Detector upgrades will further probe the properties of Quark Gluon Plasma. Future measurements with upgraded detectors will be presented. The discovery perspectives from future measurements will also be discussed.

  7. Toward design of the Collider Beam Collimation System

    SciTech Connect (OSTI)

    Drozhdin, A.; Mokhov, N.; Soundranayagam, R.; Tompkins, J.

    1994-02-01

    A multi-component beam collimation system for the Superconducting Super Collider is described. System choice justification and design requirements are presented. System consists of targets, scrapers, and collimators with appropriate cooling and radiation shielding. Each component has an independent control for positioning and aligning with respect to the beam. Results of beam loss distribution, energy deposition calculations, and thermal analyses, as well as cost estimate, are presented.

  8. Proceedings of the workshop on B physics at hadron accelerators

    SciTech Connect (OSTI)

    McBride, P.; Mishra, C.S.

    1993-12-31

    This report contains papers on the following topics: Measurement of Angle {alpha}; Measurement of Angle {beta}; Measurement of Angle {gamma}; Other B Physics; Theory of Heavy Flavors; Charged Particle Tracking and Vertexing; e and {gamma} Detection; Muon Detection; Hadron ID; Electronics, DAQ, and Computing; and Machine Detector Interface. Selected papers have been indexed separately for inclusion the in Energy Science and Technology Database.

  9. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

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

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; et al

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopymore » in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.« less

  10. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    SciTech Connect (OSTI)

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, Derek; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, David G.; Ketzer, B.; Klein, Franz J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, Vincent; McKinnon, Brian; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, Alessandro; Salgado, Carlos; Santopinto, E.; Sarantsev, Andrey V.; Sato, Toru; Schlüter, T.; da Silva, M. L.L.; Stankovic, I.; Strakovsky, Igor; Szczepaniak, Adam; Vassallo, A.; Walford, Natalie K.; Watts, Daniel P.

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  11. Audit of controls over Superconducting Super Collider Laboratory subcontractor expenditures

    SciTech Connect (OSTI)

    Not Available

    1993-10-22

    In January 1989 the Department of Energy contracted with Universities Research Association, Inc. to design, construct, manage, operate, and maintain the Superconducting Super Collider Laboratory. Through Fiscal Year 1992, costs for subcontractor goods and services accounted for about 75 percent of the Superconducting Super Collider Laboratory expenditures. The Office of Inspector General evaluated the adequacy of controls in place to ensure that subcontractor costs were reasonable, as required by the contract. The following conclusions were drawn from the audit. The Superconducting Super Collider Laboratory did not consistently exercise prudent business judgment in making subcontractor expenditures. As a result, $60 million in expenditures already made and $128 million planned with commercial subcontractors were, in the authors opinion, unnecessary, excessive, or represented uncontrolled growth. The audit also found inadequate justifications, accountability, and cost controls over $143 million in expenditures made and $47 million planned with other Department of Energy laboratories. Improvements were needed in subcontract administration and internal controls, including appropriate audit coverage of the subcontracts. In addition, Department of Energy guidance concerning procurement actions between the laboratories needed to be established.

  12. Search for strong gravity in multijet final states produced in pp collisions at √s = 13 TeV using the ATLAS detector at the LHC

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

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; et al

    2016-03-07

    A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13 TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1 TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. As a result, limits aremore » also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions.« less

  13. Erratum to: Constraining couplings of top quarks to the Z boson in $

    Office of Scientific and Technical Information (OSTI)

    t\overline{t} $ + Z production at the LHC (Journal Article) | SciTech Connect Erratum to: Constraining couplings of top quarks to the Z boson in $ t\overline{t} $ + Z production at the LHC Citation Details In-Document Search Title: Erratum to: Constraining couplings of top quarks to the Z boson in $$ t\overline{t} $$ + Z production at the LHC We study top quark pair production in association with a Z boson at the Large Hadron Collider (LHC) and investigate the prospects of measuring the

  14. Bounding the Higgs width at the LHC using full analytic results for $$gg → e^- e^+ \\mu^- \\mu^+$$

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

    Campbell, John M.; Ellis, R. Keith; Williams, Ciaran

    2014-04-09

    We revisit the hadronic production of the four-lepton final state, e– e+ μ– μ+, through the fusion of initial state gluons. This process is mediated by loops of quarks and we provide first full analytic results for helicity amplitudes that account for both the effects of the quark mass in the loop and off-shell vector bosons. The analytic results have been implemented in the Monte Carlo program MCFM and are both fast, and numerically stable in the region of low Z transverse momentum. We use our results to study the interference between Higgs-mediated and continuum production of four-lepton final states,more » which is necessary in order to obtain accurate theoretical predictions outside the Higgs resonance region. We have confirmed and extended a recent analysis of Caola and Melnikov that proposes to use a measurement of the off-shell region to constrain the total width of the Higgs boson. Using a simple cut-and-count method, existing LHC data should bound the width at the level of 25-45 times the Standard Model expectation. We investigate the power of using a matrix element method to construct a kinematic discriminant to sharpen the constraint. Furthermore, in our analysis the bound on the Higgs width is improved by a factor of about 1.6 using a simple cut on the MEM discriminant, compared to an invariant mass cut μ4l > 300 GeV.« less

  15. Smashing Protons to Smithereens

    ScienceCinema (OSTI)

    Marc-André Pleier

    2010-09-01

    Pleier discusses the extraordinary research taking place at the Large Hadron Collider (LHC) ? the world?s newest, biggest, and highest energy particle accelerator located at CERN. Pleier is one of hundreds of researchers from around the world working on ATLAS, a seven-story particle detector positioned at a point where the LHC?s oppositely circulating beams of protons slam into one another head-on.

  16. Hadronic Total Cross Sections (R) in E+E- Interactions: Data from DOE laboratory experiments as compiled in data reviews by the Durham High Energy Physics Database Group

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

    Whalley, M. R.

    A comprehensive compilation of experimental data on total hadronic cross sections, and R ratios, in e+e- interactions is presented. Published data from the Novosibirsk, Orsay, Frascati, SLAC, CORNELL, DESY, KEK and CERN e+e- colliders on both exclusive and inclusive final particle states are included from threshold energies to the highest LEP energies. The data are presented in tabular form supplemented by compilation plots of different exclusive final particle states and of different energy regions. (Taken from abstract of paper, A Compilation of Data on Hadronic Total Cross Sections in E+E- Interactions, M.R. Whalley, Journal of Physics G (Nuclear and Particle Physics), Volume 29, Number 12A, 2003). The Durham High Energy Physics (HEP) Database Group makes these data, extracted from papers and data reviews, available in one place in an easy-to-access format. The data are also included in the Durham HEP Reaction Data Database, which can be searched at http://hepdata.cedar.ac.uk/reaction

  17. Nuclear effects in squark production at the LHC

    SciTech Connect (OSTI)

    Espindola, Danusa B.; Mariotto, C. B.; Rodriguez, M. C.

    2013-03-25

    In this contribution we study the production of squarks. If squarks are found in proton-proton (pp) collisions at the LHC, they might also be produced in collisions involving nuclei (pA and AA collisions). Here we investigate the influence of nuclear effects in the production of squarks in nuclear collisions at the LHC, and estimate the transverse momentum dependence of the nuclear ratios R{sub pA} = (d{sigma}(pA)/d{sub pT})/A(d{sigma}(pp)/d{sub pT}) and R{sub AA} = (d{sigma}(AA)/d{sub pT})/A{sup 2}(d{sigma}(pp)/d{sub pT}). We demonstrate that depending on the magnitude of the nuclear effects, the production of squarks could be enhanced or suppressed, compared to proton-proton collisions at same energies.

  18. Charged Higgs Probes of Dark Bosons at the LHC

    SciTech Connect (OSTI)

    Kong, Kyoungchul; Lee, Hye-Sung; Park, Myeonghun

    2014-08-01

    A very light (GeV scale) dark gauge boson (Z?) is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6? deviation in the muon g-2 measurement. We suggest top quark decays as a venue to search for light dark force carriers at the LHC. Such Z?s can be easily boosted, and they can decay into highly collimated leptons (lepton-jet) with large branching ratio. We investigate a scenario where a top quark decays to bW accompanied by one or multiple dark force carriers and find that such a scenario could be easily probed at the early stage of LHC Run 2.

  19. LHC diphoton Higgs signal predicted by little Higgs models

    SciTech Connect (OSTI)

    Wang Lei; Yang Jinmin

    2011-10-01

    Little Higgs theory naturally predicts a light Higgs boson whose most important discovery channel at the LHC is the diphoton signal pp{yields}h{yields}{gamma}{gamma}. In this work, we perform a comparative study for this signal in some typical little Higgs models, namely, the littlest Higgs model, two littlest Higgs models with T-parity (named LHT-I and LHT-II), and the simplest little Higgs models. We find that compared with the standard model prediction, the diphoton signal rate is always suppressed and the suppression extent can be quite different for different models. The suppression is mild (< or approx. 10%) in the littlest Higgs model but can be quite severe ({approx_equal}90%) in other three models. This means that discovering the light Higgs boson predicted by the little Higgs theory through the diphoton channel at the LHC will be more difficult than discovering the standard model Higgs boson.

  20. LHC beam-beam compensation studies at RHIC

    SciTech Connect (OSTI)

    Fischer,W.; Abreu, N.; Calaga, R.; Robert-Demolaize, G.; Luo, Y.; Montag, C.

    2009-05-04

    Long-range and head-on beam-beam effects are expected to limit the LHC performance with design parameters. To mitigate long-range effects current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. To reduce the head-on beam-beam effect electron lenses were proposed for both the LHC and RHIC. We present the experimental long-range beam-beam program and report on head-on compensations studies at RHIC, which are based on simulations.