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1

Hadron colliders (SSC/LHC)  

SciTech Connect (OSTI)

The nominal SSC and LHC designs should operate conservatively at luminosities up to 10{sup 33} cm{sup {minus}2} s{sup {minus}1}. This luminosity is dictated by the event rates that can be handled by the detectors. However, this limit is event dependent (e.g. it does not take much of a detector to detect the event pp {yields} elephant; all one needs is extremely high luminosity). As such, it is useful to explore the possibility of going beyond the 10{sup 33} cm{sup {minus}2} s{sup {minus}1} level. Such exploration will also improve the accelerator physics understanding of pp collider designs. If the detector limitations are removed, the first accelerator limits occur when the luminosity is at the level of 10{sup 34} cm{sup {minus}2}s{sup {minus}1}. These accelerator limits will first be reviewed. The authors will then continue on to explore even higher luminosity as the ultimate limit of pp colliders. Accelerator technologies needed to achieve this ultimate luminosity as well as the R and D needed to reach it are discussed.

Chao, A.W. [Superconducting Super Collider Lab., Dallas, TX (United States); Palmer, R.B. [Superconducting Super Collider Lab., Dallas, TX (United States); [Stanford Linear Accelerator Center, CA (United States); Evans, L.; Gareyte, J. [CERN, Geneva (Switzerland); Siemann, R.H. [Cornell Univ., Ithaca, NY (United States)

1992-12-31T23:59:59.000Z

2

Large hadron collider (LHC) project quality assurance plan  

SciTech Connect (OSTI)

The LHC Quality Assurance Plan is a set of operating principles, requirements, and practices used to support Berkeley Lab's participation in the Large Hadron Collider Project. The LHC/QAP is intended to achieve reliable, safe, and quality performance in the LHC project activities. The LHC/QAP is also designed to fulfill the following objectives: (1) The LHC/QAP is Berkeley Lab's QA program document that describes the elements necessary to integrate quality assurance, safety management, and conduct of operations into the Berkeley Lab's portion of the LHC operations. (2) The LHC/QAP provides the framework for Berkeley Lab LHC Project administrators, managers, supervisors, and staff to plan, manage, perform, and assess their Laboratory work. (3) The LHC/QAP is the compliance document that conforms to the requirements of the Laboratory's Work Smart Standards for quality assurance (DOE O 414.1, 10 CFR 830.120), facility operations (DOE O 5480.19), and safety management (DOE P 450.4).

Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

2002-09-30T23:59:59.000Z

3

Thermal Performance of the Supporting System for the Large Hadron Collider (LHC) Superconducting Magnets  

E-Print Network [OSTI]

The LHC collider will be composed of approximately 1700 main ring superconducting magnets cooled to 1.9 K in pressurised superfluid helium and supported within their cryostats on low heat in-leak column-type supports. The precise positioning of the heavy magnets and the stringent thermal budgets imposed by the machine cryogenic system, require a sound thermo-mechanical design of the support system. Each support is composed of a main tubular thin-walled structure in glass-fibre reinforced epoxy resin, with its top part interfaced to the magnet at 1.9 K and its bottom part mounted onto the cryostat vacuum vessel at 293 K. In order to reduce the conduction heat in-leak at 1.9 K, each support mounts two heat intercepts at intermediate locations on the column, both actively cooled by cryogenic lines carrying helium gas at 4.5-10 K and 50-65 K. The need to assess the thermal performance of the supports has lead to setting up a dedicated test set-up for precision heat load measurements on prototype supports. This pa...

Castoldi, M; Parma, Vittorio; Vandoni, Giovanna

1999-01-01T23:59:59.000Z

4

Results from hadron colliders  

SciTech Connect (OSTI)

The present status of hadron collider physics is reviewed. The total cross section for {bar p} + p has been measured at 1.8 TeV: {sigma}{sub tot} = 72.1 {plus minus} 3.3 mb. New data confirm the UA2 observation of W/Z {yields} {bar q}q. Precision measurements of M{sub W} by UA2 and CDF give an average value M{sub W} = 80.13 {plus minus} 0.30 GeV/c{sup 2}. When combined with measurements of M{sub Z} from LEP and SLC this number gives sin{sup 2}{theta}{sub W} = 0.227 {plus minus} 0.006, or m{sub top} = 130{sub {minus}60}{sup +40} GeV/c{sup 2} from the EWK radiative correction term {Delta}r. Evidence for hadron colliders as practical sources of b quarks has been strengthened, while searches for t quarks have pushed the mass above M{sub W}: m{sub top} > 89 GeV/c{sup 2} 95% cl (CDF Preliminary). Searches beyond the standard model based on the missing E{sub T} signature have not yet produced any positive results. Future prospects for the discovery of the top quark in the range m{sub top} < 200 GeV/c{sup 2} look promising. 80 refs., 35 figs., 7 tabs.

Pondrom, L.G. (Wisconsin Univ., Madison, WI (USA))

1990-12-14T23:59:59.000Z

5

The Large Hadron Electron Collider Project  

E-Print Network [OSTI]

A Conceptual Design Report (CDR) for the Large Hadron Electron Collider, the LHeC, is being prepared, to which an introduction was given for the plenary panel discussion on the future of deep inelastic scattering held at DIS09. This is briefly summarised here. The CDR will comprise designs of the ep/eA collider, based on ring and linear electron accelerators, of the interaction region, designed for simultaneous $ep$ and $pp$ operation, of a new, modular detector, and it will present basics on the physics motivation for a high luminous Tera scale electron-nucleon collider as a complement to the LHC.

Max Klein

2009-08-20T23:59:59.000Z

6

Higgs boson production at hadron colliders: Signal and background processes  

SciTech Connect (OSTI)

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

David Rainwater; Michael Spira; Dieter Zeppenfeld

2004-01-12T23:59:59.000Z

7

Hadron collider physics at UCR  

SciTech Connect (OSTI)

This paper describes the research work in high energy physics by the group at the University of California, Riverside. Work has been divided between hadron collider physics and e{sup +}-e{sup {minus}} collider physics, and theoretical work. The hadron effort has been heavily involved in the startup activities of the D-Zero detector, commissioning and ongoing redesign. The lepton collider work has included work on TPC/2{gamma} at PEP and the OPAL detector at LEP, as well as efforts on hadron machines.

Kernan, A.; Shen, B.C.

1997-07-01T23:59:59.000Z

8

Statistical hadronization model predictions for charmed hadrons at LHC  

E-Print Network [OSTI]

We present predictions of the statistical hadronization model for charmed hadrons production in Pb+Pb collisions at LHC.

A Andronic; P Braun-Munzinger; K Redlich; J Stachel

2007-07-27T23:59:59.000Z

9

B Physics Theory for Hadron Colliders  

E-Print Network [OSTI]

A short overview of theoretical methods for B physics at hadron colliders is presented. The main emphasis is on the theory of two-body hadronic B decays, which provide a rich field of investigation in particular for the Tevatron and the LHC. The subject holds both interesting theoretical challenges as well as many opportunities for flavor studies and new physics tests. A brief review of the current status and recent developments is given. A few additional topics in B physics are also mentioned.

G. Buchalla

2008-09-03T23:59:59.000Z

10

Cryogenics for the Large Hadron Collider  

E-Print Network [OSTI]

The Large Hadron Collider (LHC), a 26.7 km circumference superconducting accelerator equipped with high-field magnets operating in superfluid helium below 1.9 K, has now fully entered construction at CERN, the European Laboratory for Particle Physics. The heart of the LHC cryogenic system is the quasi-isothermal magnet cooling scheme, in which flowing two-phase saturated superfluid helium removes the heat load from the 36'000 ton cold mass, immersed in some 400 m3 static pressurised superfluid helium. The LHC also makes use of supercritical helium for non-isothermal cooling of the beam screens which intercept most of the dynamic heat loads at higher temperature. Although not used in normal operation, liquid nitrogen will provide the source of refrigeration for precooling the machine. Refrigeration for the LHC is produced in eight large refrigerators, each with an equivalent capacity of about 18 kW at 4.5 K, completed by 1.8 K refrigeration units making use of several stages of hydrodynamic cold compressors. T...

Lebrun, P

1999-01-01T23:59:59.000Z

11

Cryogenics for the Large Hadron Collider  

E-Print Network [OSTI]

The Large Hadron Collider (LHC), a 26.7 km circumference superconducting accelerator equipped with high-field magnets operating in superfluid helium below 1.9 K, has now fully entered construction at CERN, the European Laboratory for Particle Physics. The heart of the LHC cryogenic system is the quasi-isothermal magnet cooling scheme, in which flowing two-phase saturated superfluid helium removes the heat load from the 36000 ton cold mass, immersed in some 400 m/sup 3/ static pressurised superfluid helium. The LHC also makes use of supercritical helium for nonisothermal cooling of the beam screens which intercept most of the dynamic heat loads at higher temperature. Although not used in normal operation, liquid nitrogen will provide the source of refrigeration for precooling the machine. Refrigeration for the LHC is produced in eight large refrigerators, each with an equivalent capacity of about 18 kW at 4.5 K, completed by 1.8 K refrigeration units making use of several stages of hydrodynamic cold compressor...

Lebrun, P

2000-01-01T23:59:59.000Z

12

Weak Boson Emission in Hadron Collider Processes  

E-Print Network [OSTI]

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

U. Baur

2006-11-17T23:59:59.000Z

13

Higgs Boson Searches at Hadron Colliders (1/4)  

SciTech Connect (OSTI)

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.

None

2010-06-21T23:59:59.000Z

14

Higgs Boson Searches at Hadron Colliders (1/4)  

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

15

Top quark studies at hadron colliders  

SciTech Connect (OSTI)

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

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

1997-01-01T23:59:59.000Z

16

The liquid helium storage system for the Large Hadron Collider.  

E-Print Network [OSTI]

The cryogenic system of the Large Hadron Collider (LHC) under operation at CERN has a total helium inventory of 140 t. Up to 50 t can be stored in gas storage tanks. The remaining inventory will be stored in a liquid helium storage system consisting of six 15-t liquid helium tanks in 4 locations. The two liquid helium tanks of specific low heat inleak design and the required infrastructure of the first location were recently commissioned. Four additional tanks shall be operational end 2010. The paper describes the features and characteristics of the liquid helium storage system and presents the measurement of the thermal performance of the two first tanks.

Benda, V; Fathallah, M; Goiffon, T; Parente, C; Perez-Duenas, E; Perret, Ph; Pirotte, O; Serio, L; Vullierme, B

2011-01-01T23:59:59.000Z

17

Discovery Mass Reach for Excited Quarks at Hadron Colliders  

E-Print Network [OSTI]

If quarks are composite particles then excited states are expected. We estimate the discovery mass reach as a function of integrated luminosity for excited quarks decaying to dijets at the Tevatron, LHC, and a Very Large Hadron Collider (VLHC). At the Tevatron the mass reach is 0.94 TeV for Run II (2 fb^-1) and 1.1 TeV for TeV33 (30 fb^-1). At the LHC the mass reach is 6.3 TeV for 100 fb^-1. At a VLHC with a center of mass energy, sqrt(s), of 50 TeV (200 TeV) the mass reach is 25 TeV (78 TeV) for an integrated luminosity of 10^4 fb^-1. However, an excited quark with a mass of 25 TeV would be discovered at a hadron collider with sqrt(s)=100 TeV and an integrated luminosity of 13 fb^-1, illustrating a physics example where a factor of 2 in machine energy is worth a factor of 1000 in luminosity.

Robert M. Harris

1996-09-11T23:59:59.000Z

18

Really large hadron collider working group summary  

SciTech Connect (OSTI)

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

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

1996-12-01T23:59:59.000Z

19

Signatures for Right-Handed Neutrinos at the Large Hadron Collider  

SciTech Connect (OSTI)

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.

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

2008-10-31T23:59:59.000Z

20

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

E-Print Network [OSTI]

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

Khalil, S

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Rare b hadron decays at the LHC  

E-Print Network [OSTI]

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

Blake, T; Hiller, G

2015-01-01T23:59:59.000Z

22

Search for Supersymmetry Using Weak Boson Fusion Processes in Proton-Proton Collisions at the Large Hadron Collider  

E-Print Network [OSTI]

In 2012, the Large Hadron Collider at CERN (LHC) collided protons at an unprecedented center-of-mass energy of 8 TeV. With data corresponding to a total integrated luminosity of 19.7 fb^(?1), the Compact Muon Solenoid (CMS) collaboration is studying...

Flanagan, Will

2014-08-08T23:59:59.000Z

23

First electron-cloud studies at the Large Hadron Collider  

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

24

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

SciTech Connect (OSTI)

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?

Quigg, Chris; /Fermilab /CERN

2007-02-01T23:59:59.000Z

25

US/LHC - Large Hadron Collider  

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

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

26

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

E-Print Network [OSTI]

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

Sun, P; Tomàs, R; Zimmermann, F

2010-01-01T23:59:59.000Z

27

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

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

28

CMSSM, naturalness and the "fine-tuning price" of the Very Large Hadron Collider  

E-Print Network [OSTI]

The absence of supersymmetry or other new physics at the Large Hadron Collider (LHC) has lead many to question naturalness arguments. With Bayesian statistics, we argue that natural models are most probable and that naturalness is not merely an aesthetic principle. We calculate a probabilistic measure of naturalness, the Bayesian evidence, for the Standard Model (SM) with and without quadratic divergences, confirming that the SM with quadratic divergences is improbable. We calculate the Bayesian evidence for the Constrained Minimal Supersymmetric Standard Model (CMSSM) with naturalness priors in three cases: with only the $M_Z$ measurement; with the $M_Z$ measurement and LHC measurements; and with the $M_Z$ measurement, $m_h$ measurement and a hypothetical null result from a $\\sqrt{s}=100\\,\\text{TeV}$ Very Large Hadron Collider (VLHC) with $3000/\\text{fb}$. The "fine-tuning price" of the VLHC given LHC results would be $\\sim400$, which is slightly less than that of the LHC results given the electroweak scale ($\\sim500$).

Andrew Fowlie

2014-03-13T23:59:59.000Z

29

TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS  

SciTech Connect (OSTI)

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.

Jabeen, Shabnam

2013-10-20T23:59:59.000Z

30

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

E-Print Network [OSTI]

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

Joseph Bramante; Jason Kumar; John Learned

2014-12-05T23:59:59.000Z

31

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

E-Print Network [OSTI]

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

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

32

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

E-Print Network [OSTI]

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

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

2010-09-08T23:59:59.000Z

33

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

SciTech Connect (OSTI)

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.

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

2012-04-30T23:59:59.000Z

34

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.

35

Learning to See at the Large Hadron Collider  

SciTech Connect (OSTI)

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

Quigg, Chris

2010-01-01T23:59:59.000Z

36

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

E-Print Network [OSTI]

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

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

2014-01-01T23:59:59.000Z

37

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

SciTech Connect (OSTI)

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

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

2011-02-04T23:59:59.000Z

38

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

E-Print Network [OSTI]

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

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

2014-09-10T23:59:59.000Z

39

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

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

40

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

E-Print Network [OSTI]

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

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

2010-11-29T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Transverse beams stability studies at the Large Hadron Collider  

E-Print Network [OSTI]

A charged particle beam travelling at the speed of light produces large electromagnetic wake fields which, through interactions with its surroundings, act back on the particles in the beam. This coupled system may become unstable, resulting in a deterioration of the beam quality. Such effects play a major role in most existing storage rings, as they limit the maximum performance achievable. In a collider, the presence of a second beam significantly changes the dynamics, as the electromagnetic interactions of the two beams on each other are usually very strong and may, also, limit the collider performances. This thesis treats the coherent stability of the two beams in a circular collider, including the effects of the electromagnetic wake fields and of the beam-beam interactions, with particular emphasis on CERN's Large Hadron Collider. As opposed to other colliders, this machine features a large number of bunches per beam each experiencing multiple long-range and head-on beam-beam interactions. Existing models...

Buffat, Xavier; Pieloni, Tatiana

2015-01-30T23:59:59.000Z

42

A 233 km tunnel for lepton and hadron colliders  

SciTech Connect (OSTI)

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.

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

2012-12-21T23:59:59.000Z

43

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

E-Print Network [OSTI]

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

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

2009-01-01T23:59:59.000Z

44

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

E-Print Network [OSTI]

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

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

2009-01-01T23:59:59.000Z

45

Looking for hints of a reconstructible seesaw model at the Large Hadron Collider  

E-Print Network [OSTI]

We study the production of heavy neutrinos at the Large Hadron Collider (LHC) through the dominant s-channel production mode as well as the vector boson fusion (VBF) process. We consider the TeV scale minimal linear seesaw model containing two heavy singlets with opposite lepton number. This model is fully reconstructible from oscillation data apart from an overall normalization constant which can be constrained from meta-stability of the electroweak vacuum and bounds coming from lepton flavor violation (LFV) searches. Dirac nature of heavy neutrinos in this model implies suppression of the conventional same-sign-dilepton signal at the LHC. We analyze the collider signatures with tri-lepton final state and missing transverse energy as well as VBF type signals which are characterized by two additional forward tagged jets. Our investigation reveals that due to stringent constraints on light-heavy mixing coming from LFV and meta-stability bounds, the model can be explored only for light to moderate mass range of heavy neutrinos. We also note that in case of a positive signal, flavor counting of the final tri-lepton channel can give information about the mass hierarchy of the light neutrinos.

Gulab Bambhaniya; Srubabati Goswami; Subrata Khan; Partha Konar; Tanmoy Mondal

2014-10-21T23:59:59.000Z

46

Statistical hadronization of charm: from FAIR to the LHC  

E-Print Network [OSTI]

We discuss the production of charmonium in nuclear collisions within the framework of the statistical hadronization model. We demonstrate that the model reproduces very well the availble data at RHIC. We provide predictions for the LHC energy where, dependently on the charm production cross section, a dramatically different behaviour of charmonium production as a function of centrality might be expected. We extend our predictions for charm production towards the threshold energies, where charm is expected to be measured at the future FAIR facility.

A. Andronic; P. Braun-Munzinger; K. Redlich; J. Stachel

2008-05-30T23:59:59.000Z

47

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

E-Print Network [OSTI]

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

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

2012-01-01T23:59:59.000Z

48

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

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

49

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

SciTech Connect (OSTI)

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.

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

2009-07-01T23:59:59.000Z

50

Top-Quark Initiated Processes at High-Energy Hadron Colliders  

E-Print Network [OSTI]

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

Tao Han; Joshua Sayre; Susanne Westhoff

2014-11-10T23:59:59.000Z

51

Phenomenology of the minimal $B-L$ Model: the Higgs sector at the Large Hadron Collider and future Linear Colliders  

E-Print Network [OSTI]

This Thesis is devoted to the study of the phenomenology of the Higgs sector of the minimal $B-L$ extension of the Standard Model at present and future colliders. Firstly, the motivations that call for the minimal $B-L$ extension are summarised. In addition, the model is analysed in its salient parts. Moreover, a detailed review of the phenomenological allowed Higgs sector parameter space is given. Finally, a complete survey of the distinctive Higgs boson signatures of the model at both the Large Hadron Collider and the future linear colliders is presented.

Giovanni Marco Pruna

2011-06-23T23:59:59.000Z

52

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

SciTech Connect (OSTI)

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.

Bruce, R.; et al.,

2013-11-21T23:59:59.000Z

53

Next-to-Leading Order Predictions for W + 3-Jet Distributions at Hadron Colliders  

SciTech Connect (OSTI)

We present next-to-leading order QCD predictions for a variety of distributions in W + 3-jet production at both the Tevatron and the Large Hadron Collider. We include all subprocesses and incorporate the decay of the W boson into leptons. Our results are in excellent agreement with existing Tevatron data and provide the first quantitatively precise next-to-leading order predictions for the LHC. We include all terms in an expansion in the number of colors, confirming that the specific leading-color approximation used in our previous study is accurate to within three percent. The dependence of the cross section on renormalization and factorization scales is reduced significantly with respect to a leading-order calculation. We study different dynamical scale choices, and find that the total transverse energy is significantly better than choices used in previous phenomenological studies. We compute the one-loop matrix elements using on-shell methods, as numerically implemented in the BlackHat code. The remaining parts of the calculation, including generation of the real-emission contributions and integration over phase space, are handled by the SHERPA package.

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

2009-12-09T23:59:59.000Z

54

Large hadron collider (LHC) project quality assurance plan  

E-Print Network [OSTI]

management, and conduct of operations into the Berkeleymanagement, and conduct of operations. For involved unitsassurance, safety, and conduct of operations are implemented

Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

2002-01-01T23:59:59.000Z

55

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

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

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

56

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

E-Print Network [OSTI]

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

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

2012-01-01T23:59:59.000Z

57

Physics Reach at Future Colliders  

SciTech Connect (OSTI)

The physics reach at future colliders is discussed, with focus on the Higgs sector. First we present the Standard Model and some results obtained at the existing high-energy hadron collider, Tevatron, together with the corresponding expectations for the Large Hadron Collider (LHC), which starts operating in 2008. Then we discuss important low energy measurements: the anomalous magnetic moment for muon and the leptonic B-decay together with b{yields}s{gamma}. Finally the potential of the planned e{sup +}e{sup -} International Linear Collider (ILC) and its possible option Photon Linear Collider (PLC), e{gamma} and {gamma}{gamma}, is shortly presented.

Krawczyk, Maria [Institute of Theoretical Physics, University of Warsaw, ul. Hoz-dota 69, 00-681 Warsaw (Poland); CERN, CH-1211 Geneva 23 (Switzerland)

2007-11-27T23:59:59.000Z

58

Production of W and Z bosons at hadron colliders  

E-Print Network [OSTI]

The article summarizes the main recent measurements related to production of the W and Z bosons at the Tevatron and the LHC experiments. The results of the measurements are compared to the standard model predictions.

A. Savin

2012-12-15T23:59:59.000Z

59

QCD effects in Higgs boson production at hadron colliders  

E-Print Network [OSTI]

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

M. Grazzini

2010-01-21T23:59:59.000Z

60

TESLA*HERA as Lepton (Photon)-Hadron Collider  

E-Print Network [OSTI]

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

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

2000-04-11T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

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)

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.

Miller, David Wilkins

2012-03-20T23:59:59.000Z

62

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

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

63

A posteriori inclusion of parton density functions in NLO QCD final-state calculations at hadron colliders: The APPLGRID Project  

E-Print Network [OSTI]

A method to facilitate the consistent inclusion of cross-section measurements based on complex final-states from HERA, TEVATRON and the LHC in proton parton density function (PDF) fits has been developed. This can be used to increase the sensitivity of LHC data to deviations from Standard Model predictions. The method stores perturbative coefficients of NLO QCD calculations of final-state observables measured in hadron colliders in look-up tables. This allows the posteriori inclusion of parton density functions (PDFs), and of the strong coupling, as well as the a posteriori variation of the renormalisation and factorisation scales in cross-section calculations. The main novelties in comparison to original work on the subject are the use of higher-order interpolation, which substantially improves the trade-off between accuracy and memory use, and a CPU and computer memory optimised way to construct and store the look-up table using modern software tools. It is demonstrated that a sufficient accuracy on the cross-section calculation can be achieved with reasonably small look-up table size by using the examples of jet production and electro-weak boson (Z, W) production in proton-proton collisions at a center-of-mass energy of 14 TeV at the LHC. The use of this technique in PDF fitting is demonstrated in a PDF-fit to HERA data and simulated LHC jet cross-sections as well as in a study of the jet cross-section uncertainties at various centre-of-mass energies.

Tancredi Carli; Dan Clements; Amanda Cooper-Sarkar; Claire Gwenlan; Gavin P. Salam; Frank Siegert; Pavel Starovoitov; Mark Sutton

2009-11-16T23:59:59.000Z

64

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

SciTech Connect (OSTI)

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.

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

2014-04-02T23:59:59.000Z

65

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

E-Print Network [OSTI]

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

Maury Cuna, H; Zimmermann, F

2012-01-01T23:59:59.000Z

66

Ion Colliders  

E-Print Network [OSTI]

High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

Fischer, W

2015-01-01T23:59:59.000Z

67

Nuclear shadowing and prompt photons at relativistic hadron colliders  

E-Print Network [OSTI]

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

C. Brenner Mariotto; V. P. Goncalves

2008-08-26T23:59:59.000Z

68

Vector- and Scalar-Bilepton Pair Production in Hadron Colliders  

E-Print Network [OSTI]

We study the double-charged vector-bilepton pair production and double-charged scalar-bilepton pair production {\\it via} $p + p \\longrightarrow Y^{++} + Y^{--} + X$ and $p + p \\longrightarrow S_1^{++} + S_1^{--} + X$, where $Y$ and $S_1$ are vector and scalar bileptons respectively, in the framework of the minimal version of the 3-3-1 model. We compute the photon, $Z$, and $Z^\\prime$ s-channel contributions for the elementary process of bilepton scalar pair production, and to keep the correct unitarity behavior for the elementary $q \\bar q$ interaction, we include the exotic quark t-channel contribution in the vector-bilepton pair production calculation. We explore a mass range for $Z^\\prime$ and we fix the exotic quark mass within the experimental bounds. In this model, the vector-bilepton mass is directly related to $M_{Z^\\prime}$ and we consider scalar mass values around the vector-bilepton mass. We show that the total cross section for vector-bilepton production is 3 orders of magnitude larger than for scalar pair production for $\\sqrt s= 7$ TeV and 14 TeV and we obtain the number of events for the proposed LHC luminosities as a function of the bilepton mass. In addition we present some invariant mass and transverse momentum distributions. When comparing these distributions we observe quite different behavior providing the determination of the bilepton nature. We conclude that one can disentangle the production rates and that the LHC can be capable of detecting these predicted particles as a signal for new physics.

E. Ramirez Barreto; Y. A. Coutinho; J. Sá Borges

2011-03-07T23:59:59.000Z

69

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

SciTech Connect (OSTI)

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.

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

2013-07-29T23:59:59.000Z

70

Construction of block-coil high-field model dipoles for future hadron colliders  

SciTech Connect (OSTI)

A family of high-field dipoles is being developed at Texas A&M University, as part of the program to improve the cost-effectiveness of superconducting magnet technology for future hadron colliders. The TAMU technology employs stress management, flux-plate control of persistent-current multipoles, conductor optimization using mixed-strand cable, and metal-filled bladders to provide pre-load and surface compliance. Construction details and status of the latest model dipole will be presented.

Blackburn, Raymond; Elliott, Tim; Henchel, William; McInturff, Al; McIntyre, Peter; Sattarov, Akhdior

2002-08-04T23:59:59.000Z

71

Second order QCD corrections to gluonic jet production at hadron colliders  

E-Print Network [OSTI]

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

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

2014-07-21T23:59:59.000Z

72

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

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

73

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

E-Print Network [OSTI]

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

Federico Colecchia

2014-12-19T23:59:59.000Z

74

Hadronically decaying color-adjoint scalars at the LHC  

E-Print Network [OSTI]

We study the phenomenology of the pair-production of scalar color-octet electroweak singlet states at the LHC. Such states appear in many extensions of the Standard Model. They can be pair-produced copiously at the LHC and will signal themselves as resonances in multijet final states. Beyond the QCD pair-production process we consider a vectorlike confinement scenario with an additional color-octet vector state. These vector particles can be produced in the s-channel and through their decay contribute to the scalar pair production. We point out the differences between the two hypotheses and device a strategy to distinguish them.

Steffen Schumann; Adrien Renaud; Dirk Zerwas

2011-08-15T23:59:59.000Z

75

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

E-Print Network [OSTI]

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

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

2015-01-26T23:59:59.000Z

76

A High Luminosity e+e- Collider in the LHC tunnel to study the Higgs Boson  

E-Print Network [OSTI]

We consider the possibility of a 120x120 GeV e+e- ring collider in the LHC tunnel. A luminosity of 10^34/cm2/s can be obtained with a luminosity life time of a few minutes. A high operation efficiency would require two machines: a low emittance collider storage ring and a separate accelerator injecting electrons and positrons into the storage ring to top up the beams every few minutes. A design inspired from the high luminosity b-factory design and from the LHeC design report is presented. Statistics of over 10^4 HZ events per year per experiment can be contemplated for a Standard Higgs Boson mass of 115-130 GeV.

Alain Blondel; Frank Zimmermann

2012-02-15T23:59:59.000Z

77

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

E-Print Network [OSTI]

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

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

2011-10-11T23:59:59.000Z

78

Universe in the light of LHC  

E-Print Network [OSTI]

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

Maria Krawczyk; Malgorzata Matej; Dorota Sokolowska; Bogumila Swiezewska

2015-01-19T23:59:59.000Z

79

Universe in the light of LHC  

E-Print Network [OSTI]

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

Krawczyk, Maria; Sokolowska, Dorota; Swiezewska, Bogumila

2015-01-01T23:59:59.000Z

80

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

SciTech Connect (OSTI)

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

Dinardo, Mauro E.; /Milan U.

2005-12-01T23:59:59.000Z

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81

Betatron squeeze optimisation at the Large Hadron Collider based on first year of operation data  

E-Print Network [OSTI]

In order to achieve the high luminosity expected from the Large Hadron Collider, the beta function at the interaction points must be minimised. As the aperture in the surroundings of the interaction points become smaller and smaller with decreasing beta function at the interaction point, the latter is kept higher during injection and energy ramp and reduced before the production of collision, by the means of the betatron squeeze. This operation as shown to be very critical in previous colliders, however, good performances were achieved early during the commissioning of the machine allowing to optimise this operation along the year. Firstly, a systematic fill by fill analysis of the beam parameters is performed in order to point out, understand and solve potential issues, allowing, in particular, to minimise the beam losses during the operation. Secondly, simulations of beam parameters based on the strength of the magnets extracted from the control system are introduced and validated with measurements. The sim...

Buffat, Xavier; Redaelli, Stefano

2011-01-01T23:59:59.000Z

82

Addendum to Distinguishing Spins in Decay Chains at the Large Hadron Collider.  

E-Print Network [OSTI]

ar X iv :h ep -p h/ 06 06 21 2v 1 2 0 Ju n 20 06 Preprint typeset in JHEP style - PAPER VERSION Cavendish–HEP–06/15 Addendum to “Distinguishing Spins in Decay Chains at the Large Hadron Collider”? Christiana Athanasiou1, Christopher G. Lester2... mass distributions of the three observable two-body combinations: dileptons (mll), quark- or antiquark-jet plus positive lepton (mjl+), and jet plus negative lepton (mjl?).1 If P (m|S) represents the normalized probability distribution of any one...

Athanasiou, Christiana; Lester, Christopher G; Smillie, Jennifer M; Webber, Bryan R

83

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

SciTech Connect (OSTI)

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.

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

2011-04-01T23:59:59.000Z

84

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

E-Print Network [OSTI]

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

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

2009-01-01T23:59:59.000Z

85

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

SciTech Connect (OSTI)

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

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

2003-05-27T23:59:59.000Z

86

Supersymmetry At LHC  

SciTech Connect (OSTI)

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.

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

2008-04-21T23:59:59.000Z

87

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

E-Print Network [OSTI]

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

Lakdawala, Samir

2013-05-02T23:59:59.000Z

88

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

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

89

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

E-Print Network [OSTI]

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

Gunion, J F

2004-01-01T23:59:59.000Z

90

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

E-Print Network [OSTI]

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

Mitsuka, Gaku

2015-01-01T23:59:59.000Z

91

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

SciTech Connect (OSTI)

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

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

2007-06-01T23:59:59.000Z

92

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

SciTech Connect (OSTI)

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

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

2011-12-05T23:59:59.000Z

93

Collimation with hollow electron beams a proposed design for the LHC upgrade  

E-Print Network [OSTI]

Collimation with hollow electron beams is a technique for halo removal in high-power hadron beams. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, we are investigating the applicability of this technique to the Large Hadron Collider and a conceptual design is being developed. We review some of the main topics related to this study: motivation; halo removal processes; development of hollow electron guns; effects on the proton beam core; and integration in the LHC machine.

Stancari, G; Valishev, A; Bruce, R; Redaelli, S; Rossi, A; Salvachua Ferrando, B; Moens, V

2013-01-01T23:59:59.000Z

94

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

E-Print Network [OSTI]

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

Gaku Mitsuka

2015-03-12T23:59:59.000Z

95

Support Vector Machine Classification on a Biased Training Set: Multi-Jet Background Rejection at Hadron Colliders  

E-Print Network [OSTI]

This paper describes an innovative way to optimize a multivariate classifier, in particular a Support Vector Machine algorithm, on a problem characterized by a biased training sample. This is possible thanks to the feedback of a signal-background template fit performed on a validation sample and included both in the optimization process and in the input variable selection. The procedure is applied to a real case of interest at hadron collider experiments: the reduction and the estimate of the multi-jet background in the $W\\to e \

Federico Sforza; Vittorio Lippi

2014-07-01T23:59:59.000Z

96

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

E-Print Network [OSTI]

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

Alexandre Arbey; Marco Battaglia; Farvah Mahmoudi

2015-02-10T23:59:59.000Z

97

Time Machine at the LHC  

E-Print Network [OSTI]

Recently, black hole and brane production at CERN's Large Hadron Collider (LHC) has been widely discussed. We suggest that there is a possibility to test causality at the LHC. We argue that if the scale of quantum gravity is of the order of few TeVs, proton-proton collisions at the LHC could lead to the formation of time machines (spacetime regions with closed timelike curves) which violate causality. One model for the time machine is a traversable wormhole. We argue that the traversable wormhole production cross section at the LHC is of the same order as the cross section for the black hole production. Traversable wormholes assume violation of the null energy condition (NEC) and an exotic matter similar to the dark energy is required. Decay of the wormholes/time machines and signatures of time machine events at the LHC are discussed.

I. Ya. Aref'eva; I. V. Volovich

2007-10-15T23:59:59.000Z

98

Large Hadron Collider probe of supersymmetric neutrinoless double beta decay mechanism  

E-Print Network [OSTI]

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

B. C. Allanach; C. H. Kom; H. Päs

2009-02-26T23:59:59.000Z

99

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

SciTech Connect (OSTI)

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.

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

2009-08-28T23:59:59.000Z

100

Klystron switching power supplies for the Internation Linear Collider  

SciTech Connect (OSTI)

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.

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

2009-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

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

SciTech Connect (OSTI)

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

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

2009-08-21T23:59:59.000Z

102

Les Houches guidebook to Monte Carlo generators for hadron collider physics  

SciTech Connect (OSTI)

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.

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

2004-03-01T23:59:59.000Z

103

Les Houches Guidebook to Monte Carlo generators for hadron collider physics  

SciTech Connect (OSTI)

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.

Dobbs, M.A

2004-08-24T23:59:59.000Z

104

PROSPECTS FOR COLLIDERS AND COLLIDER PHYSICS TO THE 1 PEV ENERGY SCALE  

SciTech Connect (OSTI)

A review is given of the prospects for future colliders and collider physics at the energy frontier. A proof-of-plausibility scenario is presented for maximizing the authors progress in elementary particle physics by extending the energy reach of hadron and lepton colliders as quickly and economically as might be technically and financially feasible. The scenario comprises 5 colliders beyond the LHC--one each of e{sup +}e{sup {minus}} and hadron colliders and three {mu}{sup +}{mu}{sup {minus}} colliders--and is able to hold to the historical rate of progress in the log-energy reach of hadron and lepton colliders, reaching the 1 PeV constituent mass scale by the early 2040's. The technical and fiscal requirements for the feasibility of the scenario are assessed and relevant long-term R and D projects are identified. Considerations of both cost and logistics seem to strongly favor housing most or all of the colliders in the scenario in a new world high energy physics laboratory.

KING,B.J.

2000-05-05T23:59:59.000Z

105

Heavy Ion Collisions at the LHC - Last Call for Predictions  

E-Print Network [OSTI]

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

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

2007-11-06T23:59:59.000Z

106

CERN and LHC - their place in global science  

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

107

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

E-Print Network [OSTI]

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

Paus, Christoph M. E.

108

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

E-Print Network [OSTI]

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

Stefan Liebler; Gudrid Moortgat-Pick; Georg Weiglein

2015-02-27T23:59:59.000Z

109

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

E-Print Network [OSTI]

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

Liebler, Stefan; Weiglein, Georg

2015-01-01T23:59:59.000Z

110

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

E-Print Network [OSTI]

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

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

2015-01-30T23:59:59.000Z

111

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

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

112

Ruling out a 4th generation using limits on hadron collider Higgs signals  

E-Print Network [OSTI]

We consider the impact of a 4th generation on Higgs to $\\gamma\\gamma$ and $WW,ZZ$ signals and demonstrate that the Tevatron and LHC have essentially eliminated the possibility of a 4th generation if the Higgs is SM-like and has mass below 200 GeV. We also show that the absence of enhanced Higgs signals in current data sets in the $\\gamma\\gamma$ and $WW,ZZ$ final states can strongly constrain the possibility of a 4th generation in two-Higgs-doublet models of type II, including the MSSM.

John F. Gunion

2011-05-23T23:59:59.000Z

113

Lepton number violating processes mediated by Majorana neutrinos at hadron colliders  

SciTech Connect (OSTI)

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.

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

2009-10-01T23:59:59.000Z

114

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

E-Print Network [OSTI]

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

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

2014-08-05T23:59:59.000Z

115

Probing Higgs Boson CP Properties with $t\\bar{t}H$ at the LHC and the 100 TeV pp Collider  

E-Print Network [OSTI]

The Higgs boson $H$ has the largest coupling to the top quark $t$ among the standard model (SM) fermions. This is one of the ideal places to investigate new physics beyond SM. In this work, we study the potential of determining Higgs boson $CP$ properties at the LHC and future 33 TeV and 100 TeV $pp$ colliders by analysing various operators formed from final states variables in $t\\bar{t}H$ production. The discrimination power from SM coupling is obtained with Higgs boson reconstructed from $ H\\to \\gamma \\gamma$ and $ H\\to b \\bar{b}$. We find that $t\\bar{t}b\\bar{b}$ process can provide more than 3$\\sigma$ discrimination power with 300 $fb^{-1}$ integrated luminosity in a wide range of allowed Higgs to top couplings for the LHC, the 33 TeV and 100 TeV colliders. For $t\\bar{t}\\gamma\\gamma$ the discrimination power will be below 3$\\sigma$ at the LHC, while for 33 TeV and 100 TeV colliders, more than 3$\\sigma$ sensitivity can be reached.

He, Xiao-Gang; Zheng, Ya-Juan

2015-01-01T23:59:59.000Z

116

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

SciTech Connect (OSTI)

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}}.

STAR Coll

2009-02-09T23:59:59.000Z

117

The ATLAS Experiment: Getting Ready for the LHC  

SciTech Connect (OSTI)

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

Jenni, Peter (CERN) [CERN

2006-05-15T23:59:59.000Z

118

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

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

119

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

E-Print Network [OSTI]

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

Howard E. Haber

2010-11-04T23:59:59.000Z

120

Modeling missing transverse energy in V+jets at CERN LHC  

E-Print Network [OSTI]

I discuss a method to model the instrumental response of the CMS and ATLAS detectors at high transverse missing energies to dominant standard model V+jets backgrounds, where V is a Z, gamma or W, using multi-jet QCD events. The method is developed for new physics searches in early data at the Large Hadron Collider (LHC) with minimal recourse to simulation.

Victor Pavlunin

2011-03-07T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

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

E-Print Network [OSTI]

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

Quaranta, Elena; Giulini Castiglioni Agosteo, Stefano Luigi Maria

122

Improving estimates of the number of fake leptons and other mis-reconstructed objects in hadron collider events: BoB's your UNCLE  

E-Print Network [OSTI]

J H E P 1 1 ( 2 0 1 4 ) 0 3 1 Published for SISSA by Springer Received: July 30, 2014 Revised: September 29, 2014 Accepted: October 20, 2014 Published: November 6, 2014 Improving estimates of the number of ‘fake’ leptons and other mis... -reconstructed objects in hadron collider events: BoB’s your UNCLE1 Thomas P.S. Gillam and Christopher G. Lester Dept of Physics, Cavendish Laboratory, JJ Thomson Avenue, Cambridge, CB3 0HE, U.K. E-mail: gillam@hep.phy.cam.ac.uk, lester@hep.phy.cam.ac.uk Abstract: We...

Gillam, Thomas P.S.; Lester, Christopher G.

2014-11-06T23:59:59.000Z

123

The Quirky Collider Signals of Folded Supersymmetry  

SciTech Connect (OSTI)

We investigate the collider signals associated with scalar quirks ('squirks') in folded supersymmetric models. As opposed to regular superpartners in supersymmetric models these particles are uncolored, but are instead charged under a new confining group, leading to radically different collider signals. Due to the new strong dynamics, squirks that are pair produced do not hadronize separately, but rather form a highly excited bound state. The excited 'squirkonium' loses energy to radiation before annihilating back into Standard Model particles. We calculate the branching fractions into various channels for this process, which is prompt on collider time-scales. The most promising annihilation channel for discovery is W+photon which dominates for squirkonium near its ground state. We demonstrate the feasibility of the LHC search, showing that the mass peak is visible above the SM continuum background and estimate the discovery reach.

Burdman, Gustavo; Chacko, Z.; Goh, Hock-Seng; Harnik, Roni; Krenke, Christopher A.

2008-08-01T23:59:59.000Z

124

Searches for BSM and Higgs boson at LHC  

SciTech Connect (OSTI)

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

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

2012-07-27T23:59:59.000Z

125

Linear Collider Physics Resource Book Snowmass 2001  

SciTech Connect (OSTI)

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

Ronan (Editor), M.T.

2001-06-01T23:59:59.000Z

126

PHYSICAL REVIEW C 81, 044910 (2010) Production of exotic atoms at energies available at the CERN Large Hadron Collider  

E-Print Network [OSTI]

one of the ions in the collider ("bound-free" pair production). In particular the process of pair several insights in the production mechanism which have not been explored in the literature. OurPHYSICAL REVIEW C 81, 044910 (2010) Production of exotic atoms at energies available at the CERN

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

127

A Silicon Strip Detector for the Phase II High Luminosity Upgrade of the ATLAS Detector at the Large Hadron Collider  

E-Print Network [OSTI]

This thesis presents the work carried out in the testing of the ATLAS Phase-II Upgrade electronic systems in the future strips tracker after 2023, to be installed for operations in the HL-LHC period. The high luminosity and number of interactions per crossing that will happen after the HL-LHC starts require a complete replacement of the ATLAS tracker. The systems that have been defined for the Phase-II Upgrade will be designed to cope with that increased radiation and have the right granularity to maintain the performance with higher pile-up. In this thesis I present results on single modules and larger structures comprising multiple modules. In the context of the current ATLAS Semiconductor Tracker studies, I present an analysis of the data taken by the detector from the beginning of operation in 2010 until the first Long Shut-down in 2013. The analysis consists of an energy loss study in the Semiconductor Tracker, a task the detector was not designed to perform. However, the availability of the Time-over-Th...

García-Argos, Carlos

2015-01-01T23:59:59.000Z

128

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

E-Print Network [OSTI]

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

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

2009-04-13T23:59:59.000Z

129

Diffraction at collider energies  

SciTech Connect (OSTI)

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

Frankfurt, L.L.

1992-12-31T23:59:59.000Z

130

Diffraction at collider energies  

SciTech Connect (OSTI)

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

Frankfurt, L.L.

1992-01-01T23:59:59.000Z

131

Probing top-Z dipole moments at the LHC and ILC  

E-Print Network [OSTI]

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. We find that LHC experiments will soon be able to probe weak dipole moments for the first time.

Raoul Röntsch; Markus Schulze

2015-01-23T23:59:59.000Z

132

Probing top-Z dipole moments at the LHC and ILC  

E-Print Network [OSTI]

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. We find that LHC experiments will soon be able to probe weak dipole moments for the first time.

Röntsch, Raoul

2015-01-01T23:59:59.000Z

133

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

E-Print Network [OSTI]

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

Lee, Yen-Jie

2011-01-01T23:59:59.000Z

134

Quark-lepton symmetric model at the LHC  

E-Print Network [OSTI]

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

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

2012-02-04T23:59:59.000Z

135

International linear collider reference design report  

SciTech Connect (OSTI)

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.

Aarons, G.

2007-06-22T23:59:59.000Z

136

The versatile link, a common project for super-LHC  

SciTech Connect (OSTI)

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.

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

2009-07-01T23:59:59.000Z

137

Parton distributions at the dawn of the LHC  

E-Print Network [OSTI]

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

Stefano Forte

2010-12-06T23:59:59.000Z

138

Higgs Boson Properties and BSM Higgs Boson Searches at LHC  

E-Print Network [OSTI]

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

Wolfgang F. Mader

2008-09-24T23:59:59.000Z

139

First Results of the LHC Longitudinal Density Monitor  

SciTech Connect (OSTI)

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

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

2012-04-19T23:59:59.000Z

140

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

E-Print Network [OSTI]

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

Shimizu, Shima; The ATLAS collaboration

2015-01-01T23:59:59.000Z

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141

LINEAR COLLIDER PHYSICS RESOURCE BOOK FOR SNOWMASS 2001.  

SciTech Connect (OSTI)

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

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

2001-05-03T23:59:59.000Z

142

Torsion phenomenology at the CERN LHC  

SciTech Connect (OSTI)

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

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

2007-02-01T23:59:59.000Z

143

Baryon Production at LHC and Very High Energy Cosmic Ray Spectra  

E-Print Network [OSTI]

The spectra of baryons at LHC can explain the features of the proton spectra in cosmic rays (CR). It seems important to study all baryon data that are available from collider experiments in wide range of energies. Transverse momentum spectra of baryons from RHIC ($\\sqrt(s)$=62 and 200 GeV) and from LHC ($\\sqrt(s)$=0.9 and 7 TeV) have been considered. It is seen that the slope of distributions at low $p_T$'s is changing with energy. The QGSM fit of these spectra gives the average transverse momenta which behave as $s^{0.06}$ that is similar to the previously observed behavior of $\\Lambda^0$ hyperon spectra. The change in average transverse momenta that are slowly growing in VHE hadron interactions at CR detectors cannot cause the "knee" in measured cosmic ray proton spectra. In addition, the available data on heavy quark hadron production from LHC-b at $\\sqrt{s}$=7 TeV were also studied. The preliminary dependence of hadron average transverse momenta on their masses at LHC energy is presented. The possible sou...

Piskounova, Olga I

2015-01-01T23:59:59.000Z

144

Production of Stoponium at the LHC  

E-Print Network [OSTI]

Although the Large Hadron Collider (LHC) has not observed supersymmetric (SUSY) partners of the Standard Model particles, their existence is not ruled out yet. One recently explored scenario in which there are light SUSY partners that have evaded current bounds from the LHC is that of a light long-lived stop quark. In this paper we consider light stop pair production at the LHC when the stop mass is between 200 and 400 GeV. If the stops are long-lived they can form a bound state, stoponium, which then undergoes two-body decays to Standard Model particles. By considering the near-threshold production of such a pair through the gluon-gluon fusion process and taking into account the strong Coulombic interactions responsible for the formation of this bound state, we obtain factorization theorems for the stop pair inclusive and differential production cross sections. We also perform a resummation of large threshold logarithms up to next-to-next-to-leading logarithmic accuracy using well-established renormalization group equations in an effective field theory methodology. These results are used to calculate the invariant mass distributions of two photons or two Z bosons coming from the decay of the stoponium at the LHC. For our choices of SUSY model parameters, the stoponium is not detectable above Standard Model backgrounds in \\gamma \\gamma or ZZ at 8 TeV, but will be visible with 400 fb^(-1) of accumulated data if its mass is below 500 GeV when the LHC runs at 14 TeV.

Chul Kim; Ahmad Idilbi; Thomas Mehen; Yeo Woong Yoon

2014-04-14T23:59:59.000Z

145

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

E-Print Network [OSTI]

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

Lilin Zhu; Rudolph C. Hwa

2014-11-05T23:59:59.000Z

146

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

E-Print Network [OSTI]

tracker at the BNL Relativistic Heavy Ion Collider). The masses and widths of these resonances are studied as a function of transverse momentum p(T). We observe that the resonance spectra follow a generalized scaling law with the transverse mass m...

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

2008-01-01T23:59:59.000Z

147

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

E-Print Network [OSTI]

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

B. Ducloué; L. Szymanowski; S. Wallon

2013-09-10T23:59:59.000Z

148

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

E-Print Network [OSTI]

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

Ducloué, B; Wallon, S

2013-01-01T23:59:59.000Z

149

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

E-Print Network [OSTI]

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

Pigny, G; Krakowski, P; Rio, B

2014-01-01T23:59:59.000Z

150

Strategies for Probing Non-Minimal Dark Sectors at Colliders: The Interplay Between Cuts and Kinematic Distributions  

E-Print Network [OSTI]

In this paper, we examine the strategies and prospects for distinguishing between traditional dark-matter models and models with non-minimal dark sectors --- including models of Dynamical Dark Matter (DDM) --- at hadron colliders. For concreteness, we focus on events with two hadronic jets and large missing transverse energy at the Large Hadron Collider (LHC). As we discuss, simple "bump-hunting" searches are not sufficient; probing non-minimal dark sectors typically requires an analysis of the actual shapes of the distributions of relevant kinematic variables. We therefore begin by identifying those kinematic variables whose distributions are particularly suited to this task. However, as we demonstrate, this then leads to a number of additional subtleties, since cuts imposed on the data for the purpose of background reduction can at the same time have the unintended consequence of distorting these distributions in unexpected ways, thereby obscuring signals of new physics. We therefore proceed to study the correlations between several of the most popular relevant kinematic variables currently on the market, and investigate how imposing cuts on one or more of these variables can impact the distributions of others. Finally, we combine our results in order to assess the prospects for distinguishing non-minimal dark sectors in this channel at the upgraded LHC.

Keith R. Dienes; Shufang Su; Brooks Thomas

2014-07-09T23:59:59.000Z

151

General-purpose event generators for LHC physics  

SciTech Connect (OSTI)

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.

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

2011-03-03T23:59:59.000Z

152

Higgs-boson production at the Photon Collider at TESLA  

E-Print Network [OSTI]

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

Piotr Niezurawski

2005-03-31T23:59:59.000Z

153

Rare exclusive hadronic W decays in a t-tbar environment  

E-Print Network [OSTI]

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

Michelangelo Mangano; Tom Melia

2014-10-28T23:59:59.000Z

154

QCD Interconnection Studies at Linear Colliders  

E-Print Network [OSTI]

Heavy objects like the W, Z and t are short-lived compared with typical hadronization times. When pairs of such particles are produced, the subsequent hadronic decay systems may therefore become interconnected. We study such potential effects at Linear Collider energies.

Valery A. Khoze; Torbjörn Sjöstrand

1999-12-10T23:59:59.000Z

155

A variable for measuring masses at hadron colliders when missing energy is expected; mT2: the truth behind the glamour  

E-Print Network [OSTI]

AMSB-like points discussed in section 4.2. The hadronic branching ratios can be found in [10]. m?+1 #7;M?˜1 Point (GeV) (MeV) ?+1 ? ?01 e+?e ?+1 ? ?01 µ+?µ SPS-300 165 886 17.0% 15.9% SPS-250 159 1798 21.9% 21.5% A-250 101 766 15.4% 13.9% A-200 97 1603... ‘natural’ way. Readers who would prefer a ‘top down’ description of mT 2, i.e. a description which starts with a definition and then works towards its consequences, are directed to skip to section 3 where this approach is taken. The concrete example which...

Barr, Alan; Lester, Christopher G; Stephens, Phil

156

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

E-Print Network [OSTI]

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

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

2012-01-01T23:59:59.000Z

157

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

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

158

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

E-Print Network [OSTI]

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

B. Ducloué; L. Szymanowski; S. Wallon

2013-12-09T23:59:59.000Z

159

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

E-Print Network [OSTI]

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

Ducloué, B; Wallon, S

2013-01-01T23:59:59.000Z

160

Validation of Geant4 Hadronic Generators versus Thin Target Data  

SciTech Connect (OSTI)

The GEANT4 toolkit is widely used for simulation of high energy physics (HEP) experiments, in particular, those at the Large Hadron Collider (LHC). The requirements of robustness, stability and quality of simulation for the LHC are demanding. This requires an accurate description of hadronic interactions for a wide range of targets over a large energy range, from stopped particle reactions to low energy nuclear interactions to interactions at the TeV energy scale. This is achieved within the Geant4 toolkit by combining a number of models, each of which are valid within a certain energy domain. Comparison of these models to thin target data over a large energy range indicates the strengths and weaknesses of the model descriptions and the energy range over which each model is valid. Software has been developed to handle the large number of validation tests required to provide the feedback needed to improve the models. An automated process for carrying out the validation and storing/displaying the results is being developed and will be discussed.

Banerjee, S.; /Fermilab; Folger, G.; /CERN; Ivanchenko, A.; /CERN /CENBG, Gradignan; Ivanchenko, V.N.; /CERN /NeurOK, Moscow /Metz U.; Kossov, M.; /CERN; Quesada, J.M.; /Seville U.; Schalicke, A.; /DESY, Zeuthen; Uzhinsky, V.; /CERN; Wenzel, H.; /Fermilab; Wright, D.H.; /SLAC; Yarba, J.; /Fermilab

2012-04-19T23:59:59.000Z

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161

A light NMSSM pseudoscalar Higgs boson at the LHC Run 2  

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

162

Upgrade of the LHC magnet interconnections thermal shielding  

SciTech Connect (OSTI)

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

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

2014-01-29T23:59:59.000Z

163

Neutrinos and Collider Physics  

E-Print Network [OSTI]

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

Deppisch, Frank F; Pilaftsis, Apostolos

2015-01-01T23:59:59.000Z

164

Searches for New Physics at the Tevatron and LHC  

SciTech Connect (OSTI)

This is an auspicious moment in experimental particle physics - there are large data samples at the Tevatron and a new energy regime being explored at the Large Hadron Collider with ever larger data samples. The coincidence of these two events suggests that we will soon be able to address the question, what lies beyond the standard model? Particle physics's current understanding of the universe is embodied in it. The model has been tested to extreme precision - better than a part in ten thousand - but we suspect that it is only an approximation, and that physics beyond this standard model will appear in the data of the Tevatron and LHC in the near future. This brief review touches on the status of searches for new physics at the time of the conference.

Wittich, Peter; /Cornell U., LEPP

2011-11-01T23:59:59.000Z

165

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

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

166

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

E-Print Network [OSTI]

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

California at Santa Cruz, University of

167

Future Hadron Physics at Fermilab  

E-Print Network [OSTI]

Today, hadron physics research occurs at Fermilab as parts of broader experimental programs. This is very likely to be the case in the future. Thus, much of this presentation focuses on our vision of that future - a future aimed at making Fermilab the host laboratory for the International Linear Collider (ILC). Given the uncertainties associated with the ILC - the level of needed R&D, the ILC costs, and the timing - Fermilab is also preparing for other program choices. I will describe these latter efforts, efforts focused on a Proton Driver to increase the numbers of protons available for experiments. As examples of the hadron physics which will be coming from Fermilab, I summarize three experiments: MIPP/E907 which is running currently, and MINER A and Drell-Yan/E906 which are scheduled for future running periods. Hadron physics coming from the Tevatron Collider program will be summarized by Arthur Maciel in another talk at Hadron05.

Jeffrey A. Appel

2005-09-23T23:59:59.000Z

168

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

SciTech Connect (OSTI)

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

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

2010-05-23T23:59:59.000Z

169

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

E-Print Network [OSTI]

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

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

170

International Linear Collider-A Technical Progress Report  

SciTech Connect (OSTI)

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.

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

2011-11-04T23:59:59.000Z

171

Practical Statistics for the LHC  

E-Print Network [OSTI]

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

Cranmer, Kyle

2015-01-01T23:59:59.000Z

172

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

E-Print Network [OSTI]

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

d'Enterria, David; Paukkunen, Hannu

2015-01-01T23:59:59.000Z

173

Muon Collider Progress: Accelerators  

E-Print Network [OSTI]

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

Michael S. Zisman

2011-09-14T23:59:59.000Z

174

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)

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.

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

2009-03-01T23:59:59.000Z

175

Superconducting Magnet Technology for Future Hadron Colliders  

E-Print Network [OSTI]

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

Scanlan, R.M.

2011-01-01T23:59:59.000Z

176

Superconducting Magnet Technology for Future Hadron Colliders  

E-Print Network [OSTI]

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

Scanlan, R.M.

2011-01-01T23:59:59.000Z

177

Higgs Hunting at the Large Hadron Collider  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun with

178

Director's colloquium March 18 large hadron collider  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series to UserProduct:Directives Templates by WebsiteFacility

179

Background Simulations for the International Linear Collider  

E-Print Network [OSTI]

on superconducting technology to collide bunches of electrons and positrons. The baseline configuration (about 31 km in a clean experimental environment with low backgrounds. The LHC will likely discover the Higgs boson accelerator directly. DESY FLC, 22603 Hamburg, Germany, adrian.vogel@desy.de 1 #12;Figure 1: Overall view

180

Testing Radiative Neutrino Mass Models at the LHC  

E-Print Network [OSTI]

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

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

2014-10-22T23:59:59.000Z

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181

Testing Radiative Neutrino Mass Models at the LHC  

E-Print Network [OSTI]

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

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

2015-02-07T23:59:59.000Z

182

Machine Protection and High Energy Density States in Matter for High Energy Hadron Accelerators  

E-Print Network [OSTI]

The Large Hadron Collider (LHC) is the largest accelerator in the world. It is designed to collide two proton beams with unprecedented particle energy of 7TeV. The energy stored in each beam is 362MJ, sufficient to melt 500kg of copper. An accidental release of even a small fraction of the beam energy can result in severe damage to the equipment. Machine protection systems are essential to safely operate the accelerator and handle all possible accidents. This thesis deals with the study of different failure scenarios and its possible consequences. It addresses failure scenarios ranging from low intensity losses on high-Z materials and superconductors to high intensity losses on carbon and copper collimators. Low beam losses are sufficient to quench the superconducting magnets and the stabilized superconducting cables (bus-bars) that connects the main magnets. If this occurs and the energy from the bus-bar is not extracted fast enough it can lead to a situation similar to the accident in 2008 at LHC during pow...

Blanco Sancho, Juan; Schmidt, R

183

UFOs in the LHC  

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

184

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

E-Print Network [OSTI]

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

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

2007-03-08T23:59:59.000Z

185

Current Lead Design for the Accelerator Project for Upgrade of LHC  

SciTech Connect (OSTI)

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

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

2010-01-01T23:59:59.000Z

186

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

SciTech Connect (OSTI)

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

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

2011-06-01T23:59:59.000Z

187

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

SciTech Connect (OSTI)

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

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

2010-08-01T23:59:59.000Z

188

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

E-Print Network [OSTI]

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

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

2009-12-01T23:59:59.000Z

189

Future Colliders Beyond the Standard Model  

E-Print Network [OSTI]

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

Murayama, Hitoshi

190

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

E-Print Network [OSTI]

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

Brennan Goddard; Werner Herr; Philippe Lebrun; Attilio Milanese

2015-01-01T23:59:59.000Z

191

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

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

192

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

SciTech Connect (OSTI)

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

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

2007-12-01T23:59:59.000Z

193

Planar Pixel Sensors for the ATLAS tracker upgrade at HL-LHC  

E-Print Network [OSTI]

The ATLAS Planar Pixel Sensor R&D Project is a collaboration of 17 institutes and more than 80 scientists. Their goal is to explore the operation of planar pixel sensors for the tracker upgrade at the High Luminosity-Large Hadron Collider (HL-LHC). This work will give a summary of the achievements on radiation studies with n-in-n and n-in-p pixel sensors, bump-bonded to ATLAS FE-I3 and FE-I4 readout chips. The summary includes results from tests with radioactive sources and tracking efficiencies extracted from test beam measurements. Analysis results of ${2\\cdot10^{16}} \\text{n}_{\\text{eq}}\\text{cm}^{-2}$ and ${1\\cdot10^{16}} \\text{n}_{\\text{eq}}\\text{cm}^{-2}$ ($1 \\text{MeV}$ neutron equivalent) irradiated n-in-n and n-in-p modules confirm the operation of planar pixel sensors for future applications.

Christian Gallrapp

2012-06-15T23:59:59.000Z

194

Coil End Optimization of the Nb3Sn Quadrupole for the High Luminosity LHC  

E-Print Network [OSTI]

As part of the Large Hadron Collider Luminosity upgrade (HiLumi-LHC) program, the US LARP collaboration and CERN are working together to design and build a 150 mm aperture quadrupole magnet that aims at providing a nominal gradient of 140 T/m. The resulting conductor peak field of more than 12 T requires the use of Nb3Sn superconducting coils. In this paper the coil design for the quadrupole short model (SQXF) is described, focusing in particular on the optimization of the end-parts. We first describe the magnetic optimization aiming at reducing the peak field enhancement in the ends and minimizing the integrated multipole content. Then we focus on the analysis and tests performed to determine the most suitable shapes of end turns and spacers, minimizing the mechanical stress on the cables. We conclude with a detailed description of the baseline end design for the first series of the short model coils.

Izquierdo Bermudez, S; Bossert, R; Cheng, D; Ferracin, P; Krave, ST; Perez, JC; Schmalzle, J; Yu, M

2015-01-01T23:59:59.000Z

195

Updated global fits of the cMSSM including the latest LHC SUSY and Higgs searches and XENON100 data  

SciTech Connect (OSTI)

We present new global fits of the constrained Minimal Supersymmetric Standard Model (cMSSM), including LHC 1/fb integrated luminosity SUSY exclusion limits, recent LHC 5/fb constraints on the mass of the Higgs boson and XENON100 direct detection data. Our analysis fully takes into account astrophysical and hadronic uncertainties that enter the analysis when translating direct detection limits into constraints on the cMSSM parameter space. We provide results for both a Bayesian and a Frequentist statistical analysis. We find that LHC 2011 constraints in combination with XENON100 data can rule out a significant portion of the cMSSM parameter space. Our results further emphasise the complementarity of collider experiments and direct detection searches in constraining extensions of Standard Model physics. The LHC 2011 exclusion limit strongly impacts on low-mass regions of cMSSM parameter space, such as the stau co-annihilation region, while direct detection data can rule out regions of high SUSY masses, such as the Focus-Point region, which is unreachable for the LHC in the near future. We show that, in addition to XENON100 data, the experimental constraint on the anomalous magnetic moment of the muon plays a dominant role in disfavouring large scalar and gaugino masses. We find that, should the LHC 2011 excess hinting towards a Higgs boson at 126 GeV be confirmed, currently favoured regions of the cMSSM parameter space will be robustly ruled out from both a Bayesian and a profile likelihood statistical perspective.

Strege, C.; Trotta, R. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Bertone, G. [GRAPPA Institute, University of Amsterdam, Science Park 904, 1090 GL Amsterdam (Netherlands); Cerdeño, D.G. [Instituto de Física Teórica UAM/CSIC, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Fornasa, M. [Instituto de Astrofísica de Andalucía (CSIC), E-18008, Granada (Spain); Austri, R. Ruiz de, E-mail: charlotte.strege09@imperial.ac.uk, E-mail: gf.bertone@gmail.com, E-mail: davidg.cerdeno@uam.es, E-mail: fornasam@gmail.com, E-mail: rruiz@ific.uv.es, E-mail: r.trotta@imperial.ac.uk [Instituto de Física Corpuscular, IFIC-UV/CSIC, Valencia (Spain)

2012-03-01T23:59:59.000Z

196

Twistor Spinoffs for Collider Physics  

SciTech Connect (OSTI)

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

Dixon, Lance

2005-12-19T23:59:59.000Z

197

Tevatron instrumentation: boosting collider performance  

SciTech Connect (OSTI)

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.

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

2006-05-01T23:59:59.000Z

198

Muon Colliders: The Next Frontier  

ScienceCinema (OSTI)

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.

Yagmur Tourun

2010-01-08T23:59:59.000Z

199

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

E-Print Network [OSTI]

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

David d'Enterria; Krisztian Krajczar; Hannu Paukkunen

2015-01-23T23:59:59.000Z

200

Charmless Hadronic B Decays at BaBar  

SciTech Connect (OSTI)

We report recent measurements for the branching fractions of charmless hadronic B decays obtained from data collected by the BABAR detector at the PEP-II asymmetric-energy collider at the Stanford Linear Accelerator Center.

Burke, James P.; /Liverpool U.

2007-12-04T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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201

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

E-Print Network [OSTI]

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

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

2011-01-01T23:59:59.000Z

202

Hadronic Atoms  

E-Print Network [OSTI]

We review the theory of hadronic atoms in QCD+QED. The non-relativistic effective Lagrangian approach, used to describe this type of bound states, is illustrated with the case of pi+pi- atoms. In addition, we discuss the evaluation of isospin-breaking corrections to hadronic atom observables by invoking chiral perturbation theory.

J. Gasser; V. E. Lyubovitskij; A. Rusetsky

2009-03-02T23:59:59.000Z

203

Possible Accelerators @ CERN Beyond the LHC  

E-Print Network [OSTI]

The physics and world-wide accelerator context for possible accelerator projects at CERN after the LHC are reviewed, including the expectation that an e+ e- linear collider in the TeV energy range will be built elsewhere. Emphasis is laid on the Higgs boson, supersymmetry and neutrino oscillations as benchmarks for physics after the LHC. The default option for CERN's next major project may be the CLIC multi-TeV e+ e- collider project. Also interesting is the option of a three-step scenario for muon storage rings, starting with a neutrino factory, continuing with one or more Higgs factories, and culminating in a mu+ mu- collider at the high-energy frontier.

John Ellis

1999-11-22T23:59:59.000Z

204

Black Hole Chromosphere at the LHC  

E-Print Network [OSTI]

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

Luis Anchordoqui; Haim Goldberg

2003-02-26T23:59:59.000Z

205

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

SciTech Connect (OSTI)

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.

Harrison, M.

2011-04-30T23:59:59.000Z

206

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

SciTech Connect (OSTI)

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.

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

2009-03-01T23:59:59.000Z

207

Muon Muon Collider: Feasibility Study  

SciTech Connect (OSTI)

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

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

2012-04-05T23:59:59.000Z

208

PROMPT PHOTON PRODUCTION IN POLARIZED HADRON COLLISIONS.  

SciTech Connect (OSTI)

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

VOGELSANG,W.

2000-04-25T23:59:59.000Z

209

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

ScienceCinema (OSTI)

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.

Giorgio Ambrosio

2010-01-08T23:59:59.000Z

210

The LHCb RICH silica aerogel performance with LHC data  

E-Print Network [OSTI]

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

Perego, D L

2010-01-01T23:59:59.000Z

211

Focusing Strength Measurements of the Main Quadrupoles for the LHC  

E-Print Network [OSTI]

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

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

2006-01-01T23:59:59.000Z

212

Searching for Low Mass Dark Portal at the LHC  

E-Print Network [OSTI]

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

Haipeng An; Ran Huo; Lian-Tao Wang

2012-12-10T23:59:59.000Z

213

The Higgs Singlet extension parameter space in the light of the LHC discovery  

E-Print Network [OSTI]

In this note we propose an overview on the current theoretical and experimental limits on a Higgs singlet extension of the Standard Model. We assume that the Boson which has recently been measured by the LHC experiments is the lightest Higgs boson of such model, while for the second Higgs Boson we consider a mass range of 600 GeV to 1 TeV, i.e. outside the range of the direct searches presented so far. In this light, we study the impact of perturbative unitarity limits, Renormalisation Group Equations analysis and experimental constraints (Electro-Weak Precision Tests, measurements of the light Higgs coupling at the Large Hadron Collider). We show that, in the case of no additional hidden sector contributions, the largest constraints for higher Higgs masses stem from the assumption of perturbativity as well as vacuum stability for scales on the order of the SM metastability scale, and that the allowed mixing range is severely restricted. We discuss implications for current LHC searches in the singlet extension, especially the expected suppression factors for SM-like decays of the heavy Higgs. We present these results in terms of a global scaling factor as well as the total width of the new scalar.

Giovanni Marco Pruna; Tania Robens

2014-02-23T23:59:59.000Z

214

Simplified SIMPs and the LHC  

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

215

DIGITAL Visual Fortran Programmer's Guide  

E-Print Network [OSTI]

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

216

Type II Seesaw at LHC: the Roadmap  

E-Print Network [OSTI]

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

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

2012-12-22T23:59:59.000Z

217

Type II Seesaw at LHC: the Roadmap  

E-Print Network [OSTI]

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

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

2012-01-01T23:59:59.000Z

218

Gamma-Gamma Colliders  

E-Print Network [OSTI]

a gamma collider, we need to discuss the laser optics in thegamma collider will be given later, coupled with some discussions of the requisite opticsoptics and an adequate laser for Compton conversion. With this approach, the luminosity for the gamma-

Kim, K.-J.

2008-01-01T23:59:59.000Z

219

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

E-Print Network [OSTI]

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

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

2012-12-13T23:59:59.000Z

220

Upgrade of the gas flow control system of the resistive current leads of the LHC inner triplet magnets: Simulation and experimental validation  

SciTech Connect (OSTI)

The 600 A and 120 A circuits of the inner triplet magnets of the Large Hadron Collider are powered by resistive gas cooled current leads. The current solution for controlling the gas flow of these leads has shown severe operability limitations. In order to allow a more precise and more reliable control of the cooling gas flow, new flowmeters will be installed during the first long shutdown of the LHC. Because of the high level of radiation in the area next to the current leads, the flowmeters will be installed in shielded areas located up to 50 m away from the current leads. The control valves being located next to the current leads, this configuration leads to long piping between the valves and the flowmeters. In order to determine its dynamic behaviour, the proposed system was simulated with a numerical model and validated with experimental measurements performed on a dedicated test bench.

Perin, A.; Casas-Cubillos, J.; Pezzetti, M. [CERN, CH-1211 Geneva 23 (Switzerland); Almeida, M. [Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte (Brazil)

2014-01-29T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Photon collider Higgs factories  

E-Print Network [OSTI]

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

V. I. Telnov

2014-09-19T23:59:59.000Z

222

Color screening, absorption and $?_{tot}^{pp}$ at LHC  

E-Print Network [OSTI]

We show that a growth of the proton-proton total cross section with energy can be entirely attributed to the purely perturbative mechanism. The infrared regularization at rather short distances, $R_c\\simeq 0.3$ fm, allows to extend the BFKL technique from deep inelastic to hadron-hadron scattering. With the account of the absorption corrections our results are in agreement with the LHC data on $\\sigma_{tot}^{pp}$.

R. Fiore; N. N. Nikolaev; V. R. Zoller

2014-03-08T23:59:59.000Z

223

Forward-backward and charge asymmetries at Tevatron and the LHC  

E-Print Network [OSTI]

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

Johann H. Kuehn; German Rodrigo

2014-11-17T23:59:59.000Z

224

Physics at the e+ e- Linear Collider  

E-Print Network [OSTI]

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

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

2015-01-01T23:59:59.000Z

225

Physics at the e+ e- Linear Collider  

E-Print Network [OSTI]

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

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

2015-04-07T23:59:59.000Z

226

MARMOSET: The Path from LHC Data to the New Standard Model via On-Shell Effective Theories  

SciTech Connect (OSTI)

We describe a coherent strategy and set of tools for reconstructing the fundamental theory of the TeV scale from LHC data. We show that On-Shell Effective Theories (OSETs) effectively characterize hadron collider data in terms of masses, production cross sections, and decay modes of candidate new particles. An OSET description of the data strongly constrains the underlying new physics, and sharply motivates the construction of its Lagrangian. Simulating OSETs allows efficient analysis of new-physics signals, especially when they arise from complicated production and decay topologies. To this end, we present MARMOSET, a Monte Carlo tool for simulating the OSET version of essentially any new-physics model. MARMOSET enables rapid testing of theoretical hypotheses suggested by both data and model-building intuition, which together chart a path to the underlying theory. We illustrate this process by working through a number of data challenges, where the most important features of TeV-scale physics are reconstructed with as little as 5 fb{sup -1} of simulated LHC signals.

Arkani-Hamed, Nima; Schuster, Philip; Toro, Natalia; /Harvard U., Phys. Dept.; Thaler, Jesse; /UC, Berkeley /LBL, Berkeley; Wang, Lian-Tao; /Princeton U.; Knuteson, Bruce; /MIT, LNS; Mrenna, Stephen; /Fermilab

2007-03-01T23:59:59.000Z

227

Challenges for highest energy circular colliders  

E-Print Network [OSTI]

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

Benedikt, M; Wenninger, J; Zimmermann, F

2014-01-01T23:59:59.000Z

228

area lhc tunnel: Topics by E-print Network  

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

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

229

Hadron physics  

SciTech Connect (OSTI)

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.

Bunce, G.

1984-05-30T23:59:59.000Z

230

Synchrotron-Radiation Photon Distribution for Highest Energy Circular Colliders  

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

231

Synchrotron-Radiation Photon Distributions for Highest Energy Circular Colliders  

E-Print Network [OSTI]

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

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

2013-01-01T23:59:59.000Z

232

Future Accelerators, Muon Colliders, and Neutrino Factories  

SciTech Connect (OSTI)

Particle physics is driven by five great topics. Neutrino oscillations and masses are now at the fore. The standard model with extensions to supersymmetry and a Higgs to generate mass explains much of the field. The origins of CP violation are not understood. The possibility of extra dimensions has raised tantalizing new questions. A fifth topic lurking in the background is the possibility of something totally different. Many of the questions raised by these topics require powerful new accelerators. It is not an overstatement to say that for some of the issues, the accelerator is almost the experiment. Indeed some of the questions require machines beyond our present capability. As this volume attests, there are parts of the particle physics program that have been significantly advanced without the use of accelerators such as the subject of neutrino oscillations and many aspects of the particle-cosmology interface. At this stage in the development of physics, both approaches are needed and important. This chapter first reviews the status of the great accelerator facilities now in operation or coming on within the decade. Next, midrange possibilities are discussed including linear colliders with the adjunct possibility of gamma-gamma colliders, muon colliders, with precursor neutrino factories, and very large hadron colliders. Finally visionary possibilities are considered including plasma and laser accelerators.

Richard A Carrigan, Jr.

2001-12-19T23:59:59.000Z

233

Stabilizing Hadron Resonance Gas Models against Future Discoveries  

E-Print Network [OSTI]

We examine the stability of hadron resonance gas models by extending them to take care of undiscovered resonances through the Hagedorn formula. We find that the influence of unknown resonances on thermodynamics is large but bounded. Hadron resonance gases are internally consistent up to a temperature higher than the cross over temperature in QCD; but by examining quark number susceptibilities we find that their region of applicability seems to end even below the QCD cross over. We model the decays of resonances and investigate the ratios of particle yields in heavy-ion collisions. We find that observables such as hydrodynamics and hadron yield ratios change little upon extending the model. As a result, heavy-ion collisions at RHIC and LHC are insensitive to a possible exponential rise in the hadronic density of states, thus increasing the stability of the predictions of hadron resonance gas models.

S. Chatterjee; R. M. Godbole; Sourendu Gupta

2009-06-14T23:59:59.000Z

234

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

E-Print Network [OSTI]

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

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

2014-05-07T23:59:59.000Z

235

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

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

236

High Energy Colliders as Tools to Understand the Early Universe  

SciTech Connect (OSTI)

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

Tait, Tim (ANL) [ANL

2008-08-16T23:59:59.000Z

237

Physics at LHC  

E-Print Network [OSTI]

The prospects for physics at the LHC are discussed, starting with the foretaste, preparation (and perhaps scoop) provided by the Tevatron, in particular, and then continuing through the successive phases of LHC operation. These include the start-up phase, the early physics runs, the possible search for new physics in double diffraction, the continuation to nominal LHC running, and the possible upgrade of the LHC luminosity. Emphasis is placed on the prospects for Higgs physics and the search for supersymmetry. The progress and discoveries of the LHC will set the time-scale and agenda for the major future accelerator projects that will follow it.

John Ellis

2006-11-17T23:59:59.000Z

238

Interactions of hadrons in the CALICE silicon tungsten electromagnetic calorimeter  

E-Print Network [OSTI]

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

Roman Pöschl; for the CALICE Collaboration

2012-03-07T23:59:59.000Z

239

The performance of the ATLAS Inner Detector Trigger Algorithms in pp collisions at the LHC  

E-Print Network [OSTI]

The ATLAS Inner Detector trigger algorithms has been running online during data taking with proton-proton collisions at the Large Hadron Collider (LHC) since December 2009. We will present preliminary results on the performance of the algorithms in collisions at centre-of-mass energies of 900GeV and 7TeV, including comparisons to the ATLAS offline tracking algorithms and to simulations. The ATLAS trigger performs the online event selection in three stages. The Inner Detector information is used in the second and third triggering stages, called Level-2 trigger (L2) and Event Filter (EF) respectively, and collectively the High Level Triggers (HLT). The HLT runs software algorithms in a large farm of commercial CPUs and is designed to reject collision events in real time, keeping the most interesting few in every thousand. The average execution time per event at L2(/EF) is about 40ms(/4s) and the Inner Detector trigger algorithms can take only a fraction of that. Within this time, the data from interesting regio...

Sutton, Mark; The ATLAS collaboration

2010-01-01T23:59:59.000Z

240

The Upgrade of the CMS RPC System during the First LHC Long Shutdown  

E-Print Network [OSTI]

The CMS muon system includes in both the barrel and endcap region Resistive Plate Chambers (RPC). They mainly serve as trigger detectors and also improve the reconstruction of muon parameters. Over the years, the instantaneous luminosity of the Large Hadron Collider gradually increases. During the LHC Phase 1 (~first 10 years of operation) an ultimate luminosity is expected above its design value of 10^34/cm^2/s at 14 TeV. To prepare the machine and also the experiments for this, two long shutdown periods are scheduled for 2013-2014 and 2018-2019. The CMS Collaboration is planning several detector upgrades during these long shutdowns. In particular, the muon detection system should be able to maintain a low-pT threshold for an efficient Level-1 Muon Trigger at high particle rates. One of the measures to ensure this, is to extend the present RPC system with the addition of a 4th layer in both endcap regions. During the first long shutdown, these two new stations will be equipped in the region |eta|control procedures.

M. Tytgat; A. Marinov; P. Verwilligen; N. Zaganidis; A. Aleksandrov; V. Genchev; P. Iaydjiev; M. Rodozov; M. Shopova; G. Sultanov; Y. Assran; M. Abbrescia; C. Calabria; A. Colaleo; G. Iaselli; F. Loddo; M. Maggi; G. Pugliese; L. Benussi; S. Bianco; M. Caponero; S. Colafranceschi; F. Felli; D. Piccolo; G. Saviano; C. Carrillo; U. Berzano; M. Gabusi; P. Vitulo; M. Kang; K. S. Lee; S. K. Park; S. Shin; A. Sharma

2012-09-10T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Testing nuclear parton distributions with pA collisions at the LHC  

E-Print Network [OSTI]

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

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

2010-02-12T23:59:59.000Z

242

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

E-Print Network [OSTI]

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

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

2014-08-15T23:59:59.000Z

243

Seesaw at LHC through Left - Right Symmetry  

E-Print Network [OSTI]

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

Goran Senjanovic

2011-03-16T23:59:59.000Z

244

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

E-Print Network [OSTI]

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

David d'Enterria; Jean-Philippe Lansberg

2010-01-11T23:59:59.000Z

245

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

E-Print Network [OSTI]

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

Dalchenko, Mykhailo; Charlot, Claude

246

Cryogenic Silicon Microstrip Detector Modules for LHC  

E-Print Network [OSTI]

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

Perea-Solano, B

2004-01-01T23:59:59.000Z

247

Searching for Top Squarks at the Large Hadron Collider  

E-Print Network [OSTI]

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi CHAPTER I INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 CHAPTER II TOP SQUARK SEARCH FROM CASCADE DECAY . . . . . . . . . . . . . . 3 II.1 Benchmark Points in Stop-neutralino Coannihilation Scenario... . . . . . . . . . . . . . . . . 10 III.1 Benchmark Points and Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 III.2 Search Strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 III.3 Results...

Wang, Kechen

2014-08-01T23:59:59.000Z

248

Establishing the Mirage Mediation Model at the Large Hadron Collider  

E-Print Network [OSTI]

Page Figure 1 The Visible Tau+Tau Invariant Mass M ?? Distribution of Benchmark Point................................................................................... 19 Figure 2 The Visible Jet+Tau Invariant Mass M j? Distribution... of Benchmark Point................................................................................... 20 Figure 3 The Visible Jet+Tau+Tau Invariant Mass M j?? Distribution of Benchmark Point...

Wang, Kechen

2012-10-19T23:59:59.000Z

249

Exploring higher dimensional black holes at the large hadron collider.  

E-Print Network [OSTI]

of extra dimensions. Throughout, we have used the ATLAS fast simulation software [20] to give a description of a typical detector and we have used the full simulation [21] to verify the main results. 2. Black hole production and decay In the black hole... evolution from present energies is questionable. Also, comparison to Standard Model pro- cesses in the trans-Planckian regime would be difficult since perturbative physics would be suppressed. 4.2 The first stages of decay CHARYBDIS does not model...

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

250

Phenomenological aspects of new physics at high energy hadron colliders  

E-Print Network [OSTI]

and the hierarchy problem. Phenomenological hints are neutrino masses, Dark Matter, the cosmological vacuum energy (also known as Dark Energy) and the quest for Grand Unification and coupling constant merging. We discuss a few of these issues here. 2... th century BC, profoundly affected those who followed him with his views on natural phenomena. His persistent beliefs included that substances that make up the Earth (‘earth’, ‘air’, ‘water’, ‘fire’) were different than those that made up the heavens...

Papaefstathiou, Andreas

2011-07-12T23:59:59.000Z

251

Detecting exotic heavy leptons at the large hadron collider.  

E-Print Network [OSTI]

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

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

252

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

E-Print Network [OSTI]

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

Fermilab

253

First Beam for Large Hadron Collider | Department of Energy  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelinesProvedDecember 2005DepartmentDecember U.S.Financial Statement:Fire Protection

254

Secondary Charmonium Production at LHC Energy  

E-Print Network [OSTI]

We consider the production of charmonium by $D\\bar D$ annihilation during the mixed and hadronic phase of Pb-Pb collision at LHC energy. The calculations for secondary $J/\\psi$ and $\\psi^,$ production are performed within a kinetic model taking into account the space-time evolution of a longitudinally and transversely expanding medium. It is shown that the yield of secondary $J/\\psi$ mesons depends strongly on the $J/\\psi$ dissociation cross section with co-moving hadrons. Within the most likely scenario for the dissociation cross section it will be negligible. The secondary production of $\\psi^,$ mesons, however, due to their large cross section above the threshold, can substantially exceed the primary yield.

P. Braun-Munzinger; K. Redlich

1999-08-06T23:59:59.000Z

255

Photon collider at TESLA  

E-Print Network [OSTI]

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

Valery Telnov

2001-03-06T23:59:59.000Z

256

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

E-Print Network [OSTI]

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

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

2014-05-05T23:59:59.000Z

257

Applying Effective Theories to Collider Phenomenology  

E-Print Network [OSTI]

Theories to Collider Phenomenology by Grigol GagikovichTheories to Collider Phenomenology Copyright 2010 by GrigolTheories to Collider Phenomenology by Grigol Gagikovich

Ovanesyan, Grigol

2010-01-01T23:59:59.000Z

258

Rare decays of B mesons and baryons at the Tevatron and the LHC  

SciTech Connect (OSTI)

The experimental study of rare decays of hadrons containing the b quark has been a fertile ground for some time, and keeps being one of the most interesting subjects in high energy physics. It has improved our understanding of hadronic processes, and allows investigating various aspects of the Standard Model and searching for hints of physics beyond the Standard Model. Examples are the comparison of branching fractions of charmless modes with predictions of models, the constraints on CKM angles (B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B {yields} DK, with D in suppressed modes), the observation of purely leptonic modes (B{sup {+-}} {yields} {tau}{sup {+-}}{nu}), the recently established difference in A{sub CP} between B{sup 0} {yields} K{sup +}{pi}{sup -} and B{sup {+-}} {yields} K{sup {+-}}{pi}{sup 0}, suspected to be a hint new physics. All of them came from a long and successful experimental activity with e{sup +}e{sup -} collisions at the {Upsilon}(4S) resonance. With hadronic colliders now coming into play, the study of rare decays is reaching new heights. Given the high cross section for production of all kinds of B hadrons, the record luminosities now provided by the Tevatron collider, and the LHC program in view for the next years, there is the potential for a rich program of interesting new measurements, including even rarer modes as the B{sub (s)}{sup 0} {yields} {mu}{sup +}{mu}{sup -}, strongly suppressed in the standard model but very sensitive to many NP scenarios. The complexity of the hadronic collision environment, however, requires detectors with high precision and high quality tracking, and a trigger system capable of complex event selections at high rates. The CDF experiment, thanks to a fast trigger on impact parameter, has been able to reconstruct many rare B decays, including previously unobserved modes B{sub s}{sup 0} {yields} K{sup +}K{sup -} and B{sub s}{sup 0} {yields} K{sup -}{pi}{sup +}, the latter being particularly interesting for its relationship with the puzzling difference in CP asymmetry between neutral and charged modes. In this thesis we go beyond B mesons, and present the first measurements of Branching fractions and CP asymmetries in charmless b-baryon modes. We study two-body {Lambda}{sub b}{sup 0} decays into final states with a proton and a charged pion or kaon. Their branching fractions can be significantly affected by New Physics contributions; under supersymmetric models with R-parity violation, they can be increased by two orders of magnitude. Their CP-violating asymmetries are also interesting to measure in search for possible further anomalies: then may reach significant size {Omicron}(30%) in the Standard Model, and are also sensitive to possible new physics sources.

Volpi, Guido; /INFN, Pisa /Siena U.

2008-07-01T23:59:59.000Z

259

Direct photon production at RHIC and LHC energies  

E-Print Network [OSTI]

Direct photon spectra and elliptic flow v2 in heavy-ion collisions at RHIC and LHC energies are investigated within a relativistic transport approach incorporating both hadronic and partonic phases - the Parton-Hadron-String Dynamics (PHSD). The results suggest that a large v2 of the direct photons - as observed by the PHENIX Collaboration - signals a significant contribution of photons produced in interactions of secondary mesons and baryons in the late stages of the collision. In order to further differentiate the origin of the direct photon azimuthal asymmetry, we compare our predictions for the centrality dependence of the direct photon yield to the recent measurements by the PHENIX Collaboration and provide predictions for Pb+Pb collisions at LHC energies with respect to the direct photon spectra and v2(pT) for 0-40% centrality.

Linnyk, O; Cassing, W

2015-01-01T23:59:59.000Z

260

Aspects of heavy-ion collisions at the LHC  

SciTech Connect (OSTI)

Three aspects of relativistic heavy-ion collisions are considered in this article: (1) Stopping and baryon transport in a QCD-based approach, (2) charged-hadron production in a nonequilibrium-statistical relativistic diffusion model (RDM), and (3) quarkonia suppression and in particular, ? suppression in PbPb at the current LHC energy of ?(s{sub NN})?=?2.76TeV.

Wolschin, G. [Institut für Theoretische Physik der Universität Heidelberg, Philosophenweg 16, D-69120 Heidelberg (Germany)

2014-01-14T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Single production of excited electrons at future e{sup +}e{sup -}, ep and pp colliders  

SciTech Connect (OSTI)

We analyzed the potential of the LC with {radical}(s)=0.5 TeV, LCxLHC based ep collider with {radical}(s)=3.74 TeV and the LHC with {radical}(s)=14 TeV to search for excited electrons through transition magnetic type couplings with gauge bosons. The e*{yields}e{gamma} signal and corresponding backgrounds are studied in detail.

Cakir, O.; Yilmaz, A.; Sultansoy, S. [Ankara University, Faculty of Sciences, Department of Physics, 06100, Tandogan, Ankara (Turkey); Gazi University, Faculty of Arts and Sciences, Department of Physics, 06500, Teknikokullar, Ankara (Turkey); Azerbaijan Academy of Sciences, Institute of Physics, H. Cavid Ave. 33, Baku (Azerbaijan)

2004-10-01T23:59:59.000Z

262

Phased approach to the LHC Insertion Upgrade and Magnet Challenges  

E-Print Network [OSTI]

The LHC is on its way for operation with beam in 2008. The first goal of CERN and the LHC community is to ensure that the collider is operated efficiently, gradually reaching its maximal performance. In parallel, discussions have started and there is already a wealth of ideas on the possible directions for upgrading the LHC insertions. In this talk, we illustrate some of the constraints limiting the upgrade scenarios, and argue that a phased approach with several intermediate targets is necessary. In the first phase, the known bottleneck in the low-? triplets needs to be removed in the perspective of the physics run of 2013. This phase relies on the mature Nb-Ti superconducting magnet technology, where improvements for a small scale production are still possible.

Ostojic, R

2008-01-01T23:59:59.000Z

263

Energy Dependent Growth of Nucleon and Inclusive Charged Hadron Distributions  

E-Print Network [OSTI]

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

Wang, Hongmin; Sun, Xian-Jing

2015-01-01T23:59:59.000Z

264

Precision predictions for Z'-production at the CERN LHC: QCD matrix elements, parton showers, and joint resummation  

E-Print Network [OSTI]

We improve the theoretical predictions for the production of extra neutral gauge bosons at hadron colliders by implementing the Z' bosons in the MC@NLO generator and by computing their differential and total cross sections in joint p_T and threshold resummation. The two improved predictions are found to be in excellent agreement with each other for mass spectra, p_T spectra, and total cross sections, while the PYTHIA parton and ``power'' shower predictions usually employed for experimental analyses show significant shortcomings both in normalization and shape. The theoretical uncertainties from scale and parton density variations and non-perturbative effects are found to be 9%, 8%, and less than 5%, respectively, and thus under good control. The implementation of our improved predictions in terms of the new MC@NLO generator or resummed K factors in the analysis chains of the Tevatron and LHC experiments should be straightforward and lead to more precise determinations or limits of the Z' boson masses and/or couplings.

B. Fuks; M. Klasen; F. Ledroit; Q. Li; J. Morel

2008-01-15T23:59:59.000Z

265

Are multiple parton interactions important at high energies? New types of hadrons production processes  

E-Print Network [OSTI]

Hadrons interaction at high energies is carried out by one color gluon exchange. All quarks and gluons contained in colliding hadrons take part in interaction and production of particles. The contribution of multiple parton interactions is negligible. Multiple hadrons production at high energies occurs only in three types of processes. The first process is hadrons production in gluon string, the second is hadrons production in two quark strings and the third is hadrons production in three quark strings. In proton-proton interaction production of only gluon string and two quark strings is possible. In proton-antiproton interaction production of gluon string, two quark strings and three quark strings is possible. Therefore multiplicity distributions in proton-proton and proton-antiproton interactions are different.

V. A. Abramovsky

2009-11-25T23:59:59.000Z

266

Constraining the Eq. of State of Super-Hadronic Matter from Heavy-Ion Collisions  

E-Print Network [OSTI]

The equation of state of QCD matter for temperatures near and above the quark-hadron transition (165 MeV) is inferred within a Bayesian framework through the comparison of data from the Relativistic Heavy Ion Collider and from the Large Hadron Collider to theoretical models. State-of- the-art statistical techniques are applied to simultaneously analyze multiple classes of observables while varying 14 independent model parameters. The resulting posterior distribution over possible equations of state is consistent with results from lattice gauge theory.

Scott Pratt; Evan Sangaline; Paul Sorensen; Hui Wang

2015-01-16T23:59:59.000Z

267

Lectures on LHC Physics  

E-Print Network [OSTI]

With the discovery of the Higgs boson the LHC experiments have closed the most important gap in our understanding of fundamental interactions. We now know that the interactions between elementary particles can be described by quantum field theory, more specifically by a renormalizable gauge theory. This theory is valid to arbitrarily high energy scales and do not require an ultraviolet completion. In these notes I cover three aspects to help understand LHC results in the Higgs sector and in searches for physics beyond the Standard Model: many facets of Higgs physics, QCD as it is relevant for LHC measurements, and standard phenomenological background knowledge. The lectures should put young graduate students into a position to really follow advanced writeups and first research papers. In that sense they can serve as a starting point for a research project in LHC physics. With this new, significantly expanded version I am confident that also some more senior colleagues will find them useful and interesting.

Tilman Plehn

2014-02-17T23:59:59.000Z

268

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

E-Print Network [OSTI]

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

Evelyne Delmeire

2007-05-15T23:59:59.000Z

269

Complementarity between collider, direct detection, and indirect detection experiments  

E-Print Network [OSTI]

We examine the capabilities of planned direct detection, indirect detection, and collider experiments in exploring the 19-parameter p(henomenological)MSSM, focusing on the complementarity between the different search techniques. In particular, we consider dark matter searches at the 7, 8 (and eventually 14) TeV LHC, \\Fermi, CTA, IceCube/DeepCore, and LZ. We see that the search sensitivities depend strongly on the WIMP mass and annihilation mechanism, with the result that different search techniques explore orthogonal territory. We also show that advances in each technique are necessary to fully explore the space of Supersymmetric WIMPs.

Matthew Cahill-Rowley

2014-11-12T23:59:59.000Z

270

Statistical Hadronization and Holography  

E-Print Network [OSTI]

In this paper we consider some issues about the statistical model of the hadronization in a holographic approach. We introduce a Rindler like horizon in the bulk and we understand the string breaking as a tunneling event under this horizon. We calculate the hadron spectrum and we get a thermal, and so statistical, shape for it.

Jacopo Bechi

2009-12-17T23:59:59.000Z

271

Collider Phenomenology with Split-UED  

SciTech Connect (OSTI)

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

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

2011-12-15T23:59:59.000Z

272

Colliding neutrino beams  

E-Print Network [OSTI]

From several neutrino oscillation experiments, we understand now that neutrinos have mass. However, we really don't know what mechanism is responsible for producing this neutrino mass. Current or planned neutrino experiments utilize neutrino beams and long-baseline detectors to explore flavor mixing but do not address the question of the origin of neutrino mass. In order to answer that question, neutrino interactions need to be explored at much higher energies. This paper outlines a program to explore neutrinos and their interactions with various particles through a series of experiments involving colliding neutrino beams.

Reinhard Schwienhorst

2007-11-08T23:59:59.000Z

273

Colliding Nuclei at High Energy  

ScienceCinema (OSTI)

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).

Brookhaven Lab

2010-01-08T23:59:59.000Z

274

audi s8 maserati: Topics by E-print Network  

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

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

275

atlas experimental area: Topics by E-print Network  

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

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

276

Standard Model Higgs Boson Discovery Potential in the Decay Channel H - > ZZ(*) - > 4 mu with the CMS Detector.  

E-Print Network [OSTI]

??The Compact Muon Solenoid (CMS) is a general purpose detector at the Large Hadron Collider (LHC) currently under construction at CERN with start-up date in… (more)

Drozdetski, Alexei Alexandrovic

2007-01-01T23:59:59.000Z

277

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

E-Print Network [OSTI]

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

CMS Collaboration

278

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

E-Print Network [OSTI]

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

Wang, Yayu

279

Hadronic sizes and observables in high-energy scattering  

E-Print Network [OSTI]

The functional dependence of the high-energy observables of total cross section and slope parameter on the sizes of the colliding hadrons predicted by the model of the stochastic vacuum and the corresponding relations used in the geometric model of Povh and H\\"ufner are confronted with the experimental data. The existence of a universal term in the expression for the slope, due purely to vacuum effects, independent of the energy and of the particular hadronic system, is investigated. Accounting for the two independent correlation functions of the QCD vacuum, we improve the simple and consistent description given by the model of the stochastic vacuum to the high-energy pp and pbar-p data, with a new determination of parameters of non-perturbative QCD. The increase of the hadronic radii with the energy accounts for the energy dependence of the observables.

Erasmo Ferreira; Flávio Pereira

1997-05-09T23:59:59.000Z

280

Search for Heavy Resonances at the LHC  

E-Print Network [OSTI]

Numerous models beyond the Standard Model theory predict new heavy particles or high energy phenomena that would appear as heavy resonances in collider data. Such a signature was thus actively searched for by the ATLAS and CMS collaborations using the LHC 8 TeV proton-proton collisions. The most recent analyses using the full dataset (~ 20 fb-1) and probing a large variety of final states are reported in this article. No sign of new physics was discovered and the results are thus interpreted as exclusion limits in a model independent way or on various models based on the presence of extra-dimensions, a new strong sector or large symmetry groups.

Crépé-Renaudin, Sabine; The ATLAS collaboration

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Searching for Multijet Resonances at the LHC  

E-Print Network [OSTI]

Recently it was shown that there is a class of models in which colored vector and scalar resonances can be copiously produced at the Tevatron with decays to multijet final states, consistent with all experimental constraints and having strong discovery potential. We investigate the collider phenomenology of TeV scale colored resonances at the LHC and demonstrate a strong discovery potential for the scalars with early data as well as the vectors with additional statistics. We argue that the signal can be self-calibrating and using this fact we propose a search strategy which we show to be robust to systematic errors typically expected from Monte Carlo background estimates. We model the resonances with a phenomenological Lagrangian that describes them as bound states of colored vectorlike fermions due to new confining gauge interactions. However, the phenomenological Lagrangian treatment is quite general and can represent other scenarios of microscopic physics as well.

Can Kilic; Steffen Schumann; Minho Son

2009-04-30T23:59:59.000Z

282

Positrons for linear colliders  

SciTech Connect (OSTI)

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)

Ecklund, S.

1987-11-01T23:59:59.000Z

283

Simplified Models for LHC New Physics Searches  

SciTech Connect (OSTI)

This document proposes a collection of simplified models relevant to the design of new-physics searches at the LHC and the characterization of their results. Both ATLAS and CMS have already presented some results in terms of simplified models, and we encourage them to continue and expand this effort, which supplements both signature-based results and benchmark model interpretations. A simplified model is defined by an effective Lagrangian describing the interactions of a small number of new particles. Simplified models can equally well be described by a small number of masses and cross-sections. These parameters are directly related to collider physics observables, making simplified models a particularly effective framework for evaluating searches and a useful starting point for characterizing positive signals of new physics. This document serves as an official summary of the results from the 'Topologies for Early LHC Searches' workshop, held at SLAC in September of 2010, the purpose of which was to develop a set of representative models that can be used to cover all relevant phase space in experimental searches. Particular emphasis is placed on searches relevant for the first {approx} 50-500 pb{sup -1} of data and those motivated by supersymmetric models. This note largely summarizes material posted at http://lhcnewphysics.org/, which includes simplified model definitions, Monte Carlo material, and supporting contacts within the theory community. We also comment on future developments that may be useful as more data is gathered and analyzed by the experiments.

Alves, Daniele; /SLAC; Arkani-Hamed, Nima; /Princeton, Inst. Advanced Study; Arora, Sanjay; /Rutgers U., Piscataway; Bai, Yang; /SLAC; Baumgart, Matthew; /Johns Hopkins U.; Berger, Joshua; /Cornell U., Phys. Dept.; Buckley, Matthew; /Fermilab; Butler, Bart; /SLAC; Chang, Spencer; /Oregon U. /UC, Davis; Cheng, Hsin-Chia; /UC, Davis; Cheung, Clifford; /UC, Berkeley; Chivukula, R.Sekhar; /Michigan State U.; Cho, Won Sang; /Tokyo U.; Cotta, Randy; /SLAC; D'Alfonso, Mariarosaria; /UC, Santa Barbara; El Hedri, Sonia; /SLAC; Essig, Rouven, (ed.); /SLAC; Evans, Jared A.; /UC, Davis; Fitzpatrick, Liam; /Boston U.; Fox, Patrick; /Fermilab; Franceschini, Roberto; /LPHE, Lausanne /Pittsburgh U. /Argonne /Northwestern U. /Rutgers U., Piscataway /Rutgers U., Piscataway /Carleton U. /CERN /UC, Davis /Wisconsin U., Madison /SLAC /SLAC /SLAC /Rutgers U., Piscataway /Syracuse U. /SLAC /SLAC /Boston U. /Rutgers U., Piscataway /Seoul Natl. U. /Tohoku U. /UC, Santa Barbara /Korea Inst. Advanced Study, Seoul /Harvard U., Phys. Dept. /Michigan U. /Wisconsin U., Madison /Princeton U. /UC, Santa Barbara /Wisconsin U., Madison /Michigan U. /UC, Davis /SUNY, Stony Brook /TRIUMF; /more authors..

2012-06-01T23:59:59.000Z

284

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

E-Print Network [OSTI]

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

A. Djouadi

2002-05-22T23:59:59.000Z

285

Discovering colorons at the early stage LHC  

SciTech Connect (OSTI)

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

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

2011-05-01T23:59:59.000Z

286

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

E-Print Network [OSTI]

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

Ramilli, M

2015-01-01T23:59:59.000Z

287

The LHC Higgs Boson Discovery: Implications for Finite Unified Theories  

E-Print Network [OSTI]

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

S. Heinemeyer; M. Mondragon; G. Zoupanos

2014-12-18T23:59:59.000Z

288

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

SciTech Connect (OSTI)

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.

RIORDAN, MICHAEL

2011-11-29T23:59:59.000Z

289

Electron-Ion Collider - taking us to the next QCD frontier  

E-Print Network [OSTI]

In this talk, I demonstrate that the proposed Electron-Ion Collider (EIC) will be an ideal and unique future facility to address many overarching questions about QCD and strong interaction physics at one place. The EIC will be the world's first polarized electron-proton (and light ion), as well as the first electron-nucleus collider at flexible collision energies. With its high luminosity and beam polarization, the EIC distinguishes itself from HERA and the other fixed target electron-hadron facilities around the world. The EIC is capable of taking us to the next QCD frontier to explore the glue that binds us all.

Jian-Wei Qiu

2014-12-08T23:59:59.000Z

290

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

E-Print Network [OSTI]

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

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

2014-10-08T23:59:59.000Z

291

[New technology for linear colliders  

SciTech Connect (OSTI)

This report discusses the following topics on research of microwave amplifiers for linear colliders: Context in current microwave technology development; gated field emission for microwave cathodes; cathode fabrication and tests; microwave cathode design using field emitters; and microwave localization.

McIntyre, P.M.

1992-08-12T23:59:59.000Z

292

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.

293

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

E-Print Network [OSTI]

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

Lebrun, Philippe

2010-01-01T23:59:59.000Z

294

B Physics at LHC  

E-Print Network [OSTI]

Three experiments, among the LHC project, are getting ready to explore the b quark flavour sector. While ATLAS and CMS are general purpose experiments, where the study of B mesons is going to proceed in parallel with the Higgs boson and supersymmetry searches, the LHCb experiment is devoted to B physics studies. The key parameters entering the physics analyses and the performances achieved in all the three experiments are presented. Given the large B physics program foreseen in the LHC experiments, the studies reported in this paper have been selected as those with higher likelihood to provide solid and interesting new results on Standard Model validation and New Physics processes search with early data.

A. Sarti

2008-09-02T23:59:59.000Z

295

Electron reconstruction in simulated Pb+Pb events in CMS  

E-Print Network [OSTI]

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

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

2008-01-01T23:59:59.000Z

296

B Physics Prospects at LHC  

E-Print Network [OSTI]

Future Experiments at LHC will have the opportunity to pursue an extensive program on B Physics and CP violation. The expected performance are presented here.

Marta Calvi

2005-06-22T23:59:59.000Z

297

Rare hadronic B decays  

E-Print Network [OSTI]

Rare hadronic B-meson decays allow us to study CP violation. The class of B decays final states containing two vector mesons provides a rich set of angular correlation observables to study. This article reviews some of the recent experimental results from the BaBar and Belle collaborations.

A. J. Bevan

2006-06-02T23:59:59.000Z

298

Delay Tolerant Bulk Data Transfers on the Internet Nikolaos Laoutaris  

E-Print Network [OSTI]

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

Sundaram, Ravi

299

Delay Tolerant Bulk Data Transfers on the Internet Nikolaos Laoutaris  

E-Print Network [OSTI]

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

Smaragdakis, Georgios

300

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

E-Print Network [OSTI]

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

Smaragdakis, Georgios

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Designing and recasting LHC analyses with MadAnalysis 5  

E-Print Network [OSTI]

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

Eric Conte; Béranger Dumont; Benjamin Fuks; Chris Wymant

2014-10-10T23:59:59.000Z

302

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

E-Print Network [OSTI]

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

K. Mazumdar

2003-08-29T23:59:59.000Z

303

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

E-Print Network [OSTI]

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

V. I. Telnov

2005-07-15T23:59:59.000Z

304

Muon collider interaction region design  

SciTech Connect (OSTI)

Design of a muon collider interaction region (IR) presents a number of challenges arising from low {beta}* < 1 cm, correspondingly large beta-function values and beam sizes at IR magnets, as well as the necessity to protect superconducting magnets and collider detectors from muon decay products. As a consequence, the designs of the IR optics, magnets and machine-detector interface are strongly interlaced and iterative. A consistent solution for the 1.5 TeV c.o.m. muon collider IR is presented. It can provide an average luminosity of 10{sup 34} cm{sup -2}s{sup -1} with an adequate protection of magnet and detector components.

Alexahin, Y.I.; Gianfelice-Wendt, E.; Kashikhin, V.V.; Mokhov, N.V.; Zlobin, A.V.; /Fermilab; Alexakhin, V.Y.; /Dubna, JINR

2010-05-01T23:59:59.000Z

305

Muon Collider Task Force Report  

SciTech Connect (OSTI)

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

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

2007-12-01T23:59:59.000Z

306

Imaging Pion Showers with the CALICE Analogue Hadron Calorimeter  

E-Print Network [OSTI]

The CALICE collaboration investigates different technology options for highly granular calorimeters for detectors at a future electron-positron collider. One of the devices constructed and tested by the collaboration is a 1m^3 prototype for an imaging scintillator-steel sampling calorimeter for hadrons with analogue readout (AHCAL). The light from 7608 small scintillator cells is detected with silicon photomultipliers. The AHCAL has been successfully operated during electron and hadron test-beam measurements at DESY, CERN, and Fermilab since 2005. The collected data allow for evaluating the novel technologies employed. In addition, these data provide a valuable basis for validating pion cascade simulations. This paper presents the current status of comparisons between the AHCAL data and predictions from different Monte Carlo models implemented in GEANT4. The comparisons cover the total visible energy, longitudinal and radial shower profiles, and the shower substructure. Furthermore, this paper discusses a sof...

Feege, Nils

2011-01-01T23:59:59.000Z

307

Performance of the Reconstruction and Identification of Hadronic Tau Decays in the ATLAS Experiment  

E-Print Network [OSTI]

Tau leptons play an important role in the physics program of the ATLAS experiment at the LHC. Identification of hadronically decaying taus is achieved by using multi-variate discriminants exploiting information from tracking and calorimeter detector components. The identification efficiencies are measured in W->tau+nu and Z->tau+tau events selected in data, and compared with the prediction of the Monte Carlo simulation. The energy scale uncertainties for taus are determined by investigating single hadron calorimeter response, as well as kinematic distributions in Z->tau+tau events.

"Scutti, F; The ATLAS collaboration

2012-01-01T23:59:59.000Z

308

Top Physics at the LHC  

E-Print Network [OSTI]

Top quark physics will be a prominent topic in Standard Model physics at the LHC. The enormous amount of top quarks expected to be produced will allow to perform a wide range of precision measurements. An overview of the planned top physics programme of the ATLAS and CMS experiments at the LHC is given.

Christian Weiser

2005-06-10T23:59:59.000Z

309

Statistical hadronization model description for rapidity densities at RHIC  

E-Print Network [OSTI]

The rapidity densities in Au-Au collisions at center-of-mass energies 200 and 130 A GeV measured at Relativistic Heavy-Ion Collider by STAR and PHENIX collaborations are analyzed within the statistical hadronization model at chemical freeze-out. We find that the model can describe the experimental rapidity densities well. The corresponding chemical freeze-out parameters are determined and they are seen to be in agreement with what we expect from our previous analyzes at lower beam energies at AGS and SPS.

Jaakko Manninen

2007-03-14T23:59:59.000Z

310

The Emerging QCD Frontier: The Electron Ion Collider  

E-Print Network [OSTI]

The self-interactions of gluons determine all the unique features of QCD and lead to a dominant abundance of gluons inside matter already at moderate $x$. Despite their dominant role, the properties of gluons remain largely unexplored. Tantalizing hints of saturated gluon densities have been found in $e$+p collisions at HERA, and in d+Au and Au+Au collisions at RHIC. Saturation physics will have a profound influence on heavy-ion collisions at the LHC. But unveiling the collective behavior of dense assemblies of gluons under conditions where their self-interactions dominate will require an Electron-Ion Collider (EIC): a new facility with capabilities well beyond those In this paper I outline the compelling physics case for $e$+A collisions at an EIC and discuss briefly the status of machine design concepts. of any existing accelerator.

Thomas Ullrich

2008-05-31T23:59:59.000Z

311

Holographic light quark jet quenching at RHIC and LHC via the shooting strings  

E-Print Network [OSTI]

A new shooting string holographic model of jet quenching of light quarks in strongly coupled plasmas is presented to overcome the phenomenological incompatibilities of previous falling string holographic scenarios that emerged when confronted with the recent LHC data. This model is based on strings with finite momentum endpoints that start close to the horizon and lose energy as they approach the boundary. This framework is applied to compute the nuclear modification factor RAA of light hadrons at RHIC and LHC, showing that this model improves greatly the comparison with the recent light hadron suppression data. The effects of the Gauss-Bonnet quadratic curvature corrections to the AdS5 geometry further improve the agreement with the data.

Andrej Ficnar; Steven S. Gubser; Miklos Gyulassy

2014-04-03T23:59:59.000Z

312

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

E-Print Network [OSTI]

We report on the status and history of the CMS commissioning, together with selected results from cosmic-ray muon data. The second part focuses on strategies for optimizing the reconstruction of jets, missing transverse energy and photons for early standard model measurements at ATLAS and CMS with the first collision data from the Large Hadron Collider at CERN.

T. Christiansen

2008-05-13T23:59:59.000Z

313

Hadron Production in Heavy Ion Collisions  

SciTech Connect (OSTI)

Heavy ion collisions are an ideal tool to explore the QCD phase diagram. The goal is to study the equation of state (EOS) and to search for possible in-medium modifications of hadrons. By varying the collision energy a variety of regimes with their specific physics interest can be studied. At energies of a few GeV per nucleon, the regime where experiments were performed first at the Berkeley Bevalac and later at the Schwer-Ionen-Synchrotron (SIS) at GSI in Darmstadt, we study the equation of state of dense nuclear matter and try to identify in-medium modifications of hadrons. Towards higher energies, the regime of the Alternating Gradient Synchrotron (AGS) at the Brookhaven National Laboratory (BNL), the Super-Proton Synchrotron (SPS) at CERN, and the Relativistic Heavy Ion Collider (RHIC) at BNL, we expect to produce a new state of matter, the Quark-Gluon Plasma (QGP). The physics goal is to identify the QGP and to study its properties. By varying the energy, different forms of matter are produced. At low energies we study dense nuclear matter, similar to the type of matter neutron stars are made of. As the energy is increased the main constituents of the matter will change. Baryon excitations will become more prevalent (resonance matter). Eventually we produce deconfined partonic matter that is thought to be in the core of neutron stars and that existed in the early universe. At low energies a great variety of collective effects is observed and a rather good understanding of the particle production has been achieved, especially that of the most abundantly produced pions and kaons. Many observations can be interpreted as time-ordered emission of various particle species. It is possible to determine, albeit model dependent, the equation of state of nuclear matter. We also have seen indications, that the kaon mass, especially the mass of the K{sup +}, might be modified by the medium created in heavy ion collisions. At AGS energies and above, emphasis shifts towards different aspects. Lattice QCD calculations predict the transition between a Quark-Gluon Plasma and a hadronic state at a critical temperature, T{sub c}, of about 150 to 190 MeV at vanishing baryon density. The energy density at the transition point is about 1:0 GeV/fm{sup 3}. It is generally assumed that chiral symmetry restoration happens simultaneously. In the high-energy regime, especially at RHIC, a rich field of phenomena [3] has revealed itself. Hot and dense matter with very strong collectivity has been created. There are indications that collectivity develops at the parton level, i.e. at a very early stage of the collision, when the constituents are partons rather than hadrons. Signs of pressure driven collective effects are our main tool for the study of the EOS. There are also strong indications that in the presence of a medium hadronization occurs through the process of quark coalescence and not through quark fragmentation, the process dominant for high-energy p+p reactions. We limit this report to the study of hadrons emitted in heavy ion reactions. The report is divided into two parts. The first part describes the phenomena observed from hadrons produced at low energies, whereas the second part concentrates on the search for signs of a partonic state at high energies.

Ritter, Hans Georg; Xu, Nu

2009-05-19T23:59:59.000Z

314

LHC - a "Why" Facility  

ScienceCinema (OSTI)

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.

Gordon Kane

2010-01-08T23:59:59.000Z

315

Colliding axisymmetric pp-waves  

E-Print Network [OSTI]

An exact solution is found describing the collision of axisymmetric pp-waves with M=0. They are impulsive in character and their coordinate singularities become point curvature singularities at the boundaries of the interaction region. The solution is conformally flat. Concrete examples are given, involving an ultrarelativistic black hole against a burst of pure radiation or two colliding beam- like waves.

B. V. Ivanov

1997-10-21T23:59:59.000Z

316

Monte Carlo approach for hadron azimuthal correlations in high energy proton and nuclear collisions  

E-Print Network [OSTI]

We use a Monte Carlo approach to study hadron azimuthal angular correlations in high energy proton-proton and central nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) energies at mid-rapidity. We build a hadron event generator that incorporates the production of $2\\to 2$ and $2\\to 3$ parton processes and their evolution into hadron states. For nucleus-nucleus collisions we include the effect of parton energy loss in the Quark-Gluon Plasma using a modified fragmentation function approach. In the presence of the medium, for the case when three partons are produced in the hard scattering, we analyze the Monte Carlo sample in parton and hadron momentum bins to reconstruct the angular correlations. We characterize this sample by the number of partons that are able to hadronize by fragmentation within the selected bins. In the nuclear environment the model allows hadronization by fragmentation only for partons with momentum above a threshold $p_T^{{\\tiny{thresh}}}=2.4$ GeV. We argue that one should treat properly the effect of those partons with momentum below the threshold, since their interaction with the medium may lead to showers of low momentum hadrons along the direction of motion of the original partons as the medium becomes diluted.

Alejandro Ayala; Isabel Dominguez; Jamal Jalilian-Marian; J. Magnin; Maria Elena Tejeda-Yeomans

2012-07-31T23:59:59.000Z

317

Energy dependence of hadron spectra and multiplicities in p+p interactions  

E-Print Network [OSTI]

The NA61/SHINE experiment at the CERN SPS aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. In order to reach these goals measurements of hadron production properties are performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as a function of collision energy and size of the colliding nuclei. Inclusive spectra of identified hadrons in p+p interactions at the SPS energies are presented as a function of transverse momentum, transverse mass and rapidity. The results are compared with the world data and theoretical models.

Pu?awski, Szymon

2015-01-01T23:59:59.000Z

318

Minijet transverse energy production in the next-to-leading order in hadron and nuclear collisions  

E-Print Network [OSTI]

The transverse energy flow generated by minijets in hadron and nuclear collisions into a given rapidity window in the central region is calculated in the next-to-leading (NLO) order in QCD at RHIC and LHC energies. The NLO transverse energy production in pp collisions cross sections are larger than the LO ones by the factors of K_{RHIC} ~ 1.9 and K_{LHC} ~ 2.1 at RHIC and LHC energies correspondingly. These results were then used to calculate transverse energy spectrum in nuclear collisions in a Glauber geometrical model. We show that accounting for NLO corrections in the elementary pp collisions leads to a substantial broadening of the E_{perp} distribution for the nuclear ones, while its form remains practically unchanged.

A. V. Leonidov; D. M. Ostrovsky

1998-11-23T23:59:59.000Z

319

Minijet transverse energy production in the next-to-leading order in hadron and nuclear collisions  

E-Print Network [OSTI]

The transverse energy flow generated by minijets in hadron and nuclear collisions into a given rapidity window in the central region is calculated in the next-to-leading (NLO) order in QCD at RHIC and LHC energies. The NLO transverse energy production in pp collisions cross sections are larger than the LO ones by the factors of $K_{RHIC} \\sim 1.9$ and $K_{LHC} \\sim 2.1$ at RHIC and LHC energies correspondingly. These results were then used to calculate transverse energy spectrum in nuclear collisions in a Glauber geometrical model. We show that accounting for NLO corrections in the elementary pp collisions leads to a substantial broadening of the $E_{\\perp}$ distribution for the nuclear ones, while its form remains practically unchanged.

Leonidov, A V

1998-01-01T23:59:59.000Z

320

LHC Higgs Boson searches  

E-Print Network [OSTI]

A summary of the Higgs boson searches by the ATLAS and CMS collabrations using 1 f b-1 of LHC data is presented, concentrating on the Standard Model Higgs boson. Both experiments have the sensitivity to exclude at 95% CL a Standard Model Higgs boson in most of the Higgs boson mass region between about 130 GeV and 400 GeV. The observed data allow the exclusion of a Higgs Boson of mass 155 GeV to 190 GeV and 295 GeV to 450 GeV (ATLAS) and 149 GeV to 206 GeV and 300 GeV to 440 GeV (CMS). The lower limits are not as constraining as might be expected due to an excess in both experiments of order 2-3{\\sigma} which could be related to a low mass Higgs boson or to a statistical fluctuation.

William Murray

2012-01-22T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Studies of forward jets and production of W, Z bosons at LHC energies  

E-Print Network [OSTI]

We report on application of QCD in calculations of forward jet and W, Z boson production cross sections at the Large Hadron Collider. In particular in case of jet production we emphasize dynamical features of the matrix elements controlling the resummation of logarithmically enhanced corrections in $\\sqrt{s}/E_T$, where $E_T$ is the jet production transverse energy. In case of production of W, Z bosons we focus on angular correlations between produced boson and hardest associated jet.

K. Kutak

2009-11-08T23:59:59.000Z

322

Left-Right Symmetry: from LHC to Neutrinoless Double Beta Decay  

E-Print Network [OSTI]

The Large Hadron Collider has a potential to probe the scale of left-right symmetry restoration and the associated lepton number violation. Moreover, it offers hope of measuring the right-handed leptonic mixing matrix. We show how this, together with constraints from lepton flavor violating processes, can be used to make predictions for neutrinoless double beta decay. We illustrate this deep connection in the case of the type-II seesaw.

Vladimir Tello; Miha Nemevsek; Fabrizio Nesti; Goran Senjanovi?; Francesco Vissani

2011-03-29T23:59:59.000Z

323

Left-Right Symmetry: From the LHC to Neutrinoless Double Beta Decay  

SciTech Connect (OSTI)

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.

Tello, Vladimir [SISSA, Trieste (Italy); Nemevsek, Miha [ICTP, Trieste (Italy); Jozef Stefan Institute, Ljubljana (Slovenia); Nesti, Fabrizio [Universita di Ferrara, Ferrara (Italy); Senjanovic, Goran [ICTP, Trieste (Italy); Vissani, Francesco [LNGS, INFN, Assergi (Italy)

2011-04-15T23:59:59.000Z

324

Operational Experience and First Results with a Highly Granular Tungsten Analog Hadron Calorimeter  

E-Print Network [OSTI]

Precision physics at future multi-TeV lepton colliders such as CLIC requires excellent jet energy resolution. The detectors need deep calorimeter systems to limit the energy leakage also for very highly energetic particles and jets. At the same time, compact physical dimensions are mandatory to permit the installation of the complete calorimeter system inside high-field solenoidal magnets. This requires very dense absorbers, making tungsten a natural choice for hadron calorimeters at such a future collider. To study the performance of such a calorimeter, a physics prototype with tungsten absorbers and scintillator tiles with SiPM readout as active elements has been constructed and has been tested in particle beams at CERN over a wide energy range from 1 GeV to 300 GeV. We report on the construction and on the operational experience obtained with muon, electron and hadron beams.

Frank Simon; for the CALICE Collaboration

2011-11-22T23:59:59.000Z

325

Strange particle production in hadronic Z{sup 0} decays  

SciTech Connect (OSTI)

A study has been made of neutral strange baryons and pseudoscalar mesons produced in hadronic decays of the weak gauge boson V. The experiment was performed at the Stanford Linear Accelerator Center, which has the unique capability of colliding highly polarized electrons with unpolarized positrons. Overall production rates and spectra of the K{sup 0} and the {Lambda}{sup 0} (+{Lambda}{sup 0}) were measured and compared with other experiments as well as with Quantum Chromodynamics calculations. The combination of the small, stable beam spots produced by the SLAC Linear Collider (SLC) and the precision vertexing capabilities of the SLC Large Detector (SLD) permitted the separation of the hadronic events into three quark flavor-enriched samples. An unfolding was performed to obtain flavor-pure samples, and for the first time measurements were made of K{sup 0} and {Lambda}{sup 0} (+{Lambda}{sup 0}) production rates and spectra in uds, c, and b quark events at the Z{sup 0} pole. This measurement revealed significant production differences. Utilizing the large quark production asymmetry due to the polarized electron beam, high-purity quark and antiquark jet samples were obtained. The first measurement of production differences of the {Lambda}{sup 0} baryon in quark and antiquark jets was performed, which provided clear evidence for a leading particle effect at high momenta.

Baird, K.G. III

1996-04-01T23:59:59.000Z

326

Heavy-quark probes of the quark-gluon plasma and interpretation of recent data taken at the BNL Relativistic Heavy Ion Collider  

E-Print Network [OSTI]

strongly interacting QGP (sQGP), as well as parton coalescence, can play an essential role in the interpretation of recent data from the BNL Relativistic Heavy-Ion Collider (RHIC), and thus illuminate the nature of the sQGP and its hadronization. Our main...

van Hees, H.; Greco, V.; Rapp, Ralf.

2006-01-01T23:59:59.000Z

327

Tsallis Fits to p_T Spectra and Multiple Hard Scattering in pp Collisions at LHC  

SciTech Connect (OSTI)

Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the fitting transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arising from the relativistic parton-parton hard-scattering and related hard processes. The effects of multiple hard-scattering and parton showering on the power law are discussed. We find that although the transverse spectra of both hadrons and jets exhibit power-law behaviour of 1/pT^n at high pT, the power indices n for hadrons are categorically greater than those for jets, for which n~4.

Wong, Cheuk-Yin [ORNL; Wilk, Grzegorz [National Centre for Nuclear Research, Warsaw, Poland

2013-01-01T23:59:59.000Z

328

Conventional power sources for colliders  

SciTech Connect (OSTI)

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.

Allen, M.A.

1987-07-01T23:59:59.000Z

329

L'Aventure du LHC  

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

330

Quantum Gravity at the LHC  

E-Print Network [OSTI]

It has recently been shown that if there is a large hidden sector in Nature, the scale of quantum gravity could be much lower than traditionally expected. We study the production of massless gravitons at the LHC and compare our results to those obtained in extra dimensional models. The signature in both cases is missing energy plus jets. In case of non observation, the LHC could be used to put the tightest limit to date on the value of the Planck mass.

Xavier Calmet; Priscila de Aquino

2009-10-08T23:59:59.000Z

331

Le LHC, un tunnel cosmique  

ScienceCinema (OSTI)

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

None

2011-10-06T23:59:59.000Z

332

Performance of the Large Scale Prototypes of the CALICE Tile Hadron Calorimeter  

E-Print Network [OSTI]

The concept of a tile hadron calorimeter (HCAL) for the International Linear Collider (ILC) has been developed. A major aspect is the improvement of the jet energy resolution by measuring details of the shower development and combining them with the data of the tracking chamber (particle flow). The concept utilizes scintillating tiles that are read out by novel Silicon Photomultipliers (SiPMs) and takes into account all design aspects that are demanded by the intended operation

Reinecke, M

2015-01-01T23:59:59.000Z

333

W gamma production in hadronic collisions using the POWHEG+MiNLO method  

E-Print Network [OSTI]

We detail a calculation of W gamma production in hadronic collision, at Next-to-Leading Order (NLO) QCD interfaced to a shower generator according to the POWHEG prescription supplemented with the MiNLO procedure. The fixed order result is matched to an interleaved QCD+QED parton shower, in such a way that the contribution arising from hadron fragmentation into photons is fully modeled. In general, our calculation illustrates a new approach to the fully exclusive simulation of prompt photon production processes accurate at the NLO level in QCD. We compare our predictions to those of the NLO program MCFM, which treats the fragmentation contribution in terms of photon fragmentation functions. We also perform comparisons to available LHC data at 7 TeV, for which we observe good agreement, and provide phenomenological results for physics studies of the W gamma production process at the Run II of the LHC. The new tool, which includes W leptonic decays and the contribution of anomalous gauge couplings, allows a fully exclusive, hadron-level description of the W gamma process, and is publicly available at the repository of the POWHEG BOX. Our approach can be easily adapted to deal with other relevant isolated photon production processes in hadronic collisions.

Luca Barze; Mauro Chiesa; Guido Montagna; Paolo Nason; Oreste Nicrosini; Fulvio Piccinini; Valeria Prosperi

2014-12-10T23:59:59.000Z

334

Phenomenology of the minimal B ? L Model: the Higgs sector at the Large Hadron Collider and future linear colliders.  

E-Print Network [OSTI]

??This thesis is devoted to the study of the phenomenology of the Higgs sector of the minimal B ?L extension of the Standard Model at… (more)

Pruna, Giovanni Marco

2011-01-01T23:59:59.000Z

335

US LHC Accelerator Project Baseline Change Request BCR Number 58  

E-Print Network [OSTI]

to correspond to the current LHC installation schedule, constrained by the U.S. LHC Project end-of-project

Large Hadron Collider Program

336

Monte Carlo approach for hadron azimuthal correlations in high energy proton and nuclear collisions  

E-Print Network [OSTI]

We use a Monte Carlo approach to study hadron azimuthal angular correlations in high energy proton-proton and central nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) energies at mid-rapidity. We build a hadron event generator that incorporates the production of $2\\to 2$ and $2\\to 3$ parton processes and their evolution into hadron states. For nucleus-nucleus collisions we include the effect of parton energy loss in the Quark-Gluon Plasma using a modified fragmentation function approach. In the presence of the medium, for the case when three partons are produced in the hard scattering, we analyze the Monte Carlo sample in parton and hadron momentum bins to reconstruct the angular correlations. We characterize this sample by the number of partons that are able to hadronize by fragmentation within the selected bins. In the nuclear environment the model allows hadronization by fragmentation only for partons with momentum above a threshold $p_T^{{\\tiny{thresh}}}=2.4$ GeV. We argue that...

Ayala, Alejandro; Jalilian-Marian, Jamal; Magnin, J; Tejeda-Yeomans, Maria Elena

2012-01-01T23:59:59.000Z

337

The influence of net-quarks on the yields and rapidity spectra of identified hadrons  

E-Print Network [OSTI]

Within a quark combination model, we study systematically the yields and rapidity spectra of various hadrons in central Au+Au collisions at $\\sqrt{s_{NN}}= 200$ GeV. We find that considering the difference in rapidity between net-quarks and newborn quarks, the data of multiplicities, rapidity distributions for $\\pi^{\\pm}$, $K^{\\pm}$, $p(\\bar{p})$ and, in particular the ratios of charged antihadron to hadron as a function of rapidity, can be well described. The effect of net-quarks on various hadrons is analysed, and the rapidity distributions for $K^{0}_{s}$, $\\Lambda(\\bar{\\Lambda})$, $\\Sigma^{+}(\\bar{\\Sigma}^{_-})$, $\\mathrm{\\Xi^{-}}$ ($\\mathrm{\\bar{\\Xi}^{_+}}$) and $\\mathrm{\\Omega^{-}}(\\mathrm{\\bar{\\Omega}}^{_+})$ are predicted. We discuss the rapidity distribution of net-baryon, and find that it reflects exactly the energy loss of colliding nuclei.

Jun Song; Feng-lan Shao; Qu-bing Xie; Yun-fei Wang; De-ming Wei

2008-02-21T23:59:59.000Z

338

Statistical Origin of Constituent-Quark Scaling in the QGP hadronization  

E-Print Network [OSTI]

Nonextensive statistics in a Blast-Wave model (TBW) is implemented to describe the identified hadron production in relativistic p+p and nucleus-nucleus collisions. Incorporating the core and corona components within the TBW formalism allows us to describe simultaneously some of the major observations in hadronic observables at the Relativistic Heavy-Ion Collider (RHIC): the Number of Constituent Quark Scaling (NCQ), the large radial and elliptic flow, the effect of gluon saturation and the suppression of hadron production at high transverse momentum (pT) due to jet quenching. In this formalism, the NCQ scaling at RHIC appears as a consequence of non-equilibrium process. Our study also provides concise reference distributions with a least chi2 fit of the available experimental data for future experiments and models.

Zebo Tang; Li Yi; Lijuan Ruan; Ming Shao; Hongfang Chen; Cheng Li; Bedangadas Mohanty; Paul Sorensen; Aihong Tang; Zhangbu Xu

2011-07-07T23:59:59.000Z

339

Chemical properties of super-hadronic matter created in relativistic heavy ion collisions  

E-Print Network [OSTI]

Preliminary charge balance functions from the STAR Collaboration at the Relativistic Heavy Ion Collider (RHIC) are compared to a model where quarks are produced in two waves. If a chemically equilibrated quark-gluon plasma (QGP) is created the strength and diffusive spread of the first wave should be governed by the chemical composition of the QGP, while the second wave should be determined by the increased number of quarks required to make the observed final-state hadrons. A simple model parameterizes the chemistry of the super-hadronic matter and the two correlation lengths for the two waves. Calculations are compared to preliminary data from the STAR Collaboration. The chemistry of the super-hadronic matter appears to be within 20\\% of expectations from lattice gauge theory.

Scott Pratt; Claudia Ratti; William Patrick McCormack

2014-09-07T23:59:59.000Z

340

Predictions on the transverse momentum spectra for charged particle production at LHC-energies from a two component model  

E-Print Network [OSTI]

Transverse momentum spectra, $d^2\\sigma/(d\\eta dp_T^2)$, of charged hadron production in $pp$-collisions are considered in terms of a recently introduced two component model. The shapes of the particle distributions vary as a function of c.m.s. energy in the collision and the measured pseudorapidity interval. In order to extract predictions on the double-differential cross-sections $d^2\\sigma/(d\\eta dp_T^2)$ of hadron production for future LHC-measurements the different sets of available experimental data have been used in this study.

Bylinkin, Alexander; Rostovtsev, Andrei

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Studies of Transverse-Momentum-Dependent distributions with A Fixed-Target ExpeRiment using the LHC beams (AFTER@LHC)  

E-Print Network [OSTI]

We report on the studies of Transverse-Momentum-Dependent distributions (TMDs) at a future fixed-target experiment --AFTER@LHC-- using the $p^+$ or Pb ion LHC beams, which would be the most energetic fixed-target experiment ever performed. AFTER@LHC opens new domains of particle and nuclear physics by complementing collider-mode experiments, in particular those of RHIC and the EIC projects. Both with an extracted beam by a bent crystal or with an internal gas target, the luminosity achieved by AFTER@LHC surpasses that of RHIC by up to 3 orders of magnitude. With an unpolarised target, it allows for measurements of TMDs such as the Boer-Mulders quark distributions and the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using polarised targets, one can access the quark and gluon Sivers TMDs through single transverse-spin asymmetries in Drell-Yan and quarkonium production. In terms of kinematics, the fixed-target mode combined with a detector covering $\\eta_{\\rm lab} \\in [1,5]$ ...

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

2015-01-01T23:59:59.000Z

342

Studies of Transverse-Momentum-Dependent distributions with A Fixed-Target ExpeRiment using the LHC beams (AFTER@LHC)  

E-Print Network [OSTI]

We report on the studies of Transverse-Momentum-Dependent distributions (TMDs) at a future fixed-target experiment --AFTER@LHC-- using the $p^+$ or Pb ion LHC beams, which would be the most energetic fixed-target experiment ever performed. AFTER@LHC opens new domains of particle and nuclear physics by complementing collider-mode experiments, in particular those of RHIC and the EIC projects. Both with an extracted beam by a bent crystal or with an internal gas target, the luminosity achieved by AFTER@LHC surpasses that of RHIC by up to 3 orders of magnitude. With an unpolarised target, it allows for measurements of TMDs such as the Boer-Mulders quark distributions and the distribution of unpolarised and linearly polarised gluons in unpolarised protons. Using polarised targets, one can access the quark and gluon Sivers TMDs through single transverse-spin asymmetries in Drell-Yan and quarkonium production. In terms of kinematics, the fixed-target mode combined with a detector covering $\\eta_{\\rm lab} \\in [1,5]$ allows one to measure these asymmetries at large $x^\\uparrow$ in the polarised nucleon.

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

2015-02-03T23:59:59.000Z

343

International Workshop on Linear Colliders 2010  

ScienceCinema (OSTI)

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

None

2011-10-06T23:59:59.000Z

344

Harmonic potential and hadron spectroscopy  

E-Print Network [OSTI]

The quark-gluon sea in the hadrons is considered as periodically correlated. Energy levels of Shrodinger equation with harmonic potential is used for describing of the spectrum of hadron masses. In the considered cases the effective potential operating on each particle of ensemble, under certain conditions becomes square-law on displacement from a equilibrium point. It can become an explanation of popularity of oscillator potential for the description of a spectrum of masses of elementary particles. The analysis shows that levels of periodic potential better agreed to the spectrum of hadron masses, than levels of other potentials used for an explanation of a spectrum of masses.

Rafael Tumanyan

2009-05-28T23:59:59.000Z

345

LHC constraints on gauge boson couplings to dark matter  

E-Print Network [OSTI]

Collider searches for energetic particles recoiling against missing transverse energy allow to place strong bounds on the interactions between dark matter (DM) and standard model particles. In this article we update and extend LHC constraints on effective dimension-7 operators involving DM and electroweak gauge bosons. A concise comparison of the sensitivity of the mono-photon, mono-W, mono-Z, mono-W/Z, invisible Higgs-boson decays in the vector boson fusion mode and the mono-jet channel is presented. Depending on the parameter choices, either the mono-photon or the mono-jet data provide the most stringent bounds at the moment. We furthermore explore the potential of improving the current 8 TeV limits at 14 TeV. Future strategies capable of disentangling the effects of the different effective operators involving electroweak gauge bosons are discussed as well.

Crivellin, Andreas; Hibbs, Anthony

2015-01-01T23:59:59.000Z

346

Probing Higgs Boson Interactions At Future Colliders.  

E-Print Network [OSTI]

??We present in this thesis a detailed analysis of Higgs boson interactions at future colliders. In particular we examine, in a model independent way, the… (more)

Biswal, Sudhansu Sekhar

2009-01-01T23:59:59.000Z

347

Subcritical Fission Reactor Based on Linear Collider  

E-Print Network [OSTI]

The beams of Linear Collider after main collision can be utilized to build an accelerator--driven sub--critical reactor.

I. F. Ginzburg

2005-07-29T23:59:59.000Z

348

Siting the International Linear Collider at Hanford  

SciTech Connect (OSTI)

Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facilityl.

Kouzes, Richard T.; Asner, David M.; Brodzinski, Ronald L.; Fast, James E.; Miley, Harry S.

2012-03-15T23:59:59.000Z

349

Siting the International Linear Collider at Hanford  

SciTech Connect (OSTI)

Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facility.

Kouzes, Richard T.; Asner, David M.; Brodzinski, Ronald L.; Fast, James E.; Miley, Harry S.

2012-05-01T23:59:59.000Z

350

Jet physics at HERA, Tevatron and LHC  

E-Print Network [OSTI]

In this short report, we discuss the Jet Physics results and perspectives at HERA, Tevatron and LHC.

C. Royon

2008-11-10T23:59:59.000Z

351

Stochastic cooling in muon colliders  

SciTech Connect (OSTI)

Analysis of muon production techniques for high energy colliders indicates the need for rapid and effective beam cooling in order that one achieve luminosities > 10{sup 30} cm{sup {minus}2}s{sup {minus}1} as required for high energy physics experiments. This paper considers stochastic cooling to increase the phase space density of the muons in the collider. Even at muon energies greater than 100 GeV, the number of muons per bunch must be limited to {approximately}10{sup 3} for the cooling rate to be less than the muon lifetime. With such a small number of muons per bunch, the final beam emittance implied by the luminosity requirement is well below the thermodynamic limit for beam electronics at practical temperatures. Rapid bunch stacking after the cooling process can raise the number of muons per bunch to a level consistent with both the luminosity goals and with practical temperatures for the stochastic cooling electronics. A major advantage of our stochastic cooling/stacking scheme over scenarios that employ only ionization cooling is that the power on the production target can be reduced below 1 MW.

Barletta, W.A.; Sessler, A.M.

1993-09-01T23:59:59.000Z

352

Pre-Town Meeting on Spin Physics at an Electron-Ion Collider  

E-Print Network [OSTI]

A polarized $ep/eA$ collider (Electron--Ion Collider, or EIC), with polarized proton and light-ion beams and unpolarized heavy-ion beams with a variable center--of--mass energy $\\sqrt{s} \\sim 20$ to $\\sim100$~GeV (upgradable to $\\sim 150$ GeV) and a luminosity up to $\\sim 10^{34} \\, \\textrm{cm}^{-2} \\textrm{s}^{-1}$, would be uniquely suited to address several outstanding questions of Quantum Chromodynamics, and thereby lead to new qualitative and quantitative information on the microscopic structure of hadrons and nuclei. During this meeting at Jefferson Lab we addressed recent theoretical and experimental developments in the spin and the three--dimensional structure of the nucleon (sea quark and gluon spatial distributions, orbital motion, polarization, and their correlations). This mini--review contains a short update on progress in these areas since the EIC White paper~\\cite{Accardi:2012qut}.

Elke-Caroline Aschenauer; Ian Balitsky; Leslie Bland; Stanley J. Brodsky; Matthias Burkardt; Volker Burkert; Jian-Ping Chen; Abhay Deshpande; Markus Diehl; Leonard Gamberg; Matthias Grosse Perdekamp; Jin Huang; Charles Hyde; Xiangdong Ji; Xiaodong Jiang; Zhong-Bo Kang; Valery Kubarovsky; John Lajoie; Keh-Fei Liu; Ming Liu; Simonetta Liuti; Wally Melnitchouk; Piet Mulders; Alexei Prokudin; Andrey Tarasov; Jian-Wei Qiu; Anatoly Radyushkin; David Richards; Ernst Sichtermann; Marco Stratmann; Werner Vogelsang; Feng Yuan

2014-10-31T23:59:59.000Z

353

The Vertex Tracker at the e+e- Linear Collider Conceptual Design, Detector R&D and Physics Performances for the Next Generation of Silicon Vertex Detectors  

E-Print Network [OSTI]

The e+e- linear collider physics programme sets highly demanding requirements on the accurate determination of charged particle trajectories close to their production point. A new generation of Vertex Trackers, based on different technologies of high resolution silicon sensors, is being developed to provide the needed performances. These developments are based on the experience with the LEP/SLC vertex detectors and on the results of the R&D programs for the LHC trackers and also define a further program of R&D specific to the linear collider applications. In this paper the present status of the conceptual tracker design, silicon detector R&D and physics studies is discussed.

Marco Battaglia; Massimo Caccia

1999-11-26T23:59:59.000Z

354

Diffusion of $?_c$ in hot hadronic medium and its impact on $?_c/D$ ratio  

E-Print Network [OSTI]

The drag and diffusion coefficients of the $\\Lambda_c(2286$ MeV) have been evaluated in the hadronic medium which is expected to be formed in the later stages of the evolving fire ball produced in heavy ion collisions at RHIC and LHC energies. The interactions between the $\\Lambda_c$ and the hadrons in the medium have been derived from an effective hadronic Lagrangian as well as from the scattering lengths, obtained in the framework of heavy baryon chiral perturbation theory (HB$\\chi$PT). In both the approaches, the magnitude of the transport coefficients are turn out to be significant. A larger value is obtained in the former approach with respect to the latter. Significant values of the coefficients indicate substantial amount of interaction of the $\\Lambda_c$ with the hadronic thermal bath. Furthermore, the transport coefficients of the $\\Lambda_c$ is found to be different from the transport coefficients of $D$ meson. Present study indicates that the hadronic medium has a significant impact on the $\\Lambda_c/D$ ratio in heavy ion collisions.

Sabyasachi Ghosh; Santosh K. Das; Vincenzo Greco; Sourav Sarkar; Jan-e Alam

2014-09-19T23:59:59.000Z

355

RHIC and LHC jet suppression in non-central collisions  

E-Print Network [OSTI]

Understanding properties of QCD matter created in ultra-relativistic heavy-ion collisions is a major goal of RHIC and LHC experiments. An excellent tool to study these properties is jet suppression of light and heavy flavor observables. Utilizing this tool requires accurate suppression predictions for different experiments, probes and experimental conditions, and their unbiased comparison with experimental data. With this goal, we here extend our dynamical energy loss formalism towards generating predictions for non-central collisions; the formalism takes into account both radiative and collisional energy loss, dynamical (as opposed to static) scattering centers, finite magnetic mass, running coupling and uses no free parameters in comparison with experimental data. Specifically, we here generate predictions for all available centrality ranges, for both LHC and RHIC experiments, and for four different probes (charged hadrons, neutral pions, D mesons and non-prompt $J/\\psi$). We obtain a very good agreement with all available non-central data, and also generate predictions for suppression measurements that will soon become available. Finally, we discuss implications of the obtained good agreement with experimental data with different medium models that are currently considered.

Magdalena Djordjevic; Marko Djordjevic; Bojana Blagojevic

2014-06-25T23:59:59.000Z

356

The history of the LHC  

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

357

Scaling patterns for the suppression of charged hadron yields in Pb+Pb collisions at Root_s = 2.76 TeV: Constraints on transport coefficients  

E-Print Network [OSTI]

Suppression measurements for charged hadrons are used to investigate the path length (L) and transverse momentum (p_T) dependent jet quenching patterns of the hot and dense QCD medium produced in Pb+Pb collisions at Root_s =2.76 TeV at the LHC. The observed scaling patterns, which are similar to those observed for Au+Au collisions at Root_s = 0.20 TeV at RHIC, show the trends predicted for jet-medium interactions dominated by radiative energy loss. They also allow a simple estimate of the transport coefficient $\\hat{q}$, which suggests that the medium produced in LHC collisions is somewhat less opaque than that produced at RHIC, if the same parton-medium coupling strength is assumed. The higher temperature produced in LHC collisions could reduce the parton-medium coupling strength to give identical values for $\\hat{q}$ in LHC and RHIC collisions.

Roy A. Lacey; N. N. Ajitanand; J. M. Alexander; J. Jia; A. Taranenko

2012-02-24T23:59:59.000Z

358

No-Scale F-SU(5) in the Light of LHC, Planck and XENON  

E-Print Network [OSTI]

We take stock of the No-Scale F-SU(5) model's experimental status and prospects in the light of results from LHC, Planck, and XENON100. Given that no conclusive evidence for light Supersymmetry (SUSY) has emerged from the 7, 8 TeV collider searches, the present work is focused on exploring and clarifying the precise nature of the high-mass cutoff enforced on this model at the point where the stau and neutralino mass degeneracy becomes so tight that cold dark matter relic density observations cannot be satisfied. This hard upper boundary on the model's mass scale constitutes a top-down theoretical mandate for a comparatively light (and testable) SUSY spectrum which does not excessively stress natural resolution of the gauge hierarchy problem. The overlap between the resulting model boundaries and the expected sensitivities of the future 14 TeV LHC and XENON 1-Ton direct detection SUSY / dark matter experiments is described.

Tianjun Li; James A. Maxin; Dimitri V. Nanopoulos; Joel W. Walker

2013-09-17T23:59:59.000Z

359

Extending LHC Coverage to Light Pseudoscalar Mediators and Coy Dark Sectors  

E-Print Network [OSTI]

Many dark matter models involving weakly interacting massive particles (WIMPs) feature new, relatively light pseudoscalars that mediate dark matter pair annihilation into Standard Model fermions. In particular, simple models of this type can explain the gamma ray excess originating in the Galactic Center as observed by the Fermi Large Area Telescope. In many cases the pseudoscalar's branching ratio into WIMPs is suppressed, making these states challenging to detect at colliders through standard dark matter searches. Here, we study the prospects for observing these light mediator states at the LHC without exploiting missing energy techniques. While existing searches effectively probe pseudoscalars with masses between 5 - 14 GeV and above 90 GeV, the LHC reach can be extended to cover much of the interesting parameter space in the intermediate 20 - 80 GeV mass range in which the mediator can have appreciable Yukawa-like couplings to Standard Model fermions but would have escaped detection by LEP and other exper...

Kozaczuk, Jonathan

2015-01-01T23:59:59.000Z

360

Systematic Analysis of Frontier Energy Collider Data  

E-Print Network [OSTI]

Ignorance of the form new physics will take suggests the importance of systematically analyzing all data collected at the energy frontier, with the goal of maximizing the chance for discovery both before and after the turn on of the LHC.

Bruce Knuteson

2005-04-23T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

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

362

Comments on "Wall-plug (AC) power consumption of a very high energy e+/e- storage ring collider" by Marc Ross  

E-Print Network [OSTI]

The paper arXiv:1308.0735 questions some of the technical assumptions made by the TLEP Steering Group when estimating in arXiv:1305.6498 the power requirement for the very high energy e+e- storage ring collider TLEP. We show that our assumptions are based solidly on CERN experience with LEP and the LHC, as well accelerators elsewhere, and confirm our earlier baseline estimate of the TLEP power consumption.

Blondel, A; Butterworth, A; Janot, P; Zimmermann, F; Aleksan, R; Azzi, P; Ellis, J; Klute, M; Zanetti, M

2013-01-01T23:59:59.000Z

363

On Field Emission in High Energy Colliders Initiated by a Relativistic Positively Charged Bunch of Particles  

E-Print Network [OSTI]

The design of the LHC and future colliders aims their operation with high intensity beams, with bunch population, $N_p$, of the order of $10^{11}$. This is dictated by a desire to study very rare processes with maximum data sample. HEP colliders are engineering structures of many kilometers in length, whose transverse compactness is achieved by the application of the superconducting technologies and limitations of cost. However the compactness of the structural elements conceals and potential danger for the stable work of the accelerator. This is because a high intensity beam of positively charged particles (protons, positrons, ions) creates around itself an electric self-field of very high intensity, $10^5 - 10^6$ V/cm. Being located near the conducting surfaces, at the distances of 1-20 mm away from them, the field of such bunches activates the field emission of electrons from the surface. These electrons, in addition to electrons from the ionization of residual gases, secondary electrons and electrons knocked out by synchrotron radiation, contribute to the development of a dense electron cloud in the transport line. The particles of the bunch, being scattered on the dense electron cloud with $N_e\\sim N_p$, leaves the beam and may cause noticeable damage. The paper presents an analysis of the conditions, under which the field emission in the LHC collimator system may become a serious problem. The analogous analysis of a prototype of the International Linear Collider (ILC) project, USLC, reveals that a noticeable field emission will accompany positron bunches on their entire path during acceleration.

B. B. Levchenko

2006-08-12T23:59:59.000Z

364

Collider searches and cosmology in the MSSM with heavy scalars  

SciTech Connect (OSTI)

In a variety of supersymmetric extensions of the Standard Model, the scalar partners of the quarks and leptons are predicted to be very heavy and beyond the reach of next-generation colliders. For instance, the realization of electroweak baryogenesis in supersymmetry requires new sources of CP-violation, which can only be naturally accommodated with electric dipole moment constraints if the first and second generation scalar fermions are beyond the TeV scale. Also in focus-point supersymmetry and split supersymmetry the scalar fermions are very heavy. In this work, the phenomenology of scenarios with electroweak baryogenesis and in the focus point region at the LHC and ILC is studied, which becomes challenging due to the presence of heavy scalar fermions. Implications for the analysis of baryogenesis and dark matter are deduced. It is found that precision measurements of superpartner properties allow an accurate determination of the dark matter relic density in both scenarios, while important but only incomplete information about the baryogenesis mechanism can be obtained.

Carena, Marcela; /Fermilab; Freitas, A.; /Zurich U.

2006-08-01T23:59:59.000Z

365

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)

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.

Geiger, K.; Longacre, R. [Brookhaven National Lab., Upton, NY (United States). Physics Dept.; Srivastava, D.K. [Variable Energy Cyclotron Centre, Calcutta (India)

1999-02-01T23:59:59.000Z

366

Tsallis fits to pT spectra and multiple hard scattering in pp collisions at the LHC  

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

Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arise from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/pnT at high pT, the power indices n for hadrons are systematically greater than those for jets, for which n?4–5.

Wong, Cheuk-Yin; Wilk, Grzegorz

2013-06-01T23:59:59.000Z

367

Tsallis fits to pT spectra and multiple hard scattering in pp collisions at the LHC  

SciTech Connect (OSTI)

Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arise from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/pnT at high pT, the power indices n for hadrons are systematically greater than those for jets, for which n?4–5.

Wong, Cheuk-Yin; Wilk, Grzegorz

2013-06-01T23:59:59.000Z

368

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

Office of Science (SC) Website

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear SecurityTensile Strain Switched5 IndustrialIsadore Perlman, 1960 The Ernest OrlandoJohnLegislativeLinac

369

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

SciTech Connect (OSTI)

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.

Gabrielli, E. [CERN, PH-TH, CH-1211 Geneva 23 (Switzerland); Mele, B. [INFN, Sezione di Roma, c/o Dipartimento di Fisica, Universita di Roma 'La Sapienza', Piazzale A. Moro 2, I-00185 Rome (Italy)

2011-04-01T23:59:59.000Z

370

Superconducting solenoids for the Muon collider  

E-Print Network [OSTI]

muon collider has superconducting solenoids as an integralLBNL-44303 SCMAG-690 Superconducting Solenoids for the MuonDE-AC03-76SFOOO98. J Superconducting Solenoids for the Muon

Green, M.A.

2011-01-01T23:59:59.000Z

371

Andy Haas -5/21/2010 Slide 1 LHC DATA!LHC DATA!  

E-Print Network [OSTI]

Andy Haas - 5/21/2010 Slide 1 LHC DATA!LHC DATA! Current status of LHC and ATLASCurrent status 21, 2010May 21, 2010 #12;Andy Haas - 5/21/2010 Slide 2 Overview LHC commissioning progress at 7 Te/21/2010 Slide 3 #12;Andy Haas - 5/21/2010 Slide 4 #12;Andy Haas - 5/21/2010 Slide 5 #12;Andy Haas - 5

California at Santa Cruz, University of

372

PHYSICS AT HIGH LUMINOSITY MUON COLLIDERS AND A FACILITY OVERVIEW.  

SciTech Connect (OSTI)

Physics potentials at future colliders including high luminosity {mu}{sup +}{mu}{sup -} colliders are discussed. Luminosity requirement, estimates for Muon collider energies of interest (0.1 TeV to 100 TeV) are calculated. Schematics and an overview of Muon Collider facility concept are also included.

PARSA,Z.

2001-07-01T23:59:59.000Z

373

Imaging Pion Showers with the CALICE Analogue Hadron Calorimeter  

E-Print Network [OSTI]

The CALICE collaboration investigates different technology options for highly granular calorimeters for detectors at a future electron-positron collider. One of the devices constructed and tested by the collaboration is a 1m^3 prototype for an imaging scintillator-steel sampling calorimeter for hadrons with analogue readout (AHCAL). The light from 7608 small scintillator cells is detected with silicon photomultipliers. The AHCAL has been successfully operated during electron and hadron test-beam measurements at DESY, CERN, and Fermilab since 2005. The collected data allow for evaluating the novel technologies employed. In addition, these data provide a valuable basis for validating pion cascade simulations. This paper presents the current status of comparisons between the AHCAL data and predictions from different Monte Carlo models implemented in GEANT4. The comparisons cover the total visible energy, longitudinal and radial shower profiles, and the shower substructure. Furthermore, this paper discusses a software compensation algorithm for improving the energy resolution of the AHCAL for single pions.

Nils Feege; for the CALICE collaboration

2011-09-09T23:59:59.000Z

374

QCD and hard diffraction at the LHC  

SciTech Connect (OSTI)

As an introduction to QCD at the LHC the author gives an overview of QCD at the Tevatron, emphasizing the high Q{sup 2} frontier which will be taken over by the LHC. After describing briefly the LHC detectors the author discusses high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. The author introduces the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

Albrow, Michael G.; /Fermilab

2005-09-01T23:59:59.000Z

375

Next-to-leading order slepton pair production at hadron colliders  

E-Print Network [OSTI]

We compute total cross sections for various slepton pair production reactions in next-to-leading order QCD. For pbarp collisions at root S=2TeV, we find leading order cross sections to be enhanced by typically 35% to 40%. For pp collisions at root S=14TeV, the enhancement ranges from 25% to 35% depending on the mass of the sleptons. We comment upon the phenomenological implications of these results.

Howard Baer; B. W. Harris; Mary Hall Reno

1997-12-09T23:59:59.000Z

376

Minimum Bias Measurements with the ATLAS Detector at the CERN Large Hadron Collider  

E-Print Network [OSTI]

background in the experimental cavern 1 . Reconstruction inand photons in the cavern. CHAPTER 4. INNER DETECTORthe ATLAS experimental cavern are also shown here. APPENDIX

Leyton, Michael A.

2009-01-01T23:59:59.000Z

377

Development of a small angle hadron calorimeter prototype for the Collider Detector at Fermilab  

E-Print Network [OSTI]

made with Ar/CqHs when the ceramic wire supports replaced the fiberglass epoxy wire supports. Table 3. Comparative count rates with and with out Fe threshhold cuts Configuration Ar/CqHs &: PC Board Ar/CqHs &r AIOs Ar/COs &r PC Board Ar/COs &r... Zl Channel 511 0 1 256 Channel 511 Pu-Be 8c Ar/CO PC Board Tcp Layer ll Hov. 1988 Pu ? Be n Ar/Co Ceramtc Tcp Layer 13 Ncv. 1988 0. 5 n 0. 5 O 256 Channel 511 256 Channel 511 Figure 12. Comparative Energy Spectrum of top plane...

Thane, John Mark

1989-01-01T23:59:59.000Z

378

The 100,000 amp dc power supply for a staged hadron collider superferric magnet  

SciTech Connect (OSTI)

A 1.5 volt 100,000 amp DC switcher power supply was developed for testing a superferric magnet string at FNAL. This supply was used during testing as both the ramping supply and holding supply powering a single magnet load with a total load resistance of 0.7{micro} Ohms. The supply consists of ten paralleled switcher cells, powered by a 400 volt/600 Amp DC power supply. Each cell consists of an IGBT H-bridge driving a step-down transformer at a switching frequency of 2 kHz. The transformer has an effective turns ratio of 224:1. The secondary consists of 32 parallel single-turn full wave rectifier windings. The rectification is done with 64 Shottky diodes. Each cell is rated at 1.5 volts/10,000 amps. During this test each cell was operated as a constant power source without load current or field feedback. This paper will describe the design of the switcher cell and control system used during testing. We will also describe the next level of improvements to the current feedback system to improve the ramp control.

Hays, Steven L.; Claypool, Bradley; Foster, G.William; /Fermilab

2005-09-01T23:59:59.000Z

379

U.S. scientists celebrate the restart of the Large Hadron Collider |  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered energy consumption by sectorlong version) The U.S.1,

380

Distinguishing spins in supersymmetric and universal extra dimension models at the large hadron collider.  

E-Print Network [OSTI]

suggested in ref. [5], we have included a full simulation of the relevant UED processes in the HERWIG Monte Carlo event generator [10, 11]. Since the corresponding SUSY processes, with full spin correlations, are already a well- established feature of HERWIG... .14) The dilepton mass distribution is potentially a good indicator of UED spin correlations, because it is the same for processes 1 and 2 and relatively easy to measure. We see from eq. (4.14) that the deviation from the linear mass spectrum of phase space or SUSY...

Smillie, Jennifer M; Webber, Bryan R

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381

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

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas ConchasPassive Solar HomePromisingStoriesSANDIA REPORT SAND 2011-39584.SCTour"

382

June 30, 2008: US portion of Large Hadron Collider completed | Department  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in3.pdfEnergy Health andofIanJennifer Somers AboutEnergy JulyNow Availableof

383

A Large Hadron Electron Collider at CERN | OSTI, US Dept of Energy, Office  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011A First Look at YeastMES- Helping theStructure

384

Fermilab | Newsroom | Fermilab/U.S. experts on the Large Hadron Collider  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc DocumentationP-Series toESnet4:Epitaxial ThinFORFALLSubscription Formphoto:Fermilab « Return

385

U.S. scientists celebrate the restart of the Large Hadron Collider...  

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

A highlight of the LHCs first run, which began in 2009, was the discovery of the Higgs boson, the last in the suite of elementary particles that make up scientists best picture...

386

Elliptic Flow from a Hybrid CGC, Full 3D Hydro and Hadronic Cascade Model  

E-Print Network [OSTI]

We investigate the robustness of the discovery of the perfect fluid through comparison of hydrodynamic calculations with the elliptic flow coefficient v_2 at midrapidity in Au+Au collisions at sqrt{s_{NN}}=200 GeV. Employing the Glauber model for initial entropy density distributions, the centrality dependence of v_2 is reasonably reproduced by using an ideal fluid description of the early QGP stage followed by a hadronic cascade in the late hadronic stage. On the other hand, initial conditions based on the Colour Glass Condensate model are found to generate larger elliptic flow due to larger initial eccentricity epsilon. We further predict v_2/epsilon at a fixed impact parameter as a function of collision energy sqrt{s_{NN}} up to the LHC energy.

Tetsufumi Hirano; Ulrich W. Heinz; Dmitri Kharzeev; Roy Lacey; Yasushi Nara

2007-03-27T23:59:59.000Z

387

LHC end-of-year jamboree  

ScienceCinema (OSTI)

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

None

2011-10-06T23:59:59.000Z

388

The Luminosity Monitoring System for the LHC: Modeling and Test Results  

SciTech Connect (OSTI)

Simulation results of the Beam Rate of Neutrals (BRAN) luminosity detector for the CERN Large Hadron Collider are presented. The detectors are intended to measure the bunch-by-bunch relative luminosity at the ATLAS and CMS experiments. Building up from experimental results from test runs at the SPS, RHIC and ALS we extend the simulated setup to the TAN neutral absorbers located at 140 m at both sides the IP1 and IP5 interaction points. The expected signal amplitudes are calculated for pp-collisions energies between 450 GeV and 7 TeV using the Monte Carlo package FLUKA and its graphical user interface FLAIR.

Ratti, A.; Beche, J.F.; Byrd, J.; Chow, K.; Denes, P.; Doolittle, L.; Ghiorso, W.; Manfredi, P.F.; Matis, H.; Monroy, M.; Plate, D.; Stezelberger, T.; Stiller, J.; Turko, B.; Turner, W.C.; Yaver, H.; Zimmermann, S.; Bravin, E.; Drees, A.; Miyamoto, R.

2009-10-25T23:59:59.000Z

389

Z'-induced Invisible Right-handed Sneutrino Decays at the LHC  

E-Print Network [OSTI]

The invisible signals of right-handed sneutrino decays originating from a Z' are analysed at the Large Hadron Collider. The possibility of accessing these events helps disentangling the B-L extension of Minimal Supersymmetric Standard Model from more popular scenarios of Supersymmetry. We assess the scope of the CERN machine in establishing the aforementioned signatures when accompanied by mono-jet, single-photon or Z-radiation probes through sophisticated signal-to-background simulations carried out in presence of parton shower, hadronisation as well as detector effects. We find substantial sensitivity to all such signals for standard luminosities at Run 2.

Abdallah, W; Khalil, S; Moretti, S

2015-01-01T23:59:59.000Z

390

Double hadron leptoproduction in the nuclear medium  

E-Print Network [OSTI]

First measurement of double-hadron production in deep-inelastic scattering has been measured with the HERMES spectrometer at HERA using a 27.6 GeV positron beam with deuterium, nitrogen, krypton and xenon targets. The influence of the nuclear medium on the ratio of double-hadron to single-hadron yields has been investigated. Nuclear effects are clearly observed but with substantially smaller magnitude and reduced $A$-dependence compared to previously measured single-hadron multiplicity ratios. The data are in fair agreement with models based on partonic or pre-hadronic energy loss, while they seem to rule out a pure absorptive treatment of the final state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter.

Airapetian, A; Akopov, Z; Amarian, M; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Belostotskii, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Borysenko, A; Brüll, A; Bryzgalov, V; Capiluppi, M; Capitani, G P; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; Demey, M; De Nardo, L; De Sanctis, E; Devitsin, E G; Diefenthaler, M; Di Nezza, P; Dreschler, J; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G; Ellinghaus, F; Elschenbroich, U; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Funel, A; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Gavrilov, G; Karibian, V; Giordano, F; Grebenyuk, O; Gregor, I M; Griffioen, K; Guler, H; Hadjidakis, C; Hartig, M; Hasch, D; Hasegawa, T; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Hristova, I; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Keri, T; Kinney, E; Kiselev, A; Kobayashi, T; Kopytin, M; Korotkov, V; Kozlov, V; Krauss, B; Kravchenko, P; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Lenisa, P; Liebing, P; Linden-Levy, L A; Lorenzon, W; Lü, J; Lu, S; Ma, B Q; Maiheu, B; Makins, N C R; Mao, Y; Marianski, B; Marukyan, H; Masoli, F; Mexner, V; Meyners, N; Michler, T; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Murray, M; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Negodaev, M; Nowak, Wolf-Dieter; Ohsuga, H; Osborne, A; Perez-Benito, R; Pickert, N; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanjiev, I; Savin, I; Schäfer, A; Schnell, G; Schüler, K P; Seele, J; Seidl, R; Seitz, B; Shearer, C; Shibata, T A; Shutov, V; Sinram, K; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stenzel, H; Stewart, J; Stinzing, F; Streit, J; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Van Haarlem, Y; Veretennikov, D; Vikhrov, V; Vogel, C; Wang, S; Ye, Y; Ye, Z; Yen, S; Zihlmann, B; Zupranski, P

2006-01-01T23:59:59.000Z

391

Status of the Higgs Singlet Extension of the Standard Model after LHC Run 1  

E-Print Network [OSTI]

We discuss the current status of theoretical and experimental constraints on the real Higgs singlet extension of the Standard Model. For the second neutral (non-standard) Higgs boson we consider the full mass range from 1 GeV to 1 TeV accessible at past and current collider experiments. We separately discuss three scenarios, namely, the case where the second Higgs boson is lighter than, approximately equal to, or heavier than the discovered Higgs state at around 125 GeV. We investigate the impact of constraints from perturbative unitarity, electroweak precision data with a special focus on higher order contributions to the W boson mass, perturbativity of the couplings as well as vacuum stability. The latter two are tested up to a scale of 4 x 10^10 GeV using renormalization group equations. Direct collider constraints from Higgs signal rate measurements at the LHC and 95% C.L. exclusion limits from Higgs searches at LEP, Tevatron and LHC are included via the public codes HiggsSignals and HiggsBounds, respecti...

Robens, Tania

2015-01-01T23:59:59.000Z

392

MSSM Forecast for the LHC  

E-Print Network [OSTI]

We perform a forecast of the MSSM with universal soft terms (CMSSM) for the LHC, based on an improved Bayesian analysis. We do not incorporate ad hoc measures of the fine-tuning to penalize unnatural possibilities: such penalization arises from the Bayesian analysis itself when the experimental value of $M_Z$ is considered. This allows to scan the whole parameter space, allowing arbitrarily large soft terms. Still the low-energy region is statistically favoured (even before including dark matter or g-2 constraints). Contrary to other studies, the results are almost unaffected by changing the upper limits taken for the soft terms. The results are also remarkable stable when using flat or logarithmic priors, a fact that arises from the larger statistical weight of the low-energy region in both cases. Then we incorporate all the important experimental constrains to the analysis, obtaining a map of the probability density of the MSSM parameter space, i.e. the forecast of the MSSM. Since not all the experimental information is equally robust, we perform separate analyses depending on the group of observables used. When only the most robust ones are used, the favoured region of the parameter space contains a significant portion outside the LHC reach. This effect gets reinforced if the Higgs mass is not close to its present experimental limit and persits when dark matter constraints are included. Only when the g-2 constraint (based on $e^+e^-$ data) is considered, the preferred region (for $\\mu>0$) is well inside the LHC scope. We also perform a Bayesian comparison of the positive- and negative-$\\mu$ possibilities.

Maria Eugenia Cabrera; Alberto Casas; Roberto Ruiz de Austri

2010-12-10T23:59:59.000Z

393

LHC Workshop Outline Welcome and Introductions  

E-Print Network [OSTI]

. Animation of CMS Wedge - Trace particle paths through CMS. (adapted by L. Quigg from CMS animation) 7 fellows) 12. ATLAS Built in 1, 3 or 5 Minutes - Video compiled from ATLAS webcam footage and still photos 13. History of Particle Detectors - PPT (from LHC fellows) 14. ATLAS Detector ­ PPT (from LHC fellows

Quigg, Chris

394

ATLAS Upgrade for sLHC Motivation  

E-Print Network [OSTI]

ATLAS Upgrade for sLHC · Motivation · LHC Upgrades · ATLAS Upgrade/schedule · R&D Variety · Russian Institutes involvement · Conclusions A.Cheplakov JINR, Dubna (on behalf of the ATLAS Collaboration) Many thanks to ATLAS colleagues for the useful information - N.Hessey, A.Loginov, A.Romaniouk, P

395

Production and propagation of heavy hadrons in air-shower simulators  

E-Print Network [OSTI]

Very energetic charm and bottom hadrons may be produced in the upper atmosphere when a primary cosmic ray or the leading hadron in an extensive air shower collide with a nucleon. At $E\\approx 10^8$ GeV their decay length becomes of the order of 10 km, implying that they tend to interact in the air instead of decaying. Since the inelasticity in these collisions is much smaller than the one in proton and pion collisions, there could be rare events where a heavy-hadron component transports a significant amount of energy deep into the atmosphere. We have developed a module for the detailed simulation of these processes and have included it in a new version of the air shower simulator AIRES. We study the frequency, the energy distribution and the depth of charm and bottom production, as well as the depth and the energy distribution of these quarks when they decay. As an illustration, we consider the production and decay of tau leptons (from $D_s$ decays) and the lepton flux at PeV energies from a 30 EeV proton primary. The proper inclusion of charm and bottom hadrons in AIRES opens the possibility to search for air-shower observables that are sensitive to heavy quark effects.

C. A. Garcia Canal; J. I. Illana; M. Masip; S. J. Sciutto

2013-05-01T23:59:59.000Z

396

Signals of a superlight gravitino at the LHC  

E-Print Network [OSTI]

Very light gravitinos could be produced at a sizeable rate at colliders and have been searched for in the mono-photon or mono-jet plus missing momentum signature. Strategies for enhancing the signal over background and interpretations of the experimental results are typically obtained within an effective field theory approach where all SUSY particles except the gravitino are heavy and are not produced resonantly. We extend this approach to a simplified model that includes squarks and gluinos in the TeV range. In such a case, the jet(s)-plus-missing-momentum signature can be generated through three different concurring mechanisms: gravitino-pair production with an extra jet, associated gravitino production with a squark or a gluino, or squark/gluino pair production with their subsequent decay to a gravitino and a jet. By using a matrix-element parton-shower merging procedure, we take into account all the relevant production processes consistently, explore the SUSY parameter space with the LHC Run-I data set, and give prospects for the Run II. We also consider the reach of other signatures involving electroweak particles, e.g., the mono-photon, -Z, or -W plus missing momentum. The current mono-jet and mono-photon LHC analyses are interpreted to set a lower bound on the gravitino mass. We show how the limit of $m_{3/2}>1.7\\times10^{-13}$ GeV obtained in the effective field theory hypothesis is modified when the squarks and/or the gluino are in the TeV range.

Fabio Maltoni; Antony Martini; Kentarou Mawatari; Bettina Oexl

2015-02-05T23:59:59.000Z

397

LHCb Data Management on the Computing Grid   

E-Print Network [OSTI]

The LHCb detector is one of the four experiments being built to harness the proton-proton collisions provided by the Large Hadron Collider (LHC) at the European Organisation for Nuclear Research (CERN). The data rate ...

Smith, Andrew Cameron

2009-01-01T23:59:59.000Z

398

Delay-Tolerant Bulk Data Transfers on the Internet NIKOLAOS LAOUTARIS GEORGIOS SMARAGDAKIS RADE STANOJEVIC  

E-Print Network [OSTI]

multiple Tbytes of data on a daily basis. Examples include pushing scientific data from particle acceler Hadron Collider (LHC) is producing daily 27 Tbytes of particle collision data that need to be pushed

Smaragdakis, Georgios

399

Improvement of the Track-based Alignment Procedure of the CMS Muon System  

E-Print Network [OSTI]

The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) is used to explore subatomic interactions through proton-proton collisions. The resulting out- burst of particles from these high energy collisions is then tracked...

Amin, Nick Jogesh

2013-12-02T23:59:59.000Z

400

Science Requirements and Conceptual Design for a Polarized Medium Energy Electron-Ion Collider at Jlab  

SciTech Connect (OSTI)

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

Abeyratne, S; Ahmed, S; Barber, D; Bisognano, J; Bogacz, A; Castilla, A; Chevtsov, P; Corneliussen, S; Deconinck, W; Degtiarenko, P; Delayen, J; Derbenev, Ya; DeSilva, S; Douglas, D; Dudnikov, V; Ent, R; Erdelyi, B; Evtushenko, P; Fujii, Yu; Filatov, Yury; Gaskell, D; Geng, R; Guzey, V; Horn, T; Hutton, A; Hyde, C; Johnson, R; Kim, Y; Klein, F; Kondratenko, A; Kondratenko, M; Krafft, G; Li, R; Lin, F; Manikonda, S; Marhauser, F; McKeown, R; Morozov, V; Dadel-Turonski, P; Nissen, E; Ostroumov, P; Pivi, M; Pilat, F; Poelker, M; Prokudin, A; Rimmer, R; Satogata, T; Sayed, H; Spata, M; Sullivan, M; Tennant, C; Terzic, B; Tiefenback, M; Wang, M; Wang, S; Weiss, C; Yunn, B

2012-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Light Hadron Spectroscopy and Charmonium  

E-Print Network [OSTI]

During the last few years there has been a renaissance in charm and charmonium spectroscopy with higher precision measurements at the $\\psi^{'}$ and $\\psi(3770)$ coming from BESII and CLEOc and many new discoveries coming from B-factories. In this paper, I review some new results on "classical" charmonium and $e^+ e^- \\to$ hadrons using B-factory Initial State Radiation and two photon events.

Frederick A. Harris

2008-10-17T23:59:59.000Z

402

Hadronic Resonances from Lattice QCD  

SciTech Connect (OSTI)

The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non-perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.

John Bulava; Robert Edwards; George Fleming; K. Jimmy Juge; Adam C. Lichtl; Nilmani Mathur; Colin Morningstar; David Richards; Stephen J. Wallace

2007-06-16T23:59:59.000Z

403

Hadronic Resonances from Lattice QCD  

SciTech Connect (OSTI)

The determination of the pattern of hadronic resonances as predicted by Quantum Chromodynamics requires the use of non-perturbative techniques. Lattice QCD has emerged as the dominant tool for such calculations, and has produced many QCD predictions which can be directly compared to experiment. The concepts underlying lattice QCD are outlined, methods for calculating excited states are discussed, and results from an exploratory Nucleon and Delta baryon spectrum study are presented.

Lichtl, Adam C. [RBRC, Brookhaven National Laboratory, Upton, NY 11973 (United States); Bulava, John; Morningstar, Colin [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Edwards, Robert; Mathur, Nilmani; Richards, David [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Fleming, George [Yale University, New Haven, CT 06520 (United States); Juge, K. Jimmy [Department of Physics, University of the Pacific, Stockton, CA 95211 (United States); Wallace, Stephen J. [University of Maryland, College Park, MD 20742 (United States)

2007-10-26T23:59:59.000Z

404

Hadronic shift in pionic hydrogen  

E-Print Network [OSTI]

The hadronic shift in pionic hydrogen has been redetermined to be $\\epsilon_{1s}=7.086\\,\\pm\\,0.007(stat)\\,\\pm\\,0.006(sys)$\\,eV by X-ray spectroscopy of ground state transitions applying various energy calibration schemes. The experiment was performed at the high-intensity low-energy pion beam of the Paul Scherrer Institut by using the cyclotron trap and an ultimate-resolution Bragg spectrometer with bent crystals.

M. Hennebach; D. F. Anagnostopoulos; A. Dax; H. Fuhrmann; D. Gotta; A. Gruber; A. Hirtl; P. Indelicato; Y. -W. Liu; B. Manil; V. E. Markushin; A. J. Rusi el Hassani; L. M. Simons; M. Trassinelli; J. Zmeskal

2014-12-17T23:59:59.000Z

405

2009 Linear Collider Workshop of the Americas  

SciTech Connect (OSTI)

The 2009 Linear Collider Workshop of the Americas was held on the campus of the University of New Mexico from 29 September to 3 October, 2009. This was a joint meeting of the American Linear Collider Physics Group and the ILC Global Design Effort. Two hundred fifty people attended. The number of scientific contributions was 333. The complete agenda, with links to all of the presentations, is available at physics.unm.edu/LCWA09/. The meeting brought together international experts as well as junior scientists, to discuss the physics potential of the linear collider and advances in detector technology. The validation of detector designs was announced, and the detector design groups planned the next phase of the effort. Detector R&D teams reported on progress on many topics including calorimetry and tracking. Recent accelerator design considerations were discussed in a special session for experimentalists and theorists.

Seidel, Sally

2009-09-29T23:59:59.000Z

406

The LHC Lead Injector Chain  

E-Print Network [OSTI]

A sizeable part of the LHC physics programme foresees lead-lead collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines [1,2]. Each LHC ring will be filled in 10 min by almost 600 bunches, each of 7×107 lead ions. Central to the scheme is the Low Energy Ion Ring (LEIR) [3,4], which transforms long pulses from Linac3 into high-brilliance bunches by means of multi-turn injection, electron cooling and accumulation. Major limitations along the chain, including space charge, intrabeam scattering, vacuum issues and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR involves new magnets and power converters, high-current electron cooling, broadband RF cavities, and a UHV vacuum system with getter (NEG) coatings to achieve a few 10-12 mbar. Major hardware changes in Linac3 and the PS are also covered. An early ion scheme with fewer bunches (but each at nominal...

Beuret, A; Blas, A; Burkhardt, H; Carli, Christian; Chanel, M; Fowler, A; Gourber-Pace, M; Hancock, S; Hourican, M; Hill, C E; Jowett, John M; Kahle, K; Küchler, D; Lombardi, A M; Mahner, E; Manglunki, Django; Martini, M; Maury, S; Pedersen, F; Raich, U; Rossi, C; Royer, J P; Schindl, Karlheinz; Scrivens, R; Sermeus, L; Shaposhnikova, Elena; Tranquille, G; Vretenar, Maurizio; Zickler, T

2004-01-01T23:59:59.000Z

407

Examining a right-handed quark mixing matrix with $b$-tags at the LHC  

E-Print Network [OSTI]

Encouraged by a hint in a search for right-handed $W$ bosons at the LHC, we investigate whether the unitarity of a right-handed quark mixing matrix and the equality of the left- and right-handed quark mixing matrices could be tested at the LHC. We propose a particular test, involving counting the numbers of $b$-tags in the final state, and simulate the test at the event level with Monte-Carlo tools for the forthcoming $\\sqrt{s}=13$ TeV LHC run. We find that testing unitarity with 20/fb will be challenging; our test successfully rejects unitarity if the right-handed quark mixing matrix is non-unitary, but only in particular cases. On the other hand, our test may provide the first opportunity to test the unitarity of a right-handed quark mixing matrix and with 3000/fb severely constrains possible departures from unitarity in the latter. We refine our previous work, testing the equality of quark mixing matrices, with full collider simulation. With 20/fb, we are sensitive to mixing angles as small as $30^\\circ$, and with 3000/fb, angles as small as $7.5^\\circ$, confirming our preliminary analysis. We briefly investigate testing the unitarity of the SM CKM matrix with a similar method by studying semileptonic $t\\bar t$ production, concluding that systematics make it particularly difficult.

Andrew Fowlie; Luca Marzola

2014-12-17T23:59:59.000Z

408

$\\Zeta$-boson as "the standard candle" for high precision W-boson physics at LHC  

E-Print Network [OSTI]

In this paper we propose a strategy for measuring the inclusive W-boson production processes at LHC. This strategy exploits simultaneously the unique flexibility of the LHC collider in running variable beam particle species at variable beam energies, and the configuration flexibility of the LHC detectors. We propose their concrete settings for a precision measurement of the Standard Model parameters. These settings optimise the use of the Z boson and Drell-Yan pair production processes as ``the standard reference candles''. The presented strategy allows to factorise and to directly measure those of the QCD effects which affect differently the W and Z production processes. It reduces to a level of 10^{-4} the impact of uncertainties in the partonic distribution functions (PDFs) and in the transverse momentum of the quarks on the measurement precision. Last but not the least, it reduces by a factor of 10 an impact of systematic measurement errors, such as the energy scale and the measurement resolution, on the ...

Krasny, M W; Placzek, W; Siodmok, A

2007-01-01T23:59:59.000Z

409

Z-boson as "the standard candle" for high precision W-boson physics at LHC  

E-Print Network [OSTI]

In this paper we propose a strategy for measuring the inclusive W-boson production processes at LHC. This strategy exploits simultaneously the unique flexibility of the LHC collider in running variable beam particle species at variable beam energies, and the configuration flexibility of the LHC detectors. We propose their concrete settings for a precision measurement of the Standard Model parameters. These dedicated settings optimise the use of the Z boson and Drell-Yan pair production processes as ``the standard reference candles''. The presented strategy allows to factorise and to directly measure those of the QCD effects which affect differently the W and Z production processes. It reduces to a level of 10^{-4} the impact of uncertainties in the partonic distribution functions (PDFs) and in the transverse momentum of the quarks on the measurement precision. Last but not the least, it reduces by a factor of 10 an impact of systematic measurement errors, such as the energy scale and the measurement resolution, on the W-boson production observables.

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

2007-03-09T23:59:59.000Z

410

Production and FCNC decay of supersymmetric Higgs bosons into heavy quarks in the LHC  

E-Print Network [OSTI]

We analyze the production and subsequent decay of the neutral MSSM Higgs bosons (h = h^0, H^0, A^0) mediated by flavor changing neutral currents (FCNC) in the LHC collider. We have computed the h-production cross-section times the FCNC branching ratio, \\sigma(pp -> h -> qq') = \\sigma(pp -> h) B(h -> qq'), in the LHC focusing on the strongly-interacting FCNC sector. Here qq' is an electrically neutral pair of quarks of different flavors, the dominant modes being those containing a heavy quark: tc or bs. We determine the maximum production rates for each of these modes and identify the relevant regions of the MSSM parameter space, after taking into account the severe restrictions imposed by low energy FCNC processes. The analysis of \\sigma(pp -> h -> qq') singles out regions of the MSSM parameter space different from those obtained by maximizing only the branching ratio, due to non-trivial correlations between the parameters that maximize/minimize each isolated factor. The production rates for the bs channel can be huge for a FCNC process (0.1-1 pb), but its detection can be problematic. The production rates for the tc channel are more modest (10^{-3}-10^{-2} pb), but its detection should be easier due to the clear-cut top quark signature. A few thousand tc events could be collected in the highest luminosity phase of the LHC, with no counterpart in the SM.

Santi Bejar; Jaume Guasch; Joan Sola

2005-10-31T23:59:59.000Z

411

Phenomenology of $E_6$-Inspired Leptophobic $Z'$ Boson at the LHC  

E-Print Network [OSTI]

We study collider phenomenology of a leptophobic $Z'$ boson existing in eight scenarios of the $E_6$ grand unified theory, differing in particle embeddings. We first review the current bound on the $Z'$ mass $m_{Z'}$ based upon the LHC data of $pp\\to t\\bar{t}$ process at 8 TeV collisions with an integrated luminosity of 19.6 fb$^{-1}$. Most scenarios have a lower bound of about 1 TeV. However, this constraint does not apply to the case where $m_{Z'} production of the $Z'$ boson that subsequently decays into a pair of bottom quarks, $pp\\to Z'\\gamma \\to b\\bar{b}\\gamma$, at the LHC to explore the constraints in the lower mass regime. We compute the expected signal significance as a function of $m_{Z'}$ using detailed simulations of signal and irreducible background events. We find constraints for two more scenarios using the 8-TeV data and taking appropriate kinematical cuts. We also show the discovery reach for each scenario at the 14-TeV LHC machine.

Cheng-Wei Chiang; Takaaki Nomura; Kei Yagyu

2014-05-21T23:59:59.000Z

412

Beam instrumentation for the Tevatron Collider  

SciTech Connect (OSTI)

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.

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

2009-10-01T23:59:59.000Z

413

Prospects for observing charginos and neutralinos at a 100 TeV proton-proton collider  

E-Print Network [OSTI]

We investigate the prospects for discovering charginos and neutralinos at a future $pp$ collider with $\\sqrt{s} = 100$ TeV. We focus on models where squarks and sleptons are decoupled -- as motivated by the LHC data. Our initial study is based on models where Higgsinos form the main component of the LSP and $W$-inos compose the heavier chargino states ($M_2 > \\mu$), though it is straightforward to consider the reverse situation also. We show that in such scenarios $W$-inos decay into $W^\\pm$, $Z$ and $h$ plus neutralinos almost universally. In the $W Z$ channel we compare signal and background in various kinematical distributions. We design simple but effective signal regions for the trilepton channel and evaluate discovery reach and exclusion limits. Assuming 3000 fb$^{-1}$ of integrated luminosity, $W$-inos could be discovered (excluded) up to 1.1 (1.8) TeV if the spectrum is not compressed.

Bobby S. Acharya; Krzysztof Bozek; Chakrit Pongkitivanichkul; Kazuki Sakurai

2014-10-06T23:59:59.000Z

414

W gamma production in hadronic collisions using the POWHEG+MiNLO method  

E-Print Network [OSTI]

We detail a calculation of W gamma production in hadronic collision, at Next-to-Leading Order (NLO) QCD interfaced to a shower generator according to the POWHEG prescription supplemented with the MiNLO procedure. The fixed order result is matched to an interleaved QCD+QED parton shower, in such a way that the contribution arising from hadron fragmentation into photons is fully modeled. In general, our calculation illustrates a new approach to the fully exclusive simulation of prompt photon production processes accurate at the NLO level in QCD. We compare our predictions to those of the NLO program MCFM, which treats the fragmentation contribution in terms of photon fragmentation functions. We also perform comparisons to available LHC data at 7 TeV, for which we observe good agreement, and provide phenomenological results for physics studies of the W gamma production process at the Run II of the LHC. The new tool, which includes W leptonic decays and the contribution of anomalous gauge couplings, allows a full...

Barze, Luca

2014-01-01T23:59:59.000Z

415

Validation of Hadronic Models in GEANT4  

SciTech Connect (OSTI)

Geant4 is a software toolkit for the simulation of the passage of particles through matter. It has abundant hadronic models from thermal neutron interactions to ultra relativistic hadrons. An overview of validations in Geant4 hadronic physics is presented based on thin target measurements. In most cases, good agreement is available between Monte Carlo prediction and experimental data; however, several problems have been detected which require some improvement in the models.

Koi, Tatsumi; Wright, Dennis H.; /SLAC; Folger, Gunter; Ivanchenko, Vladimir; Kossov, Mikhail; Starkov, Nikolai; /CERN; Heikkinen, Aatos; /Helsinki Inst. of Phys.; Truscott,; Lei, Fan; /QinetiQ; Wellisch, Hans-Peter

2007-09-26T23:59:59.000Z

416

Hadron wavefunctions and structure functions in QCD  

SciTech Connect (OSTI)

Theoretical and empirical constraints on the hadron wave function and hadron structure functions are presented. In particular, a new type of low-energy theorem is obtained for the pion wave function from ..pi../sup 0/ ..-->.. ..gamma gamma... Thus the probability of finding the valence vertical bar q anti q > state is obtained. All these constraints allow construction of a possible model that describes hadron wavefunctions, probability amplitudes, and distributions. 3 figures.

Huang, T.

1980-01-01T23:59:59.000Z

417

Fractal properties applied to hadron spectroscopy  

E-Print Network [OSTI]

A contribution is presented to the study of hadron spectroscopy through the use of fractals and discrete scale invariance implying log-periodic corrections to continuous scaling. The masses of mesons and baryons, reported by the Particle Data Group (PDG), are properly fitted with help of the equation derived from the discrete-scale invariance (DSI) model. The same property is observed for the mass ratios between different particle species. This is also the case for total widths of several hadronic species. Each fitted parameter, as a function of the hadronic masses, displays the same distribution for all hadronic species. Several masses of still unobserved mesons and baryons are tentatively predicted.

Boris Tatischeff

2011-05-05T23:59:59.000Z

418

Hadronic Final States and QCD: Summary  

SciTech Connect (OSTI)

A summary of new experimental results and recent theoretical developments discussed in the 'Hadronic Final States and QCD' working group is presented.

Gehrmann, Thomas; /Zurich U.; Grindhammer, Guenter; /Munich, Max Planck Inst.; O'Dell, Vivian; /Fermilab; Walczak, Roman; /Oxford U.

2008-08-01T23:59:59.000Z

419

PHYSICS WITH AND PHYSICS OF COLLIDING ELECTRON BEAMS  

E-Print Network [OSTI]

contributed so much to the physics of colliding beams, theyto reap so little from the physics with colliding beams.Conference on High-Energy Physics, Vienna" September 1968 (

Pellegrini, Claudio

2008-01-01T23:59:59.000Z

420

Overview of LHC physics results at ICHEP  

ScienceCinema (OSTI)

 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

None

2011-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Higgs couplings and Naturalness in the littlest Higgs model with T-parity at the LHC and TLEP  

E-Print Network [OSTI]

Motivated by the recent LHC Higgs data and null results in searches for any new physics, we investigate the Higgs couplings and naturalness in the littlest Higgs model with T-parity. By performing the global fit of the latest Higgs data, electroweak precise observables and $R_{b}$ measurements, we find that the scale $f$ can be excluded up to 600 GeV at $2\\sigma$ confidence level. The expected Higgs coupling measurements at the future collider TLEP will improve this lower limit to above 3 TeV. Besides, the top parnter mass $m_{T_{+}}$ can be excluded up to 880 GeV at $2\\sigma$ confidence level. The future HL-LHC can constrain this mass in the region $m_{T_{+}} < 2.2$ TeV corresponding to the fine-tuning being lager than 1%.

Bingfang Yang; Guofa Mi; Ning Liu

2014-09-23T23:59:59.000Z

422

Electron Ion Collider: The Next QCD Frontier  

E-Print Network [OSTI]

Electron Ion Collider: The Next QCD Frontier Executive Summary Understanding the glue that binds us . . . . . . . . . . . . . . . . . . . . 7 1.2.3 Physics Possibilities at the Intensity Frontier . . . . . . . . . . . . . 10 1 charge. This causes the gluons to interact with each other, generating nearly all the mass of the nucleon

Homes, Christopher C.

423

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

ScienceCinema (OSTI)

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.

None

2011-10-06T23:59:59.000Z

424

LHC Higgs boson mass combination  

E-Print Network [OSTI]

A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the $H \\rightarrow \\gamma\\gamma$ and $H \\rightarrow ZZ\\rightarrow 4\\ell$ decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is $m_{H} = 125.09\\pm0.21\\,\\mathrm{(stat.)}\\pm0.11\\,\\mathrm{(syst.)}~\\mathrm{GeV}$.

Adye, Tim; The ATLAS collaboration

2015-01-01T23:59:59.000Z

425

Signals of a superlight gravitino at the LHC  

E-Print Network [OSTI]

Very light gravitinos could be produced at a sizeable rate at colliders and have been searched for in the mono-photon or mono-jet plus missing momentum signature. Strategies for enhancing the signal over background and interpretations of the experimental results are typically obtained within an effective field theory approach where all SUSY particles except the gravitino are heavy and are not produced resonantly. We extend this approach to a simplified model that includes squarks and gluinos in the TeV range. In such a case, the jet(s)-plus-missing-momentum signature can be generated through three different concurring mechanisms: gravitino-pair production with an extra jet, associated gravitino production with a squark or a gluino, or squark/gluino pair production with their subsequent decay to a gravitino and a jet. By using a matrix-element parton-shower merging procedure, we take into account all the relevant production processes consistently, explore the SUSY parameter space with the LHC Run-I data set, a...

Maltoni, Fabio; Mawatari, Kentarou; Oexl, Bettina

2015-01-01T23:59:59.000Z

426

Diffractive bremsstrahlung in hadronic collisions  

E-Print Network [OSTI]

Production of heavy photons (Drell-Yan), gauge bosons, Higgs bosons, heavy flavors, which is treated within the QCD parton model as a result of hard parton-parton collision, can be considered as a bremsstrahlung process in the target rest frame. In this review, we discuss the basic features of the diffractive channels of these processes in the framework of color dipole approach. The main observation is a dramatic breakdown of diffractive QCD factorisation due to the interplay between soft and hard interactions, which dominates these processes. This observation is crucial for phenomenological studies of diffractive reactions in high-energy hadronic collisions.

Pasechnik, Roman; Potashnikova, Irina

2015-01-01T23:59:59.000Z

427

Hadron Structure from Lattice QCD  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation ProposedUsingFun with Big Sky9, 2010 The meeting wasEngineering andHQHSIHYBRID4HadronLattice

428

LASER-PLASMA-ACCELERATOR-BASED COLLIDERS C. B. Schroeder  

E-Print Network [OSTI]

LASER-PLASMA-ACCELERATOR-BASED COLLIDERS C. B. Schroeder , E. Esarey, Cs. T´oth, C. G. R. Geddes-generation linear col- lider based on laser-plasma-accelerators are discussed, and a laser-plasma-accelerator gamma-gamma () collider is considered. An example of the parameters for a 0.5 TeV laser-plasma-accelerator collider

Geddes, Cameron Guy Robinson

429

Linear Collider Calorimeter Testbeam Study Group Report  

E-Print Network [OSTI]

segmentation to distinguish energy deposits from charged and neutral hadrons, associating the energy clusters#cient single particle shower data at a wide range of energies for EFA development to construct shower librari, jet energy resolutions need to be at the level of 30%/ # E that is capable of distinguishing W and Z

Yu, Jaehoon

430

Linear Collider Calorimeter Testbeam Study Group Report  

E-Print Network [OSTI]

segmentation to distinguish energy deposits from charged and neutral hadrons, associating the energy clusters: · Sufficient single particle shower data at a wide range of energies for EFA development to construct shower , jet energy resolutions need to be at the level of 30%/ E that is capable of distinguishing W and Z

Yu, Jaehoon

431

Status of the ATLAS Liquid Argon Calorimeter and its performance after one year of LHC operation  

E-Print Network [OSTI]

The ATLAS experiment is designed to study the proton-proton collisions produced at the LHC with a centre-of-mass energy of 14 TeV. Liquid argon (LAr) sampling calorimeters are used in ATLAS for all electromagnetic calorimetry covering the pseudorapidity region ?<3.2, as well as for hadronic calorimetry from ?=1.4 to ?=4.8. The calorimeter system consists of an electromagnetic barrel calorimeter and two endcaps with electromagnetic (EMEC), hadronic (HEC) and forward (FCAL) calorimeters. The lead-liquid argon sampling technique with an accordion geometry was chosen for the barrel electromagnetic calorimeter (EMB) and adapted to the endcap (EMEC). This geometry allows a uniform acceptance over the whole azimuthal range without any gap. The hadronic endcap calorimeter (HEC) uses a copper-liquid argon sampling technique with plate geometry and is subdivided into two wheels in depth per end-cap. Finally, the forward calorimeter (FCAL) is composed of three modules featuring cylindrical electrodes with thin...

"Hoffman, J A; The ATLAS collaboration

2011-01-01T23:59:59.000Z

432

Search for hadronic resonance in multijet final states with the CDF detector  

SciTech Connect (OSTI)

This thesis describes a search for a new hadronic resonance in 3.2 fb{sup -1} of data using the Collider Detector at Fermilab. The Fermilab Tevatron accelerator collides beams of protons and antiprotons at a center of mass energy of {radical}s = 1.96 TeV. A unique approach is presented to extract multijet resonances from the large QCD background. Although the search is model independent, a pair produced supersymmetric gluino decaying through R-parity violation into three partons each is used to test our sensitivity to new physics. We measure these partons as jets, and require a minimum of six jets in an event. We make use of the kinematic features and correlations and use an ensemble of jet combinations to distinguish signal from multijet QCD backgrounds. Our background estimates also include all-hadronic t{bar t} decays that have a signature similar to signal. We observe no significant excess in an invariant mass range of 77 GeV/c{sup 2} to 240 GeV/c{sup 2} and place 95% C.L. limits on {sigma}(p{bar p} {yields} {tilde g}{tilde g} {yields} 3jets + 3jets) as a function of gluino invariant mass.

Seitz, Claudia; /Rutgers U., Piscataway

2011-01-01T23:59:59.000Z

433

Hiding a Heavy Higgs Boson at the 7 TeV LHC  

SciTech Connect (OSTI)

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.

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

2012-03-20T23:59:59.000Z

434

Observation of New Charmless Decays of Bottom Hadrons  

SciTech Connect (OSTI)

The authors search for new charmless decays of neutral b-hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb{sup -1} of integrated luminosity, they report the first observation of the B{sub s}{sup 0} {yields} K{sup +}{pi}{sup +} decay, with a significance of 8.2{sigma}, and measure {Beta}(B{sub s}{sup 0} {yields} K{sup -}{pi}{sup +}) = (5.0 {+-} 0.7 (stat.) {+-} 0.8 (syst.)) x 10{sup -6}. They also report the first observation of charmless b-baryon decays in the channels {Lambda}{sub b}{sup 0} {yields} p{pi}{sup -} and {Lambda}{sub b}{sup 0} {yields} pK{sup -} with significances of 6.0{sigma} and 11.5{sigma} respectively, and they measure {Beta}({Lambda}{sub b}{sup 0} {yields} p{pi}{sup -}) = (3.5 {+-} 0.6 (stat.) {+-} 0.9 (syst.)) x 10{sup -6} and {Beta}({Lambda}{sub b}{sup 0} {yields} pK{sup -}) = (5.6 {+-} 0.8 (stat.) {+-} 1.5 (syst.)) x 10{sup -6}. No evidence is found for the decays B{sup 0} {yields} K{sup +}K{sup -} and B{sub s}{sup 0} {yields} {pi}{sup +}{pi}{sup -}, and they set an improved upper limit {Beta}(B{sub s}{sup 0} {yields} {pi}{sup +}{pi}{sup -}) < 1.2 x 10{sup -6} at the 90% confidence level. All quoted branching fractions are measured using {Beta}(B{sup 0} {yields} K{sup +}{pi}{sup -}) as a reference.

Morello, Michael J.; /Fermilab

2010-02-01T23:59:59.000Z

435

Electromagnetic interactions at RHIC and LHC  

E-Print Network [OSTI]

At LHC energies the Lorentz factor will be 3400 for the Pb + Pb collisions and the electromagnetic interactions will play important roles. Cross sections for the electromagnetic particle productions are very large and can not be ignored for the lifetimes of the beams and background. In this article, we are going to study some of the electromagnetic processes at RHIC and LHC and show the cross section calculations of the electron-positron pair production with the giant dipole resonance of the ions.

M. C. Guclu

2008-11-15T23:59:59.000Z

436

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

SciTech Connect (OSTI)

EIC is the generic name for the nuclear science-driven Electron-Ion Collider presently considered in the US. Such an EIC would be the world’s first polarized electron-proton collider, and the world’s 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.

Rolf Ent

2012-04-01T23:59:59.000Z

437

In-Medium Modifications of Hadron Properties  

E-Print Network [OSTI]

The in-medium modifications of hadron properties are briefly discussed. We restrict the discussion to the lattice QCD calculations for the hadron masses, screening masses, decay constants and wave functions. We review the progress made so far and describe how to broaden its horizon.

A. Tawfik

2006-03-22T23:59:59.000Z

438

Mass generation in coalescence - effects on hadron spectra  

E-Print Network [OSTI]

Different scenarios for the creation of constituent mass in the hadron formation process are discussed. Effects of these may be observable in hadron momentum spectra.

T. Peitzmann

2005-11-07T23:59:59.000Z

439

Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy at the LHC  

SciTech Connect (OSTI)

The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 inverse picobarns of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model predictions, and no evidence for new physics is found. To facilitate the interpretation of our data in a broader range of new physics scenarios, information on our event selection, detector response, and efficiencies is provided.

Chatrchyan, S. [Yerevan Physics Institute (Armenia); et al.,

2011-06-01T23:59:59.000Z

440

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

SciTech Connect (OSTI)

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.

Khachatryan, Vardan; et al.

2010-11-06T23:59:59.000Z

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441

Future high energy colliders symposium. Summary report  

SciTech Connect (OSTI)

A `Future High Energy Colliders` Symposium was held October 21-25, 1996 at the Institute for Theoretical Physics (ITP) in Santa Barbara. This was one of the 3 symposia hosted by the ITP and supported by its sponsor, the National Science Foundation, as part of a 5 month program on `New Ideas for Particle Accelerators`. The long term program and symposia were organized and coordinated by Dr. Zohreh Parsa of Brookhaven National Laboratory/ITP. The purpose of the symposium was to discuss the future direction of high energy physics by bringing together leaders from the theoretical, experimental and accelerator physics communities. Their talks provided personal perspectives on the physics objectives and the technology demands of future high energy colliders. Collectively, they formed a vision for where the field should be heading and how it might best reach its objectives.

Parsa, Z. [Univ. of California, Santa Barbara, CA (United States). Institute for Theoretical Physics]|[Brookhaven National Lab., Upton, CA (United States)

1996-12-31T23:59:59.000Z

442

Fermilab collider run 1b accelerator performance  

SciTech Connect (OSTI)

This report summarizes the performance of Run 1b as of the end of July 1995. This run is the conclusion of Fermilab Collider Run 1, which consists of Run 1a (May 1992 - May 1993) and Run 1b (January 1994 - February 1996). Run 1b is characterized by being the first with the new 400 MeV Linac. At this time the run is not complete. Colliding beam physics is scheduled to resume after the summer 1995 shut down and continue until mid-February 1996. All of the operation to date is at a Tevatron energy of 900 GeV. This report emphasizes performance numbers and the various improvements made to systems to achieve this performance. It will only discuss the underlying physics to a limited extent. The report is divided into sections on: run statistics, I&C issues, proton source performance, antiproton source performance, main ring performance, Tevatron performance, and a summary.

Bharadwaj, V.; Halling, M.; Lucas, P.; McCrory, E.; Mishra, S.; Pruss, S.; Werkema, S.

1996-04-01T23:59:59.000Z

443

Shape, Transverse Size, and Charged Hadron Multiplicity of Jets in pp Collisions at 7 TeV  

SciTech Connect (OSTI)

Measurements of jet characteristics from inclusive jet production in proton-proton collisions at a centre-of-mass energy of 7 TeV are presented. The data sample was collected with the CMS detector at the LHC during 2010 and corresponds to an integrated luminosity of 36 inverse picobarns. The mean charged hadron multiplicity, the differential and integral jet shape distributions, and two independent moments of the shape distributions are measured as functions of the jet transverse momentum for jets reconstructed with the anti-kT algorithm. The measured observables are corrected to the particle level and compared with predictions from various QCD Monte Carlo generators.

Chatrchyan, Serguei; et al.

2012-06-01T23:59:59.000Z

444

1987 DOE review: First collider run operation  

SciTech Connect (OSTI)

This review covers the operations of the first run of the 1.8 TeV superconducting super collider. The papers enclosed cover: PBAR source status, fixed target operation, Tevatron cryogenic reliability and capacity upgrade, Tevatron Energy upgrade progress and plans, status of the D0 low beta insertion, 1.8 K and 4.7 K refrigeration for low-..beta.. quadrupoles, progress and plans for the LINAC and booster, near term and long term and long term performance improvements.

Childress, S.; Crawford, J.; Dugan, G.; Edwards, H.; Finley, D.A.; Fowler, W.B.; Harrison, M.; Holmes, S.; Makara, J.N.; Malamud, E.

1987-05-01T23:59:59.000Z

445

Dynamical Evolution, Hadronization and Angular De-correlation of Heavy Flavor in a Hot and Dense QCD Medium  

E-Print Network [OSTI]

We study heavy flavor evolution and hadronization in relativistic heavy-ion collisions. The in-medium evolution of heavy quarks is described using our modified Langevin framework that incorporates both collisional and radiative energy loss mechanisms. The subsequent hadronization process for heavy quarks is calculated with a fragmentation plus recombination model. We find significant contribution from gluon radiation to heavy quark energy loss at high $p_T$; the recombination mechanism can greatly enhance D meson production at medium $p_T$. Our calculation provides a good description of D meson nuclear modification at the LHC. In addition, we explore the angular correlation functions of heavy flavor pairs which may provide us a potential candidate for distinguishing different energy loss mechanisms of heavy quarks inside QGP.

Shanshan Cao; Guang-You Qin; Steffen A Bass

2014-04-03T23:59:59.000Z

446

Simulations of the LHC high luminosity monitors at beam energies from 3.5 TeV to 7.0 TeV  

SciTech Connect (OSTI)

We have constructed two pairs of fast ionization chambers (BRAN) for measurement and optimization of luminosity at IR1 and IR5 of the LHC. These devices are capable of monitoring the performance of the LHC at low luminosity 10{sup 28} cm{sup -2}s{sup -1} during beam commissioning all the way up to the expected full luminosity of 10{sup 34} cm{sup -2}s{sup -1} at 7.0 TeV. The ionization chambers measure the intensity of hadronic/electromagnetic showers produced by the forward neutral particles of LHC collisions. To predict and improve the understanding of the BRAN performance, we created a detailed FLUKA model of the detector and its surroundings. In this paper, we describe the model and the results of our simulations including the detector's estimated response to pp collisions at beam energies of 3.5, 5.0, and 7.0 TeV per beam. In addition, these simulations show the sensitivity of the BRAN to the crossing angle of the two LHC beams. It is shown that the BRAN sensitivity to the crossing angle is proportional to the measurement of crossing angle by the LHC beam position monitors.

Matis, H.S.; Miyamoto, R.; Humphreys, P.; Ratti, A.; Turner, W.C.; Stiller, J.

2011-03-28T23:59:59.000Z

447

Interpenetration and stagnation in colliding laser plasmas  

SciTech Connect (OSTI)

We have investigated plasma stagnation and interaction effects in colliding laser-produced plasmas. For generating colliding plasmas, two split laser beams were line-focused onto a hemi-circular target and the seed plasmas so produced were allowed to expand in mutually orthogonal directions. This experimental setup forced the expanding seed plasmas to come to a focus at the center of the chamber. The interpenetration and stagnation of plasmas of candidate fusion wall materials, viz., carbon and tungsten, and other materials, viz., aluminum, and molybdenum were investigated in this study. Fast-gated imaging, Faraday cup ion analysis, and optical emission spectroscopy were used for diagnosing seed and colliding plasma plumes. Our results show that high-Z target (W, Mo) plasma ions interpenetrate each other, while low-Z (C, Al) plasmas stagnate at the collision plane. For carbon seed plasmas, an intense stagnation was observed resulting in longer plasma lifetime; in addition, the stagnation layer was found to be rich with C{sub 2} dimers.

Al-Shboul, K. F. [Center for Materials Under eXtreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under eXtreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Department of Nuclear Engineering, Jordan University of Science and Technology, Irbid 22110 (Jordan); Harilal, S. S., E-mail: hari@purdue.edu; Hassan, S. M.; Hassanein, A. [Center for Materials Under eXtreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under eXtreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Costello, J. T. [School of Physical Sciences and NCPST, Dublin City University, Dublin 9 (Ireland)] [School of Physical Sciences and NCPST, Dublin City University, Dublin 9 (Ireland); Yabuuchi, T.; Tanaka, K. A. [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 5650871 (Japan)] [Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 5650871 (Japan); Hirooka, Y. [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu (Japan)] [National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu (Japan)

2014-01-15T23:59:59.000Z

448

Physics Beyond the Standard Model: Exotic Leptons and Black Holes at Future Colliders  

E-Print Network [OSTI]

The Standard Model of particle physics has been remarkably successful in describing present experimental results. However, it is assumed to be only a low-energy effective theory which will break down at higher energy scales, theoretically motivated to be around 1 TeV. There are a variety of proposed models of new physics beyond the Standard Model, most notably supersymmetric and extra dimension models. New charged and neutral heavy leptons are a feature of a number of theories of new physics, including the `intermediate scale' class of supersymmetric models. Using a time-of-flight technique to detect the charged leptons at the Large Hadron Collider, the discovery range (in the particular scenario studied in the first part of this thesis) is found to extend up to masses of 950 GeV. Extra dimension models, particularly those with large extra dimensions, allow the possible experimental production of black holes. The remainder of the thesis describes some theoretical results and computational tools necessary to model the production and decay of these miniature black holes at future particle colliders. The grey-body factors which describe the Hawking radiation emitted by higher-dimensional black holes are calculated numerically for the first time and then incorporated in a Monte Carlo black hole event generator; this can be used to model black hole production and decay at next-generation colliders. It is hoped that this generator will allow more detailed examination of black hole signatures and help to devise a method for extracting the number of extra dimensions present in nature.

Christopher M. Harris

2005-02-01T23:59:59.000Z

449

Electroweak production of $Z$jj and $W^{\\pm}W^{\\pm}$jj states at the LHC  

E-Print Network [OSTI]

Measurements of fiducial cross sections for the electroweak production of two jets in association with a $Z$ boson and in association with a pair of same-electric-charge $W$ bosons are presented. The measurements are performed using $20.3~$fb$^{-1}$ of proton-proton collision data collected at a center-of-mass energy of $\\sqrt{s}=8$~TeV by the ATLAS experiment at the Large Hadron Collider. The measured fiducial cross sections are in agreement with the Standard Model predictions. Limits at 95\\% confidence level are set on anomalous triple and quartic gauge couplings.

S. Pagan Griso; for the ATLAS Collaboration

2014-09-08T23:59:59.000Z

450

$A^t_{FB}$ Meets LHC  

SciTech Connect (OSTI)

The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large t{bar t} invariant masses. Measurements of this quantity are subtle at the LHC, due to its pp initial state, however, one can define a forward-central-charge asymmetry which captures the physics. We study the capability of the LHC to measure this asymmetry and find that within the SM a measurement at the 5{sigma} level is possible with roughly 60 fb{sup -1} at {radical}s = 14 TeV. If nature realizes a model which enhances the asymmetry (as is necessary to explain the Tevatron measurements), a significant difference from zero can be observed much earlier, perhaps even during early LHC running at {radical}s = 7 TeV. We further explore the capabilities of the 7 TeV LHC to discover resonances or contact interactions which modify the t{bar t} invariant mass distribution using recent boosted top tagging techniques. We find that TeV-scale color octet resonances can be discovered, even with small coupling strengths and that contact interactions can be probed at scales exceeding 6 TeV. Overall, the LHC has good potential to clarify the situation with regards to the Tevatron forward-backward measurement.

Hewett, JoAnne L.; /SLAC; Shelton, Jessie; /Yale U.; Spannowsky, Michael; /Oregon U.; Tait, Tim M.P.; /UC, Irvine; Takeuchi, Michihisa; /Heidelberg U.

2012-02-14T23:59:59.000Z

451

Multidimensional Study of Hadronization in Nuclei  

E-Print Network [OSTI]

Hadron multiplicities in semi-inclusive deep-inelastic scattering were measured on neon, krypton and xenon targets relative to deuterium at an electron(positron)-beam energy of 27.6 GeV at HERMES. These ratios were determined as a function of the virtual-photon energy nu, its virtuality Q2, the fractional hadron energy z and the transverse hadron momentum with respect to the virtual-photon direction pt . Dependences were analysed separately for positively and negatively charged pions and kaons as well as protons and antiprotons in a two-dimensional representation. Compared to the one-dimensional dependences, some new features were observed. In particular, when z > 0.4 positive kaons do not show the strong monotonic rise of the multiplicity ratio with nu as exhibited by pions and negative kaons. Protons were found to behave very differently from the other hadrons.

HERMES Collaboration; A. Airapetian; N. Akopov; Z. Akopov; E. C. Aschenauer; W. Augustyniak; R. Avakian; A. Avetissian; E. Avetisyan; S. Belostotski; N. Bianchi; H. P. Blok; A. Borissov; J. Bowles; I. Brodski; V. Bryzgalov; J. Burns; M. Capiluppi; G. P. Capitani; E. Cisbani; G. Ciullo; M. Contalbrigo; P. F. Dalpiaz; W. Deconinck; R. De Leo; L. De Nardo; E. De Sanctis; M. Diefenthaler; P. Di Nezza; M. Düren; M. Ehrenfried; G. Elbakian; F. Ellinghaus; R. Fabbri; A. Fantoni; L. Felawka; S. Frullani; G. Gapienko; V. Gapienko; G. Gavrilov; V. Gharibyan; F. Giordano; S. Gliske; M. Golembiovskaya; L. Grigoryan; C. Hadjidakis; M. Hartig; D. Hasch; A. Hillenbrand; M. Hoek; Y. Holler; I. Hristova; Y. Imazu; A. Ivanilov; H. E. Jackson; H. S. Jo; S. Joosten; R. Kaiser; G. Karyan; T. Keri; E. Kinney; A. Kisselev; N. Kobayashi; V. Korotkov; V. Kozlov; P. Kravchenko; V. G. Krivokhijine; L. Lagamba; L. Lapikás; I. Lehmann; P. Lenisa; A. López Ruiz; W. Lorenzon; X. -G. Lu; X. -R. Lu; B. -Q. Ma; D. Mahon; N. C. R. Makins; S. I. Manaenkov; L. Manfré; Y. Mao; B. Marianski; A. Martinez de la Ossa; H. Marukyan; C. A. Miller; Y. Miyachi; A. Movsisyan; V. Muccifora; M. Murray; A. Mussgiller; E. Nappi; Y. Naryshkin; A. Nass; M. Negodaev; W. -D. Nowak; L. L. Pappalardo; R. Perez-Benito; A. Petrosyan; M. Raithel; P. E. Reimer; A. R. Reolon; C. Riedl; K. Rith; G. Rosner; A. Rostomyan; J. Rubin; D. Ryckbosch; Y. Salomatin; F. Sanftl; A. Schäfer; G. Schnell; B. Seitz; T. -A. Shibata; V. Shutov; M. Stancari; M. Statera; E. Steffens; J. J. M. Steijger; J. Stewart; F. Stinzing; S. Taroian; R. Truty; A. Trzcinski; M. Tytgat; A. Vandenbroucke; Y. Van Haarlem; C. Van Hulse; D. Veretennikov; V. Vikhrov; I. Vilardi; C. Vogel; S. Wang; S. Yaschenko; Z. Ye; S. Yen; W. Yu; V. Zagrebelnyy; D. Zeiler; B. Zihlmann; P. Zupranski

2011-09-13T23:59:59.000Z

452

Multidimensional Study of Hadronization in Nuclei  

E-Print Network [OSTI]

Hadron multiplicities in semi-inclusive deep-inelastic scattering were measured on neon, krypton and xenon targets relative to deuterium at an electron(positron)-beam energy of 27.6 GeV at HERMES. These ratios were determined as a function of the virtual-photon energy nu, its virtuality Q2, the fractional hadron energy z and the transverse hadron momentum with respect to the virtual-photon direction pt . Dependences were analysed separately for positively and negatively charged pions and kaons as well as protons and antiprotons in a two-dimensional representation. Compared to the one-dimensional dependences, some new features were observed. In particular, when z > 0.4 positive kaons do not show the strong monotonic rise of the multiplicity ratio with nu as exhibited by pions and K- . Protons were found to behave very differently from the other hadrons.

Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetissian, A; Avetisyan, E; Belostotski, S; Bianchi, N; Blok, H P; Borissov, A; Bowles, J; Brodski, I; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gapienko, G; Gapienko, V; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Golembiovskaya, M; Hadjidakis, C; Hartig, M; Hasch, D; Hillenbrand, A; Hoek, M; Holler, Y; Hristova, I; Imazu, Y; Ivanilov, A; Jackson, H E; Jo, H S; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Kobayashi, N; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Ruiz, A López; Lorenzon, W; Lu, X -G; Lu, X -R; Ma, B -Q; Mahon, D; Makins, N C R; Manaenkov, S I; Manfré, L; Mao, Y; Marianski, B; de la Ossa, A Martinez; Marukyan, H; Miller, C A; Miyachi, Y; Movsisyan, A; Muccifora, V; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Raithel, M; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanftl, F; Schäfer, A; Schnell, G; Seitz, B; Shibata, T -A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stinzing, F; Taroian, S; Truty, R; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Vogel, C; Wang, S; Yaschenko, S; Ye, Z; Yen, S; Yu, W; Zagrebelnyy, V; Zeiler, D; Zihlmann, B; Zupranski, P

2011-01-01T23:59:59.000Z

453

Electroweak corrections to lepton pair production in association with two hard jets at the LHC  

E-Print Network [OSTI]

We compute the next-to-leading order corrections of $O(\\alpha_s^2\\alpha^3)$ to the hadronic production of two oppositely charged leptons and two hard jets, $p p \\to j j l^- l^+$, using Recola and Collier. We include electroweak and QCD corrections at the given order and all off-shell effects. We provide detailed predictions for the LHC operating at 13 TeV and obtain per-cent-level corrections for the total cross section. For differential distributions we find significant non-uniform distortions in high-energy tails at the level of several ten per cent due to electroweak Sudakov logarithms and deformations at the level of a few per cent for angular variables.

Ansgar Denner; Lars Hofer; Andreas Scharf; Sandro Uccirati

2014-11-04T23:59:59.000Z

454

Automated next-to-leading order predictions for colored scalar production at the LHC  

E-Print Network [OSTI]

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 by automatically matching next-to-leading order matrix elements with parton showers within the MadGraph5 aMC@NLO framework. We illustrate in this way, for the first time in our field, the full automation of Monte Carlo event generation at the next-to-leading order accuracy in QCD for new physics theories with an extended colored sector, the sole inputs being the model Lagrangian and the process of interest.

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

2014-12-17T23:59:59.000Z

455

Shape and flow fluctuations in ultra-central Pb+Pb collisions at the LHC  

E-Print Network [OSTI]

In ultra-central heavy-ion collisions, anisotropic hydrodynamic flow is generated by density fluctuations in the initial state rather than by geometric overlap effects. For a given centrality class, the initial fluctuation spectrum is sensitive to the method chosen for binning the events into centrality classes. We show that sorting events by total initial entropy or by total final multiplicity yields event classes with equivalent statistical fluctuation properties, in spite of viscous entropy production during the fireball evolution. With this initial entropy-based centrality definition we generate several classes of ultra-central Pb+Pb collisions at LHC energies and evolve the events using viscous hydrodynamics with non-zero shear but vanishing bulk viscosity. Comparing the predicted anisotropic flow coefficients for charged hadrons with CMS data we find that both the Monte Carlo Glauber (MC-Glb) and Monte Carlo Kharzeev-Levin-Nardi (MC-KLN) models produce initial fluctuation spectra that are incompatible w...

Shen, Chun; Heinz, Ulrich

2015-01-01T23:59:59.000Z

456

The role of finite-size effects on the spectrum of equivalent photons in proton-proton collisions at the LHC  

E-Print Network [OSTI]

Photon-photon interactions represent an important class of physics processes at the LHC, where quasi-real photons are emitted by both colliding protons. These reactions can result in the exclusive production of a final state $X$, $p+p \\rightarrow p+p+X$. When computing such cross sections, it has already been shown that finite size effects of colliding protons are important to consider for a realistic estimate of the cross sections. These first results have been essential in understanding the physics case of heavy-ion collisions in the low invariant mass range, where heavy ions collide to form an exclusive final state like a $J/\\Psi$ vector meson. In this paper, our purpose is to present some calculations that are valid also for the exclusive production of high masses final states in proton-proton collisions, like the production of a pair of $W$ bosons or the Higgs boson. Therefore, we propose a complete treatment of the finite size effects of incident protons irrespective of the mass range explored in the collision. Our expectations are shown to be in very good agreement with existing experimental data obtained at the LHC.

Mateusz Dyndal; Laurent Schoeffel

2014-12-09T23:59:59.000Z

457

SSC collider dipole magnet end mechanical design  

SciTech Connect (OSTI)

This paper describes the mechanical design of the ends of Superconducting Super Collider dipole magnets to be constructed and tested at Fermilab. Coil end clamps, end yoke configuration, and end plate design are discussed. Loading of the end plate by axial Lorentz forces is discussed. Relevant data from 40 mm and 50 mm aperture model dipole magnets built and tested at Fermilab are presented. In particular, the apparent influence of end clamp design on the quench behavior of model SSC dipoles is described. 8 refs., 3 figs.

Delchamps, S.W.; Bossert, R.C.; Carson, J.; Ewald, K.; Fulton, H.; Kerby, J.; Koska, W.; Strait, J.; Wake, S.M. (Fermi National Accelerator Lab., Batavia, IL (USA)); Leung, K.K. (Superconducting Super Collider Lab., Dallas, TX (USA))

1991-05-01T23:59:59.000Z

458

Future high energy colliders. Formal report  

SciTech Connect (OSTI)

This Report includes copies of transparencies and notes from the presentations made at the Symposium on Future High Energy Colliders, October 21-25, 1996 at the Institute for Theoretical Physics, University of California, Santa Barbara California, that was made available by the authors. Editing, reduction and changes to the authors contributions were made only to fulfill the printing and publication requirements. We would like to take this opportunity and thank the speakers for their informative presentations and for providing copies of their transparencies and notes for inclusion in this Report.

Parsa, Z. [ed.] [ed.

1996-12-31T23:59:59.000Z

459

Charged-particle multiplicity at LHC energies  

ScienceCinema (OSTI)

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. 

None

2011-10-06T23:59:59.000Z

460

Lessons from LHC elastic and diffractive data  

E-Print Network [OSTI]

In the light of LHC data, we discuss the global description of all high energy elastic and diffractive data, using a one-pomeron model, but including multi-pomeron interactions. The LHC data indicate the need of a $k_t(s)$ behaviour, where $k_t$ is the gluon transverse momentum along the partonic ladder structure which describes the pomeron. We also discuss tensions in the data, as well as the $t$ dependence of the slope of $d\\sigma_{el}/dt$ in the small $t$ domain.

A. D. Martin; V. A. Khoze; M. G. Ryskin

2014-10-13T23:59:59.000Z

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461

R-axion detection at LHC  

SciTech Connect (OSTI)

Supersymmetric models with spontaneously broken approximate R-symmetry contains a light spin 0 particle, the R-axion. The properties of the particle can be a powerful probe of the structure of the new physics. In this paper, we discuss the possibilities of the R-axion detection at the LHC experiments. It is challenge to observe this light particle in the LHC environment. However, for typical values in which the mass of the R-axion is a few hundred MeV, we show that those particles can be detected by searching for displaced vertices from R-axion decay.

Goh, Hock-Seng; /UC, Berkeley /LBL, Berkeley; Ibe, Masahiro; /SLAC

2009-06-19T23:59:59.000Z

462

QCD Factorization for heavy quarkonium production at collider energies  

E-Print Network [OSTI]

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.

Jian-Wei Qiu

2006-10-31T23:59:59.000Z

463

LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS  

E-Print Network [OSTI]

LASER-PLASMA-ACCELERATOR-BASED ?? COLLIDERS ? C. B.linear col- lider based on laser-plasma-accelerators arediscussed, and a laser-plasma-accelerator-based gamma-

Schroeder, C. B.

2010-01-01T23:59:59.000Z

464

Ovrview: The Shape of Hadrons  

E-Print Network [OSTI]

In this article we address the physical basis of the deviation of hadron shapes from spherical symmetry (non-spherical amplitudes) with focus on the nucleon and $\\Delta$. An overview of both the experimental methods and results and the current theoretical understanding of the issue is presented. At the present time the most quantitative method is the $\\gamma^{*} p \\to \\Delta$ reaction for which significant non-spherical electric (E2) and Coulomb quadrupole (C2) amplitudes have been observed with good precision as a function of Q^{2} from the photon point through 6 GeV^{2}. Quark model calculations for these quadrupole amplitudes are at least an order of magnitude too small and even have the wrong sign. Lattice QCD, chiral effective field theory, and dynamic model calculations which include the effects of the pion-cloud are in approximate agreement with experiment. This is expected due to the spontaneous breaking of chiral symmetry in QCD and the resulting, long range (low Q^{2}) effects of the pion-cloud. Other observables such as nucleon form factors and virtual Compton scattering experiments indicate that the pion-cloud is playing a significant role in nucleon structure. Semi-inclusive deep inelastic scattering experiments with transverse polarized beam and target also show the effect of non-zero quark angular momentum.

A. M. Bernstein; C. N. Papanicolas

2007-07-31T23:59:59.000Z

465

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

SciTech Connect (OSTI)

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.

Ko, P. [School of Physics, KIAS, Seoul 130-722 (Korea, Republic of)

2012-07-27T23:59:59.000Z

466

Identification techniques for highly boosted W bosons that decay into hadrons  

SciTech Connect (OSTI)

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.

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

2014-12-01T23:59:59.000Z

467

Measurement of beauty-hadron decay electrons in Pb--Pb collisions at sqrt(s_NN) = 2.76 TeV with ALICE  

E-Print Network [OSTI]

The ALICE Collaboration at the LHC studies heavy-ion collisions to investigate the properties of the Quark-Gluon Plasma (QGP). Heavy quarks (charm and beauty) are effective probes for this purpose. Both their energy loss in the medium as well as their possible thermalization yield information about the medium properties. Experimentally, the reconstruction of hadrons with charm valence quarks is possible. For hadrons with beauty valence quarks a promising strategy is the measurement of their decay electrons. To separate these from the background electrons (mainly from charm hadron decays, photon conversions or light-meson decays) the large decay length of beauty hadrons can be utilized. It leads to a relatively large typical impact parameter of the decay electrons. By comparing the impact parameter distribution of the signal electrons with those from the background sources, the signal can be statistically separated from the background. For this purpose a maximum likelihood fit is employed using impact parameter distribution templates from simulations. The resulting nuclear modification factor for electrons from beauty-hadron decays shows a sizeable suppression for p_T > 3 GeV, albeit still with large uncertainties.

Martin Völkl; for the ALICE Collaboration