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1

Hadron colliders (SSC/LHC)  

SciTech Connect

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

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

The Large Hadron Collider - At Discover's Horizon | Virtual LHC...  

NLE Websites -- All DOE Office Websites (Extended Search)

Virtual LHC Lectures These past lectures might give you a better idea of how to plan your upcoming LHC presentation. After you give your lecture, if a video of your presentation or...

4

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

NLE Websites -- All DOE Office Websites (Extended Search)

Large Hadron Collider The Large Hadron Collider The U.S. at the Large Hadron Collider LHC: The Guide Theories tested LHC Experiments The ATLAS Experiment The CMS Experiment The...

5

Exergy Analysis of the Cryogenic Helium Distribution System for the Large Hadron Collider (LHC)  

E-Print Network (OSTI)

The Large Hadron Collider (LHC) at CERN features the world’s largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility..

Claudet, S; Tavian, L; Wagner, U; 10.1063/1.3422294

2010-01-01T23:59:59.000Z

6

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

SciTech Connect

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

Darve, C.; /Fermilab

2010-07-01T23:59:59.000Z

7

EXERGY ANALYSIS OF THE CRYOGENIC HELIUM DISTRIBUTION SYSTEM FOR THE LARGE HADRON COLLIDER (LHC)  

SciTech Connect

The Large Hadron Collider (LHC) at CERN features the world's largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility.

Claudet, S.; Lebrun, Ph.; Tavian, L.; Wagner, U. [CERN, CH-1211, Geneva, 23 (Switzerland)

2010-04-09T23:59:59.000Z

8

Exotic hadrons at hadron colliders  

E-Print Network (OSTI)

In this proceeding, an overview of the recent progress of the exotic hadrons studies at hadron colliders is presented, including the experimental measurement results from CMS, LHCb, CDF and D0. The talk covers the physics properties study of X(3872); the search for Y(4140) state etc; the recent result of Z(4430); and also the extended study to bottomonium sector.

Ye Chen

2014-09-01T23:59:59.000Z

9

Director's colloquium March 18 large hadron collider  

NLE Websites -- All DOE Office Websites (Extended Search)

talk about the most complex scientific instrument ever built-the Large Hadron Collider (LHC). March 10, 2010 Los Alamos National Laboratory sits on top of a once-remote mesa in...

10

Brookhaven and the Large Hadron Collider  

NLE Websites -- All DOE Office Websites (Extended Search)

Brookhaven & the Large Hadron Collider Brookhaven & the Large Hadron Collider Home News Brookhaven & ATLAS ATLAS ATLAS Calorimeter ATLAS Muon Spectrometer Construction Computing Upgrades RHIC & LHC Education LHC tunnel ATLAS detector ATLAS detector RACF BNL built superconducting magnets Brookhaven & the LHC The world's most powerful particle accelerator, the Large Hadron Collider (LHC) in Switzerland, powers unprecedented explorations of the deepest mysteries of the universe. In addition to serving as the U.S. host laboratory for the ATLAS experiment at the LHC, Brookhaven National Lab plays multiple roles in this international collaboration, from construction and project management to data storage and distribution. ATLAS rendering Brookhaven and ATLAS Brookhaven physicists and engineers are participating in one of the most

11

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

12

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

Energy.gov (U.S. Department of Energy (DOE))

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

13

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

14

Hadron multiplicities at the LHC  

E-Print Network (OSTI)

We present the predictions for hadron multiplicities in pp, pA and AA collisions at the LHC based on our approach to the Color Glass Condensate.

D. Kharzeev; E. Levin; M. Nardi

2007-07-05T23:59:59.000Z

15

Hadron collider physics at UCR  

SciTech Connect

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

16

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

17

First Beam for Large Hadron Collider | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Beam for Large Hadron Collider Beam for Large Hadron Collider First Beam for Large Hadron Collider September 10, 2008 - 3:20pm Addthis WASHINGTON, DC - An international collaboration of scientists today sent the first beam of protons zooming at nearly the speed of light around the world's most powerful particle accelerator-the Large Hadron Collider (LHC)-located at the CERN laboratory near Geneva, Switzerland. The U.S. Department of Energy (DOE) and the National Science Foundation (NSF) invested a total $531 million in the construction of the accelerator and its detectors, which scientists believe could help unlock extraordinary discoveries about the nature of the physical universe. Celebrations across the U.S. and around the world mark the LHC's first circulating beam, an occasion more than 15 years in the making. An

18

The Large Hadron Collider  

Science Journals Connector (OSTI)

...fully from the space available in...the machine construction. The superconducting...for a single sector, the whole...therefore, as the heating increases...was made, a sector was powered...is a slight heating during ramp...Collider. | The construction of the Large...the limited space available in...

2012-01-01T23:59:59.000Z

19

Taking the 'Large' out of Large Hadron Collider: Computational Breakthrough  

NLE Websites -- All DOE Office Websites (Extended Search)

Home » News & Publications » News » Science News » Taking the 'Large' out of Large Hadron Collider Taking the 'Large' out of Large Hadron Collider Computational breakthrough hastens modeling of 'tabletop accelerators' August 9, 2010 | Tags: Accelerator Science Contact: Margie Wylie | mwylie@lbl.gov | 510-486-7421 mori1 This 3D simulation shows how laser pulses create plasma wakes that propel electrons forward, much as a surfer is propelled forward by an ocean wave. Laser wakefield acceleration promises electron accelerators that are thousands of times more powerful than, yet a fraction the size of, conventional radio frequency devices. Particle accelerators like the Large Hadron Collider (LHC) at CERN are the big rock stars of high-energy physics-really big. The LHC cost nearly

20

The Very Large Hadron Collider: The farthest energy frontier  

SciTech Connect

The Very Large Hadron Collider (or Eloisatron) represents what may well be the final step on the energy frontier of accelerator-based high energy physics. While an extremely high luminosity proton collider at 100-200 TeV center of mass energy can probably be built in one step with LHC technology, that machine would cost more than what is presently politically acceptable. This talk summarizes the strategies of collider design including staged deployment, comparison with electron-positron colliders, opportunities for major innovation, and the technical challenges of reducing costs to manageable proportions. It also presents the priorities for relevant R and D for the next few years.

Barletta, William A.

2001-06-21T23:59:59.000Z

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

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

22

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

23

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

E-Print Network (OSTI)

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

Conrad, Janet

24

From the LHC to Future Colliders  

SciTech Connect

Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300 fb{sup -1} of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb{sup -1} of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, theWorking Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.

De Roeck, A.; Ellis, J.; /CERN; Grojean, C.; Heinemeyer, S.; /Cantabria Inst. of Phys.; Jakobs, K.; /Freiburg U.; Weiglein, G.; /Durham U., IPPP; Azuelos, G.; /TRIUMF; Dawson, S.; /Brookhaven; Gripaios, B.; /CERN; Han, T.; /Wisconsin U., Madison; Hewett, J.; /SLAC; Lancaster, M.; /University Coll. London; Mariotti, C.; /INFN, Turin; Moortgat, F.; /Zurich, ETH; Moortgat-Pick, G.; /Durham U., IPPP; Polesello, G.; /INFN, Pavia; Riemann, S.; /DESY; Assamagan, K.; /Brookhaven; Bechtle, P.; /DESY; Carena, M.; /Fermilab; Chachamis, G.; /PSI, Villigen /Taiwan, Natl. Taiwan U. /INFN, Florence /Bonn U. /CERN /Bonn U. /Freiburg U. /Oxford U. /Louvain U., CP3 /Bangalore, Indian Inst. Sci. /INFN, Milan Bicocca /Munich, Max Planck Inst. /Taiwan, Natl. Taiwan U. /Frascati /Fermilab /Warsaw U. /Florida U. /Orsay, LAL /LPSC, Grenoble /Warsaw U. /Yale U. /Stockholm U., Math. Dept. /Durham U., IPPP /DESY /Rome U. /University Coll. London /UC, San Diego /Heidelberg U. /Florida State U. /SLAC /Durham U., IPPP /Southern Denmark U., CP3-Origins /McGill U. /Durham U., IPPP; /more authors.; ,

2010-06-11T23:59:59.000Z

25

Superconducting Magnet Technology for Future Hadron Colliders  

SciTech Connect

The application of superconducting magnets to large-scale particle accelerators was successfully demonstrated with the completion of the Tevatron at Fermilab in 1983. This machine, utilizing dipole magnets operating at 4.5 T, has been operating successfully for the past 12 years. This success was followed a few years later by HERA, an electron-proton collider that uses superconducting quadrupoles and dipoles of a design similar to those in the Tevatron. The next major project was the ill-fated SSC, which was cancelled in 1993. However, the SSC R&D effort did succeed in demonstrating the reliable operation of dipole magnets up to 6.6 T. The LHC, now under construction, pushes the ductile superconductor, NbTi, to its limit in dipoles designed to operate at fields of 8.6 T at 1.8 K. Several recent studies have addressed the issues involved in taking the next step beyond the LHC. The Division of Particles and Fields Workshop on Future Hadron Facilities in the U.S., held at Indiana U. in 1994, examined two possible facilities--a 2-TeV on 2-TeV collider and a 30-Tev on 30-Tev collider. The participants arrived at the following conclusions with regard to superconducting magnets: (1) Superconducting magnets are the enabling technology for high energy colliders. As such, the highest priority for the future of hadron facilities in the U.S. is the reassembly of a U.S. superconducting magnet R&D program. (2) emphasis on conductor development and new magnet designs; and (3) goals of such a program might be (a) the development of a 9-10 Tesla magnet based on NbTi technology; (b) the development of high quality quadrupoles with gradients in the range 250-300 T/m; and (c) initiation of R&D activities aimed at moving beyond the existing technology as appears to be required for the development of a magnet operating at 12-15 Tesla. In order to reach fields above 10 T, magnet designers must turn to new materials with higher critical fields than that of NbTi. Several candidate conductors exist; unfortunately, all of these new materials are brittle, and thus pose new challenges to the magnet designers. At the same time that the forces on the magnet windings are increasing due to the higher Lorentz force associated with the higher magnetic fields, the conductor tensile strain must be limited to less than about 0.5% to prevent damage to the brittle superconducting material. Also, coil fabrication methods must be changed. If the superconductor is in the reacted, or brittle, state, the coil winding procedure must be modified to prevent overstraining. If the alternative wind and react approach is used, new insulating materials must be used that can survive the high temperature reactions (650 to 800 C) necessary to form the superconducting compounds. The issues associated with high-field dipole magnets have been discussed at a number of workshops, including those at DESY in 1991 and LBL in 1992. These workshops were extremely useful in defining the problems and focusing the attention of both materials and magnet experts on high-field dipole magnets; however, since neither set of proceedings was published, the information is not readily available. More recently, a workshop was held in Erice, Italy, under the sponsorship of the Ettore Maiorana Center for Scientific Culture. This international workshop was attended by 20 scientists from Europe, Japan, and the U.S., and the summary of that work, which represents the most recent and thorough assessment of the status of high-field magnets for accelerator magnets, is presented.

Scanlan, R.M.; Barletta, W.A.; Dell'Orco, D.; McInturff, A.D.; Asner, A.; Collings, E.W.; Dahl, P.F.; Desportes, H.; Devred, A.; Garre, R.; Gregory, E.; Hassenzahl, W.; Lamm, M.; Larbalestier, D.; Leory, D.; McIntyre, P.; Miller, J.; Shintomi, T.; ten Kate, H.; Wipf, S.

1994-10-01T23:59:59.000Z

26

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

27

Top quark studies at hadron colliders  

SciTech Connect

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

28

LHC's backers in Congress prepare to take on critics  

Science Journals Connector (OSTI)

... involvement of the United States in the construction of Europe's planned Large Hadron Collider (LHC).

COLIN MACILWAIN

1994-07-07T23:59:59.000Z

29

Genesis of the Large Hadron Collider  

Science Journals Connector (OSTI)

...and beyond the discovery of the Higgs boson. organised and edited by John...and beyond the discovery of the Higgs boson . This paper describes the scientific...projects. Large Hadron Collider|Higgs boson|CERN| 1. Beginnings and background...

2015-01-01T23:59:59.000Z

30

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

31

Department of Energy assessment of the Large Hadron Collider  

SciTech Connect

This report summarizes the conclusions of the committee that assessed the cost estimate for the Large Hadron Collider (LHC). This proton-proton collider will be built at CERN, the European Laboratory for Particle Physics near Geneva, Switzerland. The committee found the accelerator-project cost estimate of 2.3 billion in 1995 Swiss francs, or about $2 billion US, to be adequate and reasonable. The planned project completion date of 2005 also appears achievable, assuming the resources are available when needed. The cost estimate was made using established European accounting procedures. In particular, the cost estimate does not include R and D, prototyping and testing, spare parts, and most of the engineering labor. Also excluded are costs for decommissioning the Large Electron-Positron collider (LEP) that now occupies the tunnel, modifications to the injector system, the experimental areas, preoperations costs, and CERN manpower. All these items are assumed by CERN to be included in the normal annual operations budget rather than the construction budget. Finally, contingency is built into the base estimate, in contrast to Department of Energy (DOE) estimates that explicitly identify contingency. The committee`s charge, given by Dr. James F. Decker, Deputy Directory of the DOE Office of Energy Research, was to understand the basis for the LHC cost estimate, identify uncertainties, and judge the overall validity of the estimate, proposed schedule, and related issues. The committee met at CERN April 22--26, 1996. The assessment was based on the October 1995 LHC Conceptual Design Report or ``Yellow Book,`` cost estimates and formal presentations made by the CERN staff, site inspection, detailed discussions with LHC technical experts, and the committee members` considerable experience.

NONE

1996-06-01T23:59:59.000Z

32

The Tevatron Hadron Collider: A short history  

SciTech Connect

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

Tollestrup, A.V.

1994-11-01T23:59:59.000Z

33

Physics requirements for the design of the ATLAS and CMS experiments at the Large Hadron Collider  

Science Journals Connector (OSTI)

...at the high-energy frontier: the...Hadron Collider are discovery experiments...responsible for dark matter; what...itself at the 1TeV energy scale. Supersymmetry...candidate for dark matter. An as...also allow the discovery of whatever Nature...store at the LHC energies. There could...

2012-01-01T23:59:59.000Z

34

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

35

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

36

Mirage Models Confront the LHC: I. Kahler-Stabilized Heterotic String Theory  

E-Print Network (OSTI)

2013 Mirage Models Confront the LHC: I. K¨ ahler-StabilizedLarge Hadron Collider (LHC). The case of heterotic stringobservationally disfavored by the LHC results. Most of the

Kaufman, Bryan L.

2014-01-01T23:59:59.000Z

37

Trilepton Higgs boson signal at hadron colliders  

Science Journals Connector (OSTI)

Most Higgs boson searches pursued at hadron colliders require Yukawa interactions either in the production or the decay of a Higgs boson. We propose a trilepton Higgs boson search based only upon the gauge interactions of the Higgs boson. This strategy can be utilized successfully for the standard model (SM) Higgs boson as well as nonstandard Higgs bosons which break electroweak symmetry but have little to do with fermion mass generation. The trileptons come from Wh production followed by Wh?WWW(*)?3l decays. A SM Higgs trilepton signal would be difficult to detect at the Fermilab Tevatron collider: with 100 fb-1 of data, only a 3? signal above background can be achieved after cuts if 140 GeVHiggs boson mass in the range 140–185 (125–200) GeV. Prospects for a trilepton Higgs boson discovery are greatly improved for models with nonstandard Higgs boson sectors where a Higgs boson couples preferentially to vector bosons rather than to fermions.

Howard Baer and James D. Wells

1998-04-01T23:59:59.000Z

38

Test of relativistic gravity for propulsion at the Large Hadron Collider  

E-Print Network (OSTI)

A design is presented of a laboratory experiment that could test the suitability of relativistic gravity for propulsion of spacecraft to relativistic speeds. An exact time-dependent solution of Einstein's gravitational field equation confirms that even the weak field of a mass moving at relativistic speeds could serve as a driver to accelerate a much lighter payload from rest to a good fraction of the speed of light. The time-dependent field of ultrarelativistic particles in a collider ring is calculated. An experiment is proposed as the first test of the predictions of general relativity in the ultrarelativistic limit by measuring the repulsive gravitational field of bunches of protons in the Large Hadron Collider (LHC). The estimated 'antigravity beam' signal strength at a resonant detector of each proton bunch is 3 nm/s^2 for 2 ns during each revolution of the LHC. This experiment can be performed off-line, without interfering with the normal operations of the LHC.

Franklin Felber

2009-10-06T23:59:59.000Z

39

Gaugino physics of split supersymmetry spectra at the LHC and future proton colliders  

Science Journals Connector (OSTI)

Discovery of the Higgs boson and lack of discovery of superpartners in the first run at the LHC are both predictions of split supersymmetry with thermal dark matter. We discuss what it would take to find gluinos at hadron supercolliders, including the LHC at 14 TeV center-of-mass energy, and future pp colliders at 100 TeV and 200 TeV. We generalize the discussion by reexpressing the search capacity in terms of the gluino to lightest superpartner mass ratio and apply results to other scenarios, such as gauge mediation and mirage mediation.

Sunghoon Jung and James D. Wells

2014-04-02T23:59:59.000Z

40

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

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

TOP AND HIGGS PHYSICS AT THE HADRON COLLIDERS  

SciTech Connect

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

42

LHC Signals from Warped Extra Dimensions  

E-Print Network (OSTI)

do mention, in the context of LHC signals, that suppressedSU-4252-838, YITP-SB-06-43 LHC Signals from Warped Extrathe Large Hadron Collider (LHC) in the framework of a warped

Agashe, K.

2009-01-01T23:59:59.000Z

43

Performance Evaluation of a Crystal-Enhanced Collimation System for the LHC.  

E-Print Network (OSTI)

??The Large Hadron Collider (LHC) has been constructed at CERN (Conseil Européen pour la Recherche Nucléaire, Geneva, Switzerland), and recently started up. The LHC beams,… (more)

Previtali, Valentina

2010-01-01T23:59:59.000Z

44

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

DOE Data Explorer (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.

45

Proceedings of the workshop on triggering, data acquisition and computing for high energy, high luminosity, hadron-hadron colliders  

SciTech Connect

These proceedings address issues in triggering, data acquisition, and off-line computing for high energy/high luminosity hadron-hadron colliders, including physics signatures; analog triggers; data filtering/acquisition and processing; networking; and special spectrometers and instrumentation.

Cox, B.; Fenner, R.; Hale, P.

1985-01-01T23:59:59.000Z

46

Beam physics in future electron hadron colliders  

E-Print Network (OSTI)

High-energy electron-hadron collisions could support a rich research programme in particle and nuclear physics. Several future projects are being proposed around the world, in particular eRHIC at BNL, MEIC at TJNAF in the US, and LHeC at CERN in Europe. This paper will highlight some of the accelerator physics issues, and describe related technical developments and challenges for these machines. In particular, optics design and beam dynamics studies are discussed, including longitudinal phase space manipulation, coherent synchrotron radiation, beam-beam kink instability, ion effects, as well as mitigation measures for beam break up and for space-charge induced emittance growth, all of which could limit the machine performance. Finally, first steps are presented towards an LHeC R&D facility, which should investigate relevant beam-physics processes.

Valloni, A; Klein, M; Schulte, D; Zimmermann, F

2013-01-01T23:59:59.000Z

47

LHC Division EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH  

E-Print Network (OSTI)

LHC Division EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH European Laboratory for Particle Physics Status of the Large Hadron Collider and Magnet Program N. Siegel for the LHC Magnet Team The Large Hadron Collider (LHC), approved by the CERN Council in December 1994, is a 7 +7 TeV proton accelerator

Laughlin, Robert B.

48

Recognizing Critical Behavior amidst Minijets at the Large Hadron Collider  

E-Print Network (OSTI)

The transition from quarks to hadrons in a heavy-ion collision at high energy is usually studied in two different contexts that involve very different transverse scales: local and non-local. Models that are concerned with the $p_T$ spectra and azimuthal anisotropy belong to the former, i.e., hadronization at a local point in $(\\eta,\\phi)$ space, such as the recombination model. The non-local problem has to do with quark-hadron phase transition where collective behavior through near-neighbor interaction can generate patterns of varying sizes in the $(\\eta,\\phi)$ space. The two types of problems are put together in this paper both as brief reviews separately and to discuss how they are related to each other. In particular, we ask how minijets produced at LHC can affect the investigation of multiplicity fluctuations as signals of critical behavior. It is suggested that the existing data from LHC have sufficient multiplicities in small $p_T$ intervals to make feasible the observation of distinctive features of clustering of soft particles, as well as voids, that characterize the critical behavior at phase transition from quarks to hadrons, without any ambiguity posed by the clustering of jet particles.

Rudolph C. Hwa

2014-11-22T23:59:59.000Z

49

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

E-Print Network (OSTI)

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

Frank Fiedler

2007-06-12T23:59:59.000Z

50

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

51

White House backs US contribution to LHC  

Science Journals Connector (OSTI)

... back a US contribution of $530 million towards construction of the Large Hadron Collider (LHC) at CERN, the European particle physics laboratory in Geneva, Switzerland.

Colin Macilwain

1997-01-09T23:59:59.000Z

52

Relief and euphoria greet decision on LHC  

Science Journals Connector (OSTI)

... the European Laboratory for Particle Physics (CERN) approved construction of the Large Hadron Collider (LHC), one of the largest basic science research projects ever undertaken.

Alison Abbott

1994-12-29T23:59:59.000Z

53

LHC caught in French budget crunch  

Science Journals Connector (OSTI)

... find a way out of the impasse over funding prospects for the Large Hadron Collider (LHC) being planned at the European Laboratory for Particle Physics (CERN).

Declan Butler

1994-09-29T23:59:59.000Z

54

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

55

Recognizing Critical Behavior amidst Minijets at the Large Hadron Collider  

E-Print Network (OSTI)

The transition from quarks to hadrons in a heavy-ion collision at high energy is usually studied in two different contexts that involve very different transverse scales: local and non-local. Models that are concerned with the $p_T$ spectra and azimuthal anisotropy belong to the former, i.e., hadronization at a local point in $(\\eta,\\phi)$ space, such as the recombination model. The non-local problem has to do with quark-hadron phase transition where collective behavior through near-neighbor interaction can generate patterns of varying sizes in the $(\\eta,\\phi)$ space. The two types of problems are put together in this paper both as brief reviews separately and to discuss how they are related to each other. In particular, we ask how minijets produced at LHC can affect the investigation of multiplicity fluctuations as signals of critical behavior. It is suggested that the existing data from LHC have sufficient multiplicities in small $p_T$ intervals to make feasible the observation of distinctive features of cl...

Hwa, Rudolph C

2014-01-01T23:59:59.000Z

56

Gluon Fusion Contribution to $VHj$ Production at Hadron Colliders  

E-Print Network (OSTI)

We study the associated production of an electroweak vector boson and the Higgs boson with a jet via gluon-gluon fusion. At the leading order, these processes occur at one-loop level. The amplitudes of these one-loop processes are gauge invariant and finite. Therefore, their contributions towards the corresponding hadronic cross sections and kinematic distributions can be calculated separately. We present results for the Large Hadron Collider and its discussed upgrades. We find that the gluon-gluon one-loop process gives dominant contribution to the $\\gamma H j$ production. We observe a destructive interference effect in the $gg\\to Z H j$ amplitude. We also find that in the high transverse momentum and central rapidity region, the $ZHj$ production cross section via gluon-gluon fusion becomes comparable to the cross section contributions coming from quark-quark and quark-gluon channels.

Agrawal, Pankaj

2014-01-01T23:59:59.000Z

57

ZZ production at hadron colliders in NNLO QCD  

E-Print Network (OSTI)

We report on the first calculation of next-to-next-to-leading order (NNLO) QCD corrections to the inclusive production of ZZ pairs at hadron colliders. Numerical results are presented for pp collisions with centre-of-mass energy ($\\sqrt{s}$) ranging from 7 to 14 TeV. The NNLO corrections increase the NLO result by an amount varying from $11\\%$ to $17\\%$ as $\\sqrt{s}$ goes from 7 to 14 TeV. The loop-induced gluon fusion contribution provides about $60\\%$ of the total NNLO effect. When going from NLO to NNLO the scale uncertainties do not decrease and remain at the $\\pm 3\\%$ level.

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

2014-05-09T23:59:59.000Z

58

ZZ production at hadron colliders in NNLO QCD  

E-Print Network (OSTI)

We report on the first calculation of next-to-next-to-leading order (NNLO) QCD corrections to the inclusive production of ZZ pairs at hadron colliders. Numerical results are presented for pp collisions with centre-of-mass energy ($\\sqrt{s}$) ranging from 7 to 14 TeV. The NNLO corrections increase the NLO result by an amount varying from $11\\%$ to $17\\%$ as $\\sqrt{s}$ goes from 7 to 14 TeV. The loop-induced gluon fusion contribution provides about $60\\%$ of the total NNLO effect. When going from NLO to NNLO the scale uncertainties do not decrease and remain at the $\\pm 3\\%$ level.

Cascioli, F; Grazzini, M; Kallweit, S; Maierhöfer, P; von Manteuffel, A; Pozzorini, S; Rathlev, D; Tancredi, L; Weihs, E

2014-01-01T23:59:59.000Z

59

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...

Bambhaniya, Gulab; Khan, Subrata; Konar, Partha; Mondal, Tanmoy

2014-01-01T23:59:59.000Z

60

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

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

LHC Phenomenology  

E-Print Network (OSTI)

The analyses of the first 1-2/fb of Large Hadron Collider (LHC) data are already having significant impacts on a wide range of models. In this talk I give my perspective on why we expect to find new physics at the LHC, and how such a discovery might unfold.

Heather E. Logan

2011-11-13T23:59:59.000Z

62

LHC further delayed  

Science Journals Connector (OSTI)

... on their newest toy. A report out today says that the Large Hadron Collider (LHC), the world's most powerful particle accelerator, located at CERN near Geneva, Switzerland ... are set to cost up to 35 million Swiss francs (US$29 million). The LHC will collide 7 TeV beams of protons together in the hopes of generating new particles ...

Geoff Brumfiel

2008-12-05T23:59:59.000Z

63

Texan goes gunning for US role in LHC  

Science Journals Connector (OSTI)

... he can to block the United States' planned participation in the Large Hadron Collider (LHC) project at CERN, the European laboratory for particle physics in Switzerland.

Colin Macilwain

1997-03-13T23:59:59.000Z

64

Precise Predictions for Z + 4 Jets at Hadron Colliders  

SciTech Connect

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

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

2011-12-09T23:59:59.000Z

65

Detection of invisible particles at hadron collider experiments through the magnetic spectrometer  

E-Print Network (OSTI)

The production of invisible particles plays great importance in high energy physics. Large part of interesting electroweak processes include production of neutrinos, while many new physics scenarios predict the existence of similarly weakly-interacting particles. In events with associated production of invisible particles and hadronic jets, the measurement of the imbalance in transverse momentum of the final state particles is the major leverage to reject the otherwise dominant source of backgrounds in hadron colliders, i.e. the generic production of many jets by QCD interactions. Here we discuss a novel technique which utilizes the information derived from the spectrometer, eventually coupled with the more straightforward calorimeter information, to infer the passage of invisible particles. We check the validity of this technique in data and Monte Carlo simulations in a broad range of topologies, starting from the simplest, with two jets in the final state, to the ones with very large jet multiplicities. We also suggest a new way, based on the same approach, to measure the yields and model the kinematics of the QCD multijet background in invisible particles plus jets signatures. The results are derived using data collected with the CDF II detector; we argue that the application to LHC experiments is straightforward.

Marco Bentivegna; Qiuguang Liu; Fabrizio Margaroli; Karolos Potamianos

2012-05-20T23:59:59.000Z

66

Effects of invisible particle emission on global inclusive variables at hadron colliders  

E-Print Network (OSTI)

We examine the effects of invisible particle emission in conjunction with QCD initial state radiation (ISR) on quantities designed to probe the mass scale of new physics at hadron colliders, which involve longitudinal as well as transverse final-state momenta. This is an extension of our previous treatment, arXiv:0903.2013, of the effects of ISR on global inclusive variables. We present resummed results on the visible invariant mass distribution and compare them to parton-level Monte Carlo results for top quark and gluino pair-production at the LHC. There is good agreement as long as the visible pseudorapidity interval is large enough (eta ~ 3). The effect of invisible particle emission is small in the case of top pair production but substantial for gluino pair production. This is due mainly to the larger mass of the intermediate particles in gluino decay (squarks rather than W-bosons). We also show Monte Carlo modelling of the effects of hadronization and the underlying event. The effect of the underlying event is large but may be approximately universal.

Andreas Papaefstathiou; Bryan Webber

2010-04-27T23:59:59.000Z

67

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

Office of Science (SC) Website

Subpanel on the Linear Collider and the Large Hadron Subpanel on the Linear Collider and the Large Hadron Collider High Energy Physics Advisory Panel (HEPAP) HEPAP Home Meetings Members .pdf file (20KB) Charges/Reports Charter .pdf file (44KB) HEP Committees of Visitors HEP Home Charges/Reports Subpanel on the Linear Collider and the Large Hadron Collider Print Text Size: A A A RSS Feeds FeedbackShare Page Joseph Lykken (FNAL) Co-Chair James Siegrist (LBNL) Co-Chair Jonathan Bagger (JHU) Barry Barish (Caltech) Neil Calder (SLAC) Jonathan Feng (UC Irvine) Fred Gilman (Carnegie Mellon) JoAnne Hewett (SLAC) John Huth (Harvard) Judy Jackson (Fermilab) Young-Kee Kim (Chicago) Rocky Kolb (Fermilab) Joe Lykken (Fermilab) Konstantin Matchev (Florida) Hitoshi Murayama (UC Berkeley) Jim Siegrist (UC Berkeley) Paris Sphicas (CERN/Athens)

68

THEORETICAL PROGRESS FOR THE ASSOCIATED PRODUCTION OF A HIGGS BOSON WITH HEAVY QUARKS AT HADRON COLLIDERS.  

SciTech Connect

The production of a Higgs boson in association with a pair of t{bar t} or b{bar b} quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief introduction, we review the results obtained for both the Tevatron and the Large Hadron Collider.

DAWSON,S.JACKSON,C.B.ORR,L.H.REINA,L.WACKEROTH,D.

2003-07-17T23:59:59.000Z

69

LHC meltdown before first collision  

Science Journals Connector (OSTI)

... The Large Hadron Collider (LHC), a US$4.1-billion machine located at CERN, Europe's particle-physics ... on 19 September, just nine days after the collider circulated its first beams. The LHC is designed to accelerate protons to energies of 7 teraelectronvolts before smashing them together. ...

Geoff Brumfiel

2008-09-22T23:59:59.000Z

70

LHC delay hits Japan's physicists  

Science Journals Connector (OSTI)

... Particle Physics (CERN) to agree on proceeding with plans for the Large Hadron Collider (LHC) has been a major setback for high-energy physicists in Japan who are trying ... high-energy phys-ics community, decided late last year to throw its weight behind the LHC following the cancellation of the US Superconducting Super Collider (SSC) project. And the ...

David Swinbanks

1994-07-21T23:59:59.000Z

71

Dark matter at colliders  

SciTech Connect

We show that colliders can impose strong constraints on dark matter. We take an effective field theory approach where dark matter couples to quarks and gluons through high dimensional operators. We discuss limits on interactions of dark matter and hadronic matter from the ATLAS experiment at the Large Hadron Collider (LHC). For spin-independent scattering, the LHC limits are stronger than those from direct detection experiments for light WIMPs. For spin-dependent scattering, the LHC sets better limits over much of parameter space.

Yu Haibo [Department of Physics, University of Michigan, Ann Arbor, MI, 48109 (United States)

2013-05-23T23:59:59.000Z

72

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

73

Hadron production at LHC in dipole momentum space  

SciTech Connect

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

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

2013-03-25T23:59:59.000Z

74

Beam-Machine Interaction Studies for the Phase II LHC Collimation System.  

E-Print Network (OSTI)

??Collimation is essential in a high Energy and Intensity hadron collider with SuperConducting magnets, like the LHC at CERN. To improve the cleaning efficiency and… (more)

Lari, Luisella

2010-01-01T23:59:59.000Z

75

On CP violation and the measurement of the dimuon charge asymmetry at hadron colliders  

E-Print Network (OSTI)

B factories measure the CP violation parameter of B^0 Bbar^0 mixing and decay. Hadron colliders measure the dimuon charge asymmetry of an admixture of B hadrons. In this note we discuss a subtle point on how the CP violation parameter of B^0_s Bbar^0_s mixing and decay can be extracted from these measurements.

B. Hoeneisen

2006-07-26T23:59:59.000Z

76

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

SciTech Connect

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

77

The Large Hadron Collider - At Discover's Horizon | Slides and...  

NLE Websites -- All DOE Office Websites (Extended Search)

photos selected by the Press Office for use by journalists) Full CERN Photo database US LHC Images Fermilab Visual Media Services (photos from Fermilab and the Tevatron)...

78

The Large Hadron Collider - At Discover's Horizon | Slides and...  

NLE Websites -- All DOE Office Websites (Extended Search)

available) Powerpoint templates and example presentations (four designs available) LHC video and images Tips to get started Publicity Work with your institution's press...

79

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

80

The future of the Large Hadron Collider and CERN  

Science Journals Connector (OSTI)

...LHC centre-of-mass energy of 7TeV and with 11...7TeV centre-of-mass energy and assuming about 101...probing the nature of dark matter. The LHC discovery reach for SUSY particles...7TeV centre-of-mass energy. The discovery reach...

2012-01-01T23:59:59.000Z

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.


81

LHC switches on  

Science Journals Connector (OSTI)

... successfully circulated the first protons around the 27-kilometre ring of the Large Hadron Collider (LHC), located at CERN outside of Geneva, Switzerland. "Merci, merci," a relieved ... at CERN outside of Geneva, Switzerland. "Merci, merci," a relieved Lyn Evans, LHC's project leader, thanked the applauding physicists and engineers. The ...

Geoff Brumfiel

2008-09-10T23:59:59.000Z

82

LHC faces further delay  

Science Journals Connector (OSTI)

... An official announcement expected within days is likely to say that the Large Hadron Collider (LHC) will not begin providing data until November — more than a year after its ... providing data until November — more than a year after its planned start date. The LHC was seriously damaged during power tests in September last year (see 'Eight-month delay ...

Geoff Brumfiel

2009-02-09T23:59:59.000Z

83

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

84

Physics Reach at Future Colliders  

SciTech Connect

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

85

LHC set to halt for upgrades  

Science Journals Connector (OSTI)

... particle collider is ready to take a well-earned rest. The Large Hadron Collider (LHC) will shut down on 11 February ahead of around two years of upgrade work. ... there will be no long holiday for the thousands of physicists who depend on the LHC for their data. A bruising schedule of maintenance, upgrades and forward planning will keep ...

Geoff Brumfiel

2013-02-06T23:59:59.000Z

86

Did design flaws doom the LHC?  

Science Journals Connector (OSTI)

... some soul-searching. One senior scientist who helped to build the Large Hadron Collider (LHC) at CERN, Europe's particle-physics laboratory near Geneva, Switzerland, is claiming that ... 2008 — could have been avoided. On 19 September 2008, just weeks before the LHC was first scheduled to start colliding protons, an electrical short caused massive damage. A ...

Geoff Brumfiel

2010-02-23T23:59:59.000Z

87

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

E-Print Network (OSTI)

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

Huichao Song

2012-10-21T23:59:59.000Z

88

Dijet Searches for Supersymmetry at the Large Hadron Collider  

Science Journals Connector (OSTI)

We present several strategies for searching for supersymmetry in dijet channels, using the two leading jets’ momenta alone rather than the full missing transverse energy. Preliminary investigations suggest that signal-to-background ratios of at least 4–5 should be achievable at the LHC, with discovery possible for squarks as heavy as ?1.7??TeV.

Lisa Randall and David Tucker-Smith

2008-11-26T23:59:59.000Z

89

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

90

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

91

Top Physics at LHC  

E-Print Network (OSTI)

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

M. Vander Donckt; for the CMS; ATLAS Collaborations

2008-05-21T23:59:59.000Z

92

Supersymmetry and LHC  

E-Print Network (OSTI)

The motivation for introduction of supersymmetry in high energy physics as well as a possibility for supersymmetry discovery at LHC (Large Hadronic Collider) are discussed. The main notions of the Minimal Supersymmetric Standard Model (MSSM) are introduced. Different regions of parameter space are analyzed and their phenomenological properties are compared. Discovery potential of LHC for the planned luminosity is shown for different channels. The properties of SUSY Higgs bosons are studied and perspectives of their observation at LHC are briefly outlined.

A. V. Gladyshev; D. I. Kazakov

2006-06-28T23:59:59.000Z

93

Top Quark Production at the LHC  

E-Print Network (OSTI)

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

Francesco Spanò; for the ATLAS; CMS collaborations

2011-12-16T23:59:59.000Z

94

Top quark physics at the LHC  

E-Print Network (OSTI)

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

Werner Bernreuther

2008-05-09T23:59:59.000Z

95

Ground Vibration Measurements at LHC Point 4  

SciTech Connect

Ground vibration was measured at Large Hadron Collider (LHC) Point 4 during the winter shutdown in February 2012. This report contains the results, including power and coherence spectra. We plan to collect and analyze vibration data from representative collider halls to inform specifications for future linear colliders, such as ILC and CLIC. We are especially interested in vibration correlations between final focus lens locations.

Bertsche, Kirk; /SLAC; Gaddi, Andrea; /CERN

2012-09-17T23:59:59.000Z

96

Low-cost hadron colliders at Fermilab: A discussion paper  

SciTech Connect

New more economic approaches are required to continue the dramatic exponential rise in collider energies as represented by the well known Livingston plot. The old idea of low cost, low field iron dominated magnets in a small diameter pipe may become feasible in the next decade with dramatic recent advances in technology: (1) advanced tunneling technologies for small diameter, non human accessible tunnels, (2) accurate remote guidance systems for tunnel survey and boring machine steering, (3) high T{sub c} superconductors operating at liquid N{sub 2} or liquid H{sub 2} temperatures, (4) industrial applications of remote manipulation and robotics, (5) digitally multiplexed electronics to minimize cables, (6) achievement of high luminosities in p-p and p-{anti P} colliders. The goal of this paper is to stimulate continuing discussions on approaches to this new collider and to identify critical areas needing calculations, construction of models, proof of principle experiments, and full scale prototypes in order to determine feasibility and arrive at cost estimates.

Foster, G.W.; Malamud, E.

1996-06-21T23:59:59.000Z

97

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

SciTech Connect

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

98

LHC students face data drought  

Science Journals Connector (OSTI)

... That's because the Large Hadron Collider (LHC), the world's largest particle accelerator at CERN, outside Geneva in Switzerland, is ... in four giant detectors spread around its 27-kilometre circumference. Physicists once hoped that the LHC would start its collisions in late 2006, but last September, after a series of ...

Geoff Brumfiel

2009-07-29T23:59:59.000Z

99

Does Europe need the LHC?  

Science Journals Connector (OSTI)

... about á£680 million) cost of building a new accelerator, the Large Hadron Collider (LHC), is particularly worrying, he said, be-cause the plan coincides with a similar ... CERN member nations must next year decide whether or not to go ahead with the LHC. Carlo Rubbia, director-general of CERN, last week declined to comment on the ...

Peter Aldhous

1991-03-14T23:59:59.000Z

100

Detector challenges at the LHC  

Science Journals Connector (OSTI)

... Four main experiments have been designed and constructed for the Large Hadron Collider (LHC) machine: ATLAS, CMS, LHCb and ALICE. ATLAS and CMS are large general- ... specifically for studies of heavy-ion collisions (see page 302). Experimental measurements at the LHC ...

Steinar Stapnes

2007-07-18T23:59:59.000Z

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

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

Science Journals Connector (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 thermodynamic and the hydrodynamic response of the target that leads to a reduction in the density. The modified density distribution is used in FLUKA to calculate new energy loss distribution and the two codes are thus run iteratively. A suitable iteration step is considered to be the time interval during which the target density along the axis decreases by 15%–20%. Our simulations suggest that the full LHC proton beam penetrates up to 25 m in solid carbon whereas the range of the shower from a single proton in solid carbon is just about 3 m (hydrodynamic tunneling effect). It is planned to perform experiments at the experimental facility HiRadMat (High Radiation Materials) at CERN using the proton beam from the Super Proton Synchrotron (SPS), to compare experimental results with the theoretical predictions. Therefore simulations of the response of a solid copper cylindrical target hit by the SPS beam were performed. The particle energy in the SPS beam is 440 GeV while it has the same bunch structure as the LHC beam, except that it has only up to 288 bunches. Beam focal spot sizes of ?=0.1, 0.2, and 0.5 mm have been considered. The phenomenon of significant hydrodynamic tunneling due to the hydrodynamic effects is also expected for the experiments.

N. A. Tahir, J. Blanco Sancho, A. Shutov, R. Schmidt, and A. R. Piriz

2012-05-08T23:59:59.000Z

102

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

2008-07-10T23:59:59.000Z

103

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

104

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

105

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

SciTech Connect

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

106

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

107

The LHC and the ILC  

E-Print Network (OSTI)

The synergy between the Large Hadron Collider and the International Linear Collider during concurrent running of the two machines has the potential to maximise the physics gain from both facilities. Some examples of detailed case studies of the interplay between the LHC and ILC are given, with a particular emphasis on new results that have been obtained after the first LHC / ILC Study Group report was released.

Georg Weiglein

2005-08-16T23:59:59.000Z

108

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

109

Substructure of High-pT Jets at the LHC  

E-Print Network (OSTI)

of high-pT Jets at the LHC Leandro G. Almeida, Seung J. Lee,of high-p T Jets at the LHC Leandro G. Almeida a , Seung J.the Large Hadron Collider (LHC), events with highly-boosted

Almeida, L.G.

2009-01-01T23:59:59.000Z

110

CERN seeks an extra $330 million for LHC  

Science Journals Connector (OSTI)

... (CERN) has confirmed its commitment to the construction of the planned Large Hadron Collider (LHC), and has asked for proposals from CERN management as to how non-member states ... design, and concluded that the project "should be approved rapidly.")

Alison Abbott

1993-12-30T23:59:59.000Z

111

Bulk matter physics and its future at the Large Hadron Collider  

E-Print Network (OSTI)

Measurements at low transverse momentum will be performed at the LHC for studying particle production mechanisms in $pp$ and heavy-ion collisions. Some of the experimental capabilities for bulk matter physics are presented, focusing on tracking elements and particle identification. In order to anticipate the study of baryon production for both colliding systems at multi-TeV energies, measurements for identified species and recent model extrapolations are discussed. Several mechanisms are expected to compete for hadro-production in the low momentum region. For this reason, experimental observables that could be used for investigating multi-parton interactions and help understanding the "underlying event" content in the first $pp$ collisions at the LHC are also mentioned.

B. Hippolyte

2009-01-21T23:59:59.000Z

112

The muon g -2: the role of hadronic effects and first lessons from the LHC  

E-Print Network (OSTI)

The muon g - 2: the role of hadronic effects and first lessons from the LHC Fred Jegerlehner fjeger + aµ) Dirac: gµ = 2 , aµ = 2 + · · · muon anomaly (q) µ(p ) µ(p) = (-ie) ¯u(p ) µ F1(q2 ) + i µq 2mµ F.00005) F. Jegerlehner Oberw¨olz, September 2012 3 #12;In a uniform magnetic field, as in muon g - 2

Röder, Beate

113

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

114

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

115

LHC hopes for collisions by Christmas  

Science Journals Connector (OSTI)

... The Large Hadron Collider (LHC) should yield its first data by Christmas, smashing protons at energies high enough to ... Switzerland, on 6 August. The 6.5-billion Swiss franc (US$6-billion) LHC has been offline for nearly a year, following an accident on 19 September 2008 ...

Eric Hand

2009-08-07T23:59:59.000Z

116

Behind the mask of the LHC  

Science Journals Connector (OSTI)

... and indeed all scientists, should rejoice that the advent of the Large Hadron Collider (LHC) has become a significant cultural event. Dubbed the 'Big Bang machine', the ... jamboree. The most obvious is the temptation for hype and false promises about what the LHC will achieve, as though all the secrets of creation are about to come tumbling ...

Philip Ball

2008-07-03T23:59:59.000Z

117

LHC prepares for data pile-up  

Science Journals Connector (OSTI)

... one of the greatest challenges this year for scientists working on the Large Hadron Collider (LHC) at CERN, Europe’s main high-energy physics laboratory near Geneva, Switzerland. If ... machine before decaying into lighter particles. Last year, the two biggest detectors at the LHC saw hints of a Higgs with a mass of about 125 gigaelectronvolts (energy and ...

Geoff Brumfiel

2012-05-04T23:59:59.000Z

118

Eight-month delay for LHC  

Science Journals Connector (OSTI)

... Details of last month's accident at the Large Hadron Collider (LHC), the world's premier particle accelerator, are emerging — and confirm that the ... confirm that the machine will not restart before late May or early June 2009. The LHC's superconducting magnets generate enormous fields by circulating huge electrical currents with virtually no resistance ...

Geoff Brumfiel

2008-10-17T23:59:59.000Z

119

LHC plans extra year for Higgs hunt  

Science Journals Connector (OSTI)

... If the plan is implemented, the Large Hadron Collider (LHC), located at CERN, near Geneva, Switzerland, will run until the end of ... management and council in January. At stake is the particle many physicists see as the LHC's raison d'être: the Higgs. Theorists believe that the Higgs particle, together ...

Geoff Brumfiel

2010-12-10T23:59:59.000Z

120

Beyond the standard model with the LHC  

Science Journals Connector (OSTI)

... The unparalleled high energy of the Large Hadron Collider (LHC), with its 7 TeV per beam and its enormously high collision rate that should ... of the Universe's dark matter and dark energy. There are high hopes that the LHC will help resolve at least some of these basic issues in cosmology and in physics ...

John Ellis

2007-07-18T23:59:59.000Z

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

LHC and space station get funding strings  

Science Journals Connector (OSTI)

... , authorizing US funding for both the International Space Station and the Large Hadron Collider (LHC) at the European Laboratory for Particle Physics (CERN) in Geneva, Switzerland, but ... both houses. But they do provide an indication of policy direction. In particular, the LHC vote represents defeat for a bid to cut funding completely, but still reflects congressional ...

Meredith Wadman

1997-04-24T23:59:59.000Z

122

CERN seeks firm commitment to LHC  

Science Journals Connector (OSTI)

... ) last week reaffirmed its intention of approving the building of its Large Hadron Collider (LHC) at its meeting in June. But the council failed to reach agreement on the ... are keen that the wording should include a firm commitment to the construction of the LHC, regardless of whether additional funding is promised by non-member states.

Alison Abbott

1994-04-21T23:59:59.000Z

123

Physicists plan to build a bigger LHC  

Science Journals Connector (OSTI)

... When Europe’s Large Hadron Collider (LHC) started up in 2008, particle physicists would not have dreamt of asking for something ... -billion machine to work. But with the 2012 discovery of the Higgs boson, the LHC has fulfilled its original promise — and physicists are beginning to get excited about designing ...

Eugenie Samuel Reich

2013-11-12T23:59:59.000Z

124

LHC sees particles circulate once more  

Science Journals Connector (OSTI)

... began circulating beams of protons around the 27-kilometre ring of the Large Hadron Collider (LHC) at CERN, Europe's particle-physics laboratory near Geneva, Switzerland. The tests bring ... at a press conference about the status of the machine. "We've shown the LHC is in superb condition." ...

Geoff Brumfiel

2009-11-23T23:59:59.000Z

125

(SUSY) Higgs Search at the LHC  

E-Print Network (OSTI)

The discovery of the Standard Model (SM) or supersymmetric (SUSY) Higgs bosons belongs to the main endeavors of the Large Hadron Collider (LHC). In this article the status of the signal and background calculations for Higgs boson production at the LHC is reviewed.

M. Margarete Muhlleitner

2008-10-07T23:59:59.000Z

126

Boson competition lifts prospects for LHC  

Science Journals Connector (OSTI)

... Higgs boson had increased his enthusiasm for the con-struction of the Large Hadron Collider (LHC) being planned for the European Laboratory for Particle Physics (CERN) in Geneva spe- ... even further in order to pay for their participation in the experimental programme on the LHC. Even so, they are warning that paying for the construction programme within current budget ...

David Dickson

1993-09-09T23:59:59.000Z

127

LHC plans for open data future  

Science Journals Connector (OSTI)

... When the Large Hadron Collider (LHC) is humming along, the data come in a deluge. The four experimental detectors ... time will be unable to reconstruct the discovery of the Higgs boson. “When the LHC programme comes to an end, it will probably be the last data at this ...

Elizabeth Gibney

2013-11-26T23:59:59.000Z

128

France, Switzerland 'must pay more' for LHC  

Science Journals Connector (OSTI)

... a spanner into negotiations over the construction of Europe ' s planned Large Hadron Collider (LHC) by unexpectedly demanding that France and Switzerland jointly provide an additional 10 per cent ... CERN council, which many had hoped would give formal approval to the construction of the LHC. In particular, negotiations on the contentious issue of inflation-linked rises in contributions seemed ...

Alison Abbott

1994-06-30T23:59:59.000Z

129

Reliability of Beam Loss Monitors System for the Large Hadron Collider  

E-Print Network (OSTI)

The employment of superconducting magnets, in the high energies colliders, opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system, the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems, which contribute to the final SIL value, are the dump system, the interlock system, the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particles losses, while at medium and higher loss time it is assisted by other systems, such as the quench protection system and the cryogenic system. For BLMS, hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS, using temperature and radiation damage experimental data as well as using standar...

Guaglio, Gianluca; Santoni, C

2004-01-01T23:59:59.000Z

130

The Cryogenic Distribution Line for the LHC: Functional Specification and Conceptual Design  

Science Journals Connector (OSTI)

The Large Hadron Collider (LHC)1 currently under construction at CERN will make use of superconducting magnets operating in superfluid helium below 2 K. The cryogenic distribution scheme for each of the eight sec...

W. Erdt; G. Riddone; R. Trant

2000-01-01T23:59:59.000Z

131

Signals of an invisibly decaying Higgs in a scalar dark matter scenario: a study for the Large Hadron Collider  

E-Print Network (OSTI)

We consider the collider phenomenology of a singlet Majoron model with softly broken lepton number. Lepton number is spontaneously broken when the real part of a new singlet scalar develops vacuum expectation value. With the additional soft terms violating lepton numbers, the imaginary part of this singlet scalar becomes a massive pseudo-Majoron which can account for the dark matter. In presence of the coupling of the pseudo-Majoron with the Standard Model (SM) Higgs, the SM Higgs mostly decays into a pair of pseudo-Majorons, giving rise to missing transverse energy signals at a hadron collider. Since the Higgs visible decay branching fractions get reduced in presence of this invisible decay mode, the bounds on the SM Higgs mass from the LEP and Tevatron experiments get diluted and the invisible decay channel of the Higgs become important for the discovery of low mass Higgs at the Large Hadron Collider.

Kirtiman Ghosh; Biswarup Mukhopadhyaya; Utpal Sarkar

2011-05-29T23:59:59.000Z

132

Next generation Higgs bosons: Theory, constraints, and discovery prospects at the Large Hadron Collider  

Science Journals Connector (OSTI)

Particle physics model building within the context of string theory suggests that further copies of the Higgs boson sector may be expected. Concerns regarding tree-level flavor-changing neutral currents are easiest to allay if little or no couplings of next generation Higgs bosons to standard model fermions are allowed. We detail the resulting general Higgs potential and mass spectroscopy in both a standard model extension and a supersymmetric extension. We present the important experimental constraints from meson-meson mixing, loop-induced b?s? decays, and LEP2 direct production limits. We investigate the energy range of the valid perturbation theory of these ideas. In the supersymmetric context we present a class of examples that marginally aids the fine-tuning problem for parameter space where the lightest Higgs boson mass is greater than the standard model limit of 114 GeV. Finally, we study collider physics signatures generic to next generation Higgs bosons, with special emphasis on Ah?hhZ?4b+2l signal events, and describe the capability of discovery at the Large Hadron Collider.

Rick S. Gupta and James D. Wells

2010-03-30T23:59:59.000Z

133

Technicolor walks at the LHC  

Science Journals Connector (OSTI)

We analyze the potential of the Large Hadron Collider (LHC) to observe signatures of phenomenologically viable walking technicolor models. We study and compare the Drell-Yan and vector boson fusion mechanisms for the production of composite heavy vectors. We find that the heavy vectors are most easily produced and detected via the Drell-Yan processes. The composite Higgs phenomenology is also studied. If technicolor walks at the LHC, its footprints will be visible and our analysis will help in uncovering them.

Alexander Belyaev; Roshan Foadi; Mads T. Frandsen; Matti Järvinen; Francesco Sannino; Alexander Pukhov

2009-02-10T23:59:59.000Z

134

Next-to-leading order QCD corrections to the top quark associated with $?$ production via model-independent flavor-changing neutral-current couplings at hadron colliders  

E-Print Network (OSTI)

We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\\gamma$ production induced by model-independent $tq\\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders, respectively. We also consider the mixing effects between the $tq\\gamma$ and $tqg$ FCNC couplings for this process. Our results show that, for the $tq\\gamma$ couplings, the NLO QCD corrections can enhance the total cross sections by about 50% and 40% at the Tevatron and LHC, respectively. Including the contributions from the $tq\\gamma$, $tqg$ FCNC couplings and their mixing effects, the NLO QCD corrections can enhance the total cross sections by about 50% for the $tu\\gamma$ and $tug$ FCNC couplings, and by about the 80% for the $tc\\gamma$ and $tcg$ FCNC couplings at the LHC, respectively. Moreover, the NLO corrections reduce the dependence of the total cross section on the renormalization and factorization scale significantly. We also evaluate the NLO corrections for several important kinematic distributions.

Yue Zhang; Bo Hua Li; Chong Sheng Li; Jun Gao; Hua Xing Zhu

2011-01-27T23:59:59.000Z

135

Physicists want 1996 link-up with LHC  

Science Journals Connector (OSTI)

... lay the groundwork for a substantial US involvement from 1996 in the Large Hadron Collider (LHC) being planned by the European Laboratory for Particle Physics (CERN) in Geneva." ... Geneva."It is perfectly possible for us to provide an intellectual contribution [to the LHC] now, with the expectation of money to follow later," says George Trilling of ...

Colin Macilwain

1993-12-16T23:59:59.000Z

136

LHC upgrades could reveal whether Higgs boson is 'standard'  

Science Journals Connector (OSTI)

... . That’s the drift from the latest measurements at CERN’s Large Hadron Collider (LHC), where physicists have been carefully characterizing the new particle they discovered in 2012. ... the most recent results show no sign of such interference, the next phase of the LHC could offer new insights; it is set to start operating at higher energies in ...

Clara Moskowitz

2014-06-27T23:59:59.000Z

137

CERN asks Japan for support to build LHC  

Science Journals Connector (OSTI)

... for his country's cooperation in the construction of CERN's planned Large Hadron Collider (LHC). The move follows numerous unofficial approaches by CERN officials dating back to June 1992 ... they were "positive", and that they had covered both Japan's potential contribution to LHC construction costs and the possibility that it might be given associate membership to CERN. ...

David Swinbanks

1995-03-09T23:59:59.000Z

138

Japan is first non-CERN contributor to LHC  

Science Journals Connector (OSTI)

... 5 billion (US$60 million) towards the construction of Europe's Large Hadron Collider (LHC). Japan is the first foreign country not belonging to the European Laboratory for Particle ... country not belonging to the European Laboratory for Particle Physics (CERN) to back the LHC. The contribution in cash will be drawn from a supplementary budget of ¥2,726 ...

David Swinbanks

1995-05-18T23:59:59.000Z

139

No black holes, but extra time at LHC  

Science Journals Connector (OSTI)

... , microscopic black holes have so far failed to appear inside the Large Hadron Collider (LHC), scientists there have revealed. The result, which will be posted this week on ... be posted this week on arXiv.org, comes as researchers make plans to keep the LHC running until the end of 2012, rather than 2011 as previously scheduled. The 27 ...

Geoff Brumfiel

2010-12-14T23:59:59.000Z

140

LHC $Z^`$ discovery potential for models with continuously distributed mass  

E-Print Network (OSTI)

We study the Large Hadron Collider (LHC) discovery potential for $Z^`$ models with continuously distributed mass for $\\sqrt{s} = 7, 10$ and 14 TeV centre-of-mass energies. One of possible LHC signatures for such models is the existence of broad resonance in Drell-Yan reaction $pp \\to Z^` + ... \\to l^+l^- + ...$.

N. V. Krasnikov

2010-04-22T23:59:59.000Z

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
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141

First Results from Pb+Pb collisions at the LHC  

E-Print Network (OSTI)

At the end of 2010, the Large Hadron Collider (LHC) at CERN started operation with heavy-ion beams, colliding lead nuclei at a center-of-mass energy of 2.76 TeV per nucleon. These collisions ushered in a new era in ...

Muller, Berndt

142

Reliability of Beam Loss Monitors System for the Large Hadron Collider  

Science Journals Connector (OSTI)

The employment of superconducting magnets in high energy colliders opens challenging failure scenarios and brings new criticalities for the whole system protection. For the LHC beam loss protection system the failure rate and the availability requirements have been evaluated using the Safety Integrity Level (SIL) approach. A downtime cost evaluation is used as input for the SIL approach. The most critical systems which contribute to the final SIL value are the dump system the interlock system the beam loss monitors system and the energy monitor system. The Beam Loss Monitors System (BLMS) is critical for short and intense particle losses while at medium and higher loss time it is assisted by other systems such as the quench protection system and the cryogenic system. For BLMS hardware and software have been evaluated in detail. The reliability input figures have been collected using historical data from the SPS using temperature and radiation damage experimental data as well as using standard databases. All the data have been processed by reliability software (Isograph). The analysis ranges from the components data to the system configuration.

G. Guaglio; B. Dehning; C. Santoni

2004-01-01T23:59:59.000Z

143

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

SciTech Connect

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

Saleev, V. A., E-mail: saleev@samsu.ru; Shipilova, A. V., E-mail: alexshipilova@samsu.ru [Samara State University (Russian Federation)

2013-11-15T23:59:59.000Z

144

Reliability of the Beam Loss Monitors System for the Large Hadron Collider at CERN  

E-Print Network (OSTI)

The energy stored in the Large Hadron Collider is unprecedented. The impact of the beam particles can cause severe damage on the superconductive magnets, resulting in significant downtime for repairing. The Beam Loss Monitors System (BLMS) detects the secondary particles shower of the lost beam particles and initiates the extraction of the beam before any serious damage to the equipment can occur. This thesis defines the BLMS specifications in term of reliability. The main goal is the design of a system minimizing both the probability to not detect a dangerous loss and the number of false alarms generated. The reliability theory and techniques utilized are described. The prediction of the hazard rates, the testing procedures, the Failure Modes Effects and Criticalities Analysis and the Fault Tree Analysis have been used to provide an estimation of the probability to damage a magnet, of the number of false alarms and of the number of generated warnings. The weakest components in the BLMS have been pointed out....

Guaglio, G; Santoni, C

2005-01-01T23:59:59.000Z

145

NNLO QCD corrections to Higgs pair production via vector boson fusion at hadron colliders  

E-Print Network (OSTI)

The measurement of the Higgs pair production via vector boson fusion can be used to test the trilinear Higgs self-coupling and the $VVHH$ $(V=Z,W)$ quartic gauge interactions. In this paper we present the calculations of the next-to-next-to-leading order (NNLO) QCD corrections to the SM Higgs boson pair production via vector boson fusion at hadron colliders with the center-of-mass energy of $14~{\\rm TeV}$, $33~{\\rm TeV}$ and $100~{\\rm TeV}$ by using the structure function approach, and study the residual uncertainties from the factorization/renormalization scale, parton distribution functions and $\\alpha_s$ on the total cross section. We also provide the distributions of transverse momenta, rapidities, invariant mass and azimuthal angle separations of final products. We observe a considerable quantitative reduction in the scale uncertainty due to the NNLO QCD corrections, and find that the total cross section is sensitive to the trilinear Higgs self-coupling.

Liu-Sheng, Ling; Wen-Gan, Ma; Lei, Guo; Wei-Hua, Li; Xiao-Zhou, Li

2014-01-01T23:59:59.000Z

146

NNLO QCD corrections to Higgs pair production via vector boson fusion at hadron colliders  

E-Print Network (OSTI)

The measurement of the Higgs pair production via vector boson fusion can be used to test the trilinear Higgs self-coupling and the $VVHH$ $(V=Z,W)$ quartic gauge interactions. In this paper we present the calculations of the next-to-next-to-leading-order QCD corrections to the SM Higgs boson pair production via vector boson fusion at hadron colliders with the center-of-mass energy of $14$, $33$, and $100 {\\rm TeV}$ by using the structure function approach, and study the residual uncertainties from the factorization/renormalization scale, parton distribution functions and $\\alpha_s$ on the total cross section. We also provide the distributions of transverse momenta, rapidities, invariant mass and azimuthal angle separations of final Higgs bosons. We observe a considerable quantitative reduction in the scale uncertainty due to the next-to-next-to-leading-order QCD corrections, and find that the total cross section is sensitive to the trilinear Higgs self-coupling.

Ling Liu-Sheng; Zhang Ren-You; Ma Wen-Gan; Guo Lei; Li Wei-Hua; Li Xiao-Zhou

2014-01-30T23:59:59.000Z

147

Same-sign trileptons and four leptons as signatures of new physics at the Large Hadron Collider  

SciTech Connect

We point out that same-sign multilepton events, not given due attention yet for new physics search, can be extremely useful at the Large Hadron Collider. After showing the easy reducibility of the standard model backgrounds, we demonstrate the viability of same-sign trilepton signals for R-parity breaking supersymmetry, at both 7 and 14 TeV. We find that same-sign four-leptons, too, can have appreciable rates. Same-sign trileptons are also expected, for example, in Little Higgs theories with T-parity broken by anomaly terms.

Mukhopadhyaya, Biswarup [Regional Centre for Accelerator-based Particle Physics, Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad - 211 019 (India); Indian Association for the Cultivation of Science, Kolkata-700 032 (India); Mukhopadhyay, Satyanarayan [Regional Centre for Accelerator-based Particle Physics, Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad - 211 019 (India)

2010-08-01T23:59:59.000Z

148

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

Science Journals Connector (OSTI)

In the minimal supersymmetric extension to the standard model, a nonzero 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 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 ?111? neutrinoless double-beta-decay mechanism and others.

B. C. Allanach; C. H. Kom; H. Päs

2009-08-25T23:59:59.000Z

149

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

150

Hard Probes at LHC  

E-Print Network (OSTI)

This talk gives a theoretical perspective of the physics issues awaiting us when heavy ions will collide in the LHC.

Berndt Müller

2006-09-19T23:59:59.000Z

151

Les Houches guidebook to Monte Carlo generators for hadron collider physics  

SciTech Connect

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

152

Les Houches Guidebook to Monte Carlo generators for hadron collider physics  

SciTech Connect

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

153

Strange prospects for LHC energies  

E-Print Network (OSTI)

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

B. Hippolyte

2006-08-31T23:59:59.000Z

154

How much does the hadronic phase contribute to the observed anisotropic flow at the LHC?  

E-Print Network (OSTI)

Elliptic flow signals the presence of multiple interactions between the constituents of the created matter in heavy-ion collisions. This includes possible contributions from the different phases, including the hadronic phase. In these proceedings I will first show that the energy dependence of elliptic flow, based on recent ALICE and STAR beam energy scan measurements, can largely be understood in terms of a boosted thermal system. In addition, a detailed comparison between the identified particle elliptic flow measured by the ALICE collaboration and viscous hydrodynamical model calculations with and without a hadronic afterburner is performed to constrain the possible effects of individual hadron-hadron re-interaction cross-sections.

Snellings, Raimond

2014-01-01T23:59:59.000Z

155

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

156

Prospects for Electroweakino Discovery at a 100 TeV Hadron Collider  

E-Print Network (OSTI)

We investigate the prospects of discovering split Supersymmetry at a future 100 TeV proton-proton collider through the direct production of electroweakino next-to-lightest-supersymmetric-particles (NLSPs). We focus on signatures with multi-lepton and missing energy: $3\\ell$, opposite-sign dileptons and same-sign dileptons. We perform a comprehensive study of different electroweakino spectra. A 100 TeV collider with 3000/fb data is expected to exclude Higgsino thermal dark matter candidates with $m_{\\rm{LSP}}\\sim 1 $ TeV if Wino NLSPs are lighter than about 3.2 TeV. The $3\\ell$ search usually offers the highest mass reach, which varies in the range of (2-4) TeV depending on scenarios. In particular, scenarios with light Higgsinos have generically simplified parameter dependences. We also demonstrate that, at a 100 TeV collider, lepton collimation becomes a crucial issue for NLSPs heavier than about 2.5 TeV. We finally compare our results with the discovery prospects of gluino pair productions and deduce which ...

Gori, Stefania; Wang, Lian-Tao; Wells, James D

2014-01-01T23:59:59.000Z

157

Prospects for Electroweakino Discovery at a 100 TeV Hadron Collider  

E-Print Network (OSTI)

We investigate the prospects of discovering split Supersymmetry at a future 100 TeV proton-proton collider through the direct production of electroweakino next-to-lightest-supersymmetric-particles (NLSPs). We focus on signatures with multi-lepton and missing energy: $3\\ell$, opposite-sign dileptons and same-sign dileptons. We perform a comprehensive study of different electroweakino spectra. A 100 TeV collider with 3000/fb data is expected to exclude Higgsino thermal dark matter candidates with $m_{\\rm{LSP}}\\sim 1 $ TeV if Wino NLSPs are lighter than about 3.2 TeV. The $3\\ell$ search usually offers the highest mass reach, which varies in the range of (2-4) TeV depending on scenarios. In particular, scenarios with light Higgsinos have generically simplified parameter dependences. We also demonstrate that, at a 100 TeV collider, lepton collimation becomes a crucial issue for NLSPs heavier than about 2.5 TeV. We finally compare our results with the discovery prospects of gluino pair productions and deduce which SUSY breaking model can be discovered first by electroweakino searches.

Stefania Gori; Sunghoon Jung; Lian-Tao Wang; James D. Wells

2014-10-23T23:59:59.000Z

158

Why LHC?  

E-Print Network (OSTI)

I discuss LHC physics in the historical perspective of the progress in particle physics. After a recap of the Standard Model of particle physics, I discuss the high energy colliders leading up to LHC and their role in the discovery of these SM particles. Then I discuss the two main physics issues of LHC, i.e. Higgs mechanism and Supersymmetry. I briefly touch upon Higgs and SUSY searches at LHC along with their cosmological implications.

D. P. Roy

2010-02-16T23:59:59.000Z

159

Charged Higgs boson in the $W^\\pm$ Higgs channel at the Large Hadron Collider  

E-Print Network (OSTI)

In light of the recent discovery of a neutral Higgs boson, $H_{\\rm obs}$, with a mass near 125 GeV, we reassess the LHC discovery potential of a charged Higgs boson, $H^\\pm$, in the $W^\\pm H_{\\rm obs}$ decay channel. This decay channel can be particularly important for a $H^\\pm$ heavier than the top quark, when it is produced through the $pp \\rightarrow tH^\\pm$ process. The knowledge of the mass of $H_{\\rm obs}$ provides an additional handle in the kinematic selection when reconstructing a Breit-Wigner resonance in the $H_{\\rm obs} \\rightarrow b\\bar{b}$ decay channel. We consider some extensions of the Standard Model Higgs sector, with and without supersymmetry, and perform a dedicated signal-to-background analysis to test the scope of this channel for the LHC running at design energy (14 TeV), for 300/fb (standard) and 3000/fb (high) integrated luminosities. We find that, while this channel does not show much promise for a supersymmetric $H^\\pm$ state, significant portions of the parameter spaces of several ...

Enberg, Rikard; Moretti, Stefano; Munir, Shoaib; Wouda, Glenn

2014-01-01T23:59:59.000Z

160

Electroweak Physics at LHC  

E-Print Network (OSTI)

The Large Hadron Collider, LHC, though meant for discovery, will provide enough data from early phase to also perform various studies of Standard Model processes in as yet unexplored kinematic regions. Precision measurements of the electroweak variables will be possible due to the large rates of W and Z boson productions combined with clean leptonic signatures. Examples of simulation results from CMS and ATLAS collaboration studies are presented to show the wide variety of measurements possible and how various issues like background estimation, determination of systematic effects will be taken care of by the experiments.

Kajari Mazumdar

2008-09-09T23:59:59.000Z

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.


161

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

SciTech Connect

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

162

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

163

The ATLAS Experiment: Getting Ready for the LHC  

SciTech Connect

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

164

Reliability of Beam Loss Monitor Systems for the Large Hadron Collider  

Science Journals Connector (OSTI)

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

G. Guaglio; B. Dehning; C. Santoni

2005-01-01T23:59:59.000Z

165

Connecting LHC, ILC, and Quintessence  

E-Print Network (OSTI)

If the cold dark matter consists of weakly interacting massive particles (WIMPs), anticipated measurements of the WIMP properties at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) will provide an unprecedented experimental probe of cosmology at temperatures of order 1 GeV. It is worth emphasizing that the expected outcome of these tests may or may not be consistent with the picture of standard cosmology. For example, in kination-dominated quintessence models of dark energy, the dark matter relic abundance can be significantly enhanced compared to that obtained from freeze out in a radiation-dominated universe. Collider measurements then will simultaneously probe both dark matter and dark energy. In this article, we investigate the precision to which the LHC and ILC can determine the dark matter and dark energy parameters under those circumstances. We use an illustrative set of four benchmark points in minimal supergravity in analogy with the four LCC benchmark points. The precision achievable together at the LHC and ILC is sufficient to discover kination-dominated quintessence, under the assumption that the WIMPs are the only dark matter component. The LHC and ILC can thus play important roles as alternative probes of both dark matter and dark energy.

Daniel J. H. Chung; Lisa L. Everett; Kyoungchul Kong; Konstantin T. Matchev

2007-06-15T23:59:59.000Z

166

DOE's Office of Science Launches Website for U.S. Role at Large Hadron  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Launches Website for U.S. Role at Large Launches Website for U.S. Role at Large Hadron Collider DOE's Office of Science Launches Website for U.S. Role at Large Hadron Collider September 12, 2007 - 2:32pm Addthis U.S. scientists join international colleagues to explore universe's mysteries at world's largest scientific experiments WASHINGTON, DC - The U.S. Department of Energy's Office of Science today launched a new website to tell the story of the U.S. role in the Large Hadron Collider (LHC), a particle accelerator that will begin operating in Europe, near Geneva, Switzerland, next year. Hundreds of physicists, engineers and students from the United States are joining with colleagues from around the globe in the largest and most complex scientific experiments ever built. The LHC experiments will address some of the most

167

Precision SUSY measurements at CERN LHC  

Science Journals Connector (OSTI)

If supersymmetry exists at the electroweak scale, then it should be discovered at the CERN Large Hadron Collider (LHC). Determining masses of supersymmetric particles, however, is more difficult. In this paper, methods are discussed to determine combinations of masses and of branching ratios precisely from experimentally observable distributions. In many cases such measurements alone can greatly constrain the particular supersymmetric model and determine its parameters with an accuracy of a few percent. Most of the results shown correspond to one year of running at LHC at “low luminosity,” 1033 cm-2s-1.

I. Hinchliffe; F. E. Paige; M. D. Shapiro; J. Söderqvist; W. Yao

1997-05-01T23:59:59.000Z

168

Gravity, Cosmic Rays and the LHC  

E-Print Network (OSTI)

The high energy proton beams expected when the Large Hadron Collider (LHC) comes online should provide a pass/fail test for a gravity-related explanation of ultrahigh energy cosmic rays. The model predicts that particles have two kinds energies, equal for null gravitational potentials and, in the potential at the Earth, differing significantly above one TeV. If correct, a 7 TeV trajectory energy proton at the LHC would deliver a 23.5 TeV particle state energy in a collision.

Richard Shurtleff

2008-01-20T23:59:59.000Z

169

Search for the Standard Model Higgs Boson in the H to to lepton-hadron and hadron-hadron Decay Modes with the ATLAS Detector  

Science Journals Connector (OSTI)

Abstract In this proceeding, a search for a Higgs boson in the H to ? + ? ? decay mode, where both taus decay hadronically or one decay hadronically and one leptonically. The analysis is based on a data sample of proton-proton collision collected by the ATLAS detector at the Large Hadron Collider (LHC) at centre-of-mass energies of 7 TeV during 2011, corresponding to an integrated luminosity of 4.7 f b ? 1 . No significant excess is observed in the Higgs boson mass range of 100–150 GeV. The observed (expected) limits on the cross-section times branching ratio for H to ? + ? ? at m H = 125 GeV are 6.2(5.9) and 6.3(6.5) for lepton-hadron and hadron-hadron decay modes, respectively.

Yuki Sakurai

2014-01-01T23:59:59.000Z

170

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

171

LHC Magnet Program | Superconducting Magnet Division  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnet Program Magnet Program The Superconducting Magnet Division is building a number of dipole magnets for the Large Hadron Collider (LHC), which is now under construction at CERN in Geneva, Switzerland. Scheduled to begin operation in 2007, this machine will collide beams of protons with the unprecedented energy of 7 TeV per beam to explore the nature of matter at its most basic level (RHIC can collide beams of protons with energies of 0.25 TeV, but is mostly used to collide heavy ions with energies of 0.1 TeV per nucleon). The magnets are being built as part of the US program, recommended by the High Energy Physics Advisory Panel (HEPAP) and approved by Congress, to contribute to the construction and, later, use of that frontier machine by the US high energy physics community. Fermi National Accelerator Laboratory (FNAL) and

172

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

173

The Large Hadron Collider  

Science Journals Connector (OSTI)

...were the dream of accelerator builders in the late...radiation. Indeed, many accelerator physicists doubted that...beams at that time. The accelerator physicists learned how...directions in the single vacuum chamber of the SPS...mediators of the weak nuclear force responsible for...

2012-01-01T23:59:59.000Z

174

The Quirky Collider Signals of Folded Supersymmetry  

SciTech Connect

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

175

Impact of LSP Character on Slepton Reach at the LHC  

E-Print Network (OSTI)

Searches for supersymmetry at the Large Hadron Collider (LHC) have significantly constrained the parameter space associated with colored superpartners, whereas the constraints on color-singlet superpartners are considerably less severe. In this study, we investigate the dependence of slepton decay branching fractions on the nature of the lightest supersymmetric particle (LSP). In particular, in the Higgsino-like LSP scenarios, both decay branching fractions of $\\tilde\\ell_L$ and $\\tilde\

Jonathan Eckel; Michael J. Ramsey-Musolf; William Shepherd; Shufang Su

2014-08-12T23:59:59.000Z

176

QCD and Top Quark Physics at the LHC  

E-Print Network (OSTI)

The expected performance of the ATLAS and CMS detectors at the Large Hadron Collider (LHC) in QCD and top quark measurements is discussed, with a focus on the early data taking phase. Such processes are amongst the primary backgrounds in the searches for new physics, and thus must be understood very well before discoveries can be made. In addition, they serve as useful detector calibration candles.

Frank-Peter Schilling

2009-01-30T23:59:59.000Z

177

Some Aspects of String Cosmology and the LHC  

E-Print Network (OSTI)

I discuss some (unconventional) aspects of String Cosmology of relevance to supersymmetric dark matter searches at the Large Hadron Collider (LHC) at CERN. In particular, I analyse the role of time-dependent dilaton fields in relaxing some of the stringent constraints that characterise minimal supersymmetric models in standard cosmology. I also study briefly CPT-violating aspects of brane Universe models with space-time brane defects at early epochs and their potential relevance to the observed Baryon Asymmetry.

Nick E. Mavromatos

2012-09-30T23:59:59.000Z

178

LHC: the emptiest space in the solar system  

Science Journals Connector (OSTI)

Proton beams have been colliding at 7 TeV in the Large Hadron Collider (LHC) since 30 March 2010, meaning that the LHC research programme is underway. Particle physicists around the world are looking forward to using the data from these collisions, as the LHC is running at an energy three and a half times higher than previously achieved at any particle accelerator. There are some important questions to be answered by the LHC experiments. What is the origin of mass? What is 96% of the universe made of? Why is there no more antimatter? To avoid colliding with gas molecules inside the accelerator, the beams of particles travel in an ultra-high vacuum—a cavity as empty as interplanetary space. The internal pressure of the LHC is 10 ? 9 Pa, one hundred times less than the pressure on the Moon! The aim of this article is to introduce a few simple physical calculations about some physics phenomena related to pressure that take place in the LHC, so that they can be directly used in the secondary school classroom and stimulate the students' interest in the greatest experiment in history.

Xabier Cid-Vidal; Ramon Cid

2011-01-01T23:59:59.000Z

179

Parton distributions: HERA-Tevatron-LHC  

E-Print Network (OSTI)

The parton distribution functions (PDFs) are a non-negotiable input to almost all theory predictions at hadron colliders. In this talk, I introduce PDF determination by global analysis and discuss selected topics concerning recent relevant data from HERA and the Tevatron, before giving some prospects for the LHC. The combination of H1 and ZEUS cross sections reduces uncertainties and will be an important input to future global PDF analyses. The theoretical description of the heavy-quark contribution to structure functions at HERA has a significant influence on predictions at the LHC. New W and Z data from the Tevatron Run II provide important PDF constraints, but there are currently problems describing the latest data on the lepton charge asymmetry from W -> l nu decays. The Tevatron Run II jet production data prefer a smaller high-x gluon than the previous Run I data, which impacts on predictions for Higgs cross sections at the Tevatron. It is now possible to consistently calculate a combined "PDF+alpha_S" uncertainty on hadronic cross sections, which is around 2-3% for the W and Z total cross sections at the LHC, reflecting their potential as a "standard candle" to measure machine luminosity. Parton luminosity functions are useful quantities for studying properties of hadronic cross sections. Precision measurements at the LHC will provide further constraints on PDFs as data accumulates in the early running period.

Graeme Watt

2010-01-22T23:59:59.000Z

180

LHC Results on Charmonium in Heavy Ions  

E-Print Network (OSTI)

In heavy-ion collisions at high energies, the quantum chromodynamics (QCD) predicts the production of the deconfined quark-gluon plasma (QGP) state. Quarkonia ($c\\bar{c}$ or $b\\bar{b}$ bound states) are a useful means to probe QGP and to investigate the behavior of QCD under the high parton-density environment. Up to now, the large hadron collider (LHC) at CERN provided two runs for PbPb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV in the years 2010 and 2011. The ALICE, ATLAS, and CMS experiments at LHC have analyzed the yields and spectra of the $J/\\psi$ and $\\Upsilon$ families. In this article, we review particularly the recent charmonium results in PbPb collisions at LHC from the 2010 run.

Byungsik Hong; on behalf of the ALICE; ATLAS; CMS collaborations

2012-08-08T23:59:59.000Z

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181

First Experiences with LHC Grid Computing and Distributed Analysis  

SciTech Connect

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

Fisk, Ian

2010-12-01T23:59:59.000Z

182

Early physics with top quarks at the LHC  

E-Print Network (OSTI)

The ATLAS and CMS experiments are now in their final installation phase and will be soon ready to study the physics of proton-proton collisions at the Large Hadron Collider. The LHC, by producing 2 $t\\bar{t}$ events per second, will provide more than 8 million top events a year at start-up. In this paper, particular emphasis is given to the $t\\bar{t}$ physics studies that can be performed at the beginning of the LHC running, with a limited amount of integrated luminosity ($\\le$10 fb$^{-1}$).

Pamela Ferrari

2007-05-21T23:59:59.000Z

183

The Higgs boson in the Standard Model—From LEP to LHC: Expectations, Searches, and Discovery of a Candidate  

Science Journals Connector (OSTI)

The quest for the Higgs boson of the Standard Model, which was a cornerstone in the physics programme at particle colliders operating at the energy frontier for several decades, is the subject of this review. After reviewing the formulation of electroweak symmetry breaking via the Higgs mechanism within the Standard Model, the phenomenology of the Higgs boson at colliders and the theoretical and phenomenological constraints on the Standard Model Higgs sector are discussed. General remarks on experimental searches and the methodology of statistical interpretation are followed by a description of the phenomenology of Higgs-boson production and the corresponding precise predictions. The strategies of the experimental searches and their findings are discussed for the Large Electron Positron Collider (LEP) at CERN, the proton–antiproton collider Tevatron at Fermilab, and the proton–proton Large Hadron Collider (LHC) at CERN. The article concludes with the description of the observation of a Higgs-like boson at the LHC.

S. Dittmaier; M. Schumacher

2013-01-01T23:59:59.000Z

184

LHC Physics Center | (none)  

NLE Websites -- All DOE Office Websites (Extended Search)

Physics Center Physics Center Fermilab Home Visit LPC Physics Programs LPC Guest and Visitors HATS@LPC, Workshops and CMSDAS Jet-Substructure HATS CMS Data Analysis School 2013 CMS Data Analysis School 2012 CMS Data Analysis School 2011 EJTERM (CMS Data Analysis School 2010) Confronting Theory with Experiment: November 2011 Standard Model Benchmarks at the Tevatron and LHC Standard Model Benchmarks at High-Energy Hadron Colliders GED workshop 20-22 Aug, 2012 Topic of the Week Upcoming Past Speakers Archive Program Info LPC Physics Forum LPC Snowmass Efforts The INFIERI Project Fellows LPC Fellows Program Newsletter - LPC Fellows LPC Fellows - 2014 LPC Fellows - 2013 LPC Fellows - 2012 LPC Fellows - 2011 Community Faces of the LPC LPC Fellows - Current LPC Coffee Hour Calendar LPC Conf. Room Calendar

185

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

186

The LHC Superconducting RF System  

E-Print Network (OSTI)

The European Laboratory for Particle Physics (CERN), the largest high energy physics laboratory worldwide, is constructing the Large Hadron Collider (LHC) in the existing 27 km circumference LEP (Large Electron Positron) collider tunnel. For the LHC, superconducting cavities, operating at 4.5 K, will provide the required acceleration field for ramping the beam energy up to 7 TeV and for keeping the colliding proton beams tightly bunched. Superconducting cavities were chosen, not only because of their high acceleration field leading to a small contribution to the machine impedance, but also because of their high stored energy which minimises the effects of periodic transient beam loading associated with the high beam intensity (0.5 A). There will be eight single-cell cavities per beam, each delivering 2 MV (5.3 MV/m) at 400 MHz. The cavities themselves are now being manufactured by industrial firms, using niobium on copper technology which gives full satisfaction at LEP. A complete cavity prototype assembly in...

Boussard, Daniel

1999-01-01T23:59:59.000Z

187

Charm and beauty at the LHC  

E-Print Network (OSTI)

The Large Hadron Collider at CERN will open a new energy domain for heavy-ion physics. Besides ALICE, the dedicated heavy-ion experiment, also ATLAS and CMS are preparing rich physics programs with nucleus-nucleus collisions. Here we focus on open heavy-flavour and quarkonia studies, among the fields that will most benefit from the high centre-of-mass energy at the LHC. We discuss a few examples of physics issues that can be addressed and we present a selection and comparison (where possible) of results on the expected capability of the three experiments.

Andrea Dainese

2006-09-27T23:59:59.000Z

188

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

189

Press Pass - Press Release - U.S. LHC first beam  

NLE Websites -- All DOE Office Websites (Extended Search)

8-15 8-15 Aug. 8, 2008 For immediate release Media Contacts: Brookhaven National Laboratory - Kendra Snyder, ksnyder@bnl.gov, 631-344-8191 Fermilab - Judy Jackson, 630-840-3351, jjackson@fnal.gov Lawrence Berkeley National Laboratory - Dan Krotz, dakrotz@lbl.gov, (510) 486-4019 and Paul Preuss, paul_preuss@lbl.gov, 510-486-6249 CERN - James Gillies, james.gillies@cern.ch, +41 22 767 4101 Photos and graphics of the Large Hadron Collider are available at: http://multimedia-gallery.web.cern.ch/multimedia-gallery/PhotoGallery_Main.aspx and http://www.uslhc.us/Images. U.S. scientists count down to LHC startup Batavia, IL, Berkeley, CA and Upton, NY - On September 10, scientists at the Large Hadron Collider will attempt for the first time to send a proton beam zooming around the 27-kilometer-long accelerator. The LHC, the world's most powerful particle accelerator, is located at CERN in Geneva, Switzerland. Journalists are invited to attend LHC first beam events at CERN and several locations within the United States. Information about the CERN event and accreditation procedures is available at . A list of LHC startup events in the U.S. and contact information for each is available at http://www.uslhc.us/first_beam.

190

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

191

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

192

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

193

Quark-lepton symmetric model at the LHC  

Science Journals Connector (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 color” 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 ±1/2 exotic leptons, and a color 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

2012-04-10T23:59:59.000Z

194

Comparison of discovery limits for extra Z bosons at future colliders  

Science Journals Connector (OSTI)

We study and compare the discovery potential for heavy neutral gauge bosons (Z’) at various e+e- and pp(-) colliders that are planned or have been proposed. Typical discovery limits are for the Fermilab Tevatron ?1 TeV, Di-Tevatron ?2 TeV, CERN LHC ?4 TeV, LSGNA (a 60 TeV pp collider) ?13 TeV while the e+e- discovery limits are 2–10× ?s with the large variation reflecting the model dependence of the limits. While both types of colliders have comparable discovery limits the hadron colliders are generally less dependent on the specific Z’ model and provide more robust limits since the signal has little background. In contrast, discovery limits for e+e- limits are more model dependent and, because they are based on indirect inferences of deviations from standard model predictions, they are more sensitive to systematic errors.

Stephen Godfrey

1995-02-01T23:59:59.000Z

195

Overview of Triple and Quartic Gauge Coupling Measurements at the LHC  

E-Print Network (OSTI)

Scrutiny of the structure of electroweak gauge boson self-interactions through triple and quartic gauge boson couplings (TGCs and QGCs) constitutes an important part of the physics program of the Large Hadron Collider (LHC). Triboson production and vector boson scattering (VBS) are directly sensitive to QGCs while vector boson fusion (VBF) offers a new window in the study of TGCs, which is complementary to conventional measurements using diboson production. In this contribution, an overview of recent TGC and QCG measurements using triboson production, VBS and VBF by the ATLAS and CMS experiments at the LHC is presented.

Takashi Kubota

2014-08-28T23:59:59.000Z

196

LHC challenges and upgrade options  

Science Journals Connector (OSTI)

The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex.

O Bruning

2008-01-01T23:59:59.000Z

197

Supersymmetry at and beyond the LHC  

E-Print Network (OSTI)

Prospects for SUSY discoveries and measurements at future colliders LHC and ILC are discussed. The problem of reconstructing the underlying theory and SUSY breaking mechanism is also addressed.

Jan Kalinowski

2008-04-17T23:59:59.000Z

198

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

SciTech Connect

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

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

2006-11-01T23:59:59.000Z

199

First Results of the LHC Longitudinal Density Monitor  

SciTech Connect

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

200

LINEAR COLLIDER PHYSICS RESOURCE BOOK FOR SNOWMASS 2001.  

SciTech Connect

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

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201

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

SciTech Connect

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

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

2011-09-01T23:59:59.000Z

202

Torsion phenomenology at the CERN LHC  

Science Journals Connector (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.

A. S. Belyaev; I. L. Shapiro; M. A. B. do Vale

2007-02-23T23:59:59.000Z

203

Studies of RF Noise Induced Bunch Lengthening at the LHC  

SciTech Connect

Radio Frequency (RF) noise induced bunch lengthening can strongly affect the Large Hadron Collider (LHC) performance through luminosity reduction, particle loss, and other effects. This work presents measurements from the LHC that better quantify the relationship between the RF noise and longitudinal emittance blowup and identify the performance limiting RF components. The experiments presented in this paper confirmed the predicted effects on the LHC bunch length growth. Dedicated measurements were conducted in the LHC to gain insight in the effect of RF noise to the longitudinal beam diffusion. It was evident that the growth rate of the bunch length is strongly related to the accelerating voltage phase noise power spectral density around f{sub s} + kf{sub rev}, as predicted in [4]. The noise threshold for 2.5 ps/hr growth was estimated to -101 dBc/Hz (SSB flat noise spectral density from f{sub s} to the edge of the closed loop bandwidth). A 9 dB margin is achieved with the current RF configuration and the BPL on. With this formalism it is now possible to estimate the effect of different operational and technical RF configurations on the LHC beam diffusion. This formalism could also be useful for the design of future RF systems and the budgeting of the allowed noise.

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

2011-08-17T23:59:59.000Z

204

From the LHC Reference Database to the Powering Interlock System  

E-Print Network (OSTI)

The protection of the magnet powering system for the Large Hadron Collider (LHC) currently being built at CERN is a major challenge due to the unprecedented complexity of the accelerator. The Powering Interlock System of the LHC will have to manage more than 1600 DC circuits for magnet powering, different in their structure, complexity and importance to the accelerator. For the coherent description of such complex system, a Reference Database as unique source of the parameters of the electrical circuits has been developed. The information, introduced via a generic circuit description language, is first used for installing the accelerator and making all electrical connections. The data is then used for tests and commissioning. During operation, the Powering Interlock System manages all critical functions. It consists of 36 PLC based controllers dis tributed around the machine and requires a flexible and transparent way of configuration, since each controller manages different numbers and types of electrical ci...

Dehavay, C; Schmidt, R; Veyrunes, E; Zerlauth, M

2003-01-01T23:59:59.000Z

205

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

206

Neutral Higgs Boson Pair Production in Standard Model with the Fourth Generation Quarks at LHC  

Science Journals Connector (OSTI)

We investigated the neutral Higgs boson pair production at the CERN Large Hadron Collider (LHC) in the SM with four families. We found that the gluon-gluon fusion mode is the most dominant one in producing neutral Higgs boson pair at the LHC, and it can be used to probe the trilinear Higgs coupling. If the heavy quarks of the fourth generation really exist within the SM, they can manifest their effect on the cross section of the Higgs pair production process at the LHC. Our numerical results show that there will be neutral Higgs boson pair production events per year if the next generation heavy quarks really exist, while there will be only events produced per year if there are only three families in the SM.

Sun Hao; Ma Wen-Gan; Zhou Ya-Jin; Sun Yan-Bin; Zhang Ren-You; Hou Hong-Sheng

2004-01-01T23:59:59.000Z

207

Towards the NNPDF3.0 parton set for the second LHC run  

E-Print Network (OSTI)

The full exploitation of the increasingly precise LHC measurements is essential in order to reduce the uncertainty of theoretical predictions at hadron colliders. The NNPDF2.3 fit was the first PDF determination including the effect of the early LHC data. Here the new NNPDF3.0 PDF set is announced and its main features are presented. The novel NNPDF analysis is based on an improved fitting methodology, statistically validated by closure tests. Over a thousand new data points are included, both the recent HERA II measurements and a wide set of new LHC data. In this contribution details on the experimental data are given and their impact on PDF uncertainties is displayed.

Maria Ubiali

2014-07-11T23:59:59.000Z

208

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

209

Production of stoponium at the LHC  

Science Journals Connector (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 ?? 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

2014-04-07T23:59:59.000Z

210

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

211

Heavy quark production in the black hole evaporation at LHC  

SciTech Connect

The understanding of Quantum Chromodynamics (QCD) and Quantum Gravity are currently two of the main open questions in Physics. In order to understand these problems some authors proposed the existence of extra dimensions in the Nature. These extra dimensions would be compacted and not visible on the macroscopic world, but the effects would be manifest in ultrarelativistic colision process. In particular, black holes (BH) could be produced in proton-proton colisions in the Large Hadron Collider (LHC) and in future colliders. The BH is an object characterized by its mass and temperature wich also characterizes the evaporation process. All kind of particle should be produced in this process. Our goal in this contribution is to study the BH production in proton - proton collisions at LHC and its evaporation rate in heavy quarks. We present our estimate considering two scenarios (with and without trapped energy corrections) and compare our predictions with those obtained using perturbative QCD. Our results demonstrate that in both scenarios the charm and bottom production in the BH evaporation are smaller than the QCD prediction at LHC. In contrast, the top production is similar or larger than the QCD prediction, if the trapped energy corrections are disregarded.

Thiel, M.; Goncalves, V. P.; Sauter, W. K. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas (Brazil)

2013-03-25T23:59:59.000Z

212

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

213

A New Boson with a Mass of 125 GeV Observed with the CMS Experiment at the Large Hadron Collider  

Science Journals Connector (OSTI)

...comprises three different types of gas-ionization detectors that enable muon momenta...and the other into hadrons. A natural process to calibrate the analysis...and Technology, and National Natural Science Foundation of China...Research Promotion Foundation, Cyprus; the Ministry of Education...

The CMS Collaboration

2012-12-21T23:59:59.000Z

214

Heavy-ion collisions at the LHC  

Science Journals Connector (OSTI)

Abstract A new era in the study of high-energy nuclear collisions began when the CERN Large Hadron Collider (LHC) provided the first collisions of lead nuclei in late 2010. In the first three years of operation the ALICE, ATLAS and CMS experiments each collected Pb–Pb data samples of more than 50 ? b ? 1  at s NN = 2.76 TeV , exceeding the previously studied collision energies by more than an order of magnitude. These data have provided new insights into the properties of QCD matter under extreme conditions, with extensive measurements of soft particle production and newly accessible hard probes of the hot and dense medium. In this review, we provide a comprehensive overview of the results obtained in heavy-ion collisions at the LHC so far, with particular emphasis on the complementary nature of the observations by the three experiments. In particular, the combination of ALICE’s strengths at hadron identification, the strengths of ATLAS and CMS to make precise measurements of high p T  probes, and the resourceful measurements of collective flow by all of the experiments have provided a rich and diverse dataset in only a few years. While the basic paradigm established at RHIC — that of a hot, dense medium that flows with a viscosity to shear-entropy ratio near the predicted lower bound, and which degrades the energy of probes, such as jets, heavy-flavours and J / ? — is confirmed at the LHC, the new data suggest many new avenues for extracting its properties in detail.

G. Roland; K. Šafa?ík; P. Steinberg

2014-01-01T23:59:59.000Z

215

Supersymmetry Searches at the LHC  

E-Print Network (OSTI)

The search for Beyond the Standard Model (BSM) physics is one of the major tasks of the LHC, CERN. In these proceedings, I review the status of searches for Supersymmetry by the ATLAS and CMS collaborations. The efforts in both the hadronic and leptonic search channels are presented. A special focus is placed on the treatment of approximately one inverse femtobarn of early LHC data, and examples of background estimation techniques in such a dataset are given. Phenomenologically, besides "typical" mSUGRA scenarios, signatures based on prompt and non-pointing photons, as well as long-lived leptons and hadrons (R-hadrons) are covered.

Oleg Brandt

2008-08-21T23:59:59.000Z

216

Towards a Muon Collider  

SciTech Connect

A multi TeV Muon Collider is required for the full coverage of Terascale physics. The physics potential for a Muon Collider at {approx}3 TeV and integrated luminosity of 1 ab{sup -1} is outstanding. Particularly strong cases can be made if the new physics is SUSY or new strong dynamics. Furthermore, a staged Muon Collider can provide a Neutrino Factory to fully disentangle neutrino physics. If a narrow s-channel resonance state exists in the multi-TeV region, the physics program at a Muon Collider could begin with less than 10{sup 31} cm{sup -2} s{sup -1} luminosity. Detailed studies of the physics case for a 1.5-4 TeV Muon Collider are just beginning. The goals of such studies are to: (1) identify benchmark physics processes; (2) study the physics dependence on beam parameters; (3) estimate detector backgrounds; and (4) compare the physics potential of a Muon Collider with those of the ILC, CLIC and upgrades to the LHC.

Eichten, E.; /Fermilab

2011-08-01T23:59:59.000Z

217

LHC Physics and Cosmology  

E-Print Network (OSTI)

In these Lectures I review possible constraints on particle physics models, obtained by means of combining the results of collider measurements with astrophysical data. I emphasize the theoretical-model dependence of these results. I discuss supersymmetric dark matter constraints at colliders (mainly LHC) in various theoretical contexts: the standard Cosmological-Constant-Cold-Dark-Matter (Lambda-CDM) model, (super)string-inspired ones and non-equilibrium relaxation dark energy models. I then investigate the capability of LHC measurements in asserting whether supersymmetric matter (if discovered) constitutes part, or all, of the astrophysical dark matter. I also discuss prospects for improving the constraints in future precision facilities, such as the International Linear Collider.

Nikolaos E. Mavromatos

2007-08-01T23:59:59.000Z

218

Parton distribution function dependence of benchmark Standard Model total cross sections at the 7 TeV LHC  

E-Print Network (OSTI)

We compare predictions for the W, Z, gg->H and t-tbar total cross sections at the Large Hadron Collider (LHC), for a centre-of-mass energy of 7 TeV, using the most recent publicly available next-to-leading order and next-to-next-to-leading order parton distribution functions (PDFs) from all PDF fitting groups. In particular, we focus on the dependence on the different values of the strong coupling, alpha_S(M_Z^2), used by each group. We also perform a comparison of the relevant quark-antiquark and gluon-gluon luminosity functions. We make some comments on the recent PDF4LHC recommendations. Finally, we discuss the comparison of data and theory for W and Z cross sections at the LHC.

Watt, G

2011-01-01T23:59:59.000Z

219

Parton distribution function dependence of benchmark Standard Model total cross sections at the 7 TeV LHC  

E-Print Network (OSTI)

We compare predictions for the W, Z, gg->H and t-tbar total cross sections at the Large Hadron Collider (LHC), for a centre-of-mass energy of 7 TeV, using the most recent publicly available next-to-leading order and next-to-next-to-leading order parton distribution functions (PDFs) from all PDF fitting groups. In particular, we focus on the dependence on the different values of the strong coupling, alpha_S(M_Z^2), used by each group. We also perform a comparison of the relevant quark-antiquark and gluon-gluon luminosity functions. We make some comments on the recent PDF4LHC recommendations. Finally, we discuss the comparison of data and theory for W and Z cross sections at the LHC.

G. Watt

2011-06-28T23:59:59.000Z

220

High energy beam impact tests on a LHC tertiary collimator at the CERN high-radiation to materials facility  

Science Journals Connector (OSTI)

The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC). The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat) facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

Marija Cauchi; O. Aberle; R.?W. Assmann; A. Bertarelli; F. Carra; K. Cornelis; A. Dallocchio; D. Deboy; L. Lari; S. Redaelli; A. Rossi; B. Salvachua; P. Mollicone; N. Sammut

2014-02-24T23:59:59.000Z

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221

Search for the minimal universal extra dimension model at the LHC with s=7??TeV  

Science Journals Connector (OSTI)

The Universal Extra Dimension (UED) model is one of the popular extension of the standard model (SM) which offers interesting phenomenology. In the minimal UED (mUED) model, Kaluza-Klein (KK) parity conservation ensures that n=1 KK states can only be pair produced at colliders and the lightest KK particle is stable. In most of the parameter space, first KK excitation of SM hypercharge gauge boson is the lightest one and it can be a viable dark matter candidate. Thus, the decay of n=1 KK particles will always involve missing transverse energy (ET) as well as leptons and jets. The production cross sections of n=1 KK particles are large and such particles may be observed at the Large Hadron Collider (LHC). We explore the mUED discovery potential of the LHC with s=7??TeV in the multileptonic final states. Since in the early LHC run, precise determination of ET may not be possible, we examine the LHC reach with and without using ET information. We observe that ET cut will not improve mUED discovery reach significantly. We have found that opposite-sign di-lepton channel is the most promising discovery mode and with first fb-1 of collected luminosity, LHC will be able to discover the strongly interacting n=1 KK particles with masses up to 800?900??GeV.

Biplob Bhattacherjee and Kirtiman Ghosh

2011-02-02T23:59:59.000Z

222

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

223

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.

Mangano, Michelangelo

2014-01-01T23:59:59.000Z

224

LHC Nobel Symposium Proceedings  

Science Journals Connector (OSTI)

In the summer of 2012, a great discovery emerged at the Large Hadron Collider (LHC) at CERN in Geneva. A plethora of new precision data had already by then been collected by the ATLAS and CMS experiments at LHC, providing further extensive support for the validity of the Standard Model of particle physics. But what now appeared was the first evidence for what was not only the last unverified prediction of the Standard Model, but also perhaps the most decisive one: the prediction made already in 1964 of a unique scalar boson required by the theory of François Englert and Peter Higgs on how fundamental particles acquire mass. At that moment in 2012, it seemed particularly appropriate to start planning a gathering of world experts in particle physics to take stock of the situation and try to answer the challenging question: what next? By May 2013, when the LHC Nobel Symposium was held at the Krusenberg Mansion outside Uppsala in Sweden, the first signs of a great discovery had already turned into fully convincing experimental evidence for the existence of a scalar boson of mass about 125 GeV, having properties compatible with the 50-year-old prediction. And in October 2013, the evidence was deemed so convincing that the Swedish Royal Academy of Sciences awarded the Nobel Prize in Physics to Englert and Higgs for their pioneering work. At the same time the search at the LHC for other particles, beyond those predicted by the Standard Model, with heavier masses up to—and in some cases beyond—1 TeV, had provided no positive result. The triumph of the Standard Model seems resounding, in particular because the mass of the discovered scalar boson is such that, when identified with the Higgs boson, the Standard Model is able to provide predictions at energies as high as the Planck mass, although at the price of accepting that the vacuum would be metastable. However, even if there were some feelings of triumph, the ambience at the LHC Nobel Symposium was more one of puzzlement. The apparent absence of hints in the LHC experimental data of new phenomena that could relate to dark matter, dark energy, the dominance of matter over antimatter in the Universe, the unification of the strong and the electroweak interactions and their further unification with gravity left the Symposium with no guidance as to how to answer the question: what next? And in experimental fundamental science it is not the confirmation of already established theories that thrills the most; it is the appearance of the unexpected that creates the greatest excitement. However, the LHC is only at the beginning of its voyage into the uncharted territories of higher energies and smaller dimensions that it was built for, so the possibilities for unexpected discoveries are only starting to be explored. The LHC will start up again in 2015 with nearly twice its previous energy and with increased luminosity—new discoveries might then appear sooner than we even dare hope for! The LHC Nobel Symposium was attended by about 60 invited participants and lasted four days. The program was divided into seven sessions; QCD and Heavy Ion Physics, B Physics, Electroweak Physics, The Higgs Boson, Connections to Neutrino Physics and Astroparticle Physics, Beyond the Standard Model and Forward Look. There were 27 plenary invited talks given by participants, each followed by lively discussions. All but one of the speakers have submitted write-ups of their talks for these proceedings. We are hopeful that the remaining talk will be published in a forthcoming issue of Physica Scripta . I am gratified that Professor Roland Allen has agreed to write a paper on the essence of the Higgs boson discovery to be published in Physica Scripta , intended for undergraduate students and educated physicists, regardless of their field of research. I wish to express my deep gratitude to all Speakers and Participants in the Symposium, to the Members of the Local and International Organizing Committees, to the referees of these Proceedings and to the staff at Uppsala University, in particular my Adminis

Tord Ekelöf

2013-01-01T23:59:59.000Z

225

The LHC String Hunter's Companion  

E-Print Network (OSTI)

The mass scale of fundamental strings can be as low as few TeV/c^2 provided that spacetime extends into large extra dimensions. We discuss the phenomenological aspects of weakly coupled low mass string theory related to experimental searches for physics beyond the Standard Model at the Large Hadron Collider (LHC). We consider the extensions of the Standard Model based on open strings ending on D-branes, with gauge bosons due to strings attached to stacks of D-branes and chiral matter due to strings stretching between intersecting D-branes. We focus on the model-independent, universal features of low mass string theory. We compute, collect and tabulate the full-fledged string amplitudes describing all 2->2 parton scattering subprocesses at the leading order of string perturbation theory. We cast our results in a form suitable for the implementation of stringy partonic cross sections in the LHC data analysis. The amplitudes involving four gluons as well as those with two gluons plus two quarks do not depend on the compactification details and are completely model-independent. They exhibit resonant behavior at the parton center of mass energies equal to the masses of Regge resonances. The existence of these resonances is the primary signal of string physics and should be easy to detect. On the other hand, the four-fermion processes like quark-antiquark scattering include also the exchanges of heavy Kaluza-Klein and winding states, whose details depend on the form of internal geometry. They could be used as ``precision tests'' in order to distinguish between various compactification scenarios.

Dieter Lust; Stephan Stieberger; Tomasz R. Taylor

2008-07-22T23:59:59.000Z

226

Scalar neutrinos at the LHC  

Science Journals Connector (OSTI)

We study a softly broken supersymmetric model whose gauge symmetry is that of the standard model gauge group times an extra Abelian symmetry U(1)?. We call this gauge-extended model the U(1)? model, and we study a U(1)? model with a secluded sector such that neutrinos acquire Dirac masses via higher-dimensional terms allowed by the U(1)? invariance. In this model the ? term of the minimal supersymmetric model (MSSM) is dynamically induced by the vacuum expectation value of a singlet scalar. In addition, the model contains exotic particles necessary for anomaly cancellation, and extra singlet bosons for achieving correct Z?/Z mass hierarchy. The neutrinos are charged under U(1)?, and thus, their production and decay channels differ from those in the MSSM in strength and topology. We implement the model into standard packages and perform a detailed analysis of sneutrino production and decay at the Large Hadron Collider, for various mass scenarios, concentrating on three types of signals: (1) 0?+MET, (2) 2?+MET, and (3) 4?+MET. We compare the results with those of the MSSM whenever possible, and analyze the standard model background for each signal. The sneutrino production and decays provide clear signatures enabling distinction of the U(1)? model from the MSSM at the LHC.

Durmu? A. Demir; Mariana Frank; Levent Selbuz; Ismail Turan

2011-05-03T23:59:59.000Z

227

Comparison of Black Hole Generators for the LHC  

E-Print Network (OSTI)

We compare Monte Carlo event generators dedicated to simulating the production and decay of extra-dimensional black holes at the Large Hadron Collider.

Douglas M. Gingrich

2006-10-17T23:59:59.000Z

228

Parton distributions: HERA-Tevatron-LHC  

E-Print Network (OSTI)

The parton distribution functions (PDFs) are a non-negotiable input to almost all theory predictions at hadron colliders. In this talk, I introduce PDF determination by global analysis and discuss selected topics concerning recent relevant data from HERA and the Tevatron, before giving some prospects for the LHC. The combination of H1 and ZEUS cross sections reduces uncertainties and will be an important input to future global PDF analyses. The theoretical description of the heavy-quark contribution to structure functions at HERA has a significant influence on predictions at the LHC. New W and Z data from the Tevatron Run II provide important PDF constraints, but there are currently problems describing the latest data on the lepton charge asymmetry from W -> l nu decays. The Tevatron Run II jet production data prefer a smaller high-x gluon than the previous Run I data, which impacts on predictions for Higgs cross sections at the Tevatron. It is now possible to consistently calculate a combined "PDF+alpha_S" u...

Watt, Graeme

2009-01-01T23:59:59.000Z

229

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

230

Large Cryogenic Infrastructure for LHC Superconducting Magnet and Cryogenic Component Tests: Layout, Commissioning and Operational Experience  

SciTech Connect

The largest cryogenic test facility at CERN, located at Zone 18, is used to validate and to test all main components working at cryogenic temperature in the LHC (Large Hadron Collider) before final installation in the machine tunnel. In total about 1300 main dipoles, 400 main quadrupoles, 5 RF-modules, eight 1.8 K refrigeration units will be tested in the coming years.The test facility has been improved and upgraded over the last few years and the first 18 kW refrigerator for the LHC machine has been added to boost the cryogenic capacity for the area via a 25,000 liter liquid helium dewar. The existing 6 kW refrigerator, used for the LHC Test String experiments, will also be employed to commission LHC cryogenic components.We report on the design and layout of the test facility as well as the commissioning and the first 10,000 hours operational experience of the test facility and the 18 kW LHC refrigerator.

Calzas, C.; Chanat, D.; Knoops, S.; Sanmarti, M.; Serio, L. [Accelerator Technology Division, CERN, 1211 Geneva 23 (Switzerland)

2004-06-23T23:59:59.000Z

231

High throughput lessons from the LHC experience.Johnston.TNC2013  

NLE Websites -- All DOE Office Websites (Extended Search)

high throughput in widely distributed data high throughput in widely distributed data management and analysis systems: Lessons from the LHC William E. Johnston ESnet, Lawrence Berkeley National Laboratory e-mail: wej@es.net Eli Dart ESnet, Lawrence Berkeley National Laboratory e-mail: dart@es.net Michael Ernst RHIC and ATLAS Computing Facility, Brookhaven National Laboratory e-mail: mernst@bnl.gov Brian Tierney ESnet, Lawrence Berkeley National Laboratory e-mail: bltierney@es.net Paper type Technical paper Abstract Today's large-scale science projects all involve world-wide collaborations that must routinely move 10s of petabytes per year between international sites in order to be successful. This is true for the two largest experiments at the Large Hadron Collider (LHC) at CERN - ATLAS and CMS - and for the climate science

232

Light stop searches at the LHC in events with two b jets and missing energy  

Science Journals Connector (OSTI)

We propose a new method to discover light top squarks (stops) in the co-annihilation region at the Large Hadron Collider (LHC). The bino-like neutralino is the lightest supersymmetric particle (LSP) and the lighter stop is the next-to-LSP. Such scenarios can be consistent with electroweak baryogenesis and also with dark matter constraints. We consider the production of two stops in association with two b-quarks, including pure QCD as well as mixed electroweak-QCD contributions. The stops decay into a charm quark and the LSP. For a higgsino-like light chargino, the electroweak contributions can exceed the pure QCD prediction. We show the size of the electroweak contributions as a function of the stop mass and present the LHC discovery reach in the stop-neutralino mass plane.

S. Bornhauser; M. Drees; S. Grab; J. S. Kim

2011-02-15T23:59:59.000Z

233

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

234

Development of Aluminium Vacuum Chambers for the LHC Experiments at CERN  

E-Print Network (OSTI)

Beam losses may cause activation of vacuum chamber walls, in particular those of the Large Hadron Collider (LHC) experiments. For the High Luminosity (HL-LHC), the activation of such vacuum chambers will increase. It is therefore necessary to use a vacuum chamber material which interacts less with the circulating beam. While beryllium is reserved for the collision point, a good compromise between cost, availability and transparency is obtained with aluminium alloys; such materials are a preferred choice with respect to austenitic stainless steel. Manufacturing a thin-wall aluminium vacuum chamber presents several challenges as the material grade needs to be machinable, weldable, leak-tight for small thicknesses, and able to withstand heating to 250°C for extended periods of time. This paper presents some of the technical challenges during the manufacture of these vacuum chambers and the methods for overcoming production difficulties, including surface treatments and Non-Evaporable Getter (NEG) thin-film coat...

Gallilee, M; Costa-Pinto, P; Lepeule, P; Perez-Espinos, J; Marques Antunes Ferreira, L; Prever-Loiri, L; Sapountzis, A

2014-01-01T23:59:59.000Z

235

Radion production at LHC via the process of vector-boson fusion  

SciTech Connect

The possibility of observing the radion in the process of vector-boson fusion at the Large Hadron Collider (LHC) in proton-proton collisions at the c.m. energy of {radical}s = 14 TeV is studied. A region of kinematical variables where background processes can be suppressed substantially and where the process in which the production of a radion is followed by its decay to two Z bosons can be separated is found. It is shown that the radion could be discovered in the process under study at an energy scale of up to 0.75 TeV at the LHC luminosity of L = 300 fb{sup -1}.

Konoplich, R. V. [New York University, Department of Physics (United States)] [New York University, Department of Physics (United States); Rubin, S. G.; Svadkovsky, I. V., E-mail: igor_svadkovsky@mail.ru [National Research Nuclear University MEPhI (Russian Federation)

2013-04-15T23:59:59.000Z

236

Validation of Geant4 Hadronic Generators versus Thin Target Data  

SciTech Connect

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

237

Heavy Color-Octet Particles at the LHC  

E-Print Network (OSTI)

Many new-physics models, especially those with a color-triplet top-quark partner, contain a heavy color-octet state. The "naturalness" argument for a light Higgs boson requires that the color-octet state be not much heavier than a TeV, and thus it can be pair-produced with large cross sections at high-energy hadron colliders. It may decay preferentially to a top quark plus a top-partner, which subsequently decays to a top quark plus a color-singlet state. This singlet can serve as a WIMP dark-matter candidate. Such decay chains lead to a spectacular signal of four top quarks plus missing energy. We pursue a general categorization of the color-octet states and their decay products according to their spin and gauge quantum numbers. We review the current bounds on the new states at the LHC and study the expected discovery reach at the 8-TeV and 14-TeV runs. We also present the production rates at a future 100-TeV hadron collider, where the cross sections will be many orders of magnitude greater than at the 14-Te...

Chen, Chien-Yi; Han, Tao; Lee, Keith S M

2014-01-01T23:59:59.000Z

238

Topological interactions in the Higgsless model at the LHC  

Science Journals Connector (OSTI)

Topological quantum interactions, namely, Chern-Simons terms and global Wess-Zumino terms, arise naturally in theories with extra dimensions of space compactified on orbifolds. If the extra dimensions become manifest at the TeV scale, experiments at the Large Hadron Collider (LHC) could observe signatures of topological interactions. Decays of Kaluza-Klein excitations of neutral electroweak gauge bosons into pairs of neutral standard model gauge bosons, Z0Z0 and Z0?, would provide a clean signature, since such decays do not occur at tree level. In this paper, we investigate the prospects for discovering such decays at the LHC, in the context of the Higgsless model of electroweak symmetry breaking. We identify the form of the relevant topological interactions, and estimate their strength. We find that in the minimal version of the model, the signal may be observed with about 100??fb-1 of data at the LHC using the Drell-Yan production process of the Kaluza-Klein gauge bosons. In addition, it is likely that the ultraviolet completion of the model would contain additional massive fermions, which can significantly enhance the signal. With two additional fermion multiplets, observation of the topological decay modes at the 3-sigma level would be possible with about 100??fb-1 of data using the highly model-independent vector-boson fusion production channel.

Maxim Perelstein and Yong-Hui Qi

2010-07-12T23:59:59.000Z

239

Searches for New Physics at the Tevatron and LHC  

SciTech Connect

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

240

Ionisation Chambers for the LHC Beam Loss Detection  

E-Print Network (OSTI)

At the Large Hadron Collider (LHC) a beam loss system will be used to prevent and protect superconducting magnets against coil quenches and coil damages. Since the stored particle beam intensity is 8 orders of magnitude larger than the lowest quench level value particular attention is paid to the design of the secondary particle shower detectors. The foreseen ionisation chambers are optimised in geometry simulating the probable loss distribution along the magnets and convoluting the loss distribution with the secondary particle shower distributions. To reach the appropriate coverage of a particle loss and to determine the quench levels with a relative accuracy of 2 the number of the detectors and their lengths is weighted against the particle intensity density variation. In addition attention is paid to the electrical ionisation chamber signal to minimise the ion tail extension. This optimisation is based on time resolved test measurements in the PS booster. A proposal for a new ionisation chamber will be pre...

Gschwendtner, E; Dehning, B; Ferioli, G; Kain, V

2003-01-01T23:59:59.000Z

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241

First Beam Measurements with the LHC Synchrotron Light Monitors  

SciTech Connect

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

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

2012-07-13T23:59:59.000Z

242

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

243

Heavy Ion Collisions at the LHC - Last Call for Predictions  

SciTech Connect

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

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

2008-02-25T23:59:59.000Z

244

Muon Collider: Plans, Progress and Challenges  

E-Print Network (OSTI)

We in the physics community expect the LHC to uncover new physics in the next few years. The character and energy scale of the new physics remain unclear, but it is likely that data from the LHC will need to be complemented by information from a lepton collider which can provide for precise examination of new phenomena. We describe the concept, accelerator design, and detector R&D for a high energy Muon Collider as well as the challenges associated with the machine and its detector environment.

Lipton, Ronald

2012-01-01T23:59:59.000Z

245

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.

246

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

SciTech Connect

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

247

Lightest supersymmetric particle stability and new Higgs signals at the LHC  

Science Journals Connector (OSTI)

The fate of R-parity in the context of the minimal supersymmetric standard model is a central issue which has profound implications for particle physics and cosmology. In this article, we discuss the possibility of testing the mechanism responsible for the stability of the lightest supersymmetric particle at the Large Hadron Collider (LHC). The simplest theoretical framework where R-parity conservation can be explained dynamically allows for two types of B-L models. In the first scenario the new Higgses decay mainly into two right-handed neutrinos, giving rise to exotic lepton number violating signals together with displaced vertices. In the second model, one could have peculiar channels with multileptons and/or multiphotons in the final state. In both cases, the local B-L gauge symmetry is broken at the TeV scale and the discovery of the new Higgs bosons may be possible at the LHC. We investigate in detail the production mechanisms for the Higgs bosons relevant for the LHC and the key decays which would shed light on how R-parity is conserved. These results may help to understand the link between the cold dark matter of the universe and the missing energy that could be observed at the LHC if supersymmetry is realized in nature.

Pavel Fileviez Pérez; Sogee Spinner; Maike K. Trenkel

2011-11-22T23:59:59.000Z

248

Probing the flavor violating scalar top quark signal at the LHC  

Science Journals Connector (OSTI)

The Large Hadron Collider (LHC) has completed its run at 8 TeV with the experiments ATLAS and CMS having collected about 25??fb?1 of data each. Discovery of a light Higgs boson coupled with lack of evidence for supersymmetry at the LHC so far, has motivated studies of supersymmetry in the context of naturalness with the principal focus being the third generation squarks. In this work, we analyze the prospects of the flavor violating decay mode t˜1?c?10 at 8 and 13 TeV center-of-mass energy at the LHC. This channel is also relevant in the dark matter context for the stop-coannihilation scenario, where the relic density depends on the mass difference between the lighter stop quark (t˜1) and the lightest neutralino (?10) states. This channel is extremely challenging to probe, especially for situations when the mass difference between the lighter stop quark and the lightest neutralino is small. Using certain kinematical properties of signal events we find that the level of backgrounds can be reduced substantially. We find that the prospect for this channel is limited due to the low production cross section for top squarks and limited luminosity at 8 TeV, but at the 13 TeV LHC with 100??fb?1 luminosity, it is possible to probe top squarks with masses up to ?450??GeV. We also discuss how the sensitivity could be significantly improved by tagging charm jets.

Genevieve Belanger; Diptimoy Ghosh; Rohini Godbole; Monoranjan Guchait; Dipan Sengupta

2014-01-06T23:59:59.000Z

249

Analysis of the electron cloud observations with 25 ns bunch spacing at LHC  

E-Print Network (OSTI)

Electron Cloud (EC) effects have been identified as a major performance limitation for the Large Hadron Collider (LHC) when operating with the nominal bunch spacing of 25 ns. During the LHC Run 1 (2010 - 2013) the luminosity production mainly used beams with 50 ns spacing, while 25 ns beams were only employed for short periods in 2011 and 2012 for test purposes. On these occasions, observables such as pressure rise, heat load in the cold sections as well as clear signatures on bunch-by-bunch emittance blow up, particle loss and energy loss indicated the presence of an EC in a large portion of the LHC. The analysis of the recorded data, together with EC build up simulations, has led to a significant improvement of our understanding of the EC effect in the different components of the LHC. Studies were carried out both at injection energy (450 GeV) and at top energy (4 TeV) aiming at determining the energy dependence of the EC formation and its impact on the quality of the proton beam.

Iadarola, G; Rumolo, G; Arduini, G; Baglin, V; Banfi, D; Claudet, S; Dominguez, O; Esteban Müller, J; Pieloni, T; Shaposhnikova, E; Tavian, L; Zannini, C; Zimmermann, F

2014-01-01T23:59:59.000Z

250

International Linear Collider-A Technical Progress Report  

SciTech Connect

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

251

Baseline review of the U.S. LHC Accelerator project  

SciTech Connect

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

NONE

1998-02-01T23:59:59.000Z

252

LHC Physics  

E-Print Network (OSTI)

The LHC is expected to resume later this year. Though results at the Tevatron make it more difficult for the LHC to pick out Higgs bosons, there are other results which are expected. Some of these are surveyed here.

Burra G. Sidharth

2009-03-27T23:59:59.000Z

253

Muon Collider Progress: Accelerators  

SciTech Connect

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

Zisman, Michael S.

2011-09-10T23:59:59.000Z

254

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

255

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

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

256

The Large Hadron Collider, a personal recollection  

Science Journals Connector (OSTI)

......package was the construction of two 2.6km-long...profits fully from the space available in the...collaboration in the machine construction. The superconducting...seven of the eight sectors had been successfully...18), so as the heating increases, the...dipole chains of Sectors 67 and 78 during......

Lyndon Evans

2014-02-01T23:59:59.000Z

257

Large Hadron Collider commissioning and first operation  

Science Journals Connector (OSTI)

...systems [4], including the collimation system [5], are crucial in the...finalizing the protection. The collimation system [5] is part of the machine...machine. The hierarchy of the collimation system (primary, secondary and tertiary...

2012-01-01T23:59:59.000Z

258

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

259

Muon Collider  

SciTech Connect

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

Palmer, R.

2009-10-19T23:59:59.000Z

260

PROCEEDINGS OF THE WORKSHOP ON LHC INTERACTION REGION CORRECTION SYSTEMS  

SciTech Connect

The Workshop on LHC Interaction Region Correction Systems was held at Brookhaven National Laboratory, Upton, New York, on 6 and 7 May 1999. It was attended by 25 participants from 5 institutions. The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region quadrupoles and dipoles. In three sessions the workshop addressed the field quality of the these magnets, reviewed the principles and efficiency of global and local correction schemes and finalized a corrector layout. The session on Field Quality Issues, chaired by J. Strait (FNAL), discussed the progress made by KEK and FNAL in achieving the best possible field quality in the interaction region quadrupoles. Results of simulation studies were presented that assess the effects of magnetic field errors with simulation studies. Attention was given to the uncertainties in predicting and measuring field errors. The session on Global Correction, chaired by J.-P. Koutchouk (CERN), considered methods of reducing the nonlinear detuning or resonance driving terms in the accelerator one-turn map by either sorting or correcting. The session also discussed the crossing angle dependence of the dynamic aperture and operational experience from LEP. The session on Local Correction, chaired by T. Taylor (CERN), discussed the location, strength and effectiveness of multipole correctors in the interaction regions for both proton and heavy ion operation. Discussions were based on technical feasibility considerations and dynamic aperture requirements. The work on linear corrections in the interaction regions was reviewed.

FISCHER,W.; WEI,J.

1999-09-02T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
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261

The radiation environment in underground workplaces of the LHC  

E-Print Network (OSTI)

Active dose-monitoring of workplaces is crucial in order to operate a high-energy particle accelerator safely. As the mixed radiation fields that are expected in the environment of the Large Hadron Collider (LHC) are very different from standard use-cases like in nuclear power plants, it is of highest importance to characterize and calibrate radiation monitoring equipment appropriately for their use in high energy mixed radiation fields. Due to their sensitivity to different particle types over a larger energy range high-pressure ionization chambers have already been used at CERN and they are foreseen to be included within the radiation monitoring system of the LHC. In the framework of this thesis a new method was developed which allows for appropriate field-specific calibration of these detectors using Monte Carlo simulations. Therefore, the application of common 238Pu-Be source based calibration in mixed radiation fields was studied and compared to more accurate field specific calibration based on FLUKA Mon...

Theis, C; Kindl, Peter

2007-01-01T23:59:59.000Z

262

Commissioning of the LHC Magnet Powering System in 2009  

E-Print Network (OSTI)

On 19th September 2008 the Large Hadron Collider (LHC) experienced a serious incident, caused by a defective electrical joint, which stopped beam operation just a few days after its beginning. During the following 14 months the damage was repaired, additional protection systems were installed and the measures to avoid a similar incident were taken, i.e. new layer of the Magnet Quench Protection System (nQPS) and more efficient He release valves. As a consequence, a large number of powering tests had to be repeated or carried out for the first time. The re-commissioning of the already existing systems as well as the commissioning of the new ones was carefully studied, then performed taking into account the history of each of the eight LHC sectors (either warmed-up or left at floating temperature). Moreover, a campaign of measurements of the bus-bar splice resistances as well as the ones internal to the cold masses was carried out with the original and the nQPS in order to spot out non conformities, thus assess...

Solfaroli Camillocci, Matteo; Bellesia, Boris; Coupard, Julie; Dahlerup-Petersen, Knud; Koratzinos, Michael; Pojer, Mirko; Schmidt, Ruediger; Siemko, Andrzej; Thiesen, Hugues; Vergara-Fernandez, Antonio; Zanetti, Marco; Zerlauth, Markus

2010-01-01T23:59:59.000Z

263

Muon Collider design status  

SciTech Connect

Muon Collider (MC) - proposed by G.I. Budker and A.N. Skrinsky a few decades ago - is now considered as the most exciting option for the energy frontier machine in the post-LHC era. A national Muon Accelerator Program (MAP) is being formed in the USA with the ultimate goal of building a MC at the Fermilab site with c.o.m. energy in the range 1.5-3 TeV and luminosity of {approx} 1.5 {center_dot} 10{sup 34} cm{sup -2} s{sup -1}. As the first step on the way to MC it envisages construction of a Neutrino Factory (NF) for high-precision neutrino experiments. The baseline scheme of the NF-MC complex is presented and possible options for its main components are discussed.

Alexahin, Y.; /Fermilab

2010-09-01T23:59:59.000Z

264

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

265

SCIPP 11/06 Fundamentals of LHC Experiments  

E-Print Network (OSTI)

SCIPP 11/06 Fundamentals of LHC Experiments Jason Nielsen Santa Cruz Institute for Particle Physics is proportional to 4 /. For example, radiation losses per turn were 0.2 µW for each electron in the LEP collider

California at Santa Cruz, University of

266

Two particle correlations with photon triggers to study hot QCD medium in ALICE at LHC  

E-Print Network (OSTI)

With the advent of the Large Hadron Collider (LHC)at the end of 2009, the new accelerator at CERN collides protons and heavy-ions at unprecedented high energies. ALICE , one of the major experiment installed at LHC, is dedicated to the study of nuclear matter under extreme conditions of energy density with the opportunity of creating a partonic medium called the Quark- Gluon-Plasma (QGP). This new experimental facility opens new avenues for the understanding of fundamental properties of the strong interaction and its vacuum. To reach the objectives of this scientific program, it is required to select a set of appropriate probes carrying relevant information on the properties of the medium created in ultra-relativistic heavy-ion collisions. Based on the information delivered by all the observables and guided by modelization of the fundamental principles in action, a coherent picture will emerge to interpret the observed phenomena. In the first part of the present document I describe the context of the scientif...

Yaxian, Mao; Shou, Daicui; Schutz, Yves

2011-01-01T23:59:59.000Z

267

Monotops at the LHC  

Science Journals Connector (OSTI)

We explore scenarios where top quarks may be produced singly in association with missing energy, a very distinctive signature, which, in analogy with monojets, we dub monotops. We find that monotops can be produced in a variety of modes, typically characterized by baryon number-violating or flavorchanging neutral interactions. We build a simplified model that encompasses all the possible (tree-level) production mechanisms and study the LHC sensitiveness to a few representative scenarios by considering fully hadronic top decays. We find that constraints on such exotic models can already be set with 1??fb-1 of integrated luminosity collected at s=7??TeV.

J. Andrea; B. Fuks; F. Maltoni

2011-10-17T23:59:59.000Z

268

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

269

Current Lead Design for the Accelerator Project for Upgrade of LHC  

SciTech Connect

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

270

NMSSM Explanations of the Galactic Gamma Ray Excess and Promising LHC Searches  

E-Print Network (OSTI)

To explain the Galactic Center Gamma-ray Excess (GCGE), we consider three possible scenarios in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with $Z_3$ symmetry: (i) The $s$-channel $A_1$ resonant annihilation scenario; (ii) The hidden sector dark matter scenario; (iii) The sbottom and stau coannihilation scenarios. We show that the first scenario is the most favourable one, and we study its LHC discovery potential via four signatures. We find that the most sensitive signals are provided by the Higgsino-like chargino and neutralino pair productions with their subsequent decays into $W$ bosons, $Z$ bosons, and dark matter. The majority of the interesting model space can be probed at the Large Hadron Collider with a centre-of-mass energy of 14 TeV and the integrated luminosity 1000 fb$^{-1}$.

Guo, Jun; Li, Tianjun; Williams, Anthony G

2014-01-01T23:59:59.000Z

271

NMSSM Explanations of the Galactic Gamma Ray Excess and Promising LHC Searches  

E-Print Network (OSTI)

To explain the Galactic Center Gamma-ray Excess (GCGE), we consider three possible scenarios in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with $Z_3$ symmetry: (i) The $s$-channel $A_1$ resonant annihilation scenario; (ii) The hidden sector dark matter scenario; (iii) The sbottom and stau coannihilation scenarios. We show that the first scenario is the most favourable one, and we study its LHC discovery potential via four signatures. We find that the most sensitive signals are provided by the Higgsino-like chargino and neutralino pair productions with their subsequent decays into $W$ bosons, $Z$ bosons, and dark matter. The majority of the interesting model space can be probed at the Large Hadron Collider with a centre-of-mass energy of 14 TeV and the integrated luminosity 1000 fb$^{-1}$.

Jun Guo; Jinmian Li; Tianjun Li; Anthony G. Williams

2014-09-28T23:59:59.000Z

272

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

273

The management of large cabling campaigns during the Long Shutdown 1 of LHC  

E-Print Network (OSTI)

The Large Hadron Collider at CERN entered into its first 18 month-long shutdown period in February 2013. During this period the entire CERN accelerator complex will undergo major consolidation and upgrade works, preparing the machines for LHC operation at nominal energy (7 TeV/beam). One of the most challenging activities concerns the cabling infrastructure (copper and optical fibre cables) serving the CERN data acquisition, networking and control systems. About 1000 kilometres of cables, distributed in different machine areas, will be installed, representing an investment of about 15 MCHF. This implies an extraordinary challenge in terms of project management, including resource and activity planning, work execution and quality control. The preparation phase of this project started well before its implementation, by defining technical solutions and setting financial plans for staff recruitment and material supply. Enhanced task coordination was further implemented by deploying selected competences to form a ...

Meroli, Stefano; Formenti, Fabio; Frans, Marten; Guillaume, Jean Claude; Ricci, Daniel

2014-01-01T23:59:59.000Z

274

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

SciTech Connect

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

275

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

276

MT2 to the Rescue -- Searching for Sleptons in Compressed Spectra at the LHC  

E-Print Network (OSTI)

We propose a novel method for probing sleptons in compressed spectra at hadron colliders. The process under study is slepton pair production in R-parity conserving supersymmetry, where the slepton decays to a neutralino LSP of mass close to the slepton mass. In order to pass the trigger and obtain large missing energy, an energetic mono-jet is required. Both leptons need to be detected in order to suppress large standard model backgrounds with one charged lepton. We study variables that can be used to distinguish the signal from the remaining major backgrounds, which include tt, WW+jet, Z+jet, and single top production. We find that the dilepton MT2, bound by the mass difference, can be used as an upper bound to efficiently reduce the backgrounds. It is estimated that sleptons with masses up to about 150 GeV can be discovered at the 14 TeV LHC with 100/fb integrated luminosity.

Han, Zhenyu

2014-01-01T23:59:59.000Z

277

Simulation of jets at colliders  

Science Journals Connector (OSTI)

Abstract We review the development of the physics behind event generators during the last decade. After a more general description of parton showers, we focus mostly on the perturbative side of the simulations. Two newer developments of parton showers, as implemented in herwig++, are described in greater detail. Matching and merging of parton showers with fixed order computations are discussed. We describe some developments of multiple partonic interactions which are relevant for the simulation of jets from the underlying event, where the implementation in herwig++  is again taken as a generic example. Finally, we compare some event generator results to collider data from LEP and the LHC.

Stefan Gieseke

2013-01-01T23:59:59.000Z

278

Twistor Spinoffs for Collider Physics  

SciTech Connect

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

279

Diffraction at the Tevatron and the LHC  

E-Print Network (OSTI)

In these lectures, we present and discuss the most recent results on inclusive diffraction at the Tevatron collider and give the prospects at the LHC. We also describe the search for exclusive events at the Tevatron. Of special interest is the exclusive production of Higgs boson and heavy objects ($W$, top, stop pairs) at the LHC which will require precise measurements and analyses of inclusive and exclusive diffraction to constrain further the gluon density in the pomeron. At the end of these lectures, we describe the projects to install forward detectors at the LHC to fulfil these measurements.

C. Royon

2008-05-02T23:59:59.000Z

280

Modelling hadronic interactions in HEP MC generators  

E-Print Network (OSTI)

HEP event generators aim to describe high-energy collisions in full exclusive detail. They combine perturbative matrix elements and parton showers with dynamical models of less well-understood phenomena such as hadronization, diffraction, and the so-called underlying event. We briefly summarise some of the main concepts relevant to the modelling of soft/inclusive hadron interactions in MC generators, in particular PYTHIA, with emphasis on questions recently highlighted by LHC data.

Skands, Peter

2014-01-01T23:59:59.000Z

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281

Muon Colliders: The Next Frontier  

SciTech Connect

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

2009-07-29T23:59:59.000Z

282

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

283

Charmless Hadronic B Decays at BaBar  

SciTech Connect

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

284

Upper bounds on sparticle masses from muon g-2 and the Higgs mass and the complementarity of future colliders  

E-Print Network (OSTI)

Supersymmetric (SUSY) explanation of the discrepancy between the measurement of $(g-2)_\\mu$ and its SM prediction puts strong upper bounds on the chargino and smuon masses. At the same time, lower experimental limits on the chargino and smuon masses, combined with the Higgs mass measurement, lead to an upper bound on the stop masses. The current LHC limits on the chargino and smuon masses (for not too compressed spectrum) set the upper bound on the stop masses of about 10 TeV. The discovery potential of the future lepton and hadron colliders should lead to the discovery of SUSY if it is responsible for the explanation of the $(g-2)_\\mu$ anomaly. This conclusion follows from the fact that the upper bound on the stop masses decreases with the increase of the lower experimental limit on the chargino and smuon masses.

Badziak, Marcin; Lewicki, Marek; Olechowski, Marek; Pokorski, Stefan

2014-01-01T23:59:59.000Z

285

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

286

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

287

Electroweak Physics Measurements at the LHC  

E-Print Network (OSTI)

Although often quoted as a discovery collider, the LHC will also allow for precise measurements. In particular, in the electroweak sector, the determination of the masses of the top quark and the W boson will benefit from high statistics and new methods.

N. Besson

2008-12-02T23:59:59.000Z

288

Muon Collider Progress: Accelerators  

E-Print Network (OSTI)

A N. V. Mokhov et al. , “Muon Collider Interaction RegionR. B. Palmer et al. , “Muon Colliders,” in the 9th AdvancedB. Palmer and R. Fernow, “Muon Collider Final Cooling in 30–

Zisman, Michael S.

2012-01-01T23:59:59.000Z

289

Parton distributions with LHC data  

E-Print Network (OSTI)

We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinations, all the relevant LHC data for which experimental systematic uncertainties are currently available: ATLAS and LHCb W and Z lepton rapidity distributions from the 2010 run, CMS W electron asymmetry data from the 2011 run, and ATLAS inclusive jet cross-sections from the 2010 run. We introduce an improved implementation of the FastKernel method which allows us to fit to this extended data set, and also to adopt a more effective minimization methodology. We present the NNPDF2.3 PDF sets, and compare them to the NNPDF2.1 sets to assess the impact of the LHC data. We find that all the LHC data are broadly consistent with each other and with all the older data sets included in the fit. We present predictions for various standard candle cross-sections, and compare them to those obtained previously using NNPDF2.1, and specifically discuss the impact of ATLAS electroweak data on the determination of the strangeness fraction of the proton. We also present collider PDF sets, constructed using only data from HERA, Tevatron and LHC, but find that this data set is neither precise nor complete enough for a competitive PDF determination.

Richard D. Ball; Valerio Bertone; Stefano Carrazza; Christopher S. Deans; Luigi Del Debbio; Stefano Forte; Alberto Guffanti; Nathan P. Hartland; Jose I. Latorre; Juan Rojo; Maria Ubiali

2012-07-05T23:59:59.000Z

290

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

291

Future hadron physics at Fermilab  

SciTech Connect

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 MINERvA 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.

Appel, Jeffrey A.; /Fermilab

2005-09-01T23:59:59.000Z

292

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

SciTech Connect

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

293

Black hole chromosphere at the CERN LHC  

Science Journals Connector (OSTI)

If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the CERN 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 and Haim Goldberg

2003-03-26T23:59:59.000Z

294

Muon Muon Collider: Feasibility Study  

SciTech Connect

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

295

Signatures of black holes at the LHC  

E-Print Network (OSTI)

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

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

2007-07-02T23:59:59.000Z

296

The Next Linear Collider: NLC2001  

SciTech Connect

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

D. Burke et al.

2002-01-14T23:59:59.000Z

297

LHC Workshop 2011  

NLE Websites -- All DOE Office Websites (Extended Search)

Fourth Generation Particles Fourth Generation Particles Scientists have built a well-tested model of the building blocks of the universe. But experiments at the Large Hadron Collider could reveal additional types of subatomic particles that make up our world. Read More Everything we see Ð from coffee cups to computers to human beings Ð is made up of just three basic particles: two types of quarks that make up the nucleus of an atom and an electron that orbits that nucleus. But scientists have found the particles most familiar to us have heavier cousins, other elementary particles that share some of their properties but have different masses. Over the past century, physicists have discovered 12 elementary particles, which they organized into the Standard Model of particle physics. It serves as a kind of periodic table of elements for

298

The \\{LHCb\\} RICH silica aerogel performance with LHC data  

Science Journals Connector (OSTI)

In the \\{LHCb\\} experiment 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 ranges, gas radiators are used (C4F10 and CF4, respectively). In the low momentum range (1–10 GeV/c), pion, kaon and proton separation is performed with solid silica aerogel radiator. A set of 16 tiles, with large transverse dimensions of up to 200 × 200 mm 2 and nominal refractive index 1.03 have been produced and integrated in the detector. These tiles have excellent optical properties and homogeneity of the refractive index at the percent level within the tile. The first data collected at the LHC are used to investigate the behaviour of the RICH; preliminary results of the performance of silica aerogel are presented and discussed.

D.L. Perego

2011-01-01T23:59:59.000Z

299

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

300

Measuring the mass of dark matter at the LHC  

Science Journals Connector (OSTI)

Many methods have been developed for measuring the mass of invisible particles that only use kinematic information available at hadron colliders. Because a particle is identified by its mass, these methods are critical when distinguishing between dark matter and fake dark matter, where a neutrino or other massless states can mimic a dark-matter signal. However, the uncertainty associated with measuring the mass of an invisible particle could be so large that it is indistinguishable from a neutrino. Monte Carlo is used to estimate lower bounds on how heavy an invisible particle must be in order for it to be distinguishable from a massless one at 95% CL, which we estimate to be O(10??GeV). This result, to a good approximation, is independent of the way the massive final-state particle is produced. If there is a light dark-matter particle with mass O(10??GeV), its presence will be difficult to unambiguously identify at the LHC, using kinematic information alone.

Andrew C. Kobach

2013-12-02T23:59:59.000Z

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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301

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

302

Top Quark Physics at the LHC  

E-Print Network (OSTI)

An overview of the prospects of top quark physics at the LHC is presented. The ATLAS and the CMS detectors are about to produce a large amount of data with high top quark contents from the LHC proton-proton collisions. A wide variet y of physics analyses is planned in both experiments, and a number of useful insights have already been obtained regarding their detector performance and physics potential. This summary is based on the talk presented at the Hadron C ollider Physics Symposium 2008, Galena, Illinois, May 27-31, 2008.

Akira Shibata

2008-07-31T23:59:59.000Z

303

The Muon Collider  

E-Print Network (OSTI)

11] D. Summers et al. , “Muon Acceleration to 750 GeV in theThe muon collider M. S. Zisman * Lawrence Berkeley Nationalnew type of accelerator, the muon collider. This accelerator

Zisman, Michael S.

2011-01-01T23:59:59.000Z

304

The Muon Collider  

E-Print Network (OSTI)

11] D. Summers et al. , “Muon Acceleration to 750 GeV in theThe muon collider M. S. Zisman * Lawrence Berkeley Nationalnew type of accelerator, the muon collider. This accelerator

Zisman, Michael S

2010-01-01T23:59:59.000Z

305

Muon collider gains momentum  

Science Journals Connector (OSTI)

... , US scientists staked their claim in a daring new venture: the world's first muon collider. The collider could overtake two more-mature concepts, each of which plan to ... expected to achieve. They are now trying to rally enthusiasm for a collider that smashes muons, a particle that is about 200 times more massive than the electron. ...

Eric Hand

2009-11-18T23:59:59.000Z

306

Measurement of the radiation field surrounding the Collider Detector at Fermilab  

SciTech Connect

We present here the first direct and detailed measurements of the spatial distribution of the ionizing radiation surrounding a hadron collider experiment. Using data from two different exposures we measure the effect of additional shielding on the radiation field around the Collider Detector at Fermilab (CDF). Employing a simple model we parameterize the ionizing radiation field surrounding the detector.

K. Kordas et al.

2004-01-28T23:59:59.000Z

307

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

308

Accounting for soft cross sections at the LHC  

SciTech Connect

We describe briefly the elements of the GLM model that successfully describes soft hadronic interactions at energies from ISR to LHC. This model is based on a single Pomeron with a large intercept {Delta}{sub IP}= 0.23 and slope {alpha} Prime {sub IP}= 0, and so provides a natural matching with perturbative QCD. We summarize themain features and results of competing models for soft interactions at LHC energies.

Gotsman, Errol [School of Physics and Astronomy, Tel Aviv University, Tel Aviv (Israel)

2013-04-15T23:59:59.000Z

309

Anapole dark matter at the LHC  

Science Journals Connector (OSTI)

The anapole moment is the only allowed electromagnetic moment for Majorana fermions. Fermionic dark matter acquiring an anapole can have a standard thermal history and be consistent with current direct detection experiments. In this paper, we calculate the collider monojet signatures of anapole dark matter and show that the current LHC results exclude anapole dark matter with mass less than 100 GeV, for an anapole coupling that leads to the correct thermal relic abundance.

Yu Gao; Chiu Man Ho; Robert J. Scherrer

2014-02-12T23:59:59.000Z

310

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

311

Upgrade of the Gas Flow Control System of the Resistive Current Leads of the LHC Inner Triplet Magnets: Simulation and Experimental Validation  

E-Print Network (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

2014-01-01T23:59:59.000Z

312

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

313

Multiple charm production at the LHC energy  

SciTech Connect

Cross sections for J/{psi} mesons produced in association with open charm and two charmed hadrons from different cc-bar pairs under LHC conditions are predicted theoretically. The respective processes are considered both in single and in double parton interactions. Particular attention is given to kinematical limits of the LHCb detector, and a comparison with the most recent experimental data is performed for them.

Berezhnoy, A. V., E-mail: Alexander.Berezhnoy@cern.ch [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Likhoded, A. K., E-mail: Anatolii.Likhoded@ihep.ru; Luchinsky, A. V., E-mail: Alexey.Luchinsky@ihep.ru; Novoselov, A. A., E-mail: Alexey.Novoselov@cern.ch [Institute for High Energy Physics (Russian Federation)

2013-01-15T23:59:59.000Z

314

Early search for supersymmetric dark matter models at the LHC without missing energy  

Science Journals Connector (OSTI)

We investigate early discovery signals for supersymmetry at the Large Hadron Collider without using information about missing transverse energy. Instead we use cuts on the number ... phenomenological models that ...

Joakim Edsjö; Erik Lundström; Sara Rydbeck; Jörgen Sjölin

2010-03-01T23:59:59.000Z

315

Muon identification with the event filter of the ATLAS experiment at CERN LHC's  

Science Journals Connector (OSTI)

The Large Hadron Collider at CERN offers unprecedented challenges to the design and construction of detectors and trigger/data acquisition systems. For ATLAS, a three level trigger system has been developed to extract interesting physics signatures with ...

Gabriella Cataldi

2005-06-01T23:59:59.000Z

316

NLO QCD CORRECTIONS TO HADRONIC HIGGS PRODUCTION WITH HEAVY QUARKS.  

SciTech Connect

The production of a Higgs boson in association with a pair of t{bar t} or b{bar b} quarks plays a very important role at both the Tevatron and the Large Hadron Collider. The theoretical prediction of the corresponding cross sections has been improved by including the complete next-to-leading order QCD corrections. After a brief description of the most relevant technical aspects of the calculation, we review the results obtained for both the Tevatron and the Large Hadron Collider.

DAWSON,S.; JACKSON,C.; ORR,L.; REINA,L.; WACHEROTH,D.

2003-07-02T23:59:59.000Z

317

Neutrino alternatives for missing energy events at colliders  

Science Journals Connector (OSTI)

If the dark matter consists of a weakly interacting massive particle, it can be produced and studied at future collider experiments like those at the LHC. The production of collider-stable weakly interacting massive particles is characterized by hard scattering events with large missing transverse energy. Here we emphasize and discuss the fact that the discovery of events inconsistent with the standard model with large missing transverse energy need not point to the existence of new, collider-stable particles. We explore an alternative explanation where the only sources of missing transverse energy are standard model neutrinos. We present concrete examples of such scenarios, focusing on supersymmetric models with R-parity violation. We also discuss means of differentiating neutrino missing energy signals from the production of new collider-stable particles. These include both model-dependent signals, such as particle tags and flavor counts, as well as model-independent tests that attempt to measure the missing particle mass.

Spencer Chang and André de Gouvêa

2009-07-15T23:59:59.000Z

318

Light sfermion interplay in the 125 GeV MSSM Higgs production and decay at the LHC  

E-Print Network (OSTI)

We study the effects from light sfermions on the lightest Higgs boson production and decay at the Large Hadron Collider (LHC) within the Minimal Supersymmetric Standard Model (MSSM). We find that the scenario with light coloured sfermions -- stops or sbottoms -- has the potential to explain a non-universal alteration, as hinted by LHC data, of the gluon-gluon Fusion ($\\mu_{ggF}$) with respect to the Vector Boson Fusion ($\\mu_{VBF}$) event rates and, in particular, can predict $\\frac{\\mu_{VBF}}{\\mu_{ggF}}>1$ for all Higgs boson decay channels in large areas of the parameter space. We also find that the scenario with a light stop/sbottom can be complemented by the scenario in which the total Higgs width, $\\Gamma_{\\rm tot}$, is reduced due to a suppressed Yukawa coupling $Y_b$. In this case, the reduction of the Higgs production rates in the $ggF$ process which occurs in the maximal mixing scenario is compensated by the reduction of the $H\\to b\\bar{b}$ partial decay width, the largest component of $\\Gamma_{\\rm t...

Belyaev, Alexander; Moretti, Stefano; Thomas, Marc

2013-01-01T23:59:59.000Z

319

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

SciTech Connect

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

320

Jet Charge at the LHC  

Science Journals Connector (OSTI)

Knowing the charge of the parton initiating a light-quark jet could be extremely useful both for testing aspects of the standard model and for characterizing potential beyond-the-standard-model signals. We show that despite the complications of hadronization and out-of-jet radiation such as pileup, a weighted sum of the charges of a jet’s constituents can be used at the LHC to distinguish among jets with different charges. Potential applications include measuring electroweak quantum numbers of hadronically decaying resonances or supersymmetric particles, as well as standard model tests, such as jet charge in dijet events or in hadronically decaying W bosons in tt¯ events. We develop a systematically improvable method to calculate moments of these charge distributions by combining multihadron fragmentation functions with perturbative jet functions and pertubative evolution equations. We show that the dependence on energy and jet size for the average and width of the jet charge can be calculated despite the large experimental uncertainty on fragmentation functions. These calculations can provide a validation tool for data independent of Monte Carlo fragmentation models.

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

2013-05-21T23:59:59.000Z

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

Future Accelerators, Muon Colliders, and Neutrino Factories  

SciTech Connect

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

322

Production of tetraquarks at the LHC  

Science Journals Connector (OSTI)

The high prompt production cross section of X(3872) at hadron colliders has shown to be very informative about the quark nature of the X, Y, Z states. We present here a number of results on X production in pp(p¯) collisions obtained with Monte Carlo hadronization methods and illustrate what can be learned from their use to improve our understanding of exotic states. In particular, a comparison between antideuteron and X production cross sections is proposed. Hadronization might be the key to solve the problem of the extra states expected in diquark-antidiquark models which are naturally favored after the recent confirmation of the Z(4430) tetraquark, together with its lower partners Zc(3900) and Zc?(4020).

A.?L. Guerrieri; F. Piccinini; A. Pilloni; A.?D. Polosa

2014-08-05T23:59:59.000Z

323

SLAC linear collider  

SciTech Connect

A brief description of the proposed SLAC Linear Collider is given. This machine would investigate the possibilities and limitations of Linear Colliders while at the same time producing thousands of Z/sup 0/ particles per day for the study of the weak interactions.

Hollebeek, R.

1980-06-01T23:59:59.000Z

324

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

SciTech Connect

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

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

2011-09-01T23:59:59.000Z

325

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

326

Papers on Muon Colliders  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnets for Muon Collider and Neutrino Storage Ring Magnets for Muon Collider and Neutrino Storage Ring (and Open Midplane Dipole for LARP): R. Gupta, et al., "High Field HTS Solenoid for a Muon Collider – Demonstrations, Challenges and Strategies, MT23, July 2013", presented at MT23, (talk) R. Weggel et al., "Open Midplane Dipoles for Muon Collider", 2011 Particle Accelerator Conference, New York (POSTER).. R. Gupta, M. Anerella, A. Ghosh, H. Kirk, R. Palmer, S. Plate, W. Sampson, Y. Shiroyanagi, P. Wanderer, B. Brandt, D. Cline, A. Garren, J. Kolonko, R. Scanlan, R. Weggel, "High field HTS R&D solenoid for muon collider", 2010 Applied Superconductivity Conference, Washington, DC, August 2010 >> Y. Shiroyanagi, W. Sampson, A. Ghosh, R. Gupta, "The Construction and

327

General NMSSM signatures at the LHC  

Science Journals Connector (OSTI)

We study the possible LHC collider signatures in the next-to-minimal supersymmetric standard model. The general next-to-minimal supersymmetric standard model consists of 29 supersymmetric particles which can be mass ordered in 29!?9×1030 ways. To reduce the number of hierarchies to a more manageable amount we assume a degeneracy of the sfermions of the first two generations with the same quantum numbers. Further assumptions about the neutralino and chargino masses leave 15 unrelated parameters. We check all 15!?1012 relevant mass orderings for the dominant decay chains and the corresponding collider signatures at the LHC. As preferred signatures, we consider charged leptons, missing transverse momentum, jets, and W, Z or Higgs bosons. We present the results for three different choices of the singlet to Higgs coupling ?: (a) small, O(?)O(Ytop). We compare these three scenarios with the MSSM expectations as well as among each other. We also mention a possible mass hierarchy leading to seven jets plus one lepton signatures at the LHC and comment briefly on the consequence of possible R-parity violation.

H. K. Dreiner; F. Staub; A. Vicente

2013-02-05T23:59:59.000Z

328

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.

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

2014-01-01T23:59:59.000Z

329

High Energy Colliders as Tools to Understand the Early Universe  

SciTech Connect

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

330

muon Collider Notes  

NLE Websites -- All DOE Office Websites (Extended Search)

Muon Collider Notes Muon Collider Notes MC-001 D. Neuffer, "Colliding Muon Beams at 90 GeV" Fermilab Note FN-319, July 1979. MC-002 D. Neuffer, "Principles and Applications of Muon Cooling" Proc. of the 12th International Conf. on High-Energy Accelerators, p. 481, 1983. MC-003 V.V. Parkhomchuk and A.N. Skrinsky, "Ionization Cooling: Physics and Applications" Proc. of the 12th International Conf. on High-Energy Accelerators, p. 485, 1983. MC-004 E.A. Perevedentsev and A.N. Skrinsky, "On the Proton Klystron" Proc. of the 12th International Conf. on High-Energy Accelerators, p. 508, 1983. MC-005 D. Neuffer, "Principles and Applications of Muon Cooling" Particle Accelerators, Vol. 14, p. 75, 1983. MC-006 D. Neuffer, "Multi-TeV Muon Colliders" Proc. of the Advanced

331

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

332

Leptonic monotops at the LHC  

Science Journals Connector (OSTI)

We study the possibility of detecting new physics (NP) phenomena at the LHC through a new search strategy looking at the monotop (top plus missing energy) signature which is common to a variety of NP models. We focus on the leptonic top decay mode and study the discovery or exclusion reach of the 2012 LHC data for three example models. Contrary to the hadronic mode, in this case the problematic QCD multijet background can be safely neglected. We find that the key kinematic variable to suppress most of the remaining SM backgrounds is the transverse mass of the charged lepton and missing energy. In fact, one could expect that the single-top production measurements already address the monotop signature in this mode. This is, however, not the case, because in the SM single-top production, the transverse mass has an end point determined by the W mass, while the NP signals typically have an additional source of missing energy. We compare, under the same conditions, our monotop search strategy with existing single-top measurements and find a considerable improvement in the monotop signature reach.

Ezequiel Alvarez; Estefania Coluccio Leskow; Jure Drobnak; Jernej F. Kamenik

2014-01-15T23:59:59.000Z

333

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

334

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

335

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

336

Brookhaven and ATLAS | Brookhaven and the LHC  

NLE Websites -- All DOE Office Websites (Extended Search)

Brookhaven and ATLAS Brookhaven and ATLAS BNL scientists install cathode strip chambers BNL scientists install cathode strip chambers - designed and built at the Laboratory - and monitored drift tubes into the ATLAS small wheel. Image credit: CERN. Brookhaven physicists and engineers are participating in one of the most ambitious scientific projects in the world - constructing, operating, doing physics analysis of the data, and upgrading a machine the size of a seven-story building that will open up new frontiers in the human pursuit of knowledge about elementary particles and their interactions. The machine, dubbed ATLAS, is one of four facilities located at the LHC near Geneva, in Switzerland. The LHC consists of two circular vacuum pipes in which protons travel in opposite directions and collide at nearly the

337

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

338

The Large Hadron Collider: lessons learned and summary  

Science Journals Connector (OSTI)

...1984 to 2011 Since 1984, the mystery of dark matter has been deepened by the discovery of dark energy, but otherwise not much has happened...the next section; -the very important discovery at LEP that there are only three light neutrinos...

2012-01-01T23:59:59.000Z

339

Establishing the Mirage Mediation Model at the Large Hadron Collider  

E-Print Network (OSTI)

), (v) ni (modular weights of matter fields and Higgs fields), (vi) la (specifying how the visible sector is constructed). I assumed ? > 0, since positive ? is favored from the muon g – 2 experiment [15]. Grand Unification implies matter... theory knowledge from Kuver. I want to extend my gratitude to the colleagues and the department faculty and staff for making my time at Texas A&M University a great experience Finally, thanks to my mother and father for their encouragement. iv TABLE...

Wang, Kechen

2012-10-19T23:59:59.000Z

340

The future of the Large Hadron Collider and CERN  

Science Journals Connector (OSTI)

...are known to have problems for high energy will be repaired or replaced. In addition, the Proton Synchroton (PS) and Super Proton Synchroton (SPS) consolidation and upgrade work will be carried out. -During this shutdown, the collimation...

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
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341

The Large Hadron Collider: lessons learned and summary  

Science Journals Connector (OSTI)

...deficiencies of the Standard Model: -the origin...particular non-standard scenario, but models...machine, with a review foreseen in 1997...proposal and long-term plan for CERN, for presentation...physics beyond the Standard ModelPhil. Trans...changed little. I will review the evolution of...

2012-01-01T23:59:59.000Z

342

The Large Hadron Collider - At Discover's Horizon | Slides and...  

NLE Websites -- All DOE Office Websites (Extended Search)

as they contain important information regarding permission to use imagery. The posters and postcards may not be sold. The user may only change the areas of text as...

343

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

344

The technical challenges of the Large Hadron Collider  

Science Journals Connector (OSTI)

...through the greater part of a physics coast), a second technical...of the possible observation of physics beyond the standard model. To...and M Tigner (eds). 1998 Handbook of accelerator physics and engineering, Singapore...

2015-01-01T23:59:59.000Z

345

The Large Hadron Collider - At Discover's Horizon | Slides and...  

NLE Websites -- All DOE Office Websites (Extended Search)

lecture at your institution, contact the appropriate people there to help with local logistics. Other venue ideas are museums, community centers, libraries, clubs and...

346

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

347

New Perspectives for QCD Physics at the LHC  

E-Print Network (OSTI)

I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as diffractive deep inelastic scattering, The antishadowing of nuclear structure functions is predicted to depend on the flavor quantum numbers of each quark and antiquark. Isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation, even at the LHC. Such "direct" processes can explain the observed deviations from pQCD predictions of the power-law fall-off of inclusive hadron cross sections as well as the "baryon anomaly" seen in high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p_T photon plus charm-jet events observed at the Tevatron and imply a large production rate for charm and bottom jets at high p_T at the LHC, as well as a novel mechanism for Higgs and Z^0 production at high x_F. The light-front wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at the amplitude level. The elimination of the renormalization scale ambiguity for the QCD coupling using the scheme-independent BLM method will increase the sensitivity of searches for new physics at the LHC. The implications of "in-hadron condensates" for the QCD contribution to the cosmological constant are also discussed.

Stanley J. Brodsky

2010-12-02T23:59:59.000Z

348

1  

NLE Websites -- All DOE Office Websites (Extended Search)

talk about the most complex scientific instrument ever built-the Large Hadron Collider (LHC). The talk, entitled "The Large Hadron Collider Adventure," is at 1:10 p.m. in Los...

349

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

350

Inclusive top pair production at Tevatron and LHC in electron/muon final states  

E-Print Network (OSTI)

Recent measurements of the inclusive top pair production at the Tevatron and LHC collider in the electron/muon final states are discussed. Measurements at the Tevatron use up to 9.7 /fb of data, and at the LHC up to 4.9 /fb of data at $\\sqrt{s}=7$ TeV and up to 20.3 /fb of data at $\\sqrt{s}=8$ TeV. For the experiments at both colliders these corresponds to the full data sets at the given center-of-mass energies. Overall results are in agreement between the experiments at the Tevatron and between the experiments at the LHC. All measurements are in agreement with recent theory calculations at NNLO QCD. Individual LHC measurements are challenging the precision of the theory calculations.

Andreas Werner Jung

2013-12-23T23:59:59.000Z

351

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

352

CP-violation in SUSY cascades at the LHC  

E-Print Network (OSTI)

We study the potential to observe CP-violating effects in SUSY cascade decay chains at the LHC. Asymmetries composed by triple products of momenta of the final state particles are sensitive to CP-violating effects. Due to large boosts that dilute the asymmetries, these can be difficult to observe. Extending the methods of momentum reconstruction we show that the original size of these asymmetries may be measurable. A study is done at the hadronic level with backgrounds to estimate the expected sensitivity at the LHC.

Jamie Tattersall; Gudrid Moortgat-Pick; Krzysztof Rolbiecki

2010-09-01T23:59:59.000Z

353

The Muon Collider  

SciTech Connect

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

Zisman, Michael S

2010-05-17T23:59:59.000Z

354

Top Jets at the LHC  

E-Print Network (OSTI)

Physics Signatures at the LHC,” talk presented at the 2007Top Jets at the LHC Leandro G. Almeida, Seung J. Lee, GiladSEPT-DPP Top Jets at the LHC Leandro G. Almeida a , Seung J.

Almeida, L.G.

2009-01-01T23:59:59.000Z

355

Bosonic quartic couplings at CERN LHC  

Science Journals Connector (OSTI)

We analyze the potential of the CERN Large Hadron Collider to study anomalous quartic vector-boson interactions ZZ??, ZZZ?, W+W-??, and W+W-Z? through the weak boson fusion processes qq?qq?? and qq?qq?Z(?l+l-) with l=e or ?. After a careful study of the backgrounds and how to extract them from the data, we show that the process pp?jj?l+l- is potentially the most sensitive to deviations from the standard model, improving the sensitivity to anomalous couplings by up to a factor of 104 (102) with respect to the present direct (indirect) limits.

O. J. P. Éboli; M. C. Gonzalez-Garcia; S. M. Lietti

2004-05-18T23:59:59.000Z

356

Medium effects and jet fragmentation at the LHC  

SciTech Connect

In this work we study the production of charged hadrons in ultrarelativistic heavy ion collisions. We quantify the medium effects by calculating the nuclear ratio R{sub AA} as a function of the transverse momentum of the produced hadron. The main ingredients are the shadowing of the nuclear parton distributions, the jet energy loss and the fragmentation functions modified by the hot and dense medium. Our results are focused on the interplay of the different effects, and results are compared with recent LHC data.

Martins, S.; Mariotto, C. B.; Mackedanz, L. F. [Instituto de Matematica, Estatistica e Fisica, Universidade Federal do Rio Grande, Caixa Postal 474, CEP 96203-900, Rio Grande, RS (Brazil)

2013-03-25T23:59:59.000Z

357

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

358

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

SciTech Connect

We report on the spin and diffractive physics at a future multi-purpose f xed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic f xed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The f xed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

Lorce, C.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Rosier, P. [IPNO, Universite Paris-Sud, CNRS/IN2P3, F-91406, Orsay (France); Anselmino, M.; Arnaldi, R.; Scomparin, E. [INFN Sez. Torino, Via P. Giuria 1,1-10125, Torino (Italy); Brodsky, S. J. [SLAC National Accelerator Laboratory, Stanford U, Stanford, CA 94309, (United States); Ferreiro, E. G. [Departamento de Fisica de Particulas, Univ. de Santiago de C, 15782 Santiago de C (Spain); Fleuret, F. [Laboratoire Leprince Ringuet, Ecole Polytechnique, CNRS/IN2P3, 91128 Palaiseau (France); Rakotozafindrabe, A. [IRFU/SPhN, CFA Society, 91191 Gifsur-Yvette Cedex (France); Schienbein, I. [LPSC, Universite Joseph Fourier, CNRS/IN2P3/INPG, F-38026 Grenoble (France); Uggerhoj, U. I. [Department of Physics and Astronomy, University of Aarhus (Denmark)

2013-04-15T23:59:59.000Z

359

Illuminating Dark Photons with High-Energy Colliders  

E-Print Network (OSTI)

High-energy colliders offer a unique sensitivity to dark photons, the mediators of a broken dark U(1) gauge theory that kinetically mixes with the Standard Model (SM) hypercharge. Dark photons can be detected in the exotic decay of the 125 GeV Higgs boson, h -> Z Z_D -> 4l, and in Drell-Yan events, pp -> Z_D -> ll. If the dark U(1) is broken by a hidden-sector Higgs mechanism, then mixing between the dark and SM Higgs bosons also allows the exotic decay h -> Z_D Z_D -> 4l. We show that the 14 TeV LHC and a 100 TeV proton-proton collider provide powerful probes of both exotic Higgs decay channels. In the case of kinetic mixing alone, direct Drell-Yan production offers the best sensitivity to Z_D, and can probe epsilon >~ 9 x 10^(-4) (4 x 10^(-4)) at the HL-LHC (100 TeV pp collider). The exotic Higgs decay h -> Z Z_D offers slightly weaker sensitivity, but both measurements are necessary to distinguish the kinetically mixed dark photon from other scenarios. If Higgs mixing is also present, then the decay h -> Z...

Curtin, David; Gori, Stefania; Shelton, Jessie

2014-01-01T23:59:59.000Z

360

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

SciTech Connect

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

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

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

362

Aspects of heavy-ion collisions at the LHC  

SciTech Connect

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

363

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

364

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

365

Overview of results from the Fermilab fixed target and collider experiments  

SciTech Connect

In this paper we present a review of recent QCD related results from Fermilab fixed target and collider experiments. Topics covered range from structure functions through W/Z production, heavy quark production and jet angular distributions. We also include the current state of knowledge about leptoquark pair production in hadronic collisions.

Montgomery, H.E.

1997-06-01T23:59:59.000Z

366

arXiv:acc-phys/9602001v112Feb1996 MUON COLLIDERS  

E-Print Network (OSTI)

, A. Garren3,7 , M. Green3 , S. Kahn1 , H. Kirk1 , Y. Y. Lee1 , F. Mills5 , N. Mokhov5 , G. Morgan1 on upgrades of the FERMILAB machines would also be possible (see second Ref. [4]). Hadron collider energies are limited by their size and technical constraints on bending magnetic fields. At very high energies it would

Wurtele, Jonathan

367

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

E-Print Network (OSTI)

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

Stanley J. Brodsky

2014-10-01T23:59:59.000Z

368

US LHC Accelerator Research Program  

E-Print Network (OSTI)

US LHC Accelerator Research Program Instrumentation Collaboration Meeting John Marriner May 9, 2003 #12;2/14/03 US LARP Instrumentation Collaboration Mtg 2 US LARP LARP = LHC Accelerator Research Program LARP is an outgrowth of the US LHC Accelerator Project The US LHC Accelerator Project built

Large Hadron Collider Program

369

Software & GRID Computing for LHC  

E-Print Network (OSTI)

Software & GRID Computing for LHC (Computing Work in a Big Group) Frederick Luehring luehring: ­ A short introduction about the LHC and ATLAS · LHC/ATLAS serves as an example of large scale scientific/P609 Presentation F. Luehring Pg. 3 #12;A Little About LHC & ATLAS February 10, 2011 P410/P609

Evans, Hal

370

Relativistic Heavy Ion Collider  

NLE Websites -- All DOE Office Websites (Extended Search)

Relativistic Heavy Ion Collider Relativistic Heavy Ion Collider managed for the U.S. Department of Energy by Brookhaven Science Associates, founded by Stony Brook University and Battelle. managed for the U.S. Department of Energy by Brookhaven Science Associates, a company founded by Stony Brook University and Battelle 07/07 Brookhaven National Laboratory Funded by the U.S. Department of Energy, Brookhaven National Laboratory is a multipurpose research institution located on a 5,300-acre site on Long Island, New York. Six Nobel Prize-winning discoveries have been made at Brookhaven Lab. The Laboratory operates large-scale scientific facilities and performs research in physics, chemistry, biology, medicine, applied science, and

371

Collider-Accelerator Department  

NLE Websites -- All DOE Office Websites (Extended Search)

RHIC Tunnel and Magnets RHIC Tunnel and Magnets RHIC Tunnel and Magnets AGS Tunnel and Magnets NSRL Beamline RF Kicker Snake 200-MeV LINAC AGS Cold Snake Magnet About the Collider-Accelerator Department The mission of the Collider-Accelerator Department is to develop, improve and operate the suite of particle / heavy ion accelerators used to carry out the program of accelerator-based experiments at BNL; to support the experimental program including design, construction and operation of the beam transports to the experiments plus support of detector and research needs of the experiments; to design and construct new accelerator facilities in support of the BNL and national missions. The C-A Department supports an international user community of over 1500 scientists. The department performs all these functions in an environmentally responsible and safe manner under a rigorous conduct of operations approach.

372

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

373

muon_collider  

NLE Websites -- All DOE Office Websites (Extended Search)

muon_collider muon_collider muon_collider FridayMeetings MCTFmeetings MondayMeetings prstab texput.log #prstab.tex# last.kumac prstab.ps arxiv.tar.gz prstab.tar.gz referee_response_II.pdf prstab.pdf prstab.aux prstab.dvi prstab.end prstab.log prstab.tex prstab.tex~ accel-010307-f03.eps accel-010307-f28.eps old conclusions.tex higgsfact.tex introduction.tex mice.tex neufact.tex physics.tex prstab.tex r_and_d.tex authors_merged.tex buncher.tex temp.prt last.kumacold ringfig.eps MICE-fig.ps chgr_norm.ps chgr_merit.ps temp.csh temp.prt~ xupdn-a-model-view-iron5.eps site1-Layout1.eps rla2.eps phaserot.eps mole-hill.eps intoap.eps emit.eps cavity.eps allcount.eps MICE-88MHz-cooling.eps changes hh_ha_susy_rtsscan.eps letter_plots.eps scott33.eps scott32b.eps scott32a.eps MICE-200MHz-long.eps MICE-resolution.eps dipole_fields.eps

374

Single neutralino production at the LHC  

Science Journals Connector (OSTI)

We consider that the direct production of a single neutralino in a proton-proton collision at the CERN Large Hadron Collider focusing on the lightest neutralino is possibly a candidate for dark matter and escapes detection. We present a comprehensive investigation of the dependence of total cross sections of the processes pp(qq¯)??˜i0g˜, pp(qg)??˜i0q˜L,R, and pp(qq¯?)??˜i0?˜j+ at tree level and pp(gg)??˜i0g˜ at one-loop level, on the center-of-mass energy, on the M2-? mass plane, on the squark mass, and on the tan?? for the Constrained Minimal Supersymmetric Standard Model and three extremely different scenarios in the Minimal Supersymmetric Standard Model. In particular, the cross section of the process pp??˜20?˜1+ in the gauginolike scenario can reach about 0.6 (1.7) pb at a center-of-mass energy of s=7(14)??TeV. We extract therefrom that our results might lead to new aspects corresponding to experimental explorations, and these dependencies might be used as the bases of experimental research of the single neutralino production at hadron colliders.

A. I. Ahmadov and M. Demirci

2013-07-12T23:59:59.000Z

375

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

376

Hadron supercolliders: The 1-TeV scale and beyond  

SciTech Connect

Greater understanding of the connection between the weak and electromagnetic interactions is central to progress in elementary-particle physics. A definitive exploration of the mechanism for electroweak symmetry breaking will require collisions between fundamental constituents at energies on the order of 1 TeV. This goal drives the design of high-energy, high-luminosity hadron colliders that will be commissioned during the next decade, but by no means completely defines their scientific potential. These three lectures are devoted to a review of the standard-model issues that motivated an experimental assault on the 1-TeV scale, an introduction to the machines and the experimental environment they will present, and a survey of possibilities for measurement and discovery with a multi-TeV hadron collider. 72 refs., 29 figs.

Quigg, C.

1990-08-10T23:59:59.000Z

377

Top quark physics expectations at the LHC  

E-Print Network (OSTI)

physics expectations at the LHC Andrei Gaponenko, on behalfbe produced copiously at the LHC. This will make possiblepurpose detectors at the LHC, which will provide proton-

Gaponenko, Andrei; ATLAS Collaboration; CMS Collaboration

2008-01-01T23:59:59.000Z

378

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

379

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

380

Muon colliders and neutrino factories  

SciTech Connect

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

Geer, S.; /Fermilab

2010-09-01T23:59:59.000Z

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.


381

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

382

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

383

RHIC | Relativistic Heavy Ion Collider  

NLE Websites -- All DOE Office Websites (Extended Search)

breakthrough accelerator could collide electrons with heavy ions or protons at nearly the speed of light to create "snapshots" of the force binding all visible matter. Accelerator...

384

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

385

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

386

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

387

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

388

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

NLE Websites -- All DOE Office Websites (Extended Search)

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

389

ESnet Extends 100G Connectivity Across Atlantic  

NLE Websites -- All DOE Office Websites (Extended Search)

and universities ultra-fast access to scientific data from the Large Hadron Collider (LHC) and other research sites in Europe. ESnet's transatlantic extension will deliver a...

390

Lecture Series  

NLE Websites -- All DOE Office Websites (Extended Search)

Resources > Lecture Series Lecture Series The US LHC community has organized two nationwide public lecture series around the themes of the Large Hadron Collider and the Angels &...

391

LHC@BNL Workshop February 8, 2010  

E-Print Network (OSTI)

LHC@BNL Workshop February 8, 2010 Rick Field ­ Florida/CDF/CMS Page 1 LHC@BNL WorkshopLHC the Tevatron to RHIC and the LHC. What is the "underlying event"? The QCD Monte-Carlo Model tunes. LHC predictions! Summary & Conclusions. The "underlying event" at STAR. Early QCD Measurements at the LHC

Field, Richard

392

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

393

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

394

Identifying extended Higgs models at the LHC  

Science Journals Connector (OSTI)

We make a complete catalog of extended Higgs sectors involving SU(2)L doublets and singlets, subject to natural flavor conservation. In each case we present the couplings of a light neutral CP-even Higgs state h in terms of the model parameters, and identify which models are distinguishable in principle based on this information. We also give explicit expressions for the model parameters in terms of h couplings and exhibit the behaviors of the couplings in the limit where the deviations from the standard model (SM) Higgs couplings are small. Finally, we discuss prospects for differentiation of extended Higgs models based on measurements at the LHC and International Linear Collider and identify the regions in which these experiments could detect deviations from the SM Higgs predictions.

Vernon Barger; Heather E. Logan; Gabe Shaughnessy

2009-06-24T23:59:59.000Z

395

Probing the seesaw mechanism at CERN LHC  

Science Journals Connector (OSTI)

We have recently proposed a simple SU(5) theory with an adjoint fermionic multiplet on top of the usual minimal spectrum. This leads to the hybrid scenario of both type I and type III seesaw and it predicts the existence of the fermionic SU(2) triplet between 100 GeV and 1 TeV for a conventional grand unified theory scale of about 1016??GeV, with main decays into W (Z) and leptons, correlated through Dirac Yukawa couplings, and lifetimes shorter than about 10-12sec?. These decays are lepton number violating and they offer an exciting signature of ?L=2 dilepton events together with 4 jets at future pp (pp¯) colliders. Increasing the triplet mass endangers the proton stability and so the seesaw mechanism could be directly testable at LHC.

Borut Bajc; Miha Nemevšek; Goran Senjanovi?

2007-09-24T23:59:59.000Z

396

Resonances from quiver theories at the LHC  

Science Journals Connector (OSTI)

We consider the collider signals of spin-one resonances present in full-hierarchy quiver theories of electroweak symmetry breaking. These four-dimensional theories result from the deconstruction of warped extra dimensional models and have very distinct phenomenological features when the number of sites is small. We study a class of generic scenarios in these theories where the color gauge group, as well as the electroweak sector, propagates in the quiver diagram. These scenarios correspond to various specific models of electroweak symmetry breaking and fermion masses. We focus on the minimum resonant content and its main features: the presence of heavy and narrow spin-one resonances. We derive bounds from the LHC data on the color-octet and color-singlet excited gauge bosons from their decays to jets and top pairs, and show their dependence on the number of sites in the quiver. We also compare them with the bounds derived from flavor violation.

Gustavo Burdman; Nayara Fonseca; Gabriela L. Lichtenstein

2013-12-09T23:59:59.000Z

397

Muon Collider Overview: Progress and Future Plans  

E-Print Network (OSTI)

NATIONAL LABORATORY Muon Collider Overview: Progress andCBP Note-263 BNL- 65627 Muon Collider Overview: Progress and9] 5 REFERENCES [1] Status of the Muon Collider Research and

Palmer, R.

2008-01-01T23:59:59.000Z

398

LHC Network Measurement Joe Metzger  

E-Print Network (OSTI)

1 HENP SIG LHC Network Measurement Challenges Joe Metzger April 22 2008 Internet2 Spring Members #12;2 Current Network Environment · Most R&E network backbones are composed of 10Gbps links · The LHC... ­ Network topology is constantly changing! ­ LHC data transfer flows are not typical internet flows ­ Many

399

Simplified Models for LHC New Physics Searches  

E-Print Network (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 ~50-500 pb-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.

Daniele Alves; Nima Arkani-Hamed; Sanjay Arora; Yang Bai; Matthew Baumgart; Joshua Berger; Matthew Buckley; Bart Butler; Spencer Chang; Hsin-Chia Cheng; Clifford Cheung; R. Sekhar Chivukula; Won Sang Cho; Randy Cotta; Mariarosaria D'Alfonso; Sonia El Hedri; Rouven Essig; Jared A. Evans; Liam Fitzpatrick; Patrick Fox; Roberto Franceschini; Ayres Freitas; James S. Gainer; Yuri Gershtein; Richard Gray; Thomas Gregoire; Ben Gripaios; Jack Gunion; Tao Han; Andy Haas; Per Hansson; JoAnne Hewett; Dmitry Hits; Jay Hubisz; Eder Izaguirre; Jared Kaplan; Emanuel Katz; Can Kilic; Hyung-Do Kim; Ryuichiro Kitano; Sue Ann Koay; Pyungwon Ko; David Krohn; Eric Kuflik; Ian Lewis; Mariangela Lisanti; Tao Liu; Zhen Liu; Ran Lu; Markus Luty; Patrick Meade; David Morrissey; Stephen Mrenna; Mihoko Nojiri; Takemichi Okui; Sanjay Padhi; Michele Papucci; Michael Park; Myeonghun Park; Maxim Perelstein; Michael Peskin; Daniel Phalen; Keith Rehermann; Vikram Rentala; Tuhin Roy; Joshua T. Ruderman; Veronica Sanz; Martin Schmaltz; Stephen Schnetzer; Philip Schuster; Pedro Schwaller; Matthew D. Schwartz; Ariel Schwartzman; Jing Shao; Jessie Shelton; David Shih; Jing Shu; Daniel Silverstein; Elizabeth Simmons; Sunil Somalwar; Michael Spannowsky; Christian Spethmann; Matthew Strassler; Shufang Su; Tim Tait; Brooks Thomas; Scott Thomas; Natalia Toro; Tomer Volansky; Jay Wacker; Wolfgang Waltenberger; Itay Yavin; Felix Yu; Yue Zhao; Kathryn Zurek

2011-05-13T23:59:59.000Z

400

Interference of thermal photons from quark and hadronic phases in relativistic collisions of heavy nuclei  

SciTech Connect

We explore intensity correlations for thermal photons having K{sub T}{<=}2 GeV/c for central collisions of heavy nuclei at Relativistic Heavy Ion Collider and Large Hadron Collider energies. These photons get competing contributions from the quark and hadronic phases. This competition gives rise to a unique structure, especially in the outward correlation function, owing to the interference between the photons from the two sources. The temporal separation of the two sources provides the lifetime of the system and their strengths provide the relative contribution of the two phases. The results are found to be quite sensitive to the quark-hadron phase transition temperature and the formation time of the plasma.

Srivastava, Dinesh Kumar; Chatterjee, Rupa [Variable Energy Cyclotron Centre, 1/AF Bidhan Nagar, Kolkata 700 064 (India)

2009-11-15T23:59:59.000Z

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.
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to obtain the most current and comprehensive results.


401

Fermilab | Muon Collider | How Does a Muon Collider Work?  

NLE Websites -- All DOE Office Websites (Extended Search)

A muon collider complex would comprise several machines and many different A muon collider complex would comprise several machines and many different components. Scientists across the world are developing and testing them. View full graphic How Does a Muon Collider Work? A muon collider complex would comprise several machines and many different components. Scientists across the world are developing and testing them. Proton accelerator To create lots of muons, scientists use a high-intensity proton accelerator that steers protons into a target. The collisions create short-lived particles called pions. Within 50 meters the pions decay into muons and neutral particles called neutrinos. The muons have an energy of about 200 MeV. Capture cavities Magnets guide the muons into and through a set of radiofrequency cavities. The electric field inside the cavities increases the energy of slow muons

402

Discovering colorons at the early stage LHC  

SciTech Connect

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

403

Quark and Gluon Tagging at the LHC  

Science Journals Connector (OSTI)

Being able to distinguish light-quark jets from gluon jets on an event-by-event basis could significantly enhance the reach for many new physics searches at the Large Hadron Collider. Through an exhaustive search of existing and novel jet substructure observables, we find that a multivariate approach can filter out over 95% of the gluon jets while keeping more than half of the light-quark jets. Moreover, a combination of two simple variables, the charge track multiplicity and the pT-weighted linear radial moment (girth), can achieve similar results. Our study is only Monte Carlo based, so other observables constructed using different jet sizes and parameters are used to highlight areas that deserve further theoretical and experimental scrutiny. Additional information, including distributions of around 10?000 variables, can be found at http://jets.physics.harvard.edu/qvg/.

Jason Gallicchio and Matthew D. Schwartz

2011-10-17T23:59:59.000Z

404

Probing Baryogenesis with Displaced Vertices at the LHC  

E-Print Network (OSTI)

The generation of the asymmetric cosmic baryon abundance requires a departure from thermal equilibrium in the early universe. In a large class of baryogenesis models, the baryon asymmetry results from the out-of-equilibrium decay of a new, massive particle. We highlight that in the interesting scenario where this particle has a weak scale mass, this out-of-equilibrium condition requires a proper decay length larger than O(1) mm. Such new fields are within reach of the LHC, at which they can be pair produced leaving a distinctive, displaced-vertex signature. This scenario is realized in the recently proposed mechanism of baryogenesis where the baryon asymmetry is produced through the freeze-out and subsequent decay of a meta-stable weakly interacting massive particle ("WIMP baryogenesis"). In analogy to missing energy searches for WIMP dark matter, the LHC is an excellent probe of these new long-lived particles responsible for baryogenesis via the low-background displaced vertex channel. In our paper, we estimate the limits on simplified models inspired by WIMP baryogenesis from two of the most sensitive collider searches by CMS and ATLAS with 8 TeV LHC data. We also estimate the LHC reach at 13 TeV using current strategies, and demonstrate that up to a factor of 100 improvement in cross-section limits can be achieved by requiring two displaced vertices while lowering kinematic thresholds. For meta-stable WIMPs produced through electroweak interactions, the high luminosity LHC is sensitive to masses up to 2.5 TeV for lifetimes around 1 cm, while for singlets pair-produced through the off-shell-Higgs portal, the LHC is sensitive to production cross sections of O(10) ab for benchmark masses around 150 GeV. Our analysis and proposals also generally apply to displaced vertex signatures from other new physics such as hidden valley models, twin Higgs models and displaced supersymmetry.

Yanou Cui; Brian Shuve

2014-09-23T23:59:59.000Z

405

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.

Heinemeyer, S; Zoupanos, G

2014-01-01T23:59:59.000Z

406

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

407

[New technology for linear colliders  

SciTech Connect

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

408

EIS-0138: Superconducting Super Collider  

Energy.gov (U.S. Department of Energy (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.

409

Stable massive particles at colliders  

SciTech Connect

We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

Fairbairn, M.; /Stockholm U.; Kraan, A.C.; /Pennsylvania U.; Milstead, D.A.; /Stockholm U.; Sjostrand, T.; /Lund U.; Skands, P.; /Fermilab; Sloan, T.; /Lancaster U.; ,

2006-11-01T23:59:59.000Z

410

RHIC | Electron-Ion Collider  

NLE Websites -- All DOE Office Websites (Extended Search)

particle accelerator could collide electrons with heavy ions or protons at nearly the speed of light to create rapid-fire, high-resolution "snapshots" of the force binding all...

411

Hadronic scattering of charmed mesons  

E-Print Network (OSTI)

The scattering cross sections of charm mesons with hadrons such as the pion, rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion collisions, rescattering of produced charm mesons by hadrons affects the invariant mass spectra...

Lin, ZW; Ko, Che Ming; Zhang, B.

2000-01-01T23:59:59.000Z

412

Discovering dark matter through flavor violation at the LHC  

Science Journals Connector (OSTI)

We show that the discovery channel for dark matter (DM) production at colliders can be through flavor violating interactions resulting in a novel signature of a single top and large missing transverse energy. We discuss several examples where the production of DM is dominated by flavor violating couplings: minimal flavor violating models with a large bottom Yukawa, models with horizontal symmetries, and DM in nontrivial flavor group representations. Discovery at the 7 TeV LHC with a few fb-1 may already be possible.

Jernej F. Kamenik and Jure Zupan

2011-12-27T23:59:59.000Z

413

Towards LHC Physics with Non-local Standard Model  

E-Print Network (OSTI)

We take a few steps towards constructing a string-inspired nonlocal extension of the Standard Model. We start by illustrating how quantum loop calculations can be performed in nonlocal scalar field theory. In particular, we show the potential to address the hierarchy problem in the nonlocal framework. Next, we construct a nonlocal abelian gauge model and derive modifications of the gauge interaction vertex and field propagators. We apply the modifications to a toy version of the nonlocal Standard Model and investigate collider phenomenology. We find the lower bound on the scale of non-locality from the 8 TeV LHC data to be 2.5-3 TeV

Tirthabir Biswas; Nobuchika Okada

2014-07-12T23:59:59.000Z

414

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

415

Reconstruction of stop quark mass at the LHC  

Science Journals Connector (OSTI)

The cascade mass reconstruction approach was applied to simulated production of the lightest stop quark at the LHC in the cascade decay g˜?t˜1t??˜20tt??˜R?tt??˜10??tt with top quarks decaying into hadrons. The stop quark mass was reconstructed assuming that the masses of gluino, slepton, and the two lightest neutralinos were reconstructed in advance. A data sample set for the SU3 model point containing 400 k supersymmetry events was generated which corresponded to an integrated luminosity of about 20??fb-1 at 14 TeV. These events were passed through the AcerDET detector simulator, which parametrized the response of a generic LHC detector. The mass of the t˜1 was reconstructed with a precision of about 10%.

Diego Casadei; Rostislav Konoplich; Rashid Djilkibaev

2010-10-15T23:59:59.000Z

416

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

417

LHC Communications project Dr Ray Mathias  

E-Print Network (OSTI)

LHC Communications project Dr Ray Mathias UK LHC Communications Manager ray.mathias@stfc.ac.uk LHC Communications project STFC Town Meeting 30/11/07 #12;LHC Communications project STFC funded Two-year project Partnership with the UK HEPP community LHC Communications project STFC Town Meeting 30/11/07 #12;Understanding

418

US LHC Accelerator Research Program For the BNL-FNAL-LBNL LHC Accelerator Collaboration  

E-Print Network (OSTI)

US LHC Accelerator Research Program Jim Strait For the BNL-FNAL-LBNL LHC Accelerator Collaboration LHC Symposium 3 May 2003 brookhaven - fermilab - berkeley US LHC Accelerator Research Program #12;LHC Symposium - 3 May 03 US LHC Accelerator Research Program - J. Strait 2 Outline Program Goals R&D to Maximize

Large Hadron Collider Program

419

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

420

New Perspectives for QCD Physics at the LHC  

SciTech Connect

I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. The soft-gluon rescattering effects, which are associated with the Wilson line of the propagating partons, also lead to Bjorken-scaling single-spin asymmetries, diffractive deep inelastic scattering, the breakdown of the Lam-Tung leading-twist relation in Drell-Yan reactions, as well as nuclear shadowing. The Gribov-Glauber theory applied to the antishadowing domain predicts that nuclear structure functions depend on the flavor quantum numbers of each quark and antiquark, thus explaining the anomalous nuclear dependence recently observed in deep-inelastic neutrino scattering. Surprisingly, isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation. The rate is predicted to be significant, even at the LHC. Such 'direct' processes can explain the observed deviations from perturbative QCD predictions in measurements of inclusive hadron cross sections at fixed x{sub T} = 2p{sub T}/{radical}(s), as well as the 'baryon anomaly', the anomalously large proton-to-pion ratio seen in high centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p{sub T} photon plus charm-jet events observed by D0 at the Tevatron. Intrinsic charm and bottom distributions also imply anomalously large production of charm and bottom jets at high p{sub T} at the LHC, as well as a novel mechanism for Higgs and Z{sup 0} production at high x{sub F}. Other novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates and the implications for the QCD contribution to the cosmological constant. The light-front wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at the amplitude level. I also note that the elimination of the renormalization scale ambiguity for the QCD coupling using the scheme-independent BLM method will greatly improve the precision of QCD predictions and thus greatly increase the sensitivity of searches for new physics at the LHC.

Brodsky, S. J. [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309 (United States); CP3-Origins, Southern Denmark University, Odense (Denmark)

2011-04-26T23:59:59.000Z

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

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

422

The LHC superconducting cavities  

E-Print Network (OSTI)

The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

1999-01-01T23:59:59.000Z

423

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

424

Parton Densities at the LHC  

E-Print Network (OSTI)

This contribution to the Italian "Workshop sui Monte Carlo, la Fisica e le Simulazioni a LHC", held at LNF, Frascati, in February, May and October 2006, summarises the status of parton density functions (PDF's) and the impact of their uncertainties on the LHC physics. Emphasis is given to methods of contraining PDF's using LHC data. Moreover, the advantages of the so-called PDF reweighting technique, which enables to quickly estimate PDF uncertainties with Monte Carlo events, are also presented.

A. Tricoli; for the ATLAS Collaboration

2008-08-19T23:59:59.000Z

425

Photoproduction at RHIC and the LHC  

E-Print Network (OSTI)

Photon Collisions at the LHC, April 22-25, 2008, CERN. H.at RHIC and the LHC The IceCube Collaboration This work wasPhotoproduction at RHIC and the LHC Spencer R. Klein Nuclear

Klein, Spencer

2009-01-01T23:59:59.000Z

426

Challenges in future linear colliders  

SciTech Connect

For decades, electron-positron colliders have been complementing proton-proton colliders. But the circular LEP, the largest e-e+ collider, represented an energy limit beyond which energy losses to synchrotron radiation necessitate moving to e-e+ linear colliders (LCs), thereby raising new challenges for accelerator builders. Japanese-American, German, and European collaborations have presented options for the Future Linear Collider (FLC). Key accelerator issues for any FLC option are the achievement of high enough energy and luminosity. Damping rings, taking advantage of the phenomenon of synchrotron radiation, have been developed as the means for decreasing beam size, which is crucial for ensuring a sufficiently high rate of particle-particle collisions. Related challenges are alignment and stability in an environment where even minute ground motion can disrupt performance, and the ability to monitor beam size. The technical challenges exist within a wider context of socioeconomic and political challenges, likely necessitating continued development of international collaboration among parties involved in accelerator-based physics.

Swapan Chattopadhyay; Kaoru Yokoya

2002-09-02T23:59:59.000Z

427

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

428

New physics at the LHC.  

SciTech Connect

With the LHC up and running, the focus of experimental and theoretical high energy physics will soon turn to an interpretation of LHC data in terms of the physics of electroweak symmetry breaking and the TeV scale. We present here a broad review of models for new TeV-scale physics and their LHC signatures. In addition, we discuss possible new physics signatures and describe how they can be linked to specific models of physics beyond the Standard Model. Finally, we illustrate how the LHC era could culminate in a detailed understanding of the underlying principles of TeV-scale physics.

Morrissey, D. E.; Plehn, T.; Tait, T. M. P. (High Energy Physics); (TRIUMF); (Harvard Univ); (Univ. of Heidelberg); (Univ. of California at Irvine); (Northwestern Univ.)

2012-01-01T23:59:59.000Z

429

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

E-Print Network (OSTI)

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

B. I. Abelev

2008-05-04T23:59:59.000Z

430

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

431

LHC Bounds on UV-Complete Models of Dark Matter  

E-Print Network (OSTI)

We analyze the sensitivity of searches for dark matter in the jets and missing energy channel in the case where the particle mediating interactions between hadronic matter and DM is collider accessible. We consider all tree level UV completions of interactions between fermion DM and quarks which contribute to direct detection, and derive bounds which apply to elastic or inelastic scattering dark matter explanations of direct detection signals. We find that studies based on effective operators give robust bounds when the mediator is heavy enough to resonantly produce the final state in question.

Jessica Goodman; William Shepherd

2011-11-09T23:59:59.000Z

432

Collider constraints on interactions of dark energy with the Standard Model  

E-Print Network (OSTI)

We study models in which a light scalar dark energy particle couples to the gauge fields of the electroweak force, the photon, Z and W bosons. Our analysis applies to a large class of interacting dark energy models, including those in which the dark energy mass can be adjusted to evade fifth-force bounds by the so-called chameleon mechanism. We conclude that--with the usual choice of Higgs sector--electroweak precision observables are screened from the indirect effects of dark energy, making such corrections effectively unobservable at present-day colliders, and limiting the dark energy discovery potential of any future International Linear Collider. We show that a similar screening effect applies to processes mediated by flavour-changing neutral currents, which can be traced to the Glashow-Iliopoulos-Maiani mechanism. However, Higgs boson production at the Large Hadron Collider via weak boson fusion may receive observable corrections.

Philippe Brax; Clare Burrage; Anne-Christine Davis; David Seery; Amanda Weltman

2009-04-20T23:59:59.000Z

433

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

434

RHIC | Relativistic Heavy Ion Collider  

NLE Websites -- All DOE Office Websites (Extended Search)

Relativistic Heavy Ion Collider Relativistic Heavy Ion Collider Photo of LINAC The Relativistic Heavy Ion Collider (RHIC) is a world-class particle accelerator at Brookhaven National Laboratory where physicists are exploring the most fundamental forces and properties of matter and the early universe. RHIC accelerates beams of particles (e.g., the nuclei of heavy atoms such as gold) to nearly the speed of light, and smashes them together to recreate a state of matter thought to have existed immediately after the Big Bang some 13.8 billion years ago. STAR and PHENIX, two large detectors located around the 2.4-mile-circumference accelerator, take "snapshots" of these collisions to reveal a glimpse of the basic constituents of visible matter, quarks and gluons. Understanding matter at

435

RHIC | Relativistic Heavy Ion Collider  

NLE Websites -- All DOE Office Websites

Brookhaven National Laboratory Brookhaven National Laboratory search U.S. Department of Energy logo Home RHIC Science News Images Videos For Scientists Björn Schenke 490th Brookhaven Lecture, 12/18 Join Björn Schenke of Brookhaven Lab's Physics Department for the 490th Brookhaven Lecture, titled 'The Shape and Flow of Heavy Ion Collisions,' on Wednesday, Dec. 18, at 4 p.m. in Berkner Hall. droplets Tiny Drops of Hot Quark Soup-How Small Can They Be? New analyses indicate that collisions of small particles with large gold nuclei at the Relativistic Heavy Ion Collider may be serving up miniscule servings of hot quark-gluon plasma. RHIC Physics RHIC is the first machine in the world capable of colliding ions as heavy as gold. The Spin Puzzle RHIC is the world's only machine capable of colliding beams of polarized

436

Linear Collider Collaboration Tech Notes  

NLE Websites -- All DOE Office Websites (Extended Search)

6, 27/05/99 6, 27/05/99 Tolerances of Random RF Jitters in X-Band Main Linacs May 27, 1999 Kiyoshi KUBO KEK Tsukuba, Japan Abstract: Tracking simulations have been performed for the main linacs of an X-band linear collider. We discuss the choice of phase of the accelerating field relative to the bunches. The tolerances of the phase and the amplitude errors are studied. Tolerances of Random RF Jitters in X-Band Main Linacs K. Kubo, KEK Abstract Tracking simulations have been performed for main linacs of X-band linear collider. We discuss about choice of the phase of the accelerating field relative to the bunches. The tolerances of the phase and the amplitude errors are studied. 1 INTRODUCTION In order to preserve the low emittance through the main linacs of future linear colliders, various effects

437

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

438

LHC Design & Construction | Brookhaven and the LHC  

NLE Websites -- All DOE Office Websites (Extended Search)

LHC Design & Construction LHC Design & Construction BNL-built superconducting magnet BNL engineers with the first of 20 BNL-built superconducting magnets for the LHC. Starting in 1996, Brookhaven scientists and engineers designed and constructed 20 of the total 1,200 superconducting magnets for the LHC. Now in place, these specialized dipole magnets, each weighing more than 25 tons, will guide the LHC's two counter-rotating beams of protons into collision. Tied to this effort, Brookhaven scientists also tested much of the associated superconducting wires and cables for the machine. In addition, Brookhaven scientists and engineers designed and built key parts of the ATLAS detector, including: pieces of the liquid argon calorimeter - a device that pinpoints electrons and photons emerging from

439

Hadron Production in Heavy Ion Collisions  

SciTech Connect

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

440

Search for Supersymmetry in the Jets + Met + TAUS Final State Using the CMS Detector at the LHC  

E-Print Network (OSTI)

Muon Solenoid detector at the Large Hadron Collider in 2011, and it corresponds to an integrated luminosity of 5fb^?1. The tau isolation variable was optimized for this search. The number of events corresponding to standard model processes in the final...

Montalvo, Roy Joaquin

2013-02-28T23:59:59.000Z

Note: This page contains sample records for the topic "hadron collider lhc" from the National Library of EnergyBeta (NLEBeta).
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441

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

442

Luminosity Measurement at the LHC  

Science Journals Connector (OSTI)

For Collider physics the parameters Luminosity ü and total center-of-mass energy ?s largely characterize the machine performance and the physics reach.

Michael Rijssenbeek

2003-01-01T23:59:59.000Z

443

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

444

Charmonium production at the LHC  

E-Print Network (OSTI)

We summarize the perspectives on quarkonium, in particular charmonium, detection at the LHC, both for proton-proton and heavy-ion collisions. We give a review of the experimental capabilities of the four LHC detectors: ALICE, ATLAS, CMS and LHCb.

Magdalena Malek

2009-11-08T23:59:59.000Z

445

Top Physics at the LHC  

E-Print Network (OSTI)

The LHC will be a top quark factory. In this note, the central role of the top quark for LHC physics will be discussed, and an overview will be given of the studies of top quark properties in preparation, with an emphasis on the systematic uncertainties that will dominate most measurements.

P. de Jong

2009-02-27T23:59:59.000Z

446

Parton Distributions and LHC data  

E-Print Network (OSTI)

In this contribution we briefly report on the progress and open problems in parton distribution functions (PDFs), with emphasis on their implications for LHC phenomenology. Then we study the impact of the recent ATLAS and CMS W lepton asymmetry data on the NNPDF2.1 parton distributions. We show that these data provide the first constrains on PDFs from LHC measurements.

Juan Rojo

2011-06-10T23:59:59.000Z

447

Critical Issues and MUON Colliders - A Summary  

E-Print Network (OSTI)

Prospects for a High Energy Muon Collider Based On Electro-and understanding of high energy muon colliders, associatedyield of muons per electron, even at the optimum energy of

Chattopadhyay, S.

2008-01-01T23:59:59.000Z

448

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

449

From Neutrino Factory to Muon Collider  

SciTech Connect

Both Muon Colliders and Neutrino Factories require a muon source capable of producing and capturing {Omicron}(10{sup 21}) muons/year. This paper reviews the similarities and differences between Neutrino Factory and Muon Collider accelerator complexes, the ongoing R&D needed for a Muon Collider that goes beyond Neutrino Factory R&D, and some thoughts about how a Neutrino Factory on the CERN site might eventually be upgraded to a Muon Collider.

Geer, S.; /Fermilab

2010-01-01T23:59:59.000Z

450

SUSY-Yukawa Sum Rule at the LHC  

E-Print Network (OSTI)

We propose the "supersymmetric (SUSY) Yukawa sum rule", a relationship between physical masses and mixing angles of the third-generation quarks and squarks. The sum rule follows directly from a relation between quark and squark couplings to the Higgs, enforced by SUSY. It is exactly this relation that ensures the cancellation of the one-loop quadratic divergence in the Higgs mass from the top sector. Testing the sum rule experimentally would thus provide a powerful consistency check on SUSY as the solution to the gauge hierarchy problem. While such a test will most likely have to await a future next-generation lepton collider, the LHC experiments may be able to make significant progress towards this goal. If some of the terms entering the sum rule are measured at the LHC, the sum rule can be used (within SUSY framework) to put interesting constraints on the other terms, such as the mixing angles among third-generation squarks. We outline how the required mass measurements could be performed, and estimate the accuracy that can be achieved at the LHC.

Monika Blanke; David Curtin; Maxim Perelstein

2010-04-29T23:59:59.000Z

451

Non-Custodial Warped Extra Dimensions at the LHC?  

E-Print Network (OSTI)

With the prospect of improved Higgs measurements at the LHC and at proposed future colliders such as ILC, CLIC and TLEP we study the non-custodial Randall-Sundrum model with bulk SM fields and compare brane and bulk Higgs scenarios. The latter bear resemblance to the well studied type III two-Higgs-doublet models. We compute the electroweak precision observables and argue that incalculable contributions to these, in the form of higher dimensional operators, could have an impact on the T-parameter. This could potentially reduce the bound on the lowest Kaluza-Klein gauge boson masses to the 5 TeV range, making them detectable at the LHC. In a second part, we compute the misalignment between fermion masses and Yukawa couplings caused by vector-like Kaluza-Klein fermions in this setup. The misalignment of the top Yukawa can easily reach 10%, making it observable at the high-luminosity LHC. Corrections to the bottom and tau Yukawa couplings can be at the percent level and detectable at ILC, CLIC or TLEP.

Barry M. Dillon; Stephan J. Huber

2014-10-27T23:59:59.000Z

452

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

453

Muon Collider Physics at Very High Energies  

E-Print Network (OSTI)

Muon colliders might greatly extend the energy frontier of collider physics. One can contemplate circular colliders with center-of-mass energies in excess of 10 TeV. Some physics issues that might be relevant at such a machine are discussed.

M. S. Berger

2000-01-03T23:59:59.000Z

454

Quarkonia and heavy flavors at the LHC  

E-Print Network (OSTI)

Perspectives for quarkonia and heavy flavors measurements in heavy ion collisions at LHC are reviewed

P. Crochet

2005-03-14T23:59:59.000Z

455

US LHC Accelerator Project and Research Program  

E-Print Network (OSTI)

US LHC Accelerator Project and Research Program Jim Strait Fermilab 13 June 2002 brookhaven - fermilab - berkeley US LHC ACCELERATOR PROJECT #12;13 June 2002 J. Strait - US LHC Accelerator Project 2 Outline US LHC Accelerator (Construction) Project Project Technical and Schedule Status Cost and Schedule

Large Hadron Collider Program

456

Ian Hinchliffe News from ATLAS at LHC  

E-Print Network (OSTI)

1 Ian Hinchliffe News from ATLAS at LHC #12;2 Outline · LHC and ATLAS performance · Comments of features · JINST 3, (2008) S08003 #12;5 Superb LHC and ATLAS performance · This talk would not be possible · Now look at physics for which LHC was designed #12;13 Reminder of Higgs production · #12;14 Reminder

California at Santa Cruz, University of

457

Early LHC Prospects for Exotic Physics  

E-Print Network (OSTI)

Early LHC Prospects for Exotic Physics Tim M.P. Tait West Coast LHC @ UCSC May 21, 2010 University of California, Irvine #12;Outline Resources Comparing LHC0.5 with Tevatron Resonances Fourth Generation Quarks #12;Resources I agreed to speak about what early LHC running can tell us about some exotic physics

California at Santa Cruz, University of

458

Measurement of the Jet Momentum Resolution and Search for a light Standard Model Higgs Boson in the H(bb)W(lv) Channel with the CMS Detector at the LHC  

E-Print Network (OSTI)

The Higgs boson is the last particle predicted by the Standard Model which remains undetected. Its potential discovery was a main objective of the construction of the Large Hadron Collider (LHC) at CERN. Its exclusion would necessitate the existence of new physics beyond the Standard Model. A search for the Higgs boson decaying into two bottom quarks in association with the production of a leptonically decaying W boson is presented based on pp collision data recorded with the CMS experiment in 2011, corresponding to an integrated luminosity of L = 4.65 fb?1. Events are selected requiring the presence of an isolated charged lepton (electron or muon), missing transverse energy and two b-jets, which are clustered with the anti-kT jet algorithm at first. The search is performed in a boosted event topology, where both the W boson and the Higgs boson candidates have high momenta and move back-to-back in the transverse detector plane. Artificial Neural Networks are employed to discriminate signal and background ev...

Held, Hauke

459

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

460

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

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.


461

Strange particle production in hadronic Z{sup 0} decays  

SciTech Connect

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

462

LHC Phenomenology for Physics Hunters  

E-Print Network (OSTI)

Welcome to the 2008 TASI lectures on the exciting topic of `tools and technicalities' (original title). Technically, LHC physics is really all about perturbative QCD in signals or backgrounds. Whenever we look for interesting signatures at the LHC we get killed by QCD. Therefore, I will focus on QCD issues which arise for example in Higgs searches or exotics searches at the LHC, and ways to tackle them nowadays. In the last section you will find a few phenomenological discussions, for example on missing energy or helicity amplitudes.

Tilman Plehn

2008-10-13T23:59:59.000Z

463

Probing resonant leptogenesis at the LHC  

Science Journals Connector (OSTI)

We explore direct collider probes of the resonant leptogenesis mechanism for the origin of matter. We work in the context of theories where the standard model (SM) is extended to include an additional gauged U(1) symmetry broken at the TeV scale, and where the light neutrinos obtain mass through a type I seesaw at this scale. The CP asymmetry that generates the observed matter-antimatter asymmetry manifests itself in a difference between the number of positive and negative like-sign dileptons N(?+?+)-N(?-?-) that arise in the decay of the new Z? gauge boson to two right-handed neutrinos N, and their subsequent decay to leptons. The relatively low efficiency of resonant leptogenesis in this class of models implies that the CP asymmetry, ?, is required to be sizable, i.e., of order one. In particular, from the sign of the baryon asymmetry of the Universe, an excess of antileptons is predicted. We identify the domains in MZ?-MN space where such a direct test is possible and find that with 300??fb-1 of data and no excess found, the LHC can set the 2? exclusion limit ??0.22.

Steve Blanchet; Z. Chacko; Solomon S. Granor; Rabindra N. Mohapatra

2010-10-25T23:59:59.000Z

464

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

465

Conventional power sources for colliders  

SciTech Connect

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

466

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

2014-08-25T23:59:59.000Z

467

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

468

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

469

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

SciTech Connect

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

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

2012-05-22T23:59:59.000Z

470

Unravelling Strings at the LHC  

E-Print Network (OSTI)

We construct LHC signature footprints for four semi-realistic string/$M$ theory vacua with an MSSM visible sector. We find that they all give rise to limited regions in LHC signature space, and are qualitatively different from each other for understandable reasons. We also propose a technique in which correlations of LHC signatures can be effectively used to distinguish among these string theory vacua. We expect the technique to be useful for more general string vacua. We argue that further systematic analysis with this approach will allow LHC data to disfavor or exclude major ``corners'' of string/$M$ theory and favor others. The technique can be used with limited integrated luminosity and improved.

Gordon L. Kane; Piyush Kumar; Jing Shao

2007-09-26T23:59:59.000Z

471

Neutralino oscillations at the LHC  

Science Journals Connector (OSTI)

We study a supersymmetric phenomenon that can give spectacular signals at the LHC: oscillations of neutralinos. Such oscillations can be naturally realized in R-symmetric models, where additional fields are introduced as Dirac mass partners of gauginos and Higgsinos. Majorana masses for gauginos, necessarily generated from anomaly mediation, can create tiny mass splittings between degenerate mass eigenstates, causing states produced at the LHC to oscillate between neutralinos and their Dirac partner fields. Scenarios where such states decay with displaced vertices can lead to striking signatures at the LHC, where the oscillation can be visible directly in the distribution of displaced vertex lengths. We elaborate on the theory and LHC phenomenology of this feature within a specific scenario of a Higgsino decaying with a displaced vertex into a gravitino and a Z boson.

Yuval Grossman; Bibhushan Shakya; Yuhsin Tsai

2013-08-30T23:59:59.000Z

472

Photons and Dileptons at LHC  

E-Print Network (OSTI)

We discuss real and virtual photon sources in heavy ion collisions and present results for dilepton yields in Pb+Pb collisions at the LHC at intermediate and large transverse momentum p_T.

Rainer J. Fries; S. Turbide; C. Gale; D. K. Srivastava

2007-07-02T23:59:59.000Z

473

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

474

Single Top production at LHC  

E-Print Network (OSTI)

The Production of single top quarks at LHC provides an ideal framework to investigate the properties of electroweak interaction, in particular of the {\\it tWb} coupling. Moreover, single top is a powerful mean to identify physics beyond the standard model. All three different production mechanisms of single top are expected to be observed at LHC. Recent studies from ATLAS and CMS are presented.

M. Mohammadi Najafabadi

2006-05-12T23:59:59.000Z

475

SUSY Predictions for the LHC  

E-Print Network (OSTI)

In the CMSSM we find preferences for sparticle masses that are relatively light. In the NUHM1 the best-fit values for many sparticle masses are even slightly smaller, but with greater uncertainties. We find that at the 95% C.L. all colored particles are in the reach of the LHC. While the light Higgs boson is bounded from above by M_h LHC searches, but might be accessible at the ILC.

S. Heinemeyer

2009-09-25T23:59:59.000Z

476

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

477

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

478

Determining the squark mass at the LHC  

Science Journals Connector (OSTI)

We propose a new way to determine the squark mass based on the shape of dijet invariant mass distribution of supersymmetry dijet events at the Large Hadron Collider. Our algorithm, which is based on event kinematics, requires that the branching ratio B(q˜?qZ˜1) is substantial for at least some types of squarks, and that mZ˜12/mq˜2?1. We select dijet events with no isolated leptons, and impose cuts on the total jet transverse energy, ETtot=ET(j1)+ET(j2), on ?=ET(j2)/mjj, and on the azimuthal angle between the two jets to reduce standard model backgrounds. The shape of the resulting dijet mass distribution depends sensitively on the squark mass, especially if the integrated luminosity is sufficient to allow a hard enough cut on ETtot and yet leave a large enough signal to obtain the mjj distribution. We simulate the signal and standard model backgrounds for 100??fb-1 integrated luminosity at 14 TeV requiring ETtot>700??GeV. We show that it should be possible to extract mq˜ to within about 3% at 95% confidence level—similar to the precision obtained using mT2—from the dijet mass distribution if mq˜?650??GeV, or to within ?5% if mq˜?1??TeV.

Vernon Barger; Yu Gao; Andre Lessa; Xerxes Tata

2011-05-19T23:59:59.000Z

479

Left-right symmetry at LHC  

Science Journals Connector (OSTI)

We revisit the issue of the limit on the scale of left-right symmetry breaking. We focus on the minimal SU(2)L×SU(2)R×U(1)B-L gauge theory with the seesaw mechanism and discuss the two possibilities of defining left-right symmetry as parity or charge conjugation. In the commonly adopted case of parity, we perform a complete numerical study of the quark mass matrices and the associated left and right mixing matrices without any assumptions usually made in the literature about the ratio of vacuum expectation values. We find that the usual lower limit on the mass of the right-handed gauge boson from the K mass difference, MWR>2.5??TeV, is subject to a possible small reduction due to the difference between right and left Cabibbo angles. In the case of charge conjugation the limit on MWR is somewhat more robust. However, the more severe bounds from CP-violating observables are absent in this case. In fact, the free phases can also resolve the present mild discrepancy between the standard model and CP violation in the B sector. Thus, even in the minimal case, both charged and neutral gauge bosons may be accessible at the Large Hadron Collider with spectacular signatures of lepton number violation.

Alessio Maiezza; Miha Nemevšek; Fabrizio Nesti; Goran Senjanovi?

2010-09-24T23:59:59.000Z

480

MSSM inflation, dark matter, and the LHC  

Science Journals Connector (OSTI)

Inflation can occur near a point of inflection in the potential of flat directions of the minimal supersymmetric standard model (MSSM). In this paper we elaborate on the complementarity between the bounds from cosmic microwave background measurements, dark matter, and particle physics phenomenology in determining the underlying parameters of MSSM inflation by specializing to the minimal supergravity scenario. We show that the future measurements from the Large Hadron Collider in tandem with all these constraints will significantly restrict the allowed parameter space. We also suggest a new perspective on the fine tuning issue of MSSM inflation. With quantum corrections taken into account, the necessary condition between the soft supersymmetry breaking parameters in the inflaton potential can be satisfied at scales of interest without a fine tuning of their boundary values at a high scale. The requirement that this happens at the inflection point determines a dimensionless coupling, which is associated with a nonrenormalizable interaction term in the Lagrangian and has no bearing for phenomenology, to very high accuracy.

Rouzbeh Allahverdi; Bhaskar Dutta; Yudi Santoso

2010-08-17T23:59:59.000Z

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481

Dilaton at the LHC  

Science Journals Connector (OSTI)

The dilaton, a pseudo-Nambu-Goldstone boson appearing in spontaneous scale symmetry breaking at a TeV scale f, may be found in Higgs boson searches. The dilaton couples to standard model fermions and weak bosons with the same structure as the Higgs boson except for the overall strength. Additionally, the dilaton couples to a Higgs boson pair. The couplings of the dilaton to a gluon pair and a photon pair, appearing at loop level, are largely enhanced compared to the corresponding Higgs couplings. We present regions of the mass and vacuum expectation value (VEV) of the dilaton allowed by WW, ZZ, and ?? limits from the LHC at 7 TeV with 1.0–2.3??fb-1 integrated luminosity. A scale of f less than 1 TeV is nearly excluded. We discuss how the dilaton ? can be distinguished from the Higgs boson h0 by observation of the decays ???? and ??h0h0?(WW)(WW).

Vernon Barger; Muneyuki Ishida; Wai-Yee Keung

2012-01-26T23:59:59.000Z

482

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

483

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

484

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

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