WorldWideScience

Sample records for collider run ii

  1. Collider shot setup for Run 2 observations and suggestions

    International Nuclear Information System (INIS)

    Annala, J.; Joshel, B.

    1996-01-01

    This note is intended to provoke discussion on Collider Run II shot setup. We hope this is a start of activities that will converge on a functional description of what is needed for shot setups in Collider Run II. We will draw on observations of the present shot setup to raise questions and make suggestions for the next Collider run. It is assumed that the reader has some familiarity with the Collider operational issues. Shot setup is defined to be the time between the end of a store and the time the Main Control Room declares colliding beams. This is the time between Tevatron clock events SCE and SCB. This definition does not consider the time experiments use to turn on their detectors. This analysis was suggested by David Finley. The operational scenarios for Run II will require higher levels of reliability and speed for shot setup. See Appendix I and II. For example, we estimate that a loss of 3 pb -1 /week (with 8 hour stores) will occur if shot setups take 90 minutes instead of 30 minutes. In other words: If you do 12 shots for one week and accept an added delay of one minute in each shot, you will loose more than 60 nb -1 for that week alone (based on a normal shot setup of 30 minutes). These demands should lead us to be much more pedantic about all the factors that affect shot setups. Shot setup will be viewed as a distinct process that is composed of several inter- dependent 'components': procedures, hardware, controls, and sociology. These components don't directly align with the different Accelerator Division departments, but are topical groupings of the needed accelerator functions. Defining these components, and categorizing our suggestions within them, are part of the goal of this document. Of course, some suggestions span several of these components

  2. Computing Models of CDF and D0 in Run II

    International Nuclear Information System (INIS)

    Lammel, S.

    1997-05-01

    The next collider run of the Fermilab Tevatron, Run II, is scheduled for autumn of 1999. Both experiments, the Collider Detector at Fermilab (CDF) and the D0 experiment are being modified to cope with the higher luminosity and shorter bunchspacing of the Tevatron. New detector components, higher event complexity, and an increased data volume require changes from the data acquisition systems up to the analysis systems. In this paper we present a summary of the computing models of the two experiments for Run II

  3. Computing Models of CDF and D0 in Run II

    International Nuclear Information System (INIS)

    Lammel, S.

    1997-01-01

    The next collider run of the Fermilab Tevatron, Run II, is scheduled for autumn of 1999. Both experiments, the Collider Detector at Fermilab (CDF) and the D0 experiment are being modified to cope with the higher luminosity and shorter bunch spacing of the Tevatron. New detector components, higher event complexity, and an increased data volume require changes from the data acquisition systems up to the analysis systems. In this paper we present a summary of the computing models of the two experiments for Run II

  4. First paper from Tevatron Run II submitted by CDF collaboration

    CERN Multimedia

    2003-01-01

    "Scientists of the Collider Detector at Fermilab submitted today (March 19) the first scientific publication of Collider Run II to the science journal Physical Review D. The paper titled "Measurement of the Mass Difference m(Ds+)-m(D+) at CDF II" summarizes the results of an analysis carried out by CDF scientists Christoph Paus and Ivan Furic, MIT, describing the mass measurement of particles containing charm quarks" (1 page).

  5. Run II of the LHC: The Accelerator Science

    Science.gov (United States)

    Redaelli, Stefano

    2015-04-01

    In 2015 the Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) starts its Run II operation. After the successful Run I at 3.5 TeV and 4 TeV in the 2010-2013 period, a first long shutdown (LS1) was mainly dedicated to the consolidation of the LHC magnet interconnections, to allow the LHC to operate at its design beam energy of 7 TeV. Other key accelerator systems have also been improved to optimize the performance reach at higher beam energies. After a review of the LS1 activities, the status of the LHC start-up progress is reported, addressing in particular the status of the LHC hardware commissioning and of the training campaign of superconducting magnets that will determine the operation beam energy in 2015. Then, the plans for the Run II operation are reviewed in detail, covering choice of initial machine parameters and strategy to improve the Run II performance. Future prospects of the LHC and its upgrade plans are also presented.

  6. The CDF Run II disk inventory manager

    International Nuclear Information System (INIS)

    Hubbard, Paul; Lammel, Stephan

    2001-01-01

    The Collider Detector at Fermilab (CDF) experiment records and analyses proton-antiproton interactions at a center-of-mass energy of 2 TeV. Run II of the Fermilab Tevatron started in April of this year. The duration of the run is expected to be over two years. One of the main data handling strategies of CDF for Run II is to hide all tape access from the user and to facilitate sharing of data and thus disk space. A disk inventory manager was designed and developed over the past years to keep track of the data on disk, to coordinate user access to the data, and to stage data back from tape to disk as needed. The CDF Run II disk inventory manager consists of a server process, a user and administrator command line interfaces, and a library with the routines of the client API. Data are managed in filesets which are groups of one or more files. The system keeps track of user access to the filesets and attempts to keep frequently accessed data on disk. Data that are not on disk are automatically staged back from tape as needed. For CDF the main staging method is based on the mt-tools package as tapes are written according to the ANSI standard

  7. Beam instrumentation for the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-10-01

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

  8. The Muon system of the run II D0 detector

    Energy Technology Data Exchange (ETDEWEB)

    Abazov, V.M.; Acharya, B.S.; Alexeev, G.D.; Alkhazov, G.; Anosov, V.A.; Baldin, B.; Banerjee, S.; Bardon, O.; Bartlett, J.F.; Baturitsky, M.A.; Beutel, D.; Bezzubov,; Bodyagin, V.; Butler, J.M.; Cease, H.; Chi, E.; Denisov, D.; Denisov, S.P.; Diehl, H.T.; Doulas, S.; Dugad, S.R.; /Beijing, Inst. High Energy Phys. /Charles U. /Prague, Tech.

    2005-03-01

    The authors describe the design, construction and performance of the upgraded D0 muon system for Run II of the Fermilab Tevatron collider. Significant improvements have been made to the major subsystems of the D0 muon detector: trigger scintillation counters, tracking detectors, and electronics. The Run II central muon detector has a new scintillation counter system inside the iron toroid and an improved scintillation counter system outside the iron toroid. In the forward region, new scintillation counter and tracking systems have been installed. Extensive shielding has been added in the forward region. A large fraction of the muon system electronics is also new.

  9. Run scenarios for the linear collider

    International Nuclear Information System (INIS)

    M. Battaglia et al. email = crathbun@fnal.gov

    2002-01-01

    We have examined how a Linear Collider program of 1000 fb -1 could be constructed in the case that a very rich program of new physics is accessible at √s ≤ 500 GeV. We have examined possible run plans that would allow the measurement of the parameters of a 120 GeV Higgs boson, the top quark, and could give information on the sparticle masses in SUSY scenarios in which many states are accessible. We find that the construction of the run plan (the specific energies for collider operation, the mix of initial state electron polarization states, and the use of special e - e - runs) will depend quite sensitively on the specifics of the supersymmetry model, as the decay channels open to particular sparticles vary drastically and discontinuously as the underlying SUSY model parameters are varied. We have explored this dependence somewhat by considering two rather closely related SUSY model points. We have called for operation at a high energy to study kinematic end points, followed by runs in the vicinity of several two body production thresholds once their location is determined by the end point studies. For our benchmarks, the end point runs are capable of disentangling most sparticle states through the use of specific final states and beam polarizations. The estimated sparticle mass precisions, combined from end point and scan data, are given in Table VIII and the corresponding estimates for the mSUGRA parameters are in Table IX. The precision for the Higgs boson mass, width, cross-sections, branching ratios and couplings are given in Table X. The errors on the top quark mass and width are expected to be dominated by the systematic limits imposed by QCD non-perturbative effects. The run plan devotes at least two thirds of the accumulated luminosity near the maximum LC energy, so that the program would be sensitive to unexpected new phenomena at high mass scales. We conclude that with a 1 ab -1 program, expected to take the first 6-7 years of LC operation, one can do

  10. Large Hadron particle collider may not have its run this November

    CERN Multimedia

    2007-01-01

    "The Large Hadron Collider (LHC), based at CERN in Geneva, Switzerland, will not run in November this year as scheduled. The LHC was supposed to have a test run this yera, before switching on the scientific search for the Higgs boson in 2008."(1 page)

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

    CERN Document Server

    Rojo, Juan; Ball, Richard D; Cooper-Sarkar, Amanda; de Roeck, Albert; Farry, Stephen; Ferrando, James; Forte, Stefano; Gao, Jun; Harland-Lang, Lucian; Huston, Joey; Glazov, Alexander; Gouzevitch, Maxime; Gwenlan, Claire; Lipka, Katerina; Lisovyi, Mykhailo; Mangano, Michelangelo; Nadolsky, Pavel; Perrozzi, Luca; Placakyte, Ringaile; Radescu, Voica; Salam, Gavin P; Thorne, Robert

    2015-01-01

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

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

    International Nuclear Information System (INIS)

    Rojo, Juan; Ball, Richard D.; CERN, Geneva

    2015-07-01

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

  13. Tevatron The Cinderella story or the art of collider

    CERN Document Server

    CERN. Geneva

    2007-01-01

    The Tevatron Collider at Fermilab (Batavia, IL, USA) is the world's highest energy particle collider at 1.8TeV c.m.e. The machine was a centerpiece of the US and world's High Energy Physics for many years. Currently, the Tevatron is in the last years of its operation in so-called Run II which started 2001 and is tentatively scheduled to end in 2010. In this lecture series, we'll try to learn from the exciting story of the Tevatron Collider Run II: the story of long preparations, great expectations, initial difficulties, years of "blood and sweat", continuous upgrades, exceeding its goals, high emotions, tune-up of accelerator organization for "combat fighting". The lectures will cover Introduction to the Tevatron, its history and Run II; "Plumbing" Issues; Beam Physics Issues; Luminosity Progress; Organization of Troops and Lessons for LHC.

  14. 1987 DOE review: First collider run operation

    International Nuclear Information System (INIS)

    Childress, S.; Crawford, J.; Dugan, G.

    1987-05-01

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

  15. Operational Experience, Improvements, and Performance of the CDF Run II Silicon Vertex Detector

    CERN Document Server

    Aaltonen, T; Boveia, A.; Brau, B.; Bolla, G; Bortoletto, D; Calancha, C; Carron, S.; Cihangir, S.; Corbo, M.; Clark, D.; Di Ruzza, B.; Eusebi, R.; Fernandez, J.P.; Freeman, J.C.; Garcia, J.E.; Garcia-Sciveres, M.; Gonzalez, O.; Grinstein, S.; Hartz, M.; Herndon, M.; Hill, C.; Hocker, A.; Husemann, U.; Incandela, J.; Issever, C.; Jindariani, S.; Junk, T.R.; Knoepfel, K.; Lewis, J.D.; Martinez-Ballarin, R.; Mathis, M.; Mattson, M.; Merkel, P; Mondragon, M.N.; Moore, R.; Mumford, J.R.; Nahn, S.; Nielsen, J.; Nelson, T.K.; Pavlicek, V.; Pursley, J.; Redondo, I.; Roser, R.; Schultz, K.; Spalding, J.; Stancari, M.; Stanitzki, M.; Stuart, D.; Sukhanov, A.; Tesarek, R.; Treptow, K.; Wallny, R.; Worm, S.

    2013-01-01

    The Collider Detector at Fermilab (CDF) pursues a broad physics program at Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and the end of operations in September 2011, the Tevatron delivered 12 fb-1 of integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics analyses undertaken by CDF require heavy flavor tagging with large charged particle tracking acceptance. To realize these goals, in 2001 CDF installed eight layers of silicon microstrip detectors around its interaction region. These detectors were designed for 2--5 years of operation, radiation doses up to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were not replaced, and the Tevatron run was extended for several years beyond its design, exposing the sensors and electronics to much higher radiation doses than anticipated. In this paper we describe the operational challenges encountered over the past 10 years of running the CDF silicon detectors, the preventive measures undertaken, an...

  16. Electroweak physics prospects for CDF in Run II

    International Nuclear Information System (INIS)

    Eric James

    2003-01-01

    The CDF collaboration will vigorously pursue a comprehensive program of electroweak physics during Run II at the Tevatron based strongly on the successful Run I program. The Run IIa integrated luminosity goal of 2 fb -1 will lead to a CDF dataset twenty times larger than that collected in Run I. In addition, an increase in the energy of the colliding beams from √s = 1.80 TeV to √s = 1.96 TeV for Run II provides a 10% increase in the W and Z boson production cross sections and a corresponding enlargement of the electroweak event samples. In the near term, CDF expects to collect a dataset with 2-3 times the integrated luminosity of Run I by September of 2003. Utilizing these new datasets CDF will be able to make improved, precision measurements of Standard Model electroweak parameters including M W , M top , Λ W , and sin 2 θ W eff . The goal of these measurements will be to improve our understanding of the self-consistency of the Standard Model and knowledge of the Higgs boson mass within the model. The top plot in Fig. 1 illustrates our current knowledge of the Standard Model Higgs mass based on measurements of M W and M top . The constraints imposed by combined CDF and D0 Run I measurements of M W (80.456 ± 0.059GeV/c 2 ) and M top (174.3 ± 5.1GeV/c 2 ) are illustrated by the shaded oval region on the plot. The hatched rectangle shows the additional constraint imposed by the recent LEP2 measurement of M W . The bottom plot in Fig. 1 illustrates the expected improvement in these constraints based on Run II CDF measurements utilizing a 2 fb -1 dataset. The shaded oval region in this plot is based on current estimates of a 40 MeV/c 2 uncertainty for measuring M W and a 2-3 GeV/c 2 uncertainty for measuring M top

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

    International Nuclear Information System (INIS)

    Rojo, Juan; Accardi, Alberto; Ball, Richard D; Cooper-Sarkar, Amanda; Gwenlan, Claire; Roeck, Albert de; Mangano, Michelangelo; Farry, Stephen; Ferrando, James; Forte, Stefano; Gao, Jun; Harland-Lang, Lucian; Huston, Joey; Glazov, Alexander; Lipka, Katerina; Gouzevitch, Maxime; Lisovyi, Mykhailo; Nadolsky, Pavel

    2015-01-01

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

  18. Tevatron instrumentation: boosting collider performance

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-05-01

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

  19. The first ep collider run and future plans

    International Nuclear Information System (INIS)

    Desy, R.B.

    1993-01-01

    After successful machine commissioning in 1991, the new electron-proton collider HERA was ready to start the experimental program in spring last year. Data taking at the ZEUS and H1 experiments began on June 26. The energy of the colliding beams was E e =26.7 GeV and E p = 820 GeV, in accord with the design. The peak luminosity obtained so far was 2.2x10 29 cm -2 s -1 . Until the end of the experimental run in November 1992 an integrated luminosity of 33 nb -1 was delivered to the experiments. Future plans concerning ep operation focus on increasing the number of colliding bunches in order to approach the design goal for the luminosity of 1.5x10 31 cm -2 s -1 . In the electron ring, up to 60% transverse spin polarization have been achieved. It is planned to install a polarized gas target experiment (Hermes, approved as the 3rd HERA experiment) which will require an electron beam with about 50% longitudinal polarization. The machine modifications required for HERMES are scheduled for the 93/94 winter shut down. Furthermore, the possibilities of installing a fixed target experiment for b-quark physics in the proton ring are being studied

  20. 2007 2008 ACADEMIC TRAINING PROGRAMME: Tevatron: The Cinderella Story or The Art Of Collider Commissioning

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 01, 03, 04, 05 October 2007 Main Auditorium, bldg. 500 Tevatron: The Cinderella Story or The Art Of Collider Commissioning V. SHILTSEV / Fermi National Accelerator Laboraty, Batavia IL, USA The Tevatron Collider at Fermilab (Batavia, IL, USA) is the world’s highest energy particle collider at 1.8TeV c.m.e. The machine was a centerpiece of the US and world’s High Energy Physics for many years. Currently, the Tevatron is in the last years of its operation in so-called Run II which started 2001 and is tentatively scheduled to end in 2010. In this lecture series, we’ll try to learn from the exciting story of the Tevatron Collider Run II: the story of long preparations, great expectations, initial difficulties, years of "blood and sweat", continuous upgrades, exceeding its goals, high emotions, tune-up of accelerator organization for "combat fighting". The lectures will cover Introduction to the Tevatron, its history and Run II; "Plumbing"...

  1. Future Hadron Colliders

    CERN Document Server

    Keil, Eberhard

    1998-01-01

    Plans for future hadron colliders are presented, and accelerator physics and engineering aspects common to these machines are discussed. The Tevatron is presented first, starting with a summary of the achievements in Run IB which finished in 1995, followed by performance predictions for Run II which will start in 1999, and the TeV33 project, aiming for a peak luminosity $L ~ 1 (nbs)^-1$. The next machine is the Large Hadron Collider LHC at CERN, planned to come into operation in 2005. The last set of machines are Very Large Hadron Colliders which might be constructed after the LHC. Three variants are presented: Two machines with a beam energy of 50 TeV, and dipole fields of 1.8 and 12.6 T in the arcs, and a machine with 100 TeV and 12 T. The discussion of accelerator physics aspects includes the beam-beam effect, bunch spacing and parasitic collisions, and the crossing angle. The discussion of the engineering aspects covers synchrotron radiation and stored energy in the beams, the power in the debris of the p...

  2. Collider and Detector Protection at Beam Accidents

    Science.gov (United States)

    Rakhno, I. L.; Mokhov, N. V.; Drozhdin, A. I.

    2003-12-01

    Dealing with beam loss due to abort kicker prefire is considered for hadron colliders. The prefires occured at Tevatron (Fermilab) during Run I and Run II are analyzed and a protection system implemented is described. The effect of accidental beam loss in the Large Hadron Collider (LHC) at CERN on machine and detector components is studied via realistic Monte Carlo calculations. The simulations show that beam loss at an unsynchronized beam abort would result in severe heating of conventional and superconducting magnets and possible damage to the collider detector elements. A proposed set of collimators would reduce energy deposition effects to acceptable levels. Special attention is paid to reducing peak temperature rise within the septum magnet and minimizing quench region length downstream of the LHC beam abort straight section.

  3. Collider and Detector Protection at Beam Accidents

    International Nuclear Information System (INIS)

    Rakhno, I.L.; Mokhov, N.V.; Drozhdin, A.I.

    2003-01-01

    Dealing with beam loss due to abort kicker prefire is considered for hadron colliders. The prefires occurred at Tevatron (Fermilab) during Run I and Run II are analyzed and a protection system implemented is described. The effect of accidental beam loss in the Large Hadron Collider (LHC) at CERN on machine and detector components is studied via realistic Monte Carlo calculations. The simulations show that beam loss at an unsynchronized beam abort would result in severe heating of conventional and superconducting magnets and possible damage to the collider detector elements. A proposed set of collimators would reduce energy deposition effects to acceptable levels. Special attention is paid to reducing peak temperature rise within the septum magnet and minimizing quench region length downstream of the LHC beam abort straight section

  4. Collider and detector protection at beam accidents

    International Nuclear Information System (INIS)

    Rakhno, I.L.; Mokhov, N.V.; Drozhdin, A.I.

    2003-01-01

    Dealing with beam loss due to abort kicker prefire is considered for hadron colliders. The prefires occurred at Tevatron (Fermilab) during Run I and Run II are analyzed and a protection system implemented is described. The effect of accidental beam loss in the Large Hadron Collider (LHC) at CERN on machine and detector components is studied via realistic Monte Carlo calculations. The simulations show that beam loss at an unsynchronized beam abort would result in severe heating of conventional and superconducting magnets and possible damage to the collider detector elements. A proposed set of collimators would reduce energy deposition effects to acceptable levels. Special attention is paid to reducing peak temperature rise within the septum magnet and minimizing quench region length downstream of the LHC beam abort straight section

  5. The Fermilab proton-antiproton collider upgrades

    International Nuclear Information System (INIS)

    Marriner, J.P.

    1996-10-01

    The plans for increases in the Tevatron proton-antiproton collider luminosity in the near future (Run II) and the more distant future (TeV33) are described. While there are many important issues, the fundamental requirement is to produce more antiprotons and to use them more efficiently

  6. Extracting the top-quark running mass using t anti t + 1-jet events produced at the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Fuster, J.; Vos, M. [IFIC, Universitat de Valencia y CSIC, Paterna (Spain); Irles, A. [Universite de Paris-Sud XI, CNRS/IN2P3, Laboratoire de l' Accelerateur Lineaire, Orsay (France); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Melini, D. [IFIC, Universitat de Valencia y CSIC, Paterna (Spain); Universidad de Granada, Departamento de Fisica Teorica y del Cosmos, Granada (Spain); Uwer, P. [Humboldt-Universitaet Berlin (Germany)

    2017-11-15

    We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data. (orig.)

  7. Extracting the top-quark running mass using t anti t+1-jet events produced at the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Fuster, J.; Vos, M. [Valencia Univ. and CSIC, Paterna (Spain). IFIC; Irles, A. [Paris-Sud XI Univ., CNRS/IN2P3, Orsay (France). Lab. de l' Accelerateur Lineaire; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Melini, D. [Valencia Univ. and CSIC, Paterna (Spain). IFIC; Granada Univ. (Spain). Dept. de Fisica Teorica y del Cosmos; Uwer, P. [Humboldt-Univ., Berlin (Germany)

    2017-04-04

    We present the calculation of the next-to-leading order QCD corrections for top quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data.

  8. Run II jet physics: Proceedings of the Run II QCD and weak boson physics workshop

    International Nuclear Information System (INIS)

    Gerald C. Blazey

    2000-01-01

    The Run II jet physics group includes the Jet Algorithms, Jet Shape/Energy Flow, and Jet Measurements/Correlations subgroups. The main goal of the jet algorithm subgroup was to explore and define standard Run II jet finding procedures for CDF and D0. The focus of the jet shape/energy flow group was the study of jets as objects and the energy flows around these objects. The jet measurements/correlations subgroup discussed measurements at different beam energies; α S measurements; and LO, NLO, NNLO, and threshold jet calculations. As a practical matter the algorithm and shape/energy flow groups merged to concentrate on the development of Run II jet algorithms that are both free of theoretical and experimental difficulties and able to reproduce Run I measurements. Starting from a review of the experience gained during Run I, the group considered a variety of cone algorithms, and K T algorithms. The current understanding of both types of algorithms, including calibration issues, are discussed in this report along with some preliminary experimental results. The jet algorithms group recommends that CDF and D0 employ the same version of both a cone algorithm and a K T algorithm during Run II. Proposed versions of each type of algorithm are discussed. The group also recommends the use of full 4-vector kinematic variables whenever possible. The recommended algorithms attempt to minimize the impact of seeds in the case of the cone algorithm and preclustering in the case of the K T algorithm. Issues regarding precluster definitions and merge/split criteria require further study

  9. The CMS Level-1 Calorimeter Trigger for LHC Run II

    CERN Document Server

    Zabi, Alexandre; Cadamuro, Luca; Davignon, Olivier; Romanteau, Thierry; Strebler, Thomas; Cepeda, Maria Luisa; Sauvan, Jean-baptiste; Wardle, Nicholas; Aggleton, Robin Cameron; Ball, Fionn Amhairghen; Brooke, James John; Newbold, David; Paramesvaran, Sudarshan; Smith, D; Taylor, Joseph Ross; Fountas, Konstantinos; Baber, Mark David John; Bundock, Aaron; Breeze, Shane Davy; Citron, Matthew; Elwood, Adam Christopher; Hall, Geoffrey; Iles, Gregory Michiel; Laner Ogilvy, Christian; Penning, Bjorn; Rose, A; Shtipliyski, Antoni; Tapper, Alexander; Durkin, Timothy John; Harder, Kristian; Harper, Sam; Shepherd-Themistocleous, Claire; Thea, Alessandro; Williams, Thomas Stephen; Dasu, Sridhara Rao; Dodd, Laura Margaret; Klabbers, Pamela Renee; Levine, Aaron; Ojalvo, Isabel Rose; Ruggles, Tyler Henry; Smith, Nicholas Charles; Smith, Wesley; Svetek, Ales; Forbes, R; Tikalsky, Jesra Lilah; Vicente, Marcelo

    2017-01-01

    Results from the completed Phase 1 Upgrade of the Compact Muon Solenoid (CMS) Level-1 Calorimeter Trigger are presented. The upgrade was completed in two stages, with the first running in 2015 for proton and Heavy Ion collisions and the final stage for 2016 data taking. The Level-1 trigger has been fully commissioned and has been used by CMS to collect over 43 fb-1 of data since the start of the Large Hadron Collider (LHC) Run II. The new trigger has been designed to improve the performance at high luminosity and large number of simultaneous inelastic collisions per crossing (pile-up). For this purpose it uses a novel design, the Time Multiplexed Trigger (TMT), which enables the data from an event to be processed by a single trigger processor at full granularity over several bunch crossings. The TMT design is a modular design based on the uTCA standard. The trigger processors are instrumented with Xilinx Virtex-7 690 FPGAs and 10 Gbps optical links. The TMT architecture is flexible and the number of trigger p...

  10. The ATLAS Muon Trigger Performance in Run I and Initial Run II Performance

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00437899; The ATLAS collaboration

    2016-01-01

    Events with muons in the final state are an important signature for many physics topics at the Large Hadron Collider. An efficient trigger on muons and a detailed understanding of its performance are required. In 2012, the last year of Run I, the instantaneous luminosity reached $7.7\\times10^{33}$ cm$^{-2}$s$^{-1}$ and the average number of interactions that occur in the same bunch crossing was 25. The ATLAS muon trigger has successfully adapted to this challenging environment by making use of isolation requirements, combined trigger signatures with electron and jet trigger objects, and by using so-called full-scan triggers, which make use of the full event information to search for di-lepton signatures, seeded by single lepton objects. A stable and highly efficient muon trigger was vital in the discovery of the Higgs boson in 2012 and for many searches for new physics. The performance of muon triggers during the Large Hadron Collider Run I data-taking campaigns is presented, together with an overview and pre...

  11. CDF run II run control and online monitor

    International Nuclear Information System (INIS)

    Arisawa, T.; Ikado, K.; Badgett, W.; Chlebana, F.; Maeshima, K.; McCrory, E.; Meyer, A.; Patrick, J.; Wenzel, H.; Stadie, H.; Wagner, W.; Veramendi, G.

    2001-01-01

    The authors discuss the CDF Run II Run Control and online event monitoring system. Run Control is the top level application that controls the data acquisition activities across 150 front end VME crates and related service processes. Run Control is a real-time multi-threaded application implemented in Java with flexible state machines, using JDBC database connections to configure clients, and including a user friendly and powerful graphical user interface. The CDF online event monitoring system consists of several parts: the event monitoring programs, the display to browse their results, the server program which communicates with the display via socket connections, the error receiver which displays error messages and communicates with Run Control, and the state manager which monitors the state of the monitor programs

  12. Electrons and photons at High Level Trigger in CMS for Run II

    CERN Document Server

    Bin Anuar, Afiq Aizuddin

    2015-01-01

    The CMS experiment has been designed with a 2-level trigger system. The first level is implemented using custom-designed electronics. The second level is the so-called High Level Trigger (HLT), a streamlined version of the CMS offline reconstruction software running on a computer farm. For Run II of the Large Hadron Collider, the increase in center-of-mass energy and luminosity will raise the event rate to a level challenging for the HLT algorithms. New approaches have been studied to keep the HLT output rate manageable while maintaining thresholds low enough to cover physics analyses. The strategy mainly relies on porting online the ingredients that have been successfully applied in the offline reconstruction, thus allowing to move HLT selection closer to offline cuts. Improvements in HLT electron and photon definitions will be presented, focusing in particular on updated clustering algorithm and the energy calibration procedure, new Particle-Flow-based isolation approach and pileup mitigation techniques, a...

  13. The CDF SVX II detector upgrade

    International Nuclear Information System (INIS)

    Skarha, J.E.

    1993-10-01

    The proposed CDF SVX II detector upgrade for secondary vertex detection during the Fermilab Tevatron Run II collider run is described. The general design and important features of this silicon vertex detector are presented. The CDF physics goals which are addressed by this detector are also given

  14. Tests of α{sub s} running from QCD fits to collider data

    Energy Technology Data Exchange (ETDEWEB)

    Kuprash, Oleg; Geiser, Achim [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Hamburg University, Institute of Experimental Physics, Hamburg (Germany)

    2015-07-01

    The running of the strong coupling constant, α{sub s}(μ), is tested in a QCD analysis using jet measurements at LHC, Tevatron and HERA in combination with inclusive DIS data. Here μ is associated with the energy scale in the process, typically with the jet transverse energy. For the α{sub s} running test, the parameter n{sub f} of the running, which gives the number of active quarks contributing to loop corrections of the jet and DIS cross sections, is replaced by n{sub f} + Δn{sub f} at energy scales greater than μ > μ{sub thresh}. A series of simultaneous α{sub s}(M{sub Z}) + Δn{sub f} + proton PDF fits to world collider cross section data is done at Next-to-Leading Order QCD, for μ{sub thresh} values ranging from 1 GeV to 1 TeV. The fitted Δn{sub f} is consistent with zero at all tested scales, which gives a precise quantitative confirmation of the QCD running of α{sub s} over 3 orders of magnitude in energy scale. The presented study also provides a new way for indirect searches of the physics beyond the Standard Model.

  15. Identifying a light charged Higgs boson at the LHC Run II

    Directory of Open Access Journals (Sweden)

    Abdesslam Arhrib

    2017-11-01

    Full Text Available We analyse the phenomenological implications of a light Higgs boson, h, within the CP-conserving 2-Higgs Doublet Model (2HDM Type-I, for the detection prospects of the charged H± state at Run II of the Large Hadron Collider (LHC, assuming s=13 TeV as energy and O(100 fb−1 as luminosity. When sufficiently light, this h state can open up the bosonic decay channel H±→W±(⁎h, which may have a branching ratio significantly exceeding those of the H±→τν and H±→cs channels. We perform a broad scan of the 2HDM Type-I parameter space, assuming the heavier of the two CP-even Higgs bosons, H, to be the observed SM-like state with a mass near 125 GeV. Through these scans we highlight regions in which mH±Run II.

  16. The status of the SLAC Linear Collider and of the Mark II detector

    International Nuclear Information System (INIS)

    Lankford, A.J.

    1987-10-01

    At SLAC we are currently involved in the exciting challenge of commissioning the first example of a new type of colliding beam accelerator, the SLAC Linear Collider, or SLC. The goals of the SLC are two-fold. It will explore the concept of linear colliders, and it will allow the study of physics on the Z 0 resonance. It accomplishes these goals by exploiting the existing SLAC linac and the large visible cross-section of approximately thirty nanobarns of the Z 0 . The MARK II detector will have the opportunity to be first to explore the physics in this regime. This paper briefly reports the status of the SLC and of the MARK II as of early October 1987, at which time commissioning efforts were interrupted in order to place the MARK II detector at the collision point and to incorporate some improvements to the SLC. The first portion of this report highlights some of the milestones achieved in the SLC commissioning and some of the problems encountered. The last portion outlines improvements made to the MARK II for physics at the SLC. 10 refs., 12 figs., 1 tab

  17. Search for chargino and neutralino at Run II of the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Canepa, Anadi [Purdue Univ., West Lafayette, IN (United States)

    2006-08-01

    In this dissertation we present a search for the associated production of charginos and neutralinos, the supersymmetric partners of the Standard Model bosons. We analyze a data sample representing 745 pb-1 of integrated luminosity collected by the CDF experiment at the p$\\bar{p}$ Tevatron collider. We compare the Standard Model predictions with the observed data selecting events with three leptons and missing transverse energy. Finding no excess, we combine the results of our search with similar analyses carried out at CDF and set an upper limit on the chargino mass in SUSY scenarios.

  18. CERN scientists take part in the Tevatron Run II performance review committee

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Tevatron Run II is under way at Fermilab, exploring the high-energy frontier with upgraded detectors that will address some of the biggest questions in particle physics.Until CERN's LHC switches on, the Tevatron proton-antiproton collider is the world's only source of top quarks. It is the only place where we can search for supersymmetry, for the Higgs boson, and for signatures of additional dimensions of space-time. The US Department of Energy (DOE) recently convened a high-level international review committee to examine Fermilab experts' first-phase plans for the accelerator complex. Pictured here with a dipole magnet in CERN's LHC magnet test facility are the four CERN scientists who took part in the DOE's Tevatron review. Left to right: Francesco Ruggiero, Massimo Placidi, Flemming Pedersen, and Karlheinz Schindl. Further information: CERN Courier 43 (1)

  19. Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, J.R.; et al.

    2016-05-16

    This Report summarizes the proceedings of the 2015 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) the new PDF4LHC parton distributions, (III) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (IV) a host of phenomenological studies essential for comparing LHC data from Run I with theoretical predictions and projections for future measurements in Run II, and (V) new developments in Monte Carlo event generators.

  20. Les Houches 2015: Physics at TeV Colliders Standard Model Working Group Report

    CERN Document Server

    Andersen, J.R.; Becker, K.; Bell, M.; Bellm, J.; Bendavid, J.; Bothmann, E.; Boughezal, R.; Butterworth, J.; Carrazza, S.; Chiesa, M.; Cieri, L.; Ciulli, V.; Denner, A.; Duehrssen-Debling, M.; Falmagne, G.; Forte, S.; Francavilla, P.; Frederix, R.; Freytsis, M.; Gao, J.; Gras, P.; Grazzini, M.; Greiner, N.; Grellscheid, D.; Heinrich, G.; Hesketh, G.; Hoche, S.; Hofer, L.; Hou, T.J.; Huss, A.; Huston, J.; Isaacson, J.; Jueid, A.; Kallweit, S.; Kar, D.; Kassabov, Z.; Konstantinides, V.; Krauss, F.; Kuttimalai, S.; Lazapoulos, A.; Lenzi, P.; Li, Y.; Lindert, J.M.; Liu, X.; Luisoni, G.; Lonnblad, L.; Maierhofer, P.; Maître, D.; Marini, A.C.; Montagna, G.; Moretti, M.; Nadolsky, P.M.; Nail, G.; Napoletano, D.; Nicrosini, O.; Oleari, C.; Pagani, D.; Pandini, C.; Perrozzi, L.; Petriello, F.; Piccinini, F.; Platzer, S.; Pogrebnyak, I.; Pozzorini, S.; Prestel, S.; Reuschle, C.; Rojo, J.; Russo, L.; Schichtel, P.; Schonherr, M.; Schumann, S.; Siodmok, A.; Skands, P.; Soper, D.; Soyez, G.; Sun, P.; Tackmann, F.J.; Tackmann, K.; Takasugi, E.; Thaler, J.; Uccirati, S.; Utku, U.; Viliani, L.; Vryonidou, E.; Wang, B.T.; Waugh, B.; Weber, M.A.; Williams, C.; Winter, J.; Xie, K.P.; Yuan, C.P.; Yuan, F.; Zapp, K.; Zaro, M.

    2016-01-01

    This Report summarizes the proceedings of the 2015 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) the new PDF4LHC parton distributions, (III) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (IV) a host of phenomenological studies essential for comparing LHC data from Run I with theoretical predictions and projections for future measurements in Run II, and (V) new developments in Monte Carlo event generators.

  1. Bounds on new contact interactions from future e+e- colliders

    International Nuclear Information System (INIS)

    Schrempp, B.; Schrempp, F.; Zeppenfeld, D.; Wisconsin Univ., Madison

    1988-01-01

    A systematic study of the 'reach' for contact interactions as a probe for new physics at future e + e - colliders is performed. A large energy range is considered, from PETRA/PEP energies at the lower end, via the Z 0 peak (SLC/LEP-I) and LEP-II, up to the TeV regime of a potential future linear e + e - collider. Lower bounds on the compositeness scale Λ for leptons are calculated for Bhabha scattering and μ-pair production using realistic assumptions on the expected luminosities and detector performances. The impact of longitudinal and transverse polarization is studied in detail. The 'reach' corresponding to high rates at the Z 0 peak is compared to the one obtained from running at higher energies. At LEP-II energies, a sensitivity to (lepton) substructure at the level of Λ ≅ 10 TeV is to be expected. At a 2 TeV e + e - collider the sensitivity can be as large as 100 TeV. (orig.)

  2. Tevatron Collider physics

    International Nuclear Information System (INIS)

    Eichten, E.J.

    1990-02-01

    The physics of hadron colliders is briefly reviewed. Issues for further study are presented. Particular attention is given to the physics opportunities for a high luminosity (≥ 100 pb -1 /experiment/run) Upgrade of the Tevatron Collider. 25 refs., 10 figs., 2 tabs

  3. Alignment of the ATLAS inner detector for the LHC Run II

    CERN Document Server

    Butti, Pierfrancesco; The ATLAS collaboration

    2015-01-01

    ATLAS a multipurpose experiment at the LHC proton-proton collider. Its physics goals require high resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system, notably quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). Offline track alignment of the ATLAS tracking system has to deal with about 700,000 degrees of freedom (DoF) defining its geometrical parameters. The task requires using very large data sets and represents a considerable numerical challenge in terms of both CPU time and precision. The adopted strategy uses a hierarchical approach to alignment, combining local and global least squares techniques. An outl...

  4. Nanosecond-Timescale Intra-Bunch-Train Feedback for the Linear Collider: Results of the FONT2 Run

    International Nuclear Information System (INIS)

    Barlow, R.; Dufau, M.; Kalinin, A.; Daresbury; Myatt, G.; Perry, C.; Oxford U.; Burrows, P.N.; Hartin, T.; Hussain, S.M.; Molloy, S.; White, G.R.; Queen Mary, U. of London; Adolphsen, C.; Frisch, J.C.; Hendrickson, L.; Jobe, R.K.; Markiewicz, T.; McCormick, D.J.; Nelson, J.; Ross, M.C.; Smith, S.; Smith, T.J.; SLAC

    2005-01-01

    We report on experimental results from the December 2003/January 2004 data run of the Feedback On Nanosecond Timescales (FONT) experiment at the Next Linear Collider Test Accelerator at SLAC. We built a second-generation prototype intra-train beam-based feedback system incorporating beam position monitors, fast analogue signal processors, a feedback circuit, fast-risetime amplifiers and stripline kickers. We applied a novel real-time charge-normalization scheme to account for beam current variations along the train. We used the system to correct the position of the 170-nanosecond-long bunchtrain at NLCTA. We achieved a latency of 53 nanoseconds, representing a significant improvement on FONT1 (2002), and providing a demonstration of intra-train feedback for the Linear Collider

  5. An investigation of triply heavy baryon production at hadron colliders

    CERN Document Server

    Gomshi Nobary, M A

    2006-01-01

    The triply heavy baryons have a rather diverse mass range. While some of them possess considerable production rates at existing facilities, others need to be produced at future high energy colliders. Here we study the direct fragmentation production of the Ωccc and Ωbbb baryons as the prototypes of triply heavy baryons at the hadron colliders with different . We present and compare the transverse momentum distributions of the differential cross sections, distributions of total cross sections and the integrated total cross sections of these states at the RHIC, the Tevatron Run II and the CERN LHC.

  6. The D0 run II trigger system

    International Nuclear Information System (INIS)

    Schwienhorst, Reinhard; Michigan State U.

    2004-01-01

    The D0 detector at the Fermilab Tevatron was upgraded for Run II. This upgrade included improvements to the trigger system in order to be able to handle the increased Tevatron luminosity and higher bunch crossing rates compared to Run I. The D0 Run II trigger is a highly exible system to select events to be written to tape from an initial interaction rate of about 2.5 MHz. This is done in a three-tier pipelined, buffered system. The first tier (level 1) processes fast detector pick-off signals in a hardware/firmware based system to reduce the event rate to about 1. 5kHz. The second tier (level 2) uses information from level 1 and forms simple Physics objects to reduce the rate to about 850 Hz. The third tier (level 3) uses full detector readout and event reconstruction on a filter farm to reduce the rate to 20-30 Hz. The D0 trigger menu contains a wide variety of triggers. While the emphasis is on triggering on generic lepton and jet final states, there are also trigger terms for specific final state signatures. In this document we describe the D0 trigger system as it was implemented and is currently operating in Run II

  7. A Final Review of the Performance of the CDF Run II Data Acquisition System

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    The CDF Collider Detector at Fermilab ceased data collection on September 30, 2011 after over twenty five years of operation. We review the performance of the CDF Run II data acquisition systems over the last ten of these years while recording nearly 10 fb-1 of proton-antiproton collisions with a high degree of efficiency. Technology choices in the online control and configuration systems and front-end embedded processing have impacted the efficiency and quality of the data accumulated by CDF, and have had to perform over a large range of instantaneous luminosity values and trigger rates. We identify significant sources of problems and successes. In particular, we present our experience computing and acquiring data in a radiation environment, and attempt to correlate system technical faults with radiation dose rate and technology choices.

  8. A Final Review of the Performance of the CDF Run II Data Acquisition System

    International Nuclear Information System (INIS)

    Badgett, W

    2012-01-01

    The CDF Collider Detector at Fermilab ceased data collection on September 30, 2011 after over twenty-five years of operation. We review the performance of the CDF Run II data acquisition systems over the last ten of these years while recording nearly 10 inverse femtobarns of proton-antiproton collisions with a high degree of efficiency - exceeding 83%. Technology choices in the online control and configuration systems and front-end embedded processing have impacted the efficiency and quality of the data accumulated by CDF, and have had to perform over a large range of instantaneous luminosity values and trigger rates. We identify significant sources of problems and successes. In particular, we present our experience computing and acquiring data in a radiation environment, and attempt to correlate system technical faults with radiation dose rate and technology choices.

  9. Physics at Future Colliders

    CERN Document Server

    Ellis, John R.

    1999-01-01

    After a brief review of the Big Issues in particle physics, we discuss the contributions to resolving that could be made by various planned and proposed future colliders. These include future runs of LEP and the Fermilab Tevatron collider, B factories, RHIC, the LHC, a linear electron-positron collider, an electron-proton collider in the LEP/LHC tunnel, a muon collider and a future larger hadron collider (FLHC). The Higgs boson and supersymmetry are used as benchmarks for assessing their capabilities. The LHC has great capacities for precision measurements as well as exploration, but also shortcomings where the complementary strengths of a linear electron-positron collider would be invaluable. It is not too soon to study seriously possible subsequent colliders.

  10. Alignment of the ATLAS Inner Detector upgraded for the LHC Run II

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00386283; The ATLAS collaboration

    2015-01-01

    ATLAS is a multipurpose experiment at the LHC proton-proton collider. Its physics goals require high resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system, notably quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). Offline track alignment of the ATLAS tracking system has to deal with about 700,000 degrees of freedom (DoF) defining its geometrical parameters. The task requires using very large data sets and represents a considerable numerical challenge in terms of both CPU time and precision. The adopted strategy uses a hierarchical approach to alignment, combining local and global least squares techniques. An o...

  11. Alignment of the ATLAS Inner Detector Upgraded for the LHC Run II

    CERN Document Server

    Butti, Pierfrancesco; The ATLAS collaboration

    2015-01-01

    ATLAS is a multipurpose experiment at the LHC proton-proton collider. Its physics goals require high resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system, notably quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). Offline track alignment of the ATLAS tracking system has to deal with about 700,000 degrees of freedom (DoF) defining its geometrical parameters. The task requires using very large data sets and represents a considerable numerical challenge in terms of both CPU time and precision. The adopted strategy uses a hierarchical approach to alignment, combining local and global least squares techniques. An o...

  12. An investigation of triply heavy baryon production at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Gomshi Nobary, M.A. [Department of Physics, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of) and Center for Theoretical Physics and Mathematics, AEOI, Roosbeh Building, PO Box 11365-8486, Tehran (Iran, Islamic Republic of)]. E-mail: mnobary@razi.ac.ir; Sepahvand, R. [Department of Physics, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

    2006-05-01

    The triply heavy baryons have a rather diverse mass range. While some of them possess considerable production rates at existing facilities, others need to be produced at future high energy colliders. Here we study the direct fragmentation production of the {omega}{sub ccc} and {omega}{sub bbb} baryons as the prototypes of triply heavy baryons at the hadron colliders with different s. We present and compare the transverse momentum distributions of the differential cross sections, p{sub T}{sup min} distributions of total cross sections and the integrated total cross sections of these states at the RHIC, the Tevatron Run II and the CERN LHC.

  13. Proton-antiproton collider physics

    CERN Document Server

    Altarelli, Guido

    1989-01-01

    This volume reviews the physics studied at the CERN proton-antiproton collider during its first phase of operation, from the first physics run in 1981 to the last one at the end of 1985. The volume consists of a series of review articles written by physicists who are actively involved with the collider research program. The first article describes the proton-antiproton collider facility itself, including the antiproton source and its principle of operation based on stochastic cooling. The subsequent six articles deal with the various physics subjects studied at the collider. Each article descr

  14. The ATLAS Muon Trigger Performance in Run I and Initial Run II Performance

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00437899; The ATLAS collaboration

    2015-01-01

    Events with muons in the final state are an important signature for many physics topics at the Large Hadron Collider (LHC). An efficient trigger on muons and a detailed understanding of its performance are required. In 2012, the last year of Run I, the instantaneous luminosity of the LHC reached 7.7x1033 cm-2s-1 and the average number of events that occur in a same bunch crossing was 25. The ATLAS Muon trigger has successfully adapted to this changing environment by making use of isolation requirements, combined trigger signatures with electron and jet trigger objects, and by using so-called full-scan triggers, which make use of the full event information to search for di-lepton signatures, seeded by single lepton objects. A stable and highly efficient muon trigger was vital in the discovery of Higgs boson in 2012 and for many searches for new physics. The performance of muon triggers during the LHC Run 1 data-taking campaigns is presented, together with an overview and preliminary results of the new muon str...

  15. Jet physics at CDF Run II

    Energy Technology Data Exchange (ETDEWEB)

    Safonov, A.; /UC, Davis

    2004-12-01

    The latest results on jet physics at CDF are presented and discussed. Particular attention is paid to studies of the inclusive jet cross section using 177 pb{sup -1} of Run II data. Also discussed is a study of gluon and quark jet fragmentation.

  16. Report of Snowmass 2001 Working Group E2: Electron-Positron Colliders from the Phi to the Z

    Energy Technology Data Exchange (ETDEWEB)

    Decker, Franz-Josef

    2002-08-07

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

  17. LHCb detector and trigger performance in Run II

    Science.gov (United States)

    Francesca, Dordei

    2017-12-01

    The LHCb detector is a forward spectrometer at the LHC, designed to perform high precision studies of b- and c- hadrons. In Run II of the LHC, a new scheme for the software trigger at LHCb allows splitting the triggering of events into two stages, giving room to perform the alignment and calibration in real time. In the novel detector alignment and calibration strategy for Run II, data collected at the start of the fill are processed in a few minutes and used to update the alignment, while the calibration constants are evaluated for each run. This allows identical constants to be used in the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. The larger timing budget, available in the trigger, allows to perform the same track reconstruction online and offline. This enables LHCb to achieve the best reconstruction performance already in the trigger, and allows physics analyses to be performed directly on the data produced by the trigger reconstruction. The novel real-time processing strategy at LHCb is discussed from both the technical and operational point of view. The overall performance of the LHCb detector on the data of Run II is presented as well.

  18. Collider workshop

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The promise of initial results after the start of operations at CERN's SPS proton-antiproton collider and the prospects for high energy hadron collisions at Fermilab (Tevatron) and Brookhaven (ISABELLE) provided a timely impetus for the recent Topical Workshop on Forward Collider Physics', held at Madison, Wisconsin, from 10-12 December. It became the second such workshop to be held, the first having been in 1979 at the College de France, Paris. The 100 or so participants had the chance to hear preliminary results from the UA1, UA4 and UA5 experiments at the CERN SPS collider, together with other new data, including that from proton-antiproton runs at the CERN Intersecting Storage Rings

  19. From the LHC to Future Colliders

    Energy Technology Data Exchange (ETDEWEB)

    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..

    2010-06-11

    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.

  20. Performance of the PEP-II B-Factory Collider at SLAC

    International Nuclear Information System (INIS)

    Seeman, J.; Browne, M.; Cai, Y.; Colocho, W.; Decker, F.J.; Donald, M.H.; Ecklund, S.; Erickson, R.A.; Fisher, A.S.; Fox, J.D.; Heifets, S.A.; Iverson, R.H.; Kulikov, A.; Li, N.; Novokhatski, A.; Ross, M.C.; Schuh, P.; Smith, T.J.; Sonnad, K.G.; Stanek, M.; Sullivan, M.K.

    2006-01-01

    PEP-II is an e + e - asymmetric B-Factory Collider located at SLAC operating at the Upsilon 4S resonance (3.1 GeV x 9 GeV). It has reached a luminosity of 9.21 x 10 33 /cm 2 /s and has delivered an integrated luminosity of 710 pb -1 in one day. PEP-II has delivered, over the past six years, an integrated luminosity to the BaBar detector of over 262 fb -1 . PEP-II operates in continuous injection mode for both beams boosting the integrated luminosity. The peak positron current has reached 2.45 A in 1588 bunches. Steady progress is being made in reaching higher luminosity. The goal over the next several years is to reach a luminosity of 2.1 x 10 34 /cm 2 /s. The accelerator physics issues being addressed in PEP-II to reach this goal include the electron cloud instability, beam-beam effects, parasitic beam-beam effects, high RF beam loading, shorter bunches, lower β* y interaction region operation, and coupling control. Figure 1 shows the PEP-II tunnel

  1. Emotions run high in race for collider

    CERN Multimedia

    Cartlidge, E

    2001-01-01

    The head of KEK expressed his dismay that SLAC has entered into a collaboration with 3 other US labs and proposes to build the next linear collider at Fermilab, Ilinois. KEK wants the next accelerator to be built somewhere in the Asian Pacific region (1 page).

  2. Instrument Front-Ends at Fermilab During Run II

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Thomas; Slimmer, David; Voy, Duane; /Fermilab

    2011-07-13

    The optimization of an accelerator relies on the ability to monitor the behavior of the beam in an intelligent and timely fashion. The use of processor-driven front-ends allowed for the deployment of smart systems in the field for improved data collection and analysis during Run II. This paper describes the implementation of the two main systems used: National Instruments LabVIEW running on PCs, and WindRiver's VxWorks real-time operating system running in a VME crate processor.

  3. Instrument front-ends at Fermilab during Run II

    International Nuclear Information System (INIS)

    Meyer, T; Slimmer, D; Voy, D

    2011-01-01

    The optimization of an accelerator relies on the ability to monitor the behavior of the beam in an intelligent and timely fashion. The use of processor-driven front-ends allowed for the deployment of smart systems in the field for improved data collection and analysis during Run II. This paper describes the implementation of the two main systems used: National Instruments LabVIEW running on PCs, and WindRiver's VxWorks real-time operating system running in a VME crate processor.

  4. Instrument Front-Ends at Fermilab During Run II

    International Nuclear Information System (INIS)

    Meyer, Thomas; Slimmer, David; Voy, Duane

    2011-01-01

    The optimization of an accelerator relies on the ability to monitor the behavior of the beam in an intelligent and timely fashion. The use of processor-driven front-ends allowed for the deployment of smart systems in the field for improved data collection and analysis during Run II. This paper describes the implementation of the two main systems used: National Instruments LabVIEW running on PCs, and WindRiver's VxWorks real-time operating system running in a VME crate processor.

  5. Measurement of the t (bar t) cross section at the Run II Tevatron using Support Vector Machines

    International Nuclear Information System (INIS)

    Whitehouse, Benjamin Eric

    2010-01-01

    This dissertation measures the t(bar t) production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p(bar p) collider with center of mass energy √s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 ± 0.1 fb -1 . A system of learning machines is developed to recognize t(bar t) events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their ability to cope with a multi-class discrimination problem is provided. The t(bar t) production cross section is then measured in this framework, and found to be σ t# bar t# = 7.14 ± 0.25 (stat) -0.86 +0.61 (sys) pb.

  6. D-Zero run II data management and access

    International Nuclear Information System (INIS)

    Lueking, L.

    1997-03-01

    During the Run II data taking period at Fermilab, scheduled to begin in 1999, D0 plans to accumulate at least 200 TB of raw and reconstructed data per year. Data access patterns observed in the Run I experience have been examined in an attempt to establish an efficient data access environment. The needs and models for storing and processing the upcoming data are discussed

  7. Luminosity Measurements at LHCb for Run II

    CERN Multimedia

    Coombs, George

    2018-01-01

    A precise measurement of the luminosity is a necessary component of many physics analyses, especially cross-section measurements. At LHCb two different direct measurement methods are used to determine the luminosity: the “van der Meer scan” (VDM) and the “Beam Gas Imaging” (BGI) methods. A combined result from these two methods gave a precision of less than 2% for Run I and efforts are ongoing to provide a similar result for Run II. Fixed target luminosity is determined with an indirect method based on the single electron scattering cross-section.

  8. Z0 physics from the Mark II at the SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Abrams, G.S.

    1989-06-01

    The MARK II detector has started to take data at the new SLAC Linear Collider. The novel aspects of the accelerator and of the MARK II are briefly described. Displays of event pictures from some of the early-on data are presented to illustrate the quality of the data. A first presentation of the results of an energy scan near the Z 0 mass that is currently in progress shows the expected resonant enhancement near 91 GeV. 2 refs., 23 figs., 1 tab

  9. Performances of the ATLAS Level-1 Muon barrel trigger during the Run-II data taking

    CERN Document Server

    Sessa, Marco; The ATLAS collaboration

    2017-01-01

    The Level-1 Muon Barrel Trigger is one of the main elements of the event selection of the ATLAS experiment at the Large Hadron Collider. It exploits the Resistive Plate Chambers (RPC) detectors to generate the trigger signal. The RPCs are placed in the barrel region of the ATLAS experiment: they are arranged in three concentric double layers and operate in a strong magnetic toroidal field. RPC detectors cover the pseudo-rapidity range $|\\eta|<1.05$ for a total surface of more than $4000\\ m^2$ and about 3600 gas volumes. The Level-1 Muon Trigger in the barrel region allows to select muon candidates with respect to their transverse momentum and associates them with the correct bunch-crossing number. The trigger system is able to take a decision within a latency of about 2 $\\mu s$. The detailed measurement of the RPC detector efficiencies and of the trigger performance during the ATLAS Run-II data taking is here presented.

  10. The ATLAS Trigger System: Ready for Run II

    CERN Document Server

    Czodrowski, Patrick; The ATLAS collaboration

    2015-01-01

    The ATLAS trigger system has been used successfully for data collection in the 2009-2013 Run 1 operation cycle of the CERN Large Hadron Collider (LHC) at center-of-mass energies of up to 8 TeV. With the restart of the LHC for the new Run 2 data-taking period at 13 TeV, the trigger rates are expected to rise by approximately a factor of 5. The trigger system consists of a hardware-based first level (L1) and a software-based high-level trigger (HLT) that reduces the event rate from the design bunch-crossing rate of 40 MHz to an average recording rate of ~ 1kHz. This presentation will give an overview of the upgrades to the ATLAS trigger system that have been implemented during the LHC shutdown period in order to deal with the increased trigger rates while efficiently selecting the physics processes of interest. These upgrades include changes to the L1 calorimeter trigger, the introduction of a new L1 topological trigger module, improvements in the L1 muon system, and the merging of the previously two-level HLT ...

  11. Instrument front-ends at Fermilab during Run II

    Science.gov (United States)

    Meyer, T.; Slimmer, D.; Voy, D.

    2011-11-01

    The optimization of an accelerator relies on the ability to monitor the behavior of the beam in an intelligent and timely fashion. The use of processor-driven front-ends allowed for the deployment of smart systems in the field for improved data collection and analysis during Run II. This paper describes the implementation of the two main systems used: National Instruments LabVIEW running on PCs, and WindRiver's VxWorks real-time operating system running in a VME crate processor. Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.

  12. The SLAC linear collider

    International Nuclear Information System (INIS)

    Phinney, N.

    1992-01-01

    The SLAC Linear Collider has begun a new era of operation with the SLD detector. During 1991 there was a first engineering run for the SLD in parallel with machine improvements to increase luminosity and reliability. For the 1992 run, a polarized electron source was added and more than 10,000 Zs with an average of 23% polarization have been logged by the SLD. This paper discusses the performance of the SLC in 1991 and 1992 and the technical advances that have produced higher luminosity. Emphasis will be placed on issues relevant to future linear colliders such as producing and maintaining high current, low emittance beams and focusing the beams to the micron scale for collisions. (Author) tab., 2 figs., 18 refs

  13. Sparticle mass hierarchies, simplified models from SUGRA unification, and benchmarks for LHC Run-II SUSY searches

    International Nuclear Information System (INIS)

    Francescone, David; Akula, Sujeet; Altunkaynak, Baris; Nath, Pran

    2015-01-01

    Sparticle mass hierarchies contain significant information regarding the origin and nature of supersymmetry breaking. The hierarchical patterns are severely constrained by electroweak symmetry breaking as well as by the astrophysical and particle physics data. They are further constrained by the Higgs boson mass measurement. The sparticle mass hierarchies can be used to generate simplified models consistent with the high scale models. In this work we consider supergravity models with universal boundary conditions for soft parameters at the unification scale as well as supergravity models with nonuniversalities and delineate the list of sparticle mass hierarchies for the five lightest sparticles. Simplified models can be obtained by a truncation of these, retaining a smaller set of lightest particles. The mass hierarchies and their truncated versions enlarge significantly the list of simplified models currently being used in the literature. Benchmarks for a variety of supergravity unified models appropriate for SUSY searches at future colliders are also presented. The signature analysis of two benchmark models has been carried out and a discussion of the searches needed for their discovery at LHC Run-II is given. An analysis of the spin-independent neutralino-proton cross section exhibiting the Higgs boson mass dependence and the hierarchical patterns is also carried out. It is seen that a knowledge of the spin-independent neutralino-proton cross section and the neutralino mass will narrow down the list of the allowed sparticle mass hierarchies. Thus dark matter experiments along with analyses for the LHC Run-II will provide strong clues to the nature of symmetry breaking at the unification scale.

  14. Collider phenomenology of light strange-beauty squarks

    International Nuclear Information System (INIS)

    Cheung, Kingman; Hou Weizshu

    2004-01-01

    Strong mixing between right-handed strange and beauty squarks is a possible solution to the CP violation discrepancy in B→φK S decay as recently suggested by the Belle data. In this scenario, thanks to the strong mixing one of the strange-beauty squarks can be as light as 200 GeV, even though the generic supersymmetry scale is at TeV. In this work, we study the production of this light right-handed strange-beauty squark at hadronic colliders and discuss the detection in various decay scenarios. Detection prospect at the Tevatron run II is good for the strange-beauty squark mass up to about 300 GeV

  15. COLLIDE Pro Helvetia Award

    CERN Multimedia

    2016-01-01

    The COLLIDE Pro Helvetia Award is run in partnership with Pro Helvetia, giving the opportunity to Swiss artists to do research at CERN for three months.   From left to right: Laura Perrenoud, Marc Dubois and Simon de Diesbach. The photo shows their VR Project, +2199. Fragment.In are the winning artists of COLLIDE Pro Helvetia. They came to CERN for two months in 2015, and will now continue their last month in the laboratory. Fragment.In is a Swiss based interaction design studio. They create innovative projects, interactive installations, video and game design. Read more about COLLIDE here.

  16. The CDF SVX II upgrade for the Tevatron Run II

    International Nuclear Information System (INIS)

    Bortoletto, Daniela

    1997-01-01

    A microstrip silicon detector SVX II has been proposed for the upgrade of CDF to be installed in 1999 for Run II of the Tevatron. Three barrels of five layers of double-sided silicon microstrip detectors will cover the interaction region. A description of the project status will be presented. Emphasis will be given to the R and D program for silicon sensors which includes capacitance minimization, the study of coupling capacitor integrity, the operation of the detectors in conjunction with the SVXH and SVX2 readout chips in two beam tests and the determination of the detectors performance deterioration due to radiation damage

  17. FERMILAB: Preparing to collide

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Against the background of stringent Environment, Safety and Health (ES&H) regulations mandated by the US Department of Energy for all national Labs, Fermilab prepared to mount the next major Tevatron proton-antiproton collider run

  18. Measurement of the t$\\bar{t}$ cross section at the Run II Tevatron using Support Vector Machines

    Energy Technology Data Exchange (ETDEWEB)

    Whitehouse, Benjamin Eric [Tufts Univ., Medford, MA (United States)

    2010-08-01

    This dissertation measures the t$\\bar{t}$ production cross section at the Run II CDF detector using data from early 2001 through March 2007. The Tevatron at Fermilab is a p$\\bar{p}$ collider with center of mass energy √s = 1.96 TeV. This data composes a sample with a time-integrated luminosity measured at 2.2 ± 0.1 fb-1. A system of learning machines is developed to recognize t$\\bar{t}$ events in the 'lepton plus jets' decay channel. Support Vector Machines are described, and their ability to cope with a multi-class discrimination problem is provided. The t$\\bar{t}$ production cross section is then measured in this framework, and found to be σt$\\bar{t}$ = 7.14 ± 0.25 (stat)-0.86+0.61(sys) pb.

  19. A calorimeter software trigger for the Mark II detector at SLC [Stanford Linear Collider

    International Nuclear Information System (INIS)

    Briggs, D.; Glanzman, T.; Grosse-Wiesmann, P.; Tinsman, J.; Holmgren, S.; Schaad, M.W.

    1989-04-01

    A new FASTBUS-based calorimeter software trigger for the upgraded Mark II at the Stanford Linear Collider (SLC) is presented. The trigger requirements for SLC and a short description of the hardware used for this purpose are given, followed by a detailed description of the software. Some preliminary results are presented. 9 refs., 4 figs

  20. Search for squarks and gluinos in the D0 experiment of the Run-II-a at the Tevatron

    International Nuclear Information System (INIS)

    Verdier, P.

    2007-11-01

    The D0 experiment is recording pp-bar collisions at a center-of-mass energy of 1.96 TeV since the beginning of the Run II-a of the Tevatron in 2001. The design of processor boards for the D0 level 2 trigger system is first presented. Those boards were installed in 2003, and they have been working perfectly since that date. Performances of missing transverse energy (/ ET ) reconstruction are then described. This quantity is important at hadron colliders especially for new particles searches. Finally, squarks and gluinos, supersymmetric partners of quarks and gluons, could be the most copiously produced supersymmetric particles at the Tevatron, if they are sufficiently light. Those particles were searched for in 0.96 fb -1 of data recorded by D0 during the Run II-a. The final state consists of jets and missing transverse energy. The numbers of observed events are in good agreement with the Standard Model predictions. Lower mass limits at 95 % confidence level are obtained on the squark and gluino masses in the framework of the mSUGRA model. Contributions to other D0 data analyses are also shortly described. Those analyses are the search for first generation leptoquarks and the search for squarks in jets+τ(s)+E T events. The possibility to constrain a 'Little Higgs' model using the results of the jets+E T searches is then discussed. (author)

  1. SVX II a silicon vertex detector for run II of the tevatron

    International Nuclear Information System (INIS)

    Bortoletto, D.

    1994-11-01

    A microstrip silicon detector SVX II has been proposed for the upgrade of the vertex detector of the CDF experiment to be installed for run II of the Tevatron in 1998. Three barrels of four layers of double sided detectors will cover the interaction region. The requirement of the silicon tracker and the specification of the sensors are discussed together with the proposed R ampersand D to verify the performance of the prototypes detectors produced by Sintef, Micron and Hamamatsu

  2. Review of recent LHCb results and prospects for Run II

    CERN Document Server

    Hicheur, A

    2015-01-01

    As first Run II data acquisition has begun, it is useful to expose the pending questions by reviewing some of the most recent results obtained with Run I data analyses. Early results of the current data taking and middle-term prospects are also shown to illustrate the efficiency of the acquisition and analysis chain.

  3. Review of recent LHCb results and expectations for Run II

    CERN Document Server

    Hicheur, Adlene

    2016-01-01

    As first Run II data acquisition has begun, it is useful to expose the pending questions by reviewing some of the most recent results obtained with Run I data analyses. Early results of the current data taking and middle-term prospects are also shown to illustrate the efficiency of the acquisition and analysis chain.

  4. Collider Physics an Experimental Introduction

    International Nuclear Information System (INIS)

    Elvezio Pagliarone, Carmine

    2011-01-01

    This paper reviews shortly a small part of the contents of a set of lectures, presented at the XIV International School of Particles and Fields in Morelia, state of Michoacan, Mexico, during November 2010. The main goal of those lectures was to introduce students to some of the basic ideas and tools required for experimental and phenomenological analysis of collider data. In particular, after an introduction to the scientific motivations, that drives the construction of powerful accelerator complexes, and the need of reaching high center of mass energies and luminosities, some basic concept about collider particle detectors will be discussed. A status about the present running colliders and collider experiments as well as future plans and research and development is also given.

  5. Physics performance and fast turn around: the challenge of calibration and alignment at the CMS experiment during the LHC Run-II

    CERN Document Server

    Di Guida, Salvatore; Franzoni, Giovanni; Govi, Giacomo; Musich, Marco; Pfeiffer, Andreas

    2017-01-01

    The CMS detector at the Large Hadron Collider (LHC) is a very complex apparatus with more than 70 million acquisition channels. To exploit its full physics potential, a very careful calibra- tion of the various components, together with an optimal knowledge of their position in space, is essential. The CMS Collaboration has set up a powerful infrastructure to allow for the best knowledge of these conditions at any given moment. The quick turnaround of these workflows was proven crucial both for the algorithms performing the online event selection and for the ul- timate resolution of the offline reconstruction of the physics objects. The contribution will report about the design and performance of these workflows during the operations of the 13TeV LHC RunII.

  6. The International Linear Collider Technical Design Report - Volume 3.II: Accelerator Baseline Design

    CERN Document Server

    Adolphsen, Chris; Barish, Barry; Buesser, Karsten; Burrows, Philip; Carwardine, John; Clark, Jeffrey; Durand, Helene Mainaud; Dugan, Gerry; Elsen, Eckhard; Enomoto, Atsushi; Foster, Brian; Fukuda, Shigeki; Gai, Wei; Gastal, Martin; Geng, Rongli; Ginsburg, Camille; Guiducci, Susanna; Harrison, Mike; Hayano, Hitoshi; Kershaw, Keith; Kubo, Kiyoshi; Kuchler, Victor; List, Benno; Liu, Wanming; Michizono, Shinichiro; Nantista, Christopher; Osborne, John; Palmer, Mark; Paterson, James McEwan; Peterson, Thomas; Phinney, Nan; Pierini, Paolo; Ross, Marc; Rubin, David; Seryi, Andrei; Sheppard, John; Solyak, Nikolay; Stapnes, Steinar; Tauchi, Toshiaki; Toge, Nobu; Walker, Nicholas; Yamamoto, Akira; Yokoya, Kaoru

    2013-01-01

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to incr...

  7. GO, an exec for running the programs: CELL, COLLIDER, MAGIC, PATRICIA, PETROS, TRANSPORT and TURTLE

    International Nuclear Information System (INIS)

    Shoaee, H.

    1982-05-01

    An exec has been written and placed on the PEP group's public disk (PUBRL 192) to facilitate the use of several PEP related computer programs available on VM. The exec's program list currently includes: CELL, COLLIDER, MAGIC, PATRICIA, PETROS, TRANSPORT, and TURTLE. In addition, provisions have been made to allow addition of new programs to this list as they become available. The GO exec is directly callable from inside the Wylbur editor (in fact, currently this is the only way to use the GO exec.) It provides the option of running any of the above programs in either interactive or batch mode. In the batch mode, the GO exec sends the data in the Wylbur active file along with the information required to run the job to the batch monitor (BMON, a virtual machine that schedules and controls execution of batch jobs). This enables the user to proceed with other VM activities at his/her terminal while the job executes, thus making it of particular interest to the users with jobs requiring much CPU time to execute and/or those wishing to run multiple jobs independently. In the interactive mode, useful for small jobs requiring less CPU time, the job is executed by the user's own Virtual Machine using the data in the active file as input. At the termination of an interactive job, the GO exec facilitates examination of the output by placing it in the Wylbur active file

  8. GO, an exec for running the programs: CELL, COLLIDER, MAGIC, PATRICIA, PETROS, TRANSPORT, and TURTLE

    International Nuclear Information System (INIS)

    Shoaee, H.

    1982-05-01

    An exec has been written and placed on the PEP group's public disk to facilitate the use of several PEP related computer programs available on VM. The exec's program list currently includes: CELL, COLLIDER, MAGIC, PATRICIA, PETROS, TRANSPORT, and TURTLE. In addition, provisions have been made to allow addition of new programs to this list as they become available. The GO exec is directly callable from inside the Wylbur editor (in fact, currently this is the only way to use the GO exec.). It provides the option of running any of the above programs in either interactive or batch mode. In the batch mode, the GO exec sends the data in the Wylbur active file along with the information required to run the job to the batch monitor (BMON, a virtual machine that schedules and controls execution of batch jobs). This enables the user to proceed with other VM activities at his/her terminal while the job executes, thus making it of particular interest to the users with jobs requiring much CPU time to execute and/or those wishing to run multiple jobs independently. In the interactive mode, useful for small jobs requiring less CPU time, the job is executed by the user's own Virtual Machine using the data in the active file as input. At the termination of an interactive job, the GO exec facilitates examination of the output by placing it in the Wylbur active file

  9. PDF4LHC recommendations for LHC Run II

    NARCIS (Netherlands)

    Butterworth, Jon; Carrazza, Stefano; Cooper-Sarkar, Amanda; Roeck, Albert de; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert S.

    2015-01-01

    We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new

  10. Achieving the optimal performance of the CMS ECAL in Run II

    CERN Document Server

    Sun, Menglei

    2016-01-01

    Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high resolution electron and photon energy measurements. Particularly important are decays of the Higgs boson resulting in electromagnetic particles in the final state. Di-photon events in CMS are also a very important channel in the search for Higgs boson production in association with other particles or in the search for possible new resonances of higher mass. The requirement for high performance electromagnetic calorimetry therefore remains high during LHC Run II. Following the excellent performance achieved in Run~I at a center of mass energy of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) started operating at the LHC in Spring 2015 with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run~II is expected to exceed the levels achieved in Run I, using 25 ns bunch spacing. The average number of concurrent proton-proton collisions per bu...

  11. Study of Beam-Beam Effects at PEP-II

    International Nuclear Information System (INIS)

    Narsky, I

    2004-01-01

    Using a self-consistent three-dimensional simulation running on parallel supercomputers, we have modeled the beam-beam interaction at the PEP-II asymmetric e + e - collider. To provide guidance for luminosity improvement, we scanned the tunes and currents in both rings and computed their impact on the luminosity and transverse beam sizes. We also studied the effects of colliding the beams with a small crossing angle. Where possible, the code was benchmarked against experimental measurements of luminosity and beam sizes, yielding an acceptable agreement

  12. The Colliding Beams Sequencer

    International Nuclear Information System (INIS)

    Johnson, D.E.; Johnson, R.P.

    1989-01-01

    The Colliding Beam Sequencer (CBS) is a computer program used to operate the pbar-p Collider by synchronizing the applications programs and simulating the activities of the accelerator operators during filling and storage. The Sequencer acts as a meta-program, running otherwise stand alone applications programs, to do the set-up, beam transfers, acceleration, low beta turn on, and diagnostics for the transfers and storage. The Sequencer and its operational performance will be described along with its special features which include a periodic scheduler and command logger. 14 refs., 3 figs

  13. Operational experience with the CMS pixel detector in LHC Run II

    CERN Document Server

    Karancsi, Janos

    2016-01-01

    The CMS pixel detector was repaired successfully, calibrated and commissioned for the second run of Large Hadron Collider during the first long shutdown between 2013 and 2015. The replaced pixel modules were calibrated separately and show the expected behavior of an un-irradiated detector. In 2015, the system performed very well with an even improved spatial resolution compared to 2012. During this time, the operational team faced various challenges including the loss of a sector in one half shell which was only partially recovered. In 2016, the detector is expected to withstand instantaneous luminosities beyond the design limits and will need a combined effort of both online and offline teams in order to provide the high quality data that is required to reach the physics goals of CMS. We present the operational experience gained during the second run of the LHC and show the latest performance results of the CMS pixel detector.

  14. Technical design report for the upgrade of the ICD for D-Zero Run II

    International Nuclear Information System (INIS)

    Sawyer, L.; De, K.; Draper, P.; Gallas, E.; Li, J.; Sosebee, M.; Stephens, R.W.; White, A.

    1998-01-01

    The Inter Cryostat Detector (ICD) used in Run I of the D0 Experiment will be inoperable in the central, high magnetic field planned for Run II. In Run I, the ICD enhanced the hermeticity and uniformity of the D0 calorimeter system, improving both missing transverse energy and jet energy resolution. The goals for the Run II ICD are the same. In this document, the physics arguments for maintaining the ICD are presented, followed by a detailed description of the planned design changes, prototype tests, construction, installation, and commissioning of the device for the Run II D0 detector. Estimates of costs and schedule can be found on //DOSERVER2/Operations/Upgrade Project/ subareas available via DZERO's WinFrame Program Manager. This detector is not intended to provide any ''L0'' capabilities (for luminosity monitoring), or to provide any EM coverage in the intermediate region, or to provide additional coverage in the intermediate regions, unlike previous upgrades proposed in this detector region. The ICD upgrade described here maintains most of the Run I capabilities in a high magnetic field environment

  15. ATLAS Strip Detector: Operational Experience and Run1-> Run2 Transition

    CERN Document Server

    Nagai, Koichi; The ATLAS collaboration

    2014-01-01

    Large hadron collider was operated very successfully during the Run1 and provided a lot of opportunities of physics studies. It currently has a consolidation work toward to the operation at $\\sqrt{s}=14 \\mathrm{TeV}$ in Run2. The ATLAS experiment has achieved excellent performance in Run1 operation, delivering remarkable physics results. The SemiConductor Tracker contributed to the precise measurement of momentum of charged particles. This paper describes the operation experience of the SemiConductor Tracker in Run1 and the preparation toward to the Run2 operation during the LS1.

  16. Prospects for Future Collider Physics

    CERN Document Server

    Ellis, John

    2016-10-20

    One item on the agenda of future colliders is certain to be the Higgs boson. What is it trying to tell us? The primary objective of any future collider must surely be to identify physics beyond the Standard Model, and supersymmetry is one of the most studied options. it Is supersymmetry waiting for us and, if so, can LHC Run 2 find it? The big surprise from the initial 13-TeV LHC data has been the appearance of a possible signal for a new boson X with a mass ~750 GeV. What are the prospects for future colliders if the X(750) exists? One of the most intriguing possibilities in electroweak physics would be the discovery of non-perturbative phenomena. What are the prospects for observing sphalerons at the LHC or a future collider?

  17. Prospects of type-II seesaw models at future colliders in light of the DAMPE e+e- excess

    Science.gov (United States)

    Sui, Yicong; Zhang, Yongchao

    2018-05-01

    The DAMPE e+e- excess at around 1.4 TeV could be explained in the type-II seesaw model with a scalar dark mater D which is stabilized by a discrete Z2 symmetry. The simplest scenario is the annihilation D D →H++H- followed by the subsequent decay H±±→e±e±, with both the DM and triplet scalars roughly 3 TeV with a small mass splitting. In addition to the Drell-Yan process at future 100 TeV hadron colliders, the doubly charged components could also be produced at lepton colliders like ILC and CLIC in the off shell mode and mediate lepton flavor violating processes e+e-→ℓi±ℓj∓ (with i ≠j ). A wide range of parameter space of the type-II seesaw could be probed, which are well below the current stringent lepton flavor constraints.

  18. Observation of Exclusive Dijet Production at the Fermilab Tevatron p-pbar Collider

    OpenAIRE

    CDF Collaboration; Aaltonen, T.

    2007-01-01

    We present the first observation and cross section measurement of exclusive dijet production in pbar-p interactions, pbar + p --> pbar + dijet + p. Using a data sample of 310 pb-1 collected by the Run II Collider Detector at Fermilab at sqrt{s}=1.96 TeV, exclusive cross sections for events with two jets of transverse energy ET >= 10 GeV have been measured as a function of minimum ET(jet). The exclusive signal is extracted from fits to data distributions based on Monte Carlo simulations of exp...

  19. The International Linear Collider Technical Design Report - Volume 3.II: Accelerator Baseline Design

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, Chris [SLAC National Accelerator Lab., Menlo Park, CA (United States); et al.

    2013-06-26

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

  20. Measurement of B(t→ b)/B(t→Wq) at the collider detector at Fermilab

    International Nuclear Information System (INIS)

    Acosta, D.

    2005-01-01

    We present a measurement of the ratio of top-quark branching fractions R = Β(t → Wb)/Β(t → Wq) using lepton-plus-jets and dilepton data sets with integrated luminosity of ∼162 pb -1 collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of t(bar t) events with different multiplicity of identified secondary vertices. We set a lower limit of R > 0.61 at 95% confidence level

  1. Performance Limitations in High-Energy Ion Colliders

    CERN Document Server

    Fischer, Wolfram

    2005-01-01

    High-energy ion colliders (hadron colliders operating with species other than protons) are premier research tools for nuclear physics. The collision energy and high luminosity are important design and operations considerations. However, the experiments also expect flexibility with frequent changes in the collision energy, lattice configuration, and ion species, including asymmetric collisions. For the creation, acceleration, and storage of bright intense ion beams, attention must be paid to space charge, charge exchange, and intra-beam scattering effects. The latter leads to luminosity lifetimes of only a few hours for heavy ions. Ultimately cooling at full energy is needed to overcome this effect. Currently, the Relativistic Heavy Ion Collider at BNL is the only operating high-energy ion collider. The Large Hadron Collider, under construction at CERN, will also run with heavy ions.

  2. Feedback systems for linear colliders

    CERN Document Server

    Hendrickson, L; Himel, Thomas M; Minty, Michiko G; Phinney, N; Raimondi, Pantaleo; Raubenheimer, T O; Shoaee, H; Tenenbaum, P G

    1999-01-01

    Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have been investigated, and improvements have been made. For the Next Linear Collider (NLC), extensive feedback systems are planned as an intregal part of the design. Feedback requiremetns for JLC (the Japanese Linear Collider) are essentially identical to NLC; some of the TESLA requirements are similar but there are significant differences. For NLC, algorithms which incorporate improvements upon the SLC implementation are being prototyped. Specialized systems for the damping rings, rf and interaction point will operate at hi...

  3. First events and prospects at the Fermilab collider

    International Nuclear Information System (INIS)

    Binkley, M.

    1986-03-01

    A brief description of the Collider Detector at Fermilab (CDF) is given including the detector components and the data acquisition system. The first test run, the first events, and the performance of the detector are discussed. Finally the prospects for future running are reviewed

  4. Ion colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.

    2011-12-01

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

  5. Ion colliders

    International Nuclear Information System (INIS)

    Fischer, W.

    2010-01-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions (77Asb1, 81Bou1). The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  6. Multibunch operation in the Tevatron Collider

    International Nuclear Information System (INIS)

    Holt, J.A.; Finley, D.A.; Bharadwaj, V.

    1993-05-01

    The Tevatron Collider at Fermilab is the world's highest energy hadron collider, colliding protons with antiprotons at a center of mass energy of 1800 GeV. At present six proton bunches collide with six antiproton bunches to generate luminosities of up to 9 x 10 30 cm -2 s -1 . It is estimated that to reach luminosities significantly greater than 10 31 cm -2 s -1 while minimizing the number of interactions per crossing, the number of bunches will have to be increased. Thirty-six bunch operation looks like the most promising plan. This paper looks at the strategies for increasing the number of particle bunches, the new hardware that needs to be designed and changes to the operating mode in filling the Tevatron. An interactive program which simulates the filling of the Tevatron collider is also presented. The time scale for multibunch operation and progress towards running greater than six bunches is given in this paper

  7. From the LHC to future colliders. CERN Theory Institute summary report

    International Nuclear Information System (INIS)

    Roeck, A. de; Ellis, J.; Wells, J.; Gripaios, B.; Dittmar, M.; Grojean, C.; Heinemeyer, S.; Jakobs, K.; Schumacher, M.; Duehrssen, M.; Weiglein, G.; Moortgat-Pick, G.; Morton-Thurtle, V.; Rolbiecki, K.; Smillie, J.; Tattersall, J.; Azuelos, G.; Dawson, S.; Assamagan, K.; Gopalakrishna, S.; Han, T.; Hewett, J.; Rizzo, T.; Lancaster, M.; Ozcan, E.; Mariotti, C.; Moortgat, F.; Polesello, G.; Riemann, S.; Bechtle, P.; Carena, M.; Juste, A.; Chachamis, G.; Chen, K.F.; Hou, W.S.; Curtis, S. de; Desch, K.; Wienemann, P.; Dreiner, H.; Foster, B.; Frandsen, M.T.; Giammanco, A.; Godbole, R.; Govoni, P.; Gunion, J.; Hollik, W.; Isidori, G.; Kalinowski, J.; Krawczyk, M.; Korytov, A.; Kou, E.; Kraml, S.; Martin, A.; Milstead, D.; Moenig, K.; Mele, B.; Pieri, M.; Plehn, T.; Reina, L.; Richter-Was, E.; Sannino, F.; Schram, M.; Sultansoy, S.; Uwer, P.; Webber, B.

    2010-01-01

    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 -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 -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, the Working 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. (orig.)

  8. Observation of exclusive dijet production at the Fermilab Tevatron pp collider

    International Nuclear Information System (INIS)

    Aaltonen, T.; Maki, T.; Mehtala, P.; Orava, R.; Osterberg, K.; Saarikko, H.; Remortel, N. van; Adelman, J.; Brubaker, E.; Fedorko, W. T.; Grosso-Pilcher, C.; Kim, Y. K.; Kwang, S.; Levy, S.; Paramonov, A. A.; Schmidt, M. A.; Shochet, M.; Wolfe, C.; Yang, U. K.; Yorita, K.

    2008-01-01

    We present the first observation and cross section measurement of exclusive dijet production in pp interactions, pp→p+dijet+p. Using a data sample of 310 pb -1 collected by the Run II Collider Detector at Fermilab at √(s)=1.96 TeV, exclusive cross sections for events with two jets of transverse energy E T jet ≥10 GeV have been measured as a function of minimum E T jet . The exclusive signal is extracted from fits to data distributions based on Monte Carlo simulations of expected dijet signal and background shapes. The simulated background distribution shapes are checked in a study of a largely independent data sample of 200 pb -1 of b-tagged jet events, where exclusive dijet production is expected to be suppressed by the J z =0 total angular momentum selection rule. Results obtained are compared with theoretical expectations, and implications for exclusive Higgs boson production at the pp Large Hadron Collider at √(s)=14 TeV are discussed.

  9. Database usage and performance for the Fermilab Run II experiments

    International Nuclear Information System (INIS)

    Bonham, D.; Box, D.; Gallas, E.; Guo, Y.; Jetton, R.; Kovich, S.; Kowalkowski, J.; Kumar, A.; Litvintsev, D.; Lueking, L.; Stanfield, N.; Trumbo, J.; Vittone-Wiersma, M.; White, S.P.; Wicklund, E.; Yasuda, T.; Maksimovic, P.

    2004-01-01

    The Run II experiments at Fermilab, CDF and D0, have extensive database needs covering many areas of their online and offline operations. Delivering data to users and processing farms worldwide has represented major challenges to both experiments. The range of applications employing databases includes, calibration (conditions), trigger information, run configuration, run quality, luminosity, data management, and others. Oracle is the primary database product being used for these applications at Fermilab and some of its advanced features have been employed, such as table partitioning and replication. There is also experience with open source database products such as MySQL for secondary databases used, for example, in monitoring. Tools employed for monitoring the operation and diagnosing problems are also described

  10. PDF4LHC recommendations for LHC Run II

    CERN Document Server

    Butterworth, Jon; Cooper-Sarkar, Amanda; De Roeck, Albert; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert

    2016-01-01

    We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new generation of PDFs, which include substantial information from experimental data from the Run I of the LHC. We then propose a new prescription for the combination of a suitable subset of the available PDF sets, which is presented in terms of a single combined PDF set. We finally discuss tools which allow for the delivery of this combined set in terms of optimized sets of Hessian eigenvectors or Monte Carlo replicas, and their usage, and provide some examples of their application to LHC phenomenology.

  11. Measurement of B(t --> Wb)/B(t--> Wq) at the collider detector at fermilab.

    Science.gov (United States)

    Acosta, D; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Ambrose, D; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Arguin, J-F; Artikov, A; Ashmanskas, W; Attal, A; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bachacou, H; Badgett, W; Barbaro-Galtieri, A; Barker, G J; Barnes, V E; Barnett, B A; Baroiant, S; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bellettini, G; Bellinger, J; Belloni, A; Ben-Haim, E; Benjamin, D; Beretvas, A; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Bourov, S; Brau, B; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Casarsa, M; Carlsmith, D; Carosi, R; Carron, S; Cavalli-Sforza, M; Castro, A; Catastini, P; Cauz, D; Cerri, A; Cerrito, L; Chapman, J; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Chuang, S; Chung, K; Chung, W-H; Chung, Y S; Cijliak, M; Ciobanu, C I; Ciocci, M A; Clark, A G; Clark, D; Coca, M; Connolly, A; Convery, M; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Cranshaw, J; Cuevas, J; Cruz, A; Culbertson, R; Currat, C; Cyr, D; Dagenhart, D; Da Ronco, S; D'Auria, S; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; Dell'Orso, M; Demers, S; Demortier, L; Deninno, M; de Pedis, D; Derwent, P F; Dionisi, C; Dittmann, J R; DiTuro, P; Dörr, C; Dominguez, A; Donati, S; Donega, M; Donini, J; D'Onofrio, M; Dorigo, T; Ebina, K; Efron, J; Ehlers, J; Erbacher, R; Erdmann, M; Errede, D; Errede, S; Eusebi, R; Fang, H-C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R D; Flanagan, G; Flores-Castillo, L R; Foland, A; Forrester, S; Foster, G W; Franklin, M; Freeman, J C; Fujii, Y; Furic, I; Gajjar, A; Gallinaro, M; Galyardt, J; Garcia-Sciveres, M; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D W; Gerchtein, E; Giagu, S; Giannetti, P; Gibson, A; Gibson, K; Ginsburg, C; Giolo, K; Giordani, M; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, D; Goldstein, J; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Gresele, A; Griffiths, M; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Handler, R; Happacher, F; Hara, K; Hare, M; Harr, R F; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Hays, C; Hayward, H; Heinemann, B; Heinrich, J; Hennecke, M; Herndon, M; Hill, C; Hirschbuehl, D; Hocker, A; Hoffman, K D; Holloway, A; Hou, S; Houlden, M A; Huffman, B T; Huang, Y; Hughes, R E; Huston, J; Ikado, K; Incandela, J; Introzzi, G; Iori, M; Ishizawa, Y; Issever, C; Ivanov, A; Iwata, Y; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jensen, H; Jeon, E J; Jones, M; Joo, K K; Jun, S Y; Junk, T; Kamon, T; Kang, J; Unel, M Karagoz; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, M S; Kim, S B; Kim, S H; Kim, Y K; Kirby, M; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kobayashi, H; Kong, D J; Kondo, K; Konigsberg, J; Kordas, K; Korn, A; Korytov, A; Kotwal, A V; Kovalev, A; Kraus, J; Kravchenko, I; Kreymer, A; Kroll, J; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecci, C; Lecompte, T; Lee, J; Lee, J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Li, K; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Liss, T M; Lister, A; Litvintsev, D O; Liu, T; Liu, Y; Lockyer, N S; Loginov, A; Loreti, M; Loverre, P; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; MacQueen, D; Madrak, R; Maeshima, K; Maksimovic, P; Manca, G; Margaroli, F; Marginean, R; Marino, C; Martin, A; Martin, M; Martin, V; Martínez, M; Maruyama, T; Matsunaga, H; Mattson, M; Mazzanti, P; McFarland, K S; McGivern, D; McIntyre, P M; McNamara, P; McNulty, R; Mehta, A; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, L; Miller, R; Miller, J S; Mills, C; Miquel, R; Miscetti, S; Mitselmakher, G; Miyamoto, A; Moggi, N; Mohr, B; Moore, R; Morello, M; Fernandez, P A Movilla; Muelmenstaedt, J; Mukherjee, A; Mulhearn, M; Muller, T; Mumford, R; Munar, A; Murat, P; Nachtman, J; Nahn, S; Nakano, I; Napier, A; Napora, R; Naumov, D; Necula, V; Nelson, T; Neu, C; Neubauer, M S; Nielsen, J; Nigmanov, T; Nodulman, L; Norniella, O; Ogawa, T; Oh, S H; Oh, Y D; Ohsugi, T; Okusawa, T; Oldeman, R; Orava, R; Orejudos, W; Osterberg, K; Pagliarone, C; Palencia, E; Paoletti, R; Papadimitriou, V; Paramonov, A A; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pitts, K T; Plager, C; Pondrom, L; Pope, G; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Rademacker, J; Rahaman, M A; Rakitine, A; Rappoccio, S; Ratnikov, F; Ray, H; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Rimondi, F; Rinnert, K; Ristori, L; Robertson, W J; Robson, A; Rodrigo, T; Rolli, S; Roser, R; Rossin, R; Rott, C; Russ, J; Rusu, V; Ruiz, A; Ryan, D; Saarikko, H; Sabik, S; Safonov, A; St Denis, R; Sakumoto, W K; Salamanna, G; Saltzberg, D; Sanchez, C; Santi, L; Sarkar, S; Sato, K; Savard, P; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Semeria, F; Sexton-Kennedy, L; Sfiligoi, I; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sill, A; Sinervo, P; Sisakyan, A; Sjolin, J; Skiba, A; Slaughter, A J; Sliwa, K; Smirnov, D; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S V; Spalding, J; Spezziga, M; Spinella, F; Squillacioti, P; Stadie, H; Stanitzki, M; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sumorok, K; Sun, H; Suzuki, T; Taffard, A; Tafirout, R; Takano, H; Takashima, R; Takeuchi, Y; Takikawa, K; Tanaka, M; Tanaka, R; Tanimoto, N; Tecchio, M; Teng, P K; Terashi, K; Tesarek, R J; Tether, S; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tollefson, K; Tomura, T; Tonelli, D; Tönnesmann, M; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuchiya, R; Tsuno, S; Tsybychev, D; Turini, N; Ukegawa, F; Unverhau, T; Uozumi, S; Usynin, D; Vacavant, L; Vaiciulis, A; Varganov, A; Vejcik, S; Velev, G; Veszpremi, V; Veramendi, G; Vickey, T; Vidal, R; Vila, I; Vilar, R; Vollrath, I; Volobouev, I; von der Mey, M; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wallny, R; Walter, T; Wan, Z; Wang, M J; Wang, S M; Warburton, A; Ward, B; Waschke, S; Waters, D; Watts, T; Weber, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wolter, M; Worcester, M; Worm, S; Wright, T; Wu, X; Würthwein, F; Wyatt, A; Yagil, A; Yamashita, T; Yamamoto, K; Yamaoka, J; Yang, C; Yang, U K; Yao, W; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, I; Yu, S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zetti, F; Zhou, J; Zucchelli, S

    2005-09-02

    We present a measurement of the ratio of top-quark branching fractions R = B(t --> Wb)/B(t --> Wq), where q can be a b, s, or a d quark, using lepton-plus-jets and dilepton data sets with an integrated luminosity of approximately 162 pb(-1) collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of tt events with different multiplicity of identified secondary vertices. We set a lower limit of R > 0.61 at 95% confidence level.

  12. R&D for Collider Beauty Physics at the LHC

    CERN Multimedia

    2002-01-01

    We propose an R&D program for the development of a Beauty trigger and innovative elements of the associated spectrometer. The program builds on the success of the recent S$\\bar{p}$pS collider run of the P238 Collaboration, in which clean signals from beam-beam interactions were observed in a large silicon strip microvertex detector running 1.5~mm from the circulating beams. A continuing successful R&D program of the type proposed could ultimately lead to a collider experiment at the LHC to study CP-violation and rare B decays. \\\\ \\\\ We request a fixed target run during late 1992 in order to demonstrate the effectiveness of a heavy flavour trigger which uses real time digital calculations on silicon strip data, implemented with a data driven processor.

  13. Online beam energy measurement of Beijing electron positron collider II linear accelerator

    Science.gov (United States)

    Wang, S.; Iqbal, M.; Liu, R.; Chi, Y.

    2016-02-01

    This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.

  14. CERN to start Large Hadron Collider november 2007

    CERN Multimedia

    2006-01-01

    "The Large Hadron Collider (LHC) is expected to provide its first collisions in November 2007, CERN has announced. A two-month run at 0.9 TeV is planned for 2007 to test the accelerating and detecting equipment, and a full power run at 14 TeV is expected in the spring of 2008."

  15. The upgraded Pixel Detector of the ATLAS Experiment for Run 2 at the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Backhaus, M., E-mail: malte.backhaus@cern.ch

    2016-09-21

    During Run 1 of the Large Hadron Collider (LHC), the ATLAS Pixel Detector has shown excellent performance. The ATLAS collaboration took advantage of the first long shutdown of the LHC during 2013 and 2014 and extracted the ATLAS Pixel Detector from the experiment, brought it to surface and maintained the services. This included the installation of new service quarter panels, the repair of cables, and the installation of the new Diamond Beam Monitor (DBM). Additionally, a completely new innermost pixel detector layer, the Insertable B-Layer (IBL), was constructed and installed in May 2014 between a new smaller beam pipe and the existing Pixel Detector. With a radius of 3.3 cm the IBL is located extremely close to the interaction point. Therefore, a new readout chip and two new sensor technologies (planar and 3D) are used in the IBL. In order to achieve best possible physics performance the material budget was improved with respect to the existing Pixel Detector. This is realized using lightweight staves for mechanical support and a CO{sub 2} based cooling system. This paper describes the improvements achieved during the maintenance of the existing Pixel Detector as well as the performance of the IBL during the construction and commissioning phase. Additionally, first results obtained during the LHC Run 2 demonstrating the distinguished tracking performance of the new Four Layer ATLAS Pixel Detector are presented.

  16. VeloTT tracking for LHCb Run II

    CERN Document Server

    Bowen, Espen Eie; Tresch, Marco

    2016-01-01

    This note describes track reconstruction in the LHCb tracking system upstream of the magnet, combining VELO tracks with hits in the TT sub-detector. The implementation of the VeloTT algorithm and its performance in terms of track reconstruction efficiency, ghost rate and execution time are presented. The algorithm has been rewritten for use in the first software trigger level for LHCb Run II. The momentum and charge information obtained for the VeloTT tracks (due to a fringe magnetic field between the VELO and TT sub-detectors) can reduce the total execution time for the full tracking sequence.

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

    CERN Multimedia

    Szumlak, Tomasz

    2015-01-01

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

  18. Prospects for new physics in τ→lμμ at current and future colliders

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Chris [Department of Physics, Oxford University,Keble Road, Oxford, OX1 3RH (United Kingdom); Mitra, Manimala [Department of Physics,Indian Institute of Science Education and Research Mohali (IISER Mohali),Sector 81, SAS Nagar, Manauli 140306 (India); Institute for Particle Physics Phenomenology, Department of Physics, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Spannowsky, Michael; Waite, Philip [Institute for Particle Physics Phenomenology, Department of Physics, Durham University,South Road, Durham, DH1 3LE (United Kingdom)

    2017-05-03

    The discovery of lepton flavour violating interactions will be striking evidence for physics beyond the Standard Model. Focusing on the three decays τ{sup ∓}→μ{sup ±}μ{sup ∓}μ{sup ∓}, τ{sup ∓}→e{sup ±}μ{sup ∓}μ{sup ∓} and τ{sup ∓}→e{sup ∓}μ{sup ∓}μ{sup ±}, we evaluate the discovery potential of current and future high-energy colliders to probe lepton flavour violation in the τ sector. Based on this potential we determine the expected constraints on parameters of new physics in the context of the Type-II Seesaw Model, the Left-Right Symmetric Model, and the Minimal Supersymmetric Standard Model. The existing and ongoing 13 TeV run of the Large Hadron Collider has the potential to produce constraints that outperform the existing e{sup +}e{sup −} collider limits for the τ{sup ∓}→μ{sup ±}μ{sup ∓}μ{sup ∓} decay and achieve a branching fraction limit of ≲10{sup −8}. With a future circular e{sup +}e{sup −} collider, constraints on the τ→lμμ branching fractions could reach as low as a few times 10{sup −12}.

  19. BTEV: a dedicated B physics detector at the Fermilab Tevatron Collider

    International Nuclear Information System (INIS)

    Butler, J.N.

    1996-11-01

    The capabilities of future Dedicated Hadron Collider B Physics experiments are discussed and compared to experiments that will run in the next few years. The design for such an experiment at the Tevatron Collider is presented and an evolutionary path for developing it is outlined. 9 refs., 3 figs., 4 tabs

  20. A Search for Supersymmetry via Chargino-Neutralino Production in Low-$p_T$ Dimuon with the Collider Detector at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Rekovic, Vladimir [Univ. of New Mexico, Albuquerque, NM (United States)

    2007-05-01

    We have searched for evidence of supersymmetry with 1 $fb^-1$ with collected with low-$p_T$ dimuon triggers of the Collider Detector on Tevatron Run II, at Fermilab. We looked for trilepton events in $p\\bar{p}$ collisions at $\\sqrt{s} = 1.96$ TeV. In the Minimal Supersymmetric Standard Model (MSSM) we expect chargino-neutralino pair production, with subsequent decay into three isolated leptons. We observe one event of three isolated muons, a possible hint of supersymmetry.

  1. Maximum Acceptance Detector for the Fermilab Collider (MAX)

    International Nuclear Information System (INIS)

    Bjorken, James

    2003-01-01

    The authors propose a detector for the Collider which will cover the largest possible ranges of angles with electromagnetic calorimetry and charged tracking, and with hadronic calorimetry for the forward direction. The goal for the complete detector would be acceptance down to approx 1 mrad, in contrast to CDF and D0, which have coverage only to approx. 40 mrad. Because of the limitations of physical space and running time in all but B0 and D0, such a detector will have to be very compact and compatible with a variety of difficult boundary conditions. For this reason, they propose to run a test program at F0 during the second of the present Collider running period, utilizing existing calorimeters and tracking systems. A less desirable option which can be installed at E0 is also described. With luck there may be the possibility of physics from the test program as well. The final version of the detector would be installed at E0 after the main Injector upgrade. the detector is designed to study processes with relatively large cross sections. The running time requirements are thus minimal and data taking would require running a small fraction of the time with the electrostatic separators turned off

  2. Performance of the CMS precision electromagnetic calorimeter at the LHC Run II and prospects for high-luminosity LHC

    CERN Document Server

    Negro, Giulia

    2017-01-01

    The Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) is a high-performance calorimeter wich will operate also at the High Luminosity Large Hadron Collider (HL-LHC). This talk will describe the strategies that have been employed to maintain the excellent performance of the CMS ECAL throughout Run 2. Performance results from the 2015-2016 data taking periods will be shown and an outlook on the expected Run 2 performance in the years to come will be provided. The status and plans for the upgraded ECAL barrel electronics for the HL-LHC will be presented, based on recent results from simulations, laboratory tests, and test beam measurements of prototype devices.

  3. Measurement of B(t→Wb)/B(t→Wq) in top-quark-pair decays using dilepton events and the full CDF Run II data set.

    Science.gov (United States)

    Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Martínez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

    2014-06-06

    We present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q represents any quark flavor, in events with two charged leptons, imbalance in total transverse energy, and at least two jets. The measurement uses proton-antiproton collision data at center-of-mass energy 1.96 TeV, corresponding to an integrated luminosity of 8.7  fb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure R to be 0.87±0.07, and extract the magnitude of the top-bottom quark coupling to be |V_{tb}|=0.93±0.04, assuming three generations of quarks. Under these assumptions, a lower limit of |V_{tb}|>0.85(0.87) at 95% (90%) credibility level is set.

  4. Higgs Boson Measurements in CMS with Run II Data

    CERN Document Server

    Kumar, Ashok

    2017-01-01

    Latest results from the CMS experiment on studies of Higgs boson production are presented. Studies involving the 125 GeV Higgs boson using various Standard Model production and decay modes have been performed using proton proton collisions from data accumulated during the LHC Run II with center-of-mass energy of 13 TeV. Similar datasets have also been used to place constraints on physics beyond the Standard Model involving extended Higgs boson sectors.

  5. From the LHC to Future Colliders

    DEFF Research Database (Denmark)

    De Roeck, A.; Ellis, J.; Grojean, C.

    2010-01-01

    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 of integrated luminosity, of the proposed sLHC luminosity up...

  6. A Measurement of the Lifetime of the Λb Baryon with the CDF Detector at the Tevatron Run II

    Energy Technology Data Exchange (ETDEWEB)

    Unverhau, Tatjana Alberta Hanna [Univ. of Glasgow, Scotland (United Kingdom)

    2004-12-01

    In March 2001 the Tevatron accelerator entered its Run II phase, providing colliding proton and anti-proton beams with an unprecedented center-of-mass energy of 1.96 TeV. The Tevatron is currently the only accelerator to produce Λb baryons, which provides a unique opportunity to measure the properties of these particles. This thesis presents a measurement of the mean lifetime of the Λb baryon in the semileptonic channel Λ$0\\atop{b}$ → Λ$+\\atop{c}$ μ- $\\bar{v}$μ. In total 186 pb-1 of data were used for this analysis, collected with the CDF detector between February 2002 and September 2003. To select the long-lived events from b-decays, the secondary vertex trigger was utilized. This significant addition to the trigger for Run II allows, for the first time, the selection of events with tracks displaced from the primary interaction vertex at the second trigger level. After the application of selection cuts this trigger sample contains approximately 991 Λb candidates. To extract the mean lifetime of Λb baryons from this sample, they transverse decay length of the candidates is fitted with an unbinned maximum likelihood fit under the consideration of the missing neutrino momentum and the bias introduced by the secondary vertex trigger. The mean lifetime of the Λb is measured to be τ = 1.29 ± 0.11(stat.) ± 0.07(syst.) ps equivalent to a mean decay length of cτ = 387 ± 33(stat.) ± 21 (syst.) μm.

  7. Alignment of the ATLAS Inner Detector in the LHC Run II

    CERN Document Server

    Barranco Navarro, Laura; The ATLAS collaboration

    2015-01-01

    ATLAS physics goals require excellent resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system and on the quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the Run II of the LHC, the system was upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). An outline of the track based alignment approach and its implementation within the ATLAS software will be presented. Special attention will be paid to integration of the IBL into the alignment framework, techniques allowing to identify and eliminate tracking systematics as well as strategies to deal with time-dependent alignment. Performance from the commissioning of Cosmic data and potentially early LHC Run II proton-proton collisions will be discussed.

  8. Dark spectroscopy at lepton colliders

    Science.gov (United States)

    Hochberg, Yonit; Kuflik, Eric; Murayama, Hitoshi

    2018-03-01

    Rich and complex dark sectors are abundant in particle physics theories. Here, we propose performing spectroscopy of the mass structure of dark sectors via mono-photon searches at lepton colliders. The energy of the mono-photon tracks the invariant mass of the invisible system it recoils against, which enables studying the resonance structure of the dark sector. We demonstrate this idea with several well-motivated models of dark sectors. Such spectroscopy measurements could potentially be performed at Belle II, BES-III and future low-energy lepton colliders.

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

    CERN Document Server

    INSPIRE-00425747; McMahon, Stephen J

    2015-01-01

    ATLAS is a particle physics experiment at the Large Hadron Collider (LHC) that detects proton-proton collisions at a centre of mass energy of 14 TeV. The Semiconductor Tracker is part of the Inner Detector, implemented using silicon microstrip detectors with binary read-out, providing momentum measurement of charged particles with excellent resolution. The operation of the LHC and the ATLAS experiment started in 2010, with ten years of operation expected until major upgrades are needed in the accelerator and the experiments. The ATLAS tracker will need to be completely replaced due to the radiation damage and occupancy of some detector elements and the data links at high luminosities. These upgrades after the first ten years of operation are named the Phase-II Upgrade and involve a re-design of the LHC, resulting in the High Luminosity Large Hadron Collider (HL-LHC). This thesis presents the work carried out in the testing of the ATLAS Phase-II Upgrade electronic systems in the future strips tracker a...

  10. Observation of Exclusive Dijet Production at the Fermilab Tevatron p-pbar Collider

    International Nuclear Information System (INIS)

    Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, M.G.; Gonzalez, B. Alvarez; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Aoki, M.

    2007-01-01

    The authors present the first observation and cross section measurement of exclusive dijet production in (bar p)p interactions, (bar p)p → (bar p) + dijet + p. Using a data sample of 310 pb -1 collected by the Run II Collider Detector at Fermilab at √s = 1.96 TeV, exclusive cross sections for events with two jets of transverse energy E T jet (ge) 10 GeV have been measured as a function of minimum E T jet . The exclusive signal is extracted from fits to data distributions based on Monte Carlo simulations of expected dijet signal and background shapes. The simulated background distribution shapes are checked in a study of a largely independent data sample of 200 pb -1 of b-tagged jet events, where exclusive dijet production is expected to be suppressed by the J z = 0 total angular momentum selection rule. Results obtained are compared with theoretical expectations, and implications for exclusive Higgs boson production at the pp Large Hadron Collider at √s = 14 TeV are discussed

  11. Mechanical design of the CDF SVX II silicon vertex detector

    International Nuclear Information System (INIS)

    Skarha, J.E.

    1994-08-01

    A next generation silicon vertex detector is planned at CDF for the 1998 Tevatron collider run with the Main Injector. The SVX II silicon vertex detector will allow high luminosity data-taking, enable online triggering of secondary vertex production, and greatly increase the acceptance for heavy flavor physics at CDF. The design specifications, geometric layout, and early mechanical prototyping work for this detector are discussed

  12. A New Chicane Experiment In PEP-II to Test Mitigations of the Electron Cloud Effect for Linear Colliders

    International Nuclear Information System (INIS)

    Pivi, M

    2008-01-01

    Beam instability caused by the electron cloud has been observed in positron and proton storage rings, and it is expected to be a limiting factor in the performance of future colliders [1-3]. The effect is expected to be particularly severe in magnetic field regions. To test possible mitigation methods in magnetic fields, we have installed a new 4-dipole chicane experiment in the PEP-II Low Energy Ring (LER) at SLAC with both bare and TiN-coated aluminum chambers. In particular, we have observed a large variation of the electron flux at the chamber wall as a function of the chicane dipole field. We infer this is a new high order resonance effect where the energy gained by the electrons in the positron beam depends on the phase of the electron cyclotron motion with respect to the bunch crossing, leading to a modulation of the secondary electron production. Presumably the cloud density is modulated as well and this resonance effect could be used to reduce its magnitude in future colliders. We present the experimental results obtained during January 2008 until the April final shut-down of the PEP-II machine

  13. Muon reconstruction and identification with the Run II D0 detector

    Czech Academy of Sciences Publication Activity Database

    Abazov, V. M.; Abbott, B.; Acharya, B.S.; Kupčo, Alexander; Lokajíček, Miloš

    2014-01-01

    Roč. 737, Feb (2014), s. 281-294 ISSN 0168-9002 R&D Projects: GA MŠk(CZ) LG12006 Institutional support: RVO:68378271 Keywords : Fermilab * D0 * Tevatron Run II * muon identification * muon reconstruction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.216, year: 2014

  14. Feedback Systems for Linear Colliders

    International Nuclear Information System (INIS)

    1999-01-01

    Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have been investigated, and improvements have been made. For the Next Linear Collider (NLC), extensive feedback systems are planned as an integral part of the design. Feedback requirements for JLC (the Japanese Linear Collider) are essentially identical to NLC; some of the TESLA requirements are similar but there are significant differences. For NLC, algorithms which incorporate improvements upon the SLC implementation are being prototyped. Specialized systems for the damping rings, rf and interaction point will operate at high bandwidth and fast response. To correct for the motion of individual bunches within a train, both feedforward and feedback systems are planned. SLC experience has shown that feedback systems are an invaluable operational tool for decoupling systems, allowing precision tuning, and providing pulse-to-pulse diagnostics. Feedback systems for the NLC will incorporate the key SLC features and the benefits of advancing technologies

  15. The upgraded Pixel detector and the commissioning of the Inner Detector tracking of the ATLAS experiment for Run-2 at the Large Hadron Collider

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00019188; The ATLAS collaboration

    2016-01-01

    Run-2 of the Large Hadron Collider (LHC) will provide new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. Therefore the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). The IBL is a fourth layer of pixel detectors, and has been installed in May 2014 at a radius of 3.3 cm between the existing Pixel Detector and a new smaller radius beam-pipe. The new detector, built to cope with the high radiation and expected occupancy, is the first large scale application of 3D detectors and CMOS 130~nm technology. In addition, the Pixel detector was refurbished with a new service quarter panel to recover about 3% of defective modules lost during Run-1 and a new optical readout system to readout the data at higher speed while reducing the occupancy when running with increased luminosity. Complementing detector improvements, many improvements to Inner Detector track and vertex reconstr...

  16. CMS detector tracking performance in Run-II

    CERN Document Server

    Brondolin, Erica

    2017-01-01

    Since the start of Run-II in June 2015, LHC has delivered pp collisions at a center of mass energy of 13TeV and with a bunch time separation of 25 ns. On avarage, more than 25 inelastic collisions are superimposed on the event of interest. Under these new conditions, the CMS collaboration has re-calibrated and verified the performance of the whole detector. In particular, the CMS tracking performance has been measured both directly and indirectly. Direct measurements are, among others, the beam spot determination, the vertex resolution and the muon reconstruction efficiency with the tag and probe technique. An indirect assessment can be given by the pion reconstruction efficiency and the low-mass resonance parameters as a function of different single track kinematics.

  17. Status of the MEIC ion collider ring design

    International Nuclear Information System (INIS)

    Morozov, Vasiliy; Derbenev, Yaroslav; Harwood, Leigh; Hutton, Andrew; Lin, Fanglei; Pilat, Fulvia; Zhang, Yuhong; Cai, Yunhai; Nosochkov, Y. M.; Sullivan, Michael; Wang, M.-H.; Wienands, Uli; Gerity, James; Mann, Thomas; McIntyre, Peter; Pogue, Nathaniel; Sattarov, Akhdiyor

    2015-09-01

    We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated super-conducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.

  18. Status of the MEIC ion collider ring design

    International Nuclear Information System (INIS)

    Morozov, V. S.; Derbenev, Ya. S.; Harwood, L.; Hutton, A.; Lin, F.; Pilat, F.; Zhang, Y.; Cai, Y.; Nosochkov, Y. M.; Sullivan, M.; Wang, M-H; Wienands, U.; Gerity, J.; Mann, T.; McIntyre, P.; Pogue, N. J.; Satttarov, A.

    2015-01-01

    We present an update on the design of the ion collider ring of the Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab. The design is based on the use of super-ferric magnets. It provides the necessary momentum range of 8 to 100 GeV/c for protons and ions, matches the electron collider ring design using PEP-II components, fits readily on the JLab site, offers a straightforward path for a future full-energy upgrade by replacing the magnets with higher-field ones in the same tunnel, and is more cost effective than using presently available current-dominated superconducting magnets. We describe complete ion collider optics including an independently-designed modular detector region.

  19. arXiv Proceedings of the Sixth International Workshop on Multiple Partonic Interactions at the Large Hadron Collider

    CERN Document Server

    Astalos, R.; Bartalini, P.; Belyaev, I.; Bierlich, Ch.; Blok, B.; Buckley, A.; Ceccopieri, F.A.; Cherednikov, I.; Christiansen, J.R.; Ciangottini, D.; Deak, M.; Ducloue, B.; Field, R.; Gaunt, J.R.; Golec-Biernat, K.; Goerlich, L.; Grebenyuk, A.; Gueta, O.; Gunnellini, P.; Helenius, I.; Jung, H.; Kar, D.; Kepka, O.; Klusek-Gawenda, M.; Knutsson, A.; Kotko, P.; Krasny, M.W.; Kutak, K.; Lewandowska, E.; Lykasov, G.; Maciula, R.; Moraes, A.M.; Martin, T.; Mitsuka, G.; Motyka, L.; Myska, M.; Otwinowski, J.; Pierog, T.; Pleskot, V.; Rinaldi, M.; Schafer, W.; Siodmok, A.; Sjostrand, T.; Snigirev, A.; Stasto, A.; Staszewski, R.; Stebel, T.; Strikman, M.; Szczurek, A.; Treleani, D.; Trzebinski, M.; van Haevermaet, H.; van Hameren, A.; van Mechelen, P.; Waalewijn, W.; Wang, W.Y.; MPI@LHC 2014

    2014-01-01

    Multiple Partonic Interactions are often crucial for interpreting results obtained at the Large Hadron Collider (LHC). The quest for a sound understanding of the dynamics behind MPI - particularly at this time when the LHC is due to start its "Run II" operations - has focused the aim of this workshop. MPI@LHC2014 concentrated mainly on the phenomenology of LHC measurements whilst keeping in perspective those results obtained at previous hadron colliders. The workshop has also debated some of the state-of-the-art theoretical considerations and the modeling of MPI in Monte Carlo event generators. The topics debated in the workshop included: Phenomenology of MPI processes and multiparton distributions; Considerations for the description of MPI in Quantum Chromodynamics (QCD); Measuring multiple partonic interactions; Experimental results on inelastic hadronic collisions: underlying event, minimum bias, forward energy flow; Monte Carlo generator development and tuning; Connections with low-x phenomena, diffractio...

  20. Beam-beam issues in asymmetric colliders

    International Nuclear Information System (INIS)

    Furman, M.A.

    1992-07-01

    We discuss generic beam-beam issues for proposed asymmetric e + - e - colliders. We illustrate the issues by choosing, as examples, the proposals by Cornell University (CESR-B), KEK, and SLAC/LBL/LLNL (PEP-II)

  1. Promise of Higgs fails to save CERN collider

    CERN Multimedia

    Abbott, A

    2000-01-01

    After eleven years and a three-month reprieve, the death knell for LEP has finally been sounded. Luciano Maiani, director-general of CERN, rejected requests to keep the collider running for another year, ruling it shoud be dismantled in the new year (1/2 page).

  2. Improvements to ATLAS Track Reconstruction for Run-II

    CERN Document Server

    Cairo, Valentina Maria; The ATLAS collaboration

    2015-01-01

    Run-II of the LHC will provide new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which has been inserted at the centre of ATLAS during the shutdown of the LHC. We will discuss improvements to track reconstruction developed during the two year shutdown of the LHC. These include novel techniques developed to improve the performance in the dense cores of jets, optimisation for the expected conditions, and a big software campaign which lead to more than a factor of three decrease in the CPU time needed to process each recorded event.

  3. The CMS Level-1 trigger for LHC Run II

    Science.gov (United States)

    Tapper, A.

    2018-02-01

    During LHC Run II the centre-of-mass energy of pp collisions has increased from 8 TeV up to 13 TeV and the instantaneous luminosity has progressed towards 2 × 1034 cm-2s-1. In order to guarantee a successful and ambitious physics programme under these conditions, the CMS trigger system has been upgraded. The upgraded CMS Level-1 trigger is designed to improve performance at high luminosity and large number of simultaneous inelastic collisions per crossing. The trigger design, implementation and commissioning are summarised, and performance results are described.

  4. LHCb-The LHCb trigger in Run II

    CERN Multimedia

    Michielin, Emanuele

    2016-01-01

    The LHCb trigger system has been upgraded to exploit the real-time alignment, calibration and analysis capabilities of LHCb in Run-II. An increase in the CPU and disk capacity of the event filter farm, combined with improvements to the reconstruction software, mean that efficient, exclusive selections can be made in the first stage of the High Level Trigger (HLT1). The output of HLT1 is buffered to the 5 PB of disk on the event filter farm, while the detector is aligned and calibrated in real time. The second stage, HLT2, performs complete, offline quality, event reconstruction. Physics analyses can be performed directly on this information, and for the majority of charm physics selections, a reduced event format can be written out, which permits higher event rates.

  5. Measurement of the s dependence of jet production at the CERN pp collider

    DEFF Research Database (Denmark)

    Appel, J.A.; Bagnaia, P.; Banner, M.

    1985-01-01

    The production of very large transverse momentum (pT) hadron jets has been measured in the UA2 experiment at the CERN pp Collider for s=630 GeV. The inclusive jet production cross sections exhibit a pT-dependent increase with respect to the s=546 GeV data from previous Collider runs. This increase...

  6. The Stanford Linear Collider

    International Nuclear Information System (INIS)

    Emma, P.

    1995-01-01

    The Stanford Linear Collider (SLC) is the first and only high-energy e + e - linear collider in the world. Its most remarkable features are high intensity, submicron sized, polarized (e - ) beams at a single interaction point. The main challenges posed by these unique characteristics include machine-wide emittance preservation, consistent high intensity operation, polarized electron production and transport, and the achievement of a high degree of beam stability on all time scales. In addition to serving as an important machine for the study of Z 0 boson production and decay using polarized beams, the SLC is also an indispensable source of hands-on experience for future linear colliders. Each new year of operation has been highlighted with a marked improvement in performance. The most significant improvements for the 1994-95 run include new low impedance vacuum chambers for the damping rings, an upgrade to the optics and diagnostics of the final focus systems, and a higher degree of polarization from the electron source. As a result, the average luminosity has nearly doubled over the previous year with peaks approaching 10 30 cm -2 s -1 and an 80% electron polarization at the interaction point. These developments as well as the remaining identifiable performance limitations will be discussed

  7. Evaluation of CCTF Core-II second acceptance Test C2-AC2 (Run 052)

    International Nuclear Information System (INIS)

    Okubo, Tsutomu; Murao, Yoshio

    1984-03-01

    In order to investigate the thermo-hydrodynamic behavior in a PWR during the reflood phase of the LOCA, large scale reflooding tests have been conducted at JAERI using the CCTF Core-I and Core-II facilities. This report presents the investigation on the difference in the thermo-hydrodynamic behavior observed between in the CCTF Core-I and Core-II facilities. For this purpose the test data of the second CCTF Core-II acceptance test C2-AC2 (Run 052) were evaluated by using the data of the Test CL-21 (Run 040) in the Core-I test series. The experimental conditions for these two tests were almost identical. Comparing the data of those two tests, the following is obtained. 1. The system behavior observed in the Core-II facility was nearly identical to that observed in the Core-I facility. 2. The core behavior observed in the Core-II facility was also nearly identical to that observed in the Core-I facility except for the top quenching behavior. 3. The differences in the top quenching behavior between the two facilities were as follows: (1) The selective occurrence of top quenching below the open holes of the upper core support plate observed in the Core-I facility was not observed in the Core-II facility. (2) Top quenching tended to occur less in the Core-II facility in the region where the initial average linear power density was over 1.69 kW/m. (author)

  8. Performance of the CMS electromagnetic calorimeter in Run II and its role in the measurement of the Higgs boson properties

    CERN Document Server

    Organtini, Giovanni

    2017-01-01

    The characterisation of the Higgs boson discovered in 2012 around 125 GeV, and confirmed with the data collected in Run II, requires the precise determination of its mass, width and couplings. The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid Experiment (CMS) is crucial for measurements in the highest resolution channels, $H\\to \\gamma \\gamma$ and $H\\to 4$ leptons. In particular the energy resolution, the scale uncertainty and the position resolution for electrons and photons are required to be as good as possible.During Run II the LHC is continuously operating with 25 ns bunch spacing and increasing instantaneous luminosity. The calorimeter reconstruction algorithm has been adapted to cope with increasing levels of pile-up and the calibration and monitoring strategy have been optimised to maintain the excellent performance of the CMS ECAL throughout Run II. We show first performance results from the Run II data taking periods, achieved through energy calibrations using physics events, with...

  9. Improvements to ATLAS track reconstruction for Run II

    Energy Technology Data Exchange (ETDEWEB)

    Cairo, Valentina Maria Martina, E-mail: valentina.maria.cairo@cern.ch [University of Calabria, Arcavacata di Rende (Italy); CERN, Meyrin (Switzerland)

    2016-07-11

    Run II of the LHC will provide new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. A major change to the Inner Detector layout during the shutdown period has been the installation of the Insertable B-Layer, a fourth pixel layer located at a radius of 33 mm. This contribution discusses improvements to track reconstruction developed during the two year shutdown of the LHC. These include novel techniques developed to improve the performance in the dense cores of jets, optimisation for the expected conditions, and a big software campaign which lead to more than a factor of three decrease in the CPU time needed to process each recorded event.

  10. LHCb siliicon detectors: the Run 1 to Run 2 transition and first experience of Run 2

    CERN Document Server

    Rinnert, Kurt

    2015-01-01

    LHCb is a dedicated experiment to study New Physics in the decays of heavy hadrons at the Large Hadron Collider (LHC) at CERN. The detector includes a high precision tracking system consisting of a silicon-strip vertex detector (VELO) surrounding the pp interaction region, a large- area silicon-strip detector located upstream of a dipole magnet (TT), and three stations of silicon- strip detectors (IT) and straw drift tubes placed downstream (OT). The operational transition of the silicon detectors VELO, TT and IT from LHC Run 1 to Run 2 and first Run 2 experiences will be presented. During the long shutdown of the LHC the silicon detectors have been maintained in a safe state and operated regularly to validate changes in the control infrastructure, new operational procedures, updates to the alarm systems and monitoring software. In addition, there have been some infrastructure related challenges due to maintenance performed in the vicinity of the silicon detectors that will be discussed. The LHCb silicon dete...

  11. Muon Physics at Run-I and its upgrade plan

    Directory of Open Access Journals (Sweden)

    Benekos Nektarios Chr.

    2015-01-01

    Full Text Available The Large Hadron Collider (LHC and its multi-purpose Detector, ATLAS, has been operated successfully at record centre-of-mass energies of 7 and TeV. After this successful LHC Run-1, plans are actively advancing for a series of upgrades, culminating roughly 10 years from now in the high luminosity LHC (HL-LHC project, delivering of order five times the LHC nominal instantaneous luminosity along with luminosity leveling. The final goal is to extend the data set from about few hundred fb−1 expected for LHC running to 3000 fb−1 by around 2030. To cope with the corresponding rate increase, the ATLAS detector needs to be upgraded. The upgrade will proceed in two steps: Phase I in the LHC shutdown 2018/19 and Phase II in 2023-25. The largest of the ATLAS Phase-1 upgrades concerns the replacement of the first muon station of the highrapidity region, the so called New Small Wheel. This configuration copes with the highest rates expected in Phase II and considerably enhances the performance of the forward muon system by adding triggering functionality to the first muon station. Prospects for the ongoing and future data taking are presented. This article presents the main muon physics results from LHC Run-1 based on a total luminosity of 30 fb^-1. Prospects for the ongoing and future data taking are also presented. We will conclude with an update of the status of the project and the steps towards a complete operational system, ready to be installed in ATLAS in 2018/19.

  12. Optimising charged Higgs boson searches at the Large Hadron Collider across bb¯W± final states

    Directory of Open Access Journals (Sweden)

    Stefano Moretti

    2016-09-01

    Full Text Available In the light of the most recent data from Higgs boson searches and analyses, we re-assess the scope of the Large Hadron Collider in accessing heavy charged Higgs boson signals in bb¯W± final states, wherein the contributing channels can be H+→tb¯, hW±, HW± and AW±. We consider a 2-Higgs Doublet Model Type-II and we assume as production mode bg→tH−+c.c., the dominant one over the range MH±≥480 GeV, as dictated by b→sγ constraints. Prospects of detection are found to be significant for various Run 2 energy and luminosity options.

  13. Boosted H­->bb Tagger In Run II

    CERN Document Server

    Sahinsoy, Merve; The ATLAS collaboration

    2016-01-01

    Several searches for Higgs bosons decaying to b­quark pairs benefit from the increased Run II centre­of­mass energy by exploiting the large transvers­momentum (boosted) Higgs boson regime, where the two b­jets are merged into one large­radius jet. ATLAS uses a boosted H­>bb tagger algorithm to separate the Higgs signal from the background processes (QCD, W and Z bosons, top quarks). The tagger takes as input a large­R=1.0 jet calibrating the pseudorapidity, energy and mass scale. The tagger employs b­tagging, Higgs candidate mass, and substructure information. The performance of several operating points in Higgs boson signal and QCD and ttbar all­hadronic backgrounds are presented. Systematic uncertainties are evaluated so that this tagger can be used in analyses.

  14. Search for non-standard model signatures in the WZ/ZZ final state at CDF Run II

    International Nuclear Information System (INIS)

    Norman, Matthew

    2009-01-01

    This thesis discusses a search for non-Standard Model physics in heavy diboson production in the dilepton-dijet final state, using 1.9 fb -1 of data from the CDF Run II detector. New limits are set on the anomalous coupling parameters for ZZ and WZ production based on limiting the production cross-section at high (cflx s). Additionally limits are set on the direct decay of new physics to ZZ andWZ diboson pairs. The nature and parameters of the CDF Run II detector are discussed, as are the influences that it has on the methods of our analysis.

  15. Search for non-standard model signatures in the WZ/ZZ final state at CDF run II

    Energy Technology Data Exchange (ETDEWEB)

    Norman, Matthew [Univ. of California, San Diego, CA (United States)

    2009-01-01

    This thesis discusses a search for non-Standard Model physics in heavy diboson production in the dilepton-dijet final state, using 1.9 fb -1 of data from the CDF Run II detector. New limits are set on the anomalous coupling parameters for ZZ and WZ production based on limiting the production cross-section at high š. Additionally limits are set on the direct decay of new physics to ZZ andWZ diboson pairs. The nature and parameters of the CDF Run II detector are discussed, as are the influences that it has on the methods of our analysis.

  16. MAX: an expert system for running the modular transport code APOLLO II

    International Nuclear Information System (INIS)

    Loussouarn, O.; Ferraris, C.; Boivineau, A.

    1990-01-01

    MAX is an expert system built to help users of the APOLLO II code to prepare the input data deck to run a job. APOLLO II is a modular transport-theory code for calculating the neutron flux in various geometries. The associated GIBIANE command language allows the user to specify the physical structure and the computational method to be used in the calculation. The purpose of MAX is to bring into play expertise in both neutronic and computing aspects of the code, as well as various computational schemes, in order to generate automatically a batch data set corresponding to the APOLLO II calculation desired by the user. MAX is implemented on the SUN 3/60 workstation with the S1 tool and graphic interface external functions

  17. Colliders

    CERN Document Server

    Chou, Weiren

    2014-01-01

    The idea of colliding two particle beams to fully exploit the energy of accelerated particles was first proposed by Rolf Wideröe, who in 1943 applied for a patent on the collider concept and was awarded the patent in 1953. The first three colliders — AdA in Italy, CBX in the US, and VEP-1 in the then Soviet Union — came to operation about 50 years ago in the mid-1960s. A number of other colliders followed. Over the past decades, colliders defined the energy frontier in particle physics. Different types of colliers — proton–proton, proton–antiproton, electron–positron, electron–proton, electron-ion and ion-ion colliders — have played complementary roles in fully mapping out the constituents and forces in the Standard Model (SM). We are now at a point where all predicted SM constituents of matter and forces have been found, and all the latest ones were found at colliders. Colliders also play a critical role in advancing beam physics, accelerator research and technology development. It is timel...

  18. Supersymmetric Higgs pair discovery prospects at hadron colliders

    CERN Document Server

    Belyaev, A; Éboli, Oscar J P; Mizukoshi, J K; Novaes, S F

    2000-01-01

    We study the potential of hadron colliders in the search for the pair production of neutral Higgs bosons in the framework of the Minimal Supersymmetric Standard Model. Using analytical expressions for the relevant amplitudes, we perform a detailed signal and background analysis, working out efficient kinematical cuts for the extraction of the signal. The important role of squark loop contributions to the signal is emphasised. If the signal is sufficiently enhanced by these contributions, it could even be observable at the next run of the upgraded Tevatron collider in the near future. At the LHC the pair production of light and heavy Higgs bosons might be detectable simultaneously.

  19. LHC collider phenomenology of minimal universal extra dimensions

    Science.gov (United States)

    Beuria, Jyotiranjan; Datta, AseshKrishna; Debnath, Dipsikha; Matchev, Konstantin T.

    2018-05-01

    We discuss the collider phenomenology of the model of Minimal Universal Extra Dimensions (MUED) at the Large hadron Collider (LHC). We derive analytical results for all relevant strong pair-production processes of two level 1 Kaluza-Klein partners and use them to validate and correct the existing MUED implementation in the fortran version of the PYTHIA event generator. We also develop a new implementation of the model in the C++ version of PYTHIA. We use our implementations in conjunction with the CHECKMATE package to derive the LHC bounds on MUED from a large number of published experimental analyses from Run 1 at the LHC.

  20. First measurement of the W-boson mass in run II of the Tevatron.

    Science.gov (United States)

    Aaltonen, T; Abulencia, A; Adelman, J; Affolder, T; Akimoto, T; Albrow, M G; Amerio, S; Amidei, D; Anastassov, A; Anikeev, K; Annovi, A; Antos, J; Aoki, M; Apollinari, G; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carrillo, S; Carlsmith, D; Carosi, R; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, I; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Cilijak, M; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Coca, M; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Almenar, C Cuenca; Cuevas, J; Culbertson, R; Cully, J C; Daronco, S; Datta, M; D'Auria, S; Davies, T; Dagenhart, D; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'orso, M; Delli Paoli, F; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Dörr, C; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, I; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garcia, J E; Garberson, F; Garfinkel, A F; Gay, C; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; da Costa, J Guimaraes; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Holloway, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jang, D; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Karchin, P E; Kato, Y; Kemp, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraan, A C; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Liss, T M; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lu, R-S; Lucchesi, D; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marginean, R; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Matsunaga, H; Mattson, M E; Mazini, R; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyamoto, A; Moed, S; Moggi, N; Mohr, B; Moon, C S; Moore, R; Morello, M; Fernandez, P Movilla; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; Staveris-Polykalas, A; Denis, R St; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tsuno, S; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vazquez, F; Velev, G; Vellidis, C; Veramendi, G; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Vollrath, I; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zhou, J; Zucchelli, S

    2007-10-12

    We present a measurement of the W-boson mass using 200 pb{-1} of data collected in pp[over ] collisions at sqrt[s]=1.96 TeV by the CDF II detector at run II of the Fermilab Tevatron. With a sample of 63 964 W-->enu candidates and 51 128 W-->munu candidates, we measure M_{W}=80 413+/-34{stat}+/-34{syst}=80,413+/-48 MeV/c;{2}. This is the most precise single measurement of the W-boson mass to date.

  1. Interaction Region for a 100 TeV Proton-Proton Collider

    CERN Document Server

    Martin, R; Dalena, B

    2015-01-01

    As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, FCC-hh, running at center-of-mass energies of up to 100 TeV, pushing the energy frontier of fundamental physics to a new limit. At a circumference of 80-100 km, this machine is planned to use the same tunnel as FCC-ee, a proposed 90-350 GeV high luminosity electron-positron collider. This paper presents the design progress and technical challenges for the interaction region of FCC-hh.

  2. LHCb Run II tracking performance and prospects for the Upgrade

    CERN Multimedia

    2016-01-01

    The LHCb tracking system consists of a Vertex Locator around the interaction point, a tracking station with four layers of silicon strip detectors in front of the magnet, and three tracking stations, using either straw-tubes or silicon strip detectors, behind the magnet. This system allows to reconstruct charged particles with a high efficiency (typically > 95% for particles with momentum > 5 GeV) and an excellent momentum resolution (0.5% for particles with momentum < 20 GeV). The high momentum resolution results in very narrow mass peaks, leading to a very good signal-to-background ratio in such key channels as $B_s\\to\\mu^+\\mu^-$. Furthermore an optimal decay time resolution is an essential element in the studies of time dependent CP violation. For Run II a novel reconstruction strategy was adopted, allowing to run the same track reconstruction in the software trigger as offline. This convergence was possible due to a staged approach in the track reconstruction and a large reduction in the processing tim...

  3. The ATLAS Muon Trigger Performance : Run 1 and initial Run 2.

    CERN Document Server

    Kasahara, Kota; The ATLAS collaboration

    2015-01-01

    The ATLAS Muon Trigger Performance: Run 1 and Initial Run 2 Performance

Events with muons in the final state are an important signature for many physics topics at the Large Hadron Collider (LHC). An efficient trigger on muons and a detailed understanding of its performance are required. In 2012, the last year of Run 1, the instantaneous luminosity of the LHC reached 7.7x10^33 cm -2s-1 and the average number of events that occur in a same bunch crossing was 25. The ATLAS Muon trigger has successfully adapted to this changing environment by making use of isolation requirements, combined trigger signatures with electron and jet trigger objects, and by using so-called full-scan triggers, which make use of the full event information to search for di-lepton signatures, seeded by single lepton objects. A stable and highly efficient muon trigger was vital in the discovery of Higgs boson in 2012 and for many searches for new physics. 
The performance of muon triggers during the LHC Run 1 data-taking campaigns i...

  4. Beauty and charm rare decays at the LHC: prospects for Run II

    CERN Document Server

    Fiorendi, Sara; De Sanctis, Umberto

    2016-01-01

    The main results on the searches for rare decays of B and D mesons from ATLAS, CMS and LHCb experiments are summarised in this report. Particular attention will be given to the measurements performed by at least two of the three experiments, where common aspects and differences are highlighted. Detector improvements and perspectives of the three experiments for Run II ongoing data campaign are also discussed.

  5. Higgs measurement at $e^+e^-$ circular colliders

    CERN Document Server

    Ruan, Manqi

    2016-01-01

    Now that the mass of the Higgs boson is known, circular electron positron colliders, able to measure the properties of these particles with high accuracy, are receiving considerable attention. Design studies have been launched (i) at CERN with the Future Circular Colliders (FCC), of which an e+e- collider is a potential first step (FCC-ee, formerly caller TLEP) and (ii) in China with the Circular Electron Positron Collider (CEPC). Hosted in a tunnel of at least 50 km (CEPC) or 80-100 km (FCC), both projects can deliver very high luminosity from the Z peak to HZ threshold (CEPC) and even to the top pair threshold and above (FCC-ee). At the ZH production optimum, around 240 GeV, the FCC-ee (CEPC) will be able to deliver 10 (5) ab-1 integrated luminosity in 5 (10) years with 4 (2) interaction points: hence to produce millions of Higgs bosons through the Higgsstrahlung process and vector boson fusion processes. This sample opens the possibility of subper- cent precision absolute measurements of the Higgs boson co...

  6. Higgs Measurement at e+e- Circular Colliders

    CERN Document Server

    Ruan, M

    2014-01-01

    Now that the mass of the Higgs boson is known, circular electron positron colliders, able to measure the properties of these particles with high accuracy, are receiving considerable attention. Design studies have been launched (i) at CERN with the Future Circular Colliders (FCC), of which an e+e- collider is a potential first step (FCC-ee, formerly caller TLEP) and (ii) in China with the Circular Electron Positron Collider (CEPC). Hosted in a tunnel of at least 50 km (CEPC) or 80-100 km (FCC), both projects can deliver very high luminosity from the Z peak to HZ threshold (CEPC) and even to the top pair threshold and above (FCC-ee). At the ZH production optimum, around 240 GeV, the FCC-ee (CEPC) will be able to deliver 10 (5) ab-1 integrated luminosity in 5 (10) years with 4 (2) interaction points: hence to produce millions of Higgs bosons through the Higgsstrahlung process and vector boson fusion processes. This sample opens the possibility of subper-cent precision absolute measurements of the Higgs boson cou...

  7. RUN COORDINATION

    CERN Multimedia

    Christophe Delaere

    2012-01-01

      On Wednesday 14 March, the machine group successfully injected beams into LHC for the first time this year. Within 48 hours they managed to ramp the beams to 4 TeV and proceeded to squeeze to β*=0.6m, settings that are used routinely since then. This brought to an end the CMS Cosmic Run at ~Four Tesla (CRAFT), during which we collected 800k cosmic ray events with a track crossing the central Tracker. That sample has been since then topped up to two million, allowing further refinements of the Tracker Alignment. The LHC started delivering the first collisions on 5 April with two bunches colliding in CMS, giving a pile-up of ~27 interactions per crossing at the beginning of the fill. Since then the machine has increased the number of colliding bunches to reach 1380 bunches and peak instantaneous luminosities around 6.5E33 at the beginning of fills. The average bunch charges reached ~1.5E11 protons per bunch which results in an initial pile-up of ~30 interactions per crossing. During the ...

  8. Discovering supersymmetry with m02<0 in the first CERN LHC physics run

    International Nuclear Information System (INIS)

    Rajaraman, Arvind; Smith, Bryan T.

    2007-01-01

    In minimal supergravity, the parameter space where the slepton is the lightest superpartner is usually neglected, because of strong constraints on charged dark matter. When the gravitino is the true lightest superpartner, this region avoids these constraints and offers spectacular collider signals. We investigate this scenario for the Large Hadron Collider and find that a large portion of the ignored minimal supergravity parameter space can lead to discovery within the first physics run, with 1-4 fb -1 of data. We find that there are regions where discovery is feasible with only 1 d of running

  9. CERN-Fermilab Hadron Collider Physics Summer School 2013 open for applications

    CERN Multimedia

    2013-01-01

    Mark your calendar for 28 August - 6 September 2013, when CERN will welcome students to the eighth CERN-Fermilab Hadron Collider Physics Summer School.   Experiments at hadron colliders will continue to provide our best tools for exploring physics at the TeV scale for some time. With the completion of the 7-8 TeV runs of the LHC, and the final results from the full Tevatron data sample becoming available, a new era in particle physics is beginning, heralded by the Higgs-like particle recently discovered at 125 GeV. To realize the full potential of these developments, CERN and Fermilab are jointly offering a series of "Hadron Collider Physics Summer Schools", to prepare young researchers for these exciting times. The school has alternated between CERN and Fermilab, and will return to CERN for the eighth edition, from 28 August to 6 September 2013. The CERN-Fermilab Hadron Collider Physics Summer School is an advanced school which particularly targets young postdocs in exper...

  10. Electroweak production of the top quark in the Run II of the D0 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Clement, Benoit [Louis Pasteur Univ., Strasbourg (France)

    2006-04-28

    The work exposed in this thesis deals with the search for electroweak production of top quark (single top) in proton-antiproton collisions at √s = 1.96 TeV. This production mode has not been observed yet. Analyzed data have been collected during the Run II of the D0 experiment at the Fermilab Tevatron collider. These data correspond to an integrated luminosity of 370 pb-1. In the Standard Model, the decay of a top quark always produce a high momentum bottom quark. Therefore bottom quark jets identification plays a major role in this analysis. The large lifetime of b hadrons and the subsequent large impact parameters relative to the interaction vertex of charged particle tracks are used to tag bottom quark jets. Impact parameters of tracks attached to a jet are converted into the probability for the jet to originate from the primary vertex. This algorithm has a 45% tagging efficiency for a 0.5% mistag rate. Two processes (s and t channels) dominate single top production with slightly different final states. The searched signature consists in 2 to 4 jets with at least one bottom quark jet, one charged lepton (electron or muon) and missing energy accounting for a neutrino. This final state is background dominated and multivariate techniques are needed to separate the signal from the two main backgrounds: associated production of a W boson and jets and top quarks pair production. The achieved sensitivity is not enough to reach observation and we computed upper limits at the 95% confidence level at 5 pb (s-channel) and 4.3 pb (t-channel) on single top production cross-sections.

  11. Operation of the DC current transformer intensity monitors at FNAL during run II

    Energy Technology Data Exchange (ETDEWEB)

    Crisp, J.; Fellenz, B.; Heikkinen, D.; Ibrahim, M.A.; Meyer, T.; Vogel, G.; /Fermilab

    2012-01-01

    Circulating beam intensity measurements at FNAL are provided by five DC current transformers (DCCT), one per machine. With the exception of the DCCT in the Recycler, all DCCT systems were designed and built at FNAL. This paper presents an overview of both DCCT systems, including the sensor, the electronics, and the front-end instrumentation software, as well as their performance during Run II.

  12. Run II performance of luminosity and beam condition monitors at CMS

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, Jessica Lynn [DESY, Hamburg (Germany)

    2016-07-01

    The BRIL (Beam Radiation Instrumentation and Luminosity) system of CMS consists of instrumentation to measure the luminosity online and offline, and to monitor the LHC beam conditions inside CMS. An accurate luminosity measurement is essential to the CMS physics program, and measurement of the beam background is necessary to ensure safe operation of CMS. Many of the BRIL subsystems have been upgraded and others have been added for LHC Run II to complement the existing measurements. The beam condition monitor (BCM) consists of several sets of diamond sensors used to measure online luminosity and beam background with a single-bunch-crossing resolution. The BCM also detects when beam conditions become unfavorable for CMS running and may trigger a beam abort to protect the detector. The beam halo monitor (BHM) uses quartz bars to measure the background of the incoming beams at larger radii. The pixel luminosity telescope (PLT) consists of telescopes of silicon sensors designed to provide a CMS online and offline luminosity measurement. In addition, the forward hadronic calorimeter (HF) delivers an independent luminosity measurement, making the whole system robust and allowing for cross-checks of the systematics. An overview of the performance during 2015 LHC running for the new/updated BRIL subsystems will be given, including the uncertainties of the luminosity measurements.

  13. The LHC Tier1 at PIC: Experience from first LHC run

    International Nuclear Information System (INIS)

    Flix, J.; Perez-Calero Yzquierdo, A.; Accion, E.; Acin, V.; Acosta, C.; Bernabeu, G.; Bria, A.; Casals, J.; Caubet, M.; Cruz, R.; Delfino, M.; Espinal, X.; Lanciotti, E.; Lopez, F.; Martinez, F.; Mendez, V.; Merino, G.; Pacheco, A.; Planas, E.; Porto, M. C.; Rodriguez, B.; Sedov, A.

    2013-01-01

    This paper summarizes the operational experience of the Tier1 computer center at Port d'Informacio Cientifica (PIC) supporting the commissioning and first run (Run1) of the Large Hadron Collider (LHC). The evolution of the experiment computing models resulting from the higher amounts of data expected after there start of the LHC are also described. (authors)

  14. Status and plans of the Compact Linear Collider Study

    CERN Document Server

    Doebert, Steffen

    2016-01-01

    The Compact Linear Collider (CLIC) project is exploring the possibility of constructing a multiTeV linear electron-positron collider for high-energy frontier physics studies beyond the LHC era. The CLIC concept is based on high-gradient normal-conducting accelerating structures. The RF power for the acceleration of the colliding beams is produced by a two-beam acceleration scheme, where power is extracted from a high current drive beam that runs parallel with the main linac. The key ongoing studies involve accelerator parameter optimisation, technical studies and component development, alignment and stability, and include a number of system performance studies in test-facilities around the world. The CLIC physics potential and main detector issues, as well as possible implementation staging, are being studied in parallel. A summary of the progress and status of the corresponding studies will be given, as well as an outline of the preparation and work towards developing a CLIC implementation plan by 2018/19

  15. Novel Real-time Calibration and Alignment Procedure for LHCb Run II

    CERN Multimedia

    Prouve, Claire

    2016-01-01

    In order to achieve optimal detector performance the LHCb experiment has introduced a novel real-time detector alignment and calibration strategy for Run II of the LHC. For the alignment tasks, data is collected and processed at the beginning of each fill while the calibrations are performed for each run. This real time alignment and calibration allows the same constants being used in both the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. Additionally the newly computed alignment and calibration constants can be instantly used in the trigger, making it more efficient. The online alignment and calibration of the RICH detectors also enable the use of hadronic particle identification in the trigger. The computing time constraints are met through the use of a new dedicated framework using the multi-core farm infrastructure for the LHCb trigger. An overview of all alignment and calibration tasks is presented and their performance is shown.

  16. Search for the Production of Gluinos and Squarks with the CDF II Experiment at the Tevatron Collider

    Energy Technology Data Exchange (ETDEWEB)

    De Lorenzo, Gianluca [Autonomous Univ. of Barcelona (Spain)

    2010-05-19

    This thesis reports on two searches for the production of squarks and gluinos, supersymmetric partners of the Standard Model (SM) quarks and gluons, using the CDF detector at the Tevatron √s = 1.96 TeV p$\\bar{p}$ collider. An inclusive search for squarks and gluinos pair production is performed in events with large ET and multiple jets in the final state, based on 2 fb-1 of CDF Run II data. The analysis is performed within the framework of minimal supergravity (mSUGRA) and assumes R-parity conservation where sparticles are produced in pairs. The expected signal is characterized by the production of multiple jets of hadrons from the cascade decays of squarks and gluinos and large missing transverse energy ET from the lightest supersymmetric particles (LSP). The measurements are in good agreement with SM predictions for backgrounds. The results are translated into 95% confidence level (CL) upper limits on production cross sections and squark and gluino masses in a given mSUGRA scenario. An upper limit on the production cross section is placed in the range between 1 pb and 0.1 pb, depending on the gluino and squark masses considered. The result of the search is negative for gluino and squark masses up to 392 GeV/c2 in the region where gluino and squark masses are close to each other, gluino masses up to 280 GeV/c2 regardless of the squark mass, and gluino masses up to 423 GeV=c2 for squark masses below 378 GeV/c2. These results are compatible with the latest limits on squark/gluino production obtained by the D0 Collaboration and considerably improve the previous exclusion limits from direct and indirect searches at LEP and the Tevatron. The inclusive search is then extended to a scenario where the pair production of sbottom squarks is dominant. The new search is performed in a generic MSSM scenario with R-parity conservation. A specific SUSY particle mass hierarchy is assumed such that the

  17. Heavy ion operation from run 2 to HL-LHC

    CERN Document Server

    Jowett, J M; Versteegen, R

    2014-01-01

    The nuclear collision programme of the LHC will continue with Pb-Pb and p-Pb collisions in Run 2 and beyond. Extrapolating from the performance at lower energies in Run 1, it is already clear that Run 2 will substantially exceed design performance. Beyond that, future high-luminosity heavy ion operation of LHC depends on a somewhat different set of (more modest) upgrades to the collider and its injectors from p-p. The high-luminosity phase will start sooner, in Run 3, when necessary upgrades to detectors should be completed. It follows that the upgrades for heavy-ion operation need high priority in LS2.

  18. Performance of the CMS precision electromagnetic calorimeter at LHC Run II and prospects for High-Luminosity LHC

    Science.gov (United States)

    Zhang, Zhicai

    2018-04-01

    Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high-resolution electron and photon energy measurements. Following the excellent performance achieved during LHC Run I at center-of-mass energies of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) is operating at the LHC with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run II has achieved unprecedented levels. The average number of concurrent proton-proton collisions per bunch-crossing (pileup) has reached up to 40 interactions in 2016 and may increase further in 2017. These high pileup levels necessitate a retuning of the ECAL readout and trigger thresholds and reconstruction algorithms. In addition, the energy response of the detector must be precisely calibrated and monitored. We present new reconstruction algorithms and calibration strategies that were implemented to maintain the excellent performance of the CMS ECAL throughout Run II. We will show performance results from the 2015-2016 data taking periods and provide an outlook on the expected Run II performance in the years to come. Beyond the LHC, challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL-LHC) . We review the design and R&D studies for the CMS ECAL and present first test beam studies. Particular challenges at HL-LHC are the harsh radiation environment, the increasing data rates, and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. We present test beam results of hadron irradiated PbWO crystals up to fluences expected at the HL-LHC . We also report on the R&D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

  19. LHCb computing in Run II and its evolution towards Run III

    CERN Document Server

    Falabella, Antonio

    2016-01-01

    his contribution reports on the experience of the LHCb computing team during LHC Run 2 and its preparation for Run 3. Furthermore a brief introduction on LHCbDIRAC, i.e. the tool to interface to the experiment distributed computing resources for its data processing and data management operations, is given. Run 2, which started in 2015, has already seen several changes in the data processing workflows of the experiment. Most notably the ability to align and calibrate the detector between two different stages of the data processing in the high level trigger farm, eliminating the need for a second pass processing of the data offline. In addition a fraction of the data is immediately reconstructed to its final physics format in the high level trigger and only this format is exported from the experiment site to the physics analysis. This concept have successfully been tested and will continue to be used for the rest of Run 2. Furthermore the distributed data processing has been improved with new concepts and techn...

  20. Beam-Beam Effects in the SPS Proton-Anti Proton Collider

    CERN Document Server

    Cornelis, K.

    2014-01-01

    During the proton-anti proton collider run several experiments were carried out in order to understand the effect of the beam-beam interaction on backgrounds and lifetimes. In this talk a selection of these experiments will be presented. From these experiments, the importance of relative beam sizes and tune ripple could be demonstrated.

  1. The upgraded Pixel Detector of the ATLAS Experiment for Run-II at the Large Hadron Collider

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00407702

    2016-01-01

    The Pixel Detector of the ATLAS experiment has shown excellent performance during the whole Run-1 of the LHC. Taking advantage of the detector development period 2013 – 2014, the detector was extracted from the experiment and brought to surface to equip it with new service panels and to repair modules furthermore this helped with the installation of the Insertable B-Layer (IBL), fourth layer of pixel, installed in between the existing Pixel Detector and a new beam-pipe at a radius of 3.3 cm. To cope with the high radiation and increased pixel occupancy due to the proximity to the interaction point, two different silicon sensor technologies (planar and 3D) have been used. A new readout chip has been designed with CMOS 130nm technology with larger area, smaller pixel size and faster readout capability. Dedicated design features in combination with a new composite material were considered and used in order to reduce the material budget of the support structure while keeping the optimal thermo-mechanical perfor...

  2. New physics hints in Β decays and collider outlook

    International Nuclear Information System (INIS)

    Hou, George W.S.

    2006-01-01

    There are currently two hints for new physics involving CP violation in b →s transitions: ΔS ≡ S f - S J/ ψK ≠ 0, and difference in direct CP asymmetry ΔA Kπ ≡ A K + π 0 - A K + π - ≠0. We explore the two scenarios with a large and unique new CP phase in b s transitions. Motivated by ΔS ≠ 0, we update on the right-handed strange beauty squark sb 1R at TeV scale. Motivated by ΔA Kπ ≠ 0, we explore sequential fourth generation t and b quarks. Both scenarios can survive constraints such as SM level b→sγ, sll and Β s mixing, and predict sizable CP violation in Β s mixing. The fourth generation picture predicts sizable K L → π 0 νν. Direct search for sb R , b' and t' at hadronic colliders, such as Tevatron Run II and LHC, can complement further CP violation studies at these machines, as well as at the future Super Β factory. (author)

  3. Progress report on the SLAC Linear Collider

    International Nuclear Information System (INIS)

    Kozanecki, W.

    1987-11-01

    In this paper we report on the status of the SLAC Linear Collider (SLC), the prototype of a new generation of colliding beam accelerators. This novel type of machine holds the potential of extending electron-positron colliding beam studies to center-of-mass (c.m.) energies far in excess of what is economically achievable with colliding beam storage rings. If the technical challenges posed by linear colliders are solvable at a reasonable cost, this new approach would provide an attractive alternative to electron-positron rings, where, because of rapidly rising synchrotron radiation losses, the cost and size of the ring increases with the square of the c.m. energy. In addition to its role as a test vehicle for the linear collider principle, the SLC aims at providing an abundant source of Z 0 decays to high energy physics experiments. Accordingly, two major detectors, the upgraded Mark II, now installed on the SLC beam line, and the state-of-the-art SLD, currently under construction, are preparing to probe the Standard Model at the Z 0 pole. The SLC project was originally funded in 1983. Since the completion of construction, we have been commissioning the machine to bring it up to a performance level adequate for starting the high energy physics program. In the remainder of this paper, we will discuss the status, problems and performance of the major subsystems of the SLC. We will conclude with a brief outline of the physics program, and of the planned enhancements to the capabilities of the machine. 26 refs., 7 figs

  4. 2007 2008 ACADEMIC TRAINING PROGRAMME

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 01, 03, 04, 05 October 2007 11:00 to 12:00 - Main Auditorium, bldg. 500 Tevatron: The Cinderella Story or The Art Of Collider Commissioning V. SHILTSEV / Fermi National Accelerator Laboraty, Batavia IL, USA The Tevatron Collider at Fermilab (Batavia, IL, USA) is the world’s highest energy particle collider at 1.8TeV c.m.e. The machine was a centerpiece of the US and world’s High Energy Physics for many years. Currently, the Tevatron is in the last years of its operation in so-called Run II which started 2001 and is tentatively scheduled to end in 2010. In this lecture series, we’ll try to learn from the exciting story of the Tevatron Collider Run II: the story of long preparations, great expectations, initial difficulties, years of "blood and sweat", continuous upgrades, exceeding its goals, high emotions, tune-up of accelerator organization for "combat fighting". The lectures will cover Introduction to the Tevatron, its history and Run II; "Plumbing" I...

  5. 2007 2008 ACADEMIC TRAINING PROGRAMME

    CERN Multimedia

    2007-01-01

    LECTURE SERIES 01, 03, 04, 05 October 2007 11:00-12:00 - Main Auditorium, bldg. 500 Tevatron: The Cinderella Story or The Art Of Collider Commissioning V. SHILTSEV / Fermi National Accelerator Laboraty, Batavia IL, USA The Tevatron Collider at Fermilab (Batavia, IL, USA) is the world’s highest energy particle collider at 1.8TeV c.m.e. The machine was a centerpiece of the US and world’s High Energy Physics for many years. Currently, the Tevatron is in the last years of its operation in so-called Run II which started 2001 and is tentatively scheduled to end in 2010. In this lecture series, we’ll try to learn from the exciting story of the Tevatron Collider Run II: the story of long preparations, great expectations, initial difficulties, years of "blood and sweat", continuous upgrades, exceeding its goals, high emotions, tune-up of accelerator organization for "combat fighting". The lectures will cover Introduction to the Tevatron, its history and Run II; "Plumbing" Issu...

  6. The Mark II detector for the SLC

    International Nuclear Information System (INIS)

    Abrams, G.; Baden, A.R.; Boyer, J.; Butler, F.; Drell, P.S.; Fay, J.; Gidal, G.; Goldhaber, G.; Haggerty, J.; Harr, R.; Hearty, C.; Herrup, D.; Holmgren, S.O.; Jaffre, M.; Juricic, I.; Kadyk, J.A.; Kral, J.F.; Levi, M.E.; Lynch, G.R.; Richman, J.D.; Rouse, F.R.; Schaad, M.W.; Schmidke, W.B.; Schumm, B.A.; Trilling, G.H.; Wood, D.R.; Akerlof, C.; Bonvicini, G.; Chapman, J.; Chmeissani, M.; Frey, R.; Gero, E.; Hong, S.J.; Koska, W.; Nitz, D.; Petradza, M.; Thun, R.; Tschirhart, R.; Veltman, H.; Alexander, J.P.; Ballam, J.; Barklow, T.; Bartelt, J.; De Boer, W.; Boyarski, A.; Braune, K.; Bulos, F.; Burke, D.L.; Cords, D.; Coupal, D.P.; Destaebler, H.C.; Dorfan, J.M.; Feldman, G.J.; Fernandes, D.; Field, R.C.; Fordham, C.; Fujino, D.; Gan, K.K.; Glanzman, T.; Grosse-Wiesmann, P.; Hanson, G.; Hayes, K.; Himel, T.; Hutchinson, D.; Innes, W.R.; Jacobsen, R.G.; Jaros, J.A.; Jung, C.K.; Karlen, D.; Klein, S.R.; Koetke, D.; Komamiya, M.; Kowalski, L.A.; Kozanecki, W.; Lankford, A.J.; Larsen, R.R.; Lueth, V.; Mattison, T.; Moffeit, K.C.; Mueller, L.; Munger, C.T.; Nash, J.; Ong, R.A.; O'Shaughnessy, K.F.; Perl, J.; Perl, M.L.; Perrier, F.; Petersen, A.; Pitthan, R.; Riles, K.; Swartz, M.; Taylor, R.E.; Van Kooten, R.; Voruganti, P.; Weigend, A.; Woods, M.; Wormser, G.; Wright, R.; Alvarez, M.; Calvino, F.; Fernandez, E.; Ford, W.T.; Hinshaw, D.A.; Rankin, P.; Smith, J.G.; Wagner, S.R.; Weber, P.; White, S.L.; Averill, D.; Blockus, D.; Brabson, B.; Brom, J.M.; Murray, W.N.; Ogren, H.; Rust, D.R.; Snyder, A.; Yurko, M.; Barish, B.C.; Hawkes, C.M.; Hoenk, M.; Kuhlen, M.; Li, Z.; McKenna, J.A.; Milliken, B.D.; Nelson, M.E.; Peck, C.; Porter, F.C.; Soderstrom, E.; Stroynowski, R.; Weinstein, A.J.; Weir, A.J.; Wicklund, E.; Wolf, R.C.; Wu, D.Y.; Barnett, B.A.; Boswell, C.; Dauncey, P.; Drewer, D.C.; Harral, B.; Hylen, J.; Matthews, J.A.J.; Stoker, D.P.; Vejcik, S.; Breakstone, A.; Cence, R.J.; Gong, X.; Harris, F.A.; Koide, A.; Parker, S.I.; Green, A.; Lawrence Berkeley Lab., CA; California Univ., Berkeley

    1989-01-01

    The Mark II detector has been upgraded in preparation for its role as the first detector to take data at the Stanford Linear Collider. The new detector components include the central drift chamber, the time-of-flight system, the coil, the endcap electromagnetic calorimeters and the beam energy and luminosity measuring devices. There have also been improvements in detector hermeticity. All of the major components were installed for a test run at the PEP storage ring (√s=29 GeV) in 1985. This paper describes the upgraded detector, including its trigger and data acquisition systems, and gives performance figures for its components. Future improvements are also discussed. (orig.)

  7. LUCID Upgrade for ATLAS Luminosity Measurement in Run II

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00444244; The ATLAS collaboration

    2016-01-01

    The main ATLAS luminosity monitor, LUCID, and its read-out electronics have been completely rebuilt for the LHC Run II in order to cope with a higher center of mass energy ($\\sqrt{s}$=13 TeV) and the 25 ns bunch-spacing. The LUCID detector is measuring Cherenkov light produced in photomultiplier quartz windows and in quartz optical fibers. It has a novel calibration system that uses radioactive $^{207}$Bi sources that produce internal-conversion electrons with energy above the Cherenkov threshold in quartz. The new electronics can count signals with amplitude above a predefined threshold (hits) as well as the integrated pulseheight of the signals, which makes it possible to measure luminosity with complementary methods. The new detector, calibration system and electronics will be described, together with the results of the 2015 luminosity measurement.

  8. Muon colliders

    International Nuclear Information System (INIS)

    Cline, David

    1995-01-01

    The increasing interest in the possibility of positive-negative muon colliders was reflected in the second workshop on the Physics Potential and Development of Muon Colliders, held in Sausalito, California, from 16-19 November, with some 60 attendees. It began with an overview of the particle physics goals, detector constraints, the muon collider and mu cooling, and source issues. The major issue confronting muon development is the possible luminosity achievable. Two collider energies were considered: 200 + 200 GeV and 2 + 2 TeV. The major particle physics goals are the detection of the higgs boson(s) for the lower energy collider, together with WW scattering and supersymmetric particle discovery. At the first such workshop, held in Napa, California, in 1992, it was estimated that a luminosity of some 10 30 and 3 x 10 32 cm -2 s -1 for the low and high energy collider might be achieved (papers from this meeting were published in the October issue of NIM). This was considered a somewhat conservative estimate at the time. At the Sausalito workshop the goal was to see if a luminosity of 10 32 to 10 34 for the two colliders might be achievable and usable by a detector. There were five working groups - physics, 200 + 200 GeV collider, 2 + 2 TeV collider, detector design and backgrounds, and muon cooling and production methods. Considerable progress was made in all these areas at the workshop.

  9. Compromise between neutrino masses and collider signatures in the type-II seesaw model

    International Nuclear Information System (INIS)

    Chao Wei; Luo Shu; Xing Zhizhong; Zhou Shun

    2008-01-01

    A natural extension of the standard SU(2) L xU(1) Y gauge model to accommodate massive neutrinos is to introduce one Higgs triplet and three right-handed Majorana neutrinos, leading to a 6x6 neutrino mass matrix which contains three 3x3 submatrices, M L , M D and M R . We show that three light Majorana neutrinos (i.e., the mass eigenstates of ν e , ν μ , and ν τ ) are exactly massless in this model, if and only if M L =M D M R -1 M D T exactly holds. This no-go theorem implies that small but nonvanishing neutrino masses may result from a significant but incomplete cancellation between M L and M D M R -1 M D T terms in the Type-II seesaw formula, provided three right-handed Majorana neutrinos are of O(1) TeV and experimentally detectable at the LHC. We propose three simple Type-II seesaw scenarios with the A 4 xU(1) X flavor symmetry and its explicit breaking to interpret the observed neutrino mass spectrum and neutrino mixing pattern. Such a TeV-scale neutrino model can be tested in two complementary ways: (1) searching for possible collider signatures of lepton number violation induced by the right-handed Majorana neutrinos and doubly-charged Higgs particles; and (2) searching for possible consequences of unitarity violation of the 3x3 neutrino mixing matrix in the future long-baseline neutrino oscillation experiments

  10. Measurements of $\\sigma(V+D^{*})/\\sigma(V)$ in $9.7$ fb$^{-1}$ at CDF Run II

    Energy Technology Data Exchange (ETDEWEB)

    Matera, Keith [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2014-01-01

    The Standard Model of particle physics has been remarkably successful, but the non-perturbative features of quantum chromodynamics must be tested and modeled with data. There have been many such tests, focused primarily on the use of jet-based probes of heavy flavor (bottom and charm quark) production at hadron colliders. In this thesis, we propose and test a strategy for identifying heavy flavor in events containing a W or Z vector boson (a V boson); this technique probes a much lower energy regime than can be explored by jet-based methods. In a sample of W and Z events skimmed from 9.7 fb-1 of high- pT electron and muon data from CDF Run II p p collisions at center of mass energy √s = 1:96 GeV , we identify charm by fully reconstructing D* (2010) → D0(→ Kπ )π s decays at the track level. Using a binned fit of Δm=m(Kππ s) m(Kπ ) to count reconstructed D* candidates, we then unfold these raw counts with acceptance values derived from Monte Carlo, and present measurements of σ(W + D* )/ σ(W) and σ(Z + D* )/ σ(Z) in the W/Z leptonic decay channels. All measurements are found to be in agreement with the predictions of Pythia 6.2 (PDF set CTEQ5L). These results include the first measurement of W/Z + c production in events with zero jet objects at the Tevatron, and the first measurement of W/Z +c production with pT (c) < 15 GeV at the Tevatron.

  11. Constraining top quark effective theory in the LHC Run II era

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, Andy; Englert, Christoph; Ferrando, James; Miller, David J.; Moore, Liam; Russell, Michael; White, Chris D. [School of Physics and Astronomy, Scottish Universities Physics Alliance, University of Glasgow,Glasgow G12 8QQ, Scotland (United Kingdom); Collaboration: The TopFitter collaboration

    2016-04-04

    We perform an up-to-date global fit of top quark effective theory to experimental data from the Tevatron, and from LHC Runs I and II. Experimental data includes total cross-sections up to 13 TeV, as well as differential distributions, for both single top and pair production. We also include the top quark width, charge asymmetries, and polarisation information from top decay products. We present bounds on the coefficients of dimension six operators, and examine the interplay between inclusive and differential measurements, and Tevatron/LHC data. All results are currently in good agreement with the Standard Model.

  12. Open-Midplane Dipoles for a Muon Collider

    International Nuclear Information System (INIS)

    Weggel, R.; Gupta, R.; Kolonko, J.; Scanlan, R.; Cline, D.; Ding, X.; Anerella, M.; Kirk, H.; Palmer, B.; Schmalzle, J.

    2011-01-01

    For a muon collider with copious decay particles in the plane of the storage ring, open-midplane dipoles (OMD) may be preferable to tungsten-shielded cosine-theta dipoles of large aperture. The OMD should have its midplane completely free of material, so as to dodge the radiation from decaying muons. Analysis funded by a Phase I SBIR suggests that a field of 10-20 T should be feasible, with homogeneity of 1 x 10 -4 and energy deposition low enough for conduction cooling to 4.2 K helium. If funded, a Phase II SBIR would refine the analysis and build and test a proof-of-principle magnet. A Phase I SBIR has advanced the feasibility of open-midplane dipoles for the storage ring of a muon collider. A proposed Phase II SBIR would refine these predictions of stresses, deformations, field quality and energy deposition. Design optimizations would continue, leading to the fabrication and test, for the first time, of a proof-of-principle dipole of truly open-midplane design.

  13. Results on QCD Physics from the CDF-II Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pagliarone, C.; /Cassino U. /INFN, Pisa

    2006-12-01

    In this paper the authors review a selection of recent results obtained, in the area of QCD physics, from the CDF-II experiment that studies p{bar p} collisions at {radical}s = 1.96 TeV provided by the Fermilab Tevatron Collider. All results shown correspond to analysis performed using the Tevatron Run II data samples. In particular they will illustrate the progress achieved and the status of the studies on the following QCD processes: jet inclusive production, using different jet clustering algorithm, W({yields} e{nu}{sub e}) + jets and Z({yields} e{sup +}e{sup -}) + jets production, {gamma} + b-jet production, dijet production in double pomeron exchange and finally exclusive e{sup +}e{sup -} and {gamma}{gamma} production. No deviations from the Standard Model have been observed so far.

  14. Muon colliders

    International Nuclear Information System (INIS)

    Palmer, R.B.; Sessler, A.; Skrinsky, A.

    1996-01-01

    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should thus be regarded as complementary. Parameters are given of 4 TeV and 0.5 TeV high luminosity micro + micro - colliders, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleration and storage in a collider ring. Problems of detector background are also discussed

  15. Demonstration of two-beam acceleration in CTF II

    CERN Document Server

    Bossart, Rudolf; Carron, G; Chanudet, M; Chautard, F; Delahaye, J P; Godot, J C; Hutchins, S; Kamber, I; Martínez, C; Suberlucq, Guy; Tenenbaum, P G; Thorndahl, L; Valentini, M; Wilson, Ian H; Wuensch, Walter

    1999-01-01

    The second phase of the Compact LInear Collider (CLIC) Test Facility (CTF II) at CERN has demon-strated the feasibility of two-beam acceleration at 30 GHz using a high-charge drive beam, running paral lel to the main beam, as the RF power source. To date accelerating gradients of 59 MV/m at 30 GHz have been achieved. In CTF II, the two beams are generated by 3 GHz RF photo-injectors and are acceler ated in 3 GHz linacs, before injection into the 30 GHz modules. The drive beam linac has to accelerate a 16 ns long train of 48 bunches, each with a nominal charge of 13.4 nC. To cope with the very su bstantial beam-loading special accelerating structures are used (running slightly off the bunch repetition frequency). A magnetic chicane compresses the bunches to less than 5 ps fwhm, this is needed for efficient 30 GHz power generation. The 30 GHz modules are fully-engineered representative sections of CLIC, they include a 30 GHz decelerator for the drive beam, a 30 GHz accelerator for the main beam, high resolution...

  16. CMS Software and Computing Ready for Run 2

    CERN Document Server

    Bloom, Kenneth

    2015-01-01

    In Run 1 of the Large Hadron Collider, software and computing was a strategic strength of the Compact Muon Solenoid experiment. The timely processing of data and simulation samples and the excellent performance of the reconstruction algorithms played an important role in the preparation of the full suite of searches used for the observation of the Higgs boson in 2012. In Run 2, the LHC will run at higher intensities and CMS will record data at a higher trigger rate. These new running conditions will provide new challenges for the software and computing systems. Over the two years of Long Shutdown 1, CMS has built upon the successes of Run 1 to improve the software and computing to meet these challenges. In this presentation we will describe the new features in software and computing that will once again put CMS in a position of physics leadership.

  17. A realistic study on a forward geometry collider spectrometer: Performance of a typical fixed target spectrometer at the tevatron collider

    International Nuclear Information System (INIS)

    Lebrun, P.

    1993-01-01

    The performance of a forward heavy quark experiment at the collider can be estimated in a very realistic way, by simply carrying an existing fixed target spectrometer (E687) to the Tevatron Collider, changing only the beam/target configuration while keeping all reconstruction cuts identical to those used in reconstructing real charmed particles collected during the last fixed target run. Based on the golden - and typical - decay mode D → Kππ, it is found that the overall charm acceptance x efficiency is ∼ 3%, the 5-body B decay B → Dππ being about .6%. Such an experiment compares very favorably to E-831 and has real potential to study in great detail doubly suppressed Cabbibo decays and to observe D 0 - D 0 mixing. In addition, this exercise allows one to perform a rough but effective reality check on similar design (e.g. COBEX)

  18. Drell-Yan and diphoton production at hadron colliders and low scale gravity model

    International Nuclear Information System (INIS)

    Cheung, Kingman; Landsberg, Greg

    2000-01-01

    In the model of Arkani-Hamed, Dimopoulos, and Dvali where gravity is allowed to propagate in the extra dimensions of very large size, virtual graviton exchange between the standard model particles can give rise to signatures that can be tested in collider experiments. We study these effects in dilepton and diphoton production at hadron colliders. Specifically, we examine the double differential cross section in the invariant mass and scattering angle, which is found to be useful in separating the gravity effects from the standard model. In this work, sensitivity obtained using the double differential cross section is higher than that in previous studies based on single differential distributions. Assuming no excess of events over the standard model predictions, we obtain the following 95% confidence level lower limits on the effective Planck scale: 0.9-1.5 TeV in the Fermilab Tevatron run I, 1.3-2.5 TeV in run IIa, 1.7-3.5 TeV in run IIb, and 6.5-12.8 TeV at the CERN LHC. The range of numbers corresponds to the number of extra dimensions n=7-2. (c) 2000 The American Physical Society

  19. Search for new physics using high mass tau pairs with ppbar collisions at 1.96 Tev using cdf ii

    International Nuclear Information System (INIS)

    Acosta, D.; The CDF Collaboration

    2005-01-01

    We present the results of a search for anomalous resonant production of tau lepton pairs with large invariant mass, the first such search using the CDF II Detector in Run II of the Tevatron p(bar p) collider. Such anomalous production could arise from various new physics processes. In a data sample corresponding to 195 pb -1 of integrated luminosity we predict 2.8 ± 0.5 events from Standard Model background processes and observe 4. We use this result to set limits on the production of heavy scalar and vector particles decaying to tau lepton pairs

  20. Physics at the SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Swartz, M.L.

    1990-11-01

    The SLAC Linear Collider (SLC) was constructed in the years 1983--1987 for two principal reasons: to develop the accelerator physics and technology that are necessary for the construction of future linear electron-positron colliders; and to produce electron-positron collisions at the Z 0 pole and to study the physics of the weak neutral current. To date, the SLC program has been quite successful at achieving the first goal. The machine has produced and collided high energy electron and positron beams of three-micron transverse size. The problems of operating an open geometry detector in an environment that is more akin to those found in fixed-target experiments than in storage rings have largely been solved. As a physics producing venture, the SLC has been less successful than was originally hoped but more successful than is commonly believed. Some of the results that have been produced by the Mark II experiment with a very modest data sample are competitive with those that have been produced with much larger samples by the four LEP collaborations. At the current, time, SLAC is engaged in an ambitious program to upgrade the SLC luminosity and to exploit one of its unique features, a spin polarized electron beam. These lectures are therefore organized into three sections: a brief description of the SLC; a review of the physics results that have been achieved with the Mark II detector; a description of the SLC's future: the realization and use of a polarized electron beam

  1. Boosted $H\\rightarrow b \\bar{b}$ Tagger in Run II

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00394595; The ATLAS collaboration

    2016-01-01

    Many searches for Higgs bosons decaying to b quark pairs benefit from the increased Run II centre of mass energy by exploiting the large transverse momentum (boosted) Higgs boson regime, where the two b-jets are merged into one large radius jet. ATLAS uses a boosted $H \\rightarrow b\\bar{b}$ tagger algorithm to separate Higgs signal from background processes (QCD, W and Z bosons, top quarks). The tagger takes as input a large R=1.0 jet with calibrated pseudorapidity, energy and mass scale. It employs b-tagging, Higgs candidate mass, and substructure information. The performance of several operating points in Higgs boson signal, QCD and $t\\bar{t}$ all-hadronic backgrounds are presented. Systematic uncertainties are evaluated so that this tagger can be used in analyses.

  2. Electron cloud studies for the LHC and future proton colliders

    CERN Document Server

    Domínguez Sánchez de la Blanca, César Octavio; Zimmermann, Frank

    2014-01-01

    The Large Hadron Collider (LHC) is the world’s largest and most powerful particle collider. Its main objectives are to explore the validity of the standard model of particle physics and to look for new physics beyond it, at unprecedented collision energies and rates. A good luminosity performance is imperative to attain these goals. In the last stage of the LHC commissioning (2011-2012), the limiting factor to achieving the design bunch spacing of 25 ns has been the electron cloud effects. The electron cloud is also expected to be the most important luminosity limitation after the first Long Shut-Down of the LHC (LS1), when the machine should be operated at higher energy and with 25-ns spacing, as well as for the planned luminosity upgrade (HL-LHC) and future high energy proton colliders (HE-LHC and VHE-LHC). This thesis contributes to the understanding of the electron cloud observations during the first run of the LHC (2010-2012), presents the first beam dynamics analysis for the next generation of high en...

  3. Status Report on PEP-II Performance

    International Nuclear Information System (INIS)

    Matter, Regina S.

    2002-01-01

    PEP-II [1-9] is an e+e- collider with asymmetric energies (3.1 and 9 GeV, respectively) in a 2200 m tunnel at the Stanford Linear Accelerator Center. The collider produces B mesons to study a particle physics effect called CP violation as well as other physics topics. PEP-II was completed in 1998 with the first luminosity generated in July of that year. The installation of the BaBar Detector was finished in May 1999. The overall layout of PEP-II is shown in Figure 1 and the interaction region of PEP-II in Figure 2. The accelerator parameters and achievements of the High Energy Ring (HER) are listed in Table 1 and those for the Low Energy Ring (LER) in Table 2. The two beams collide at a single point in the IR2 hall where the BaBar detector is located. Beam parameters at the best luminosity are shown in Table 3 and PEP-II milestones in Table 4. In August 1999 PEP-II passed the world's record for luminosity which was 8.1x10 32 /cm 2 /s. The present luminosity in PEP-II is 2.15x10 33 /cm 2 /s which is 72% of the design. In June 2000 PEP-II delivered an integrated luminosity of 150 pb -1 in one day, which is above the design integrated luminosity per day of 135 pb -1 . Over the past year PEP-II has delivered over 12 fb -1 to BaBar. BaBar has logged over 11 pb -1 . The present plan is collide until the end of October 2000 followed by a three month installation period

  4. Searching for doubly-charged Higgs bosons at future colliders

    International Nuclear Information System (INIS)

    Gunion, J.F.; Pitts, K.T.

    1996-10-01

    Doubly-charged Higgs bosons (Δ -- /Δ ++ ) appear in several extensions to the Standard Model and can be relatively light. We review the theoretical motivation for these states and present a study of the discovery reach in future runs of the Fermilab Tevatron for pair-produced doubly-charged Higgs bosons decaying to like-sign lepton pairs. We also comment on the discovery potential at other future colliders. 16 refs., 3 figs., 1 tab

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

    International Nuclear Information System (INIS)

    KING, B.J.

    2000-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    KING,B.J.

    2000-05-05

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

  7. Crabbing system for an electron-ion collider

    Energy Technology Data Exchange (ETDEWEB)

    Castilla, Alejandro [Old Dominion Univ., Norfolk, VA (United States)

    2017-05-01

    As high energy and nuclear physicists continue to push further the boundaries of knowledge using colliders, there is an imperative need, not only to increase the colliding beams' energies, but also to improve the accuracy of the experiments, and to collect a large quantity of events with good statistical sensitivity. To achieve the latter, it is necessary to collect more data by increasing the rate at which these processes are being produced and detected in the machine. This rate of events depends directly on the machine's luminosity. The luminosity itself is proportional to the frequency at which the beams are being delivered, the number of particles in each beam, and inversely proportional to the cross-sectional size of the colliding beams. There are several approaches that can be considered to increase the events statistics in a collider other than increasing the luminosity, such as running the experiments for a longer time. However, this also elevates the operation expenses, while increasing the frequency at which the beams are delivered implies strong physical changes along the accelerator and the detectors. Therefore, it is preferred to increase the beam intensities and reduce the beams cross-sectional areas to achieve these higher luminosities. In the case where the goal is to push the limits, sometimes even beyond the machines design parameters, one must develop a detailed High Luminosity Scheme. Any high luminosity scheme on a modern collider considers|in one of their versions|the use of crab cavities to correct the geometrical reduction of the luminosity due to the beams crossing angle. In this dissertation, we present the design and testing of a proof-of-principle compact superconducting crab cavity, at 750 MHz, for the future electron-ion collider, currently under design at Jefferson Lab. In addition to the design and validation of the cavity prototype, we present the analysis of the first order beam dynamics and the integration of the

  8. Particle identification using dE/dx in the Mark II detector at the SLC

    International Nuclear Information System (INIS)

    Boyarski, A.; Coupal, D.P.; Feldman, G.J.; Hanson, G.; Nash, J.; O'Shaughnessy, K.F.; Rankin, P.; Van Kooten, R.

    1989-04-01

    The central drift chamber in the Mark II detector at the SLAC Linear Collider has been instrumented with 100-MHz Flash-ADCs. Pulse digitization provides particle identification through the measurement of average ionization loss in the chamber. We present the results of a study of system performance and outline the systematic corrections that optimize resolution. The data used are from a short test run at PEP with one-third of the FADCs installed and an extensive cosmic ray sample with the fully instrumented chamber. 11 refs., 9 figs

  9. Dedicated OO expertise applied to Run II software projects

    International Nuclear Information System (INIS)

    Amidei, D.

    2000-01-01

    The change in software language and methodology by CDF and D0 to object-oriented from procedural Fortran is significant. Both experiments requested dedicated expertise that could be applied to software design, coding, advice and review. The Fermilab Run II offline computing outside review panel agreed strongly with the request and recommended that the Fermilab Computing Division hire dedicated OO expertise for the CDF/D0/Computing Division joint project effort. This was done and the two experts have been an invaluable addition to the CDF and D0 upgrade software projects and to the Computing Division in general. These experts have encouraged common approaches and increased the overall quality of the upgrade software. Advice on OO techniques and specific advice on C++ coding has been used. Recently a set of software reviews has been accomplished. This has been a very successful instance of a targeted application of computing expertise, and constitutes a very interesting study of how to move toward modern computing methodologies in HEP

  10. High energy accelerator and colliding beam user group

    International Nuclear Information System (INIS)

    1990-09-01

    This report discusses the following topics: OPAL experiment at LEP; Dφ experiment at Fermilab; deep inelastic muon interactions at TEV II; CYGNUS experiment; final results from ν e -e elastic scattering; physics with CLEO detector at CESR; results from JADE at PETRA; rare kaon-decay experiment at BNL; search for top quark; and super conducting super collider activities

  11. Novel real-time alignment and calibration of LHCb detector for Run II and tracking for the upgrade.

    CERN Document Server

    AUTHOR|(CDS)2091576

    2016-01-01

    LHCb has introduced a novel real-time detector alignment and calibration strategy for LHC Run II. Data collected at the start of the fill is processed in a few minutes and used to update the alignment, while the calibration constants are evaluated for each run. The procedure aims to improve the quality of the online selection and performance stability. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. A similar scheme is planned to be used for Run III foreseen to start in 2020. At that time LHCb will run at an instantaneous luminosity of $2 \\times 10^{33}$ cm$^2$ s$^1$ and a fully software based trigger strategy will be used. The new running conditions and the tighter timing constraints in the software trigger (only 13 ms per event are available) represent a big challenge for track reconstruction. The new software based trigger strategy implies a full detector read-out at the collision rate of 40 MHz. High performance ...

  12. Performance of the ATLAS Calorimeters in LHC Run-1 and Run-2

    CERN Document Server

    Burghgrave, Blake; The ATLAS collaboration

    2016-01-01

    The ATLAS experiment at the Large Hadron Collider (LHC) is equipped with electromagnetic and hadronic liquid-argon (LAr) calorimeters and a hadronic scintillator-steel sampling calorimeter (TileCal) for measuring energy and direction of final state particles in the pseudorapidity range |η|<4.9. The calibration and performance of the calorimetry system was established during beam tests, cosmic ray muon measurements and in particular the first three years of pp collision data-taking. During this period, referred to as Run-1, approximately 27~fb−1 of data have been collected at the center-of-mass energies of 7 and 8~TeV. Following a period of detector consolidation during a long shutdown, Run-2 started in 2015 with approximately 3.9~fb−1 of data at a center-of-mass energy of 13~TeV recorded in this year. Results on the calorimeter operation, monitoring and data quality, as well as their performance will be presented, including the calibration and stability of the electromagnetic scale, response uniformit...

  13. Performance of the ATLAS Calorimeters in LHC Run-1 and Run-2

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00354209; The ATLAS collaboration

    2016-01-01

    The ATLAS experiment at the Large Hadron Collider (LHC) is equipped with electromagnetic and hadronic liquid-argon (LAr) calorimeters and a hadronic scintillator-steel sampling calorimeter (TileCal) for measuring energy and direction of final state particles in the pseudorapidity range $|\\eta|<4.9$. The calibration and performance of the calorimetry system was established through beam tests, cosmic ray muon measurements and in particular the first three years of pp collision data-taking. During this period, referred to as Run-1, approximately 27~\\ifb of proton-proton collision data were collected at the center-of-mass energies of 7 and 8~TeV. Following a period of detector consolidation during a long shutdown, Run-2 started in 2015 with approximately 3.9~\\ifb of data at a center-of-mass energy of 13~TeV recorded in the first year. We present a summary of the calorimeter operation, monitoring and data quality, as well as their performance, including the calibration and stability of the electromagnetic scale...

  14. B physics with the CDF Run II upgrade

    International Nuclear Information System (INIS)

    DeJongh, F.

    1996-01-01

    During the Run 1 data taking period, from 1992 through 1995, CDF has acquired 110 pb -1 of p anti p collisions at a center of mass energy of 1,800 GeV. This data has provided many results on B physics, and provides a basis for extrapolating to Run 2, which is scheduled to start in 1999 after major upgrades to both the accelerator and detector. The authors present herein a summary of Run 1 results relevant to an analysis of the CP asymmetry in B → J/ψK s , the CDF upgrade plans for Run 2, and some of the main B physics goals related to the exploration of the origin of CP violation

  15. Analysis of failed ramps during the RHIC FY09 run

    Energy Technology Data Exchange (ETDEWEB)

    Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-08-15

    The Relativistic Heavy Ion Collider (RHIC) is a versatile accelerator that supports operation with polarized protons of up to 250 GeV and ions with up to 100 GeV/nucleon. During any running period, various operating scenarios with different particle species, beam energies or accelerator optics are commissioned. In this report the beam commissioning periods for establishing full energy beams (ramp development periods) from the FY09 run are summarized and, for the purpose of motivating further developments, we analyze the reasons for all failed ramps.

  16. Analysis of failed ramps during the RHIC FY09 run

    International Nuclear Information System (INIS)

    Minty, M.

    2014-01-01

    The Relativistic Heavy Ion Collider (RHIC) is a versatile accelerator that supports operation with polarized protons of up to 250 GeV and ions with up to 100 GeV/nucleon. During any running period, various operating scenarios with different particle species, beam energies or accelerator optics are commissioned. In this report the beam commissioning periods for establishing full energy beams (ramp development periods) from the FY09 run are summarized and, for the purpose of motivating further developments, we analyze the reasons for all failed ramps.

  17. Future proton and electron colliders: Dreams for the 1990's

    International Nuclear Information System (INIS)

    Richter, B.

    1988-10-01

    In this paper I have reviewed the possibilities for new colliders that might be available in the 1990's. One or more new proton should be available in the late-90s based on plans of Europe, the US and the USSR. The two very high energy machines, LHC and SSC, are quite expensive, and their construction will be more decided by the politicians' view on the availability of resources than by the physicists' view of the need for new machines. Certainly something will be built, but the question is when. New electron colliders beyond LEP II could be available in the late 1990's as well. Most of the people who have looked at this problem believe that at a minimum three years of RandD are required before a proposal can be made, two years will be required to convince the authorities to go ahead, and five years will be required to build such a machine. Thus the earliest time a new electron collider at high energy could be available is around 1988. A strong international RandD program will be required to meet that schedule. In the field of B factories, PSI's proposal is the first serious step beyond the capabilities of CESR. There are other promising techniques but these need more RandD. The least RandD would be required for the asymmetric storage ring systems, while the most would be required for high luminosity linear colliders. For the next decade, high energy physics will be doing its work at the high energy frontier with Tevatron I and II, UNK, SLC, LEP I and II, and HERA. The opportunities for science presented by experiments at these facilities are very great, and it is to be hoped that the pressure for funding to construct the next generation facilities will not badly affect the operating budgets of the ones we now have or which will soon be turning on. 9 refs., 12 figs., 6 tabs

  18. ATLAS + CMS top production and properties: Run 1 legacy

    CERN Document Server

    AUTHOR|(SzGeCERN)641905; The ATLAS collaboration

    2015-01-01

    The large Run 1 data sample of top-quark events collected at the Large Hadron Collider allows a variety of measurements to analyse the production and properties of the top quark. Measurements of top-quark production cross sections and top-quark properties in proton-proton collisions with the ATLAS and CMS detectors at the LHC are presented.

  19. Run 2 analysis computing for CDF and D0

    International Nuclear Information System (INIS)

    Fuess, S.

    1995-11-01

    Two large experiments at the Fermilab Tevatron collider will use upgraded of running. The associated analysis software is also expected to change, both to account for higher data rates and to embrace new computing paradigms. A discussion is given to the problems facing current and future High Energy Physics (HEP) analysis computing, and several issues explored in detail

  20. Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2016-01-01

    In response to a request from the 2013 Update of the European Strategy for Particle Physics, the global Future Circular Collider (FCC) study is preparing the foundation for a next-generation large-scale accelerator infrastructure in the heart of Europe. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh), to be accommodated in a new ∼100 km tunnel near Geneva. It also includes the design of a high-luminosity electron-positron collider (FCC-ee), which could be installed in the same tunnel as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detector, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb$_{3}$Sn superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton collider. The int...

  1. Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2016-01-01

    In response to a request from the 2013 Update of the European Strategy for Particle Physics, the global Future Circular Collider (FCC) study is preparing the foundation for a next-generation large-scale accelerator infrastructure in the heart of Europe. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh), to be accommodated in a new ∼100 km tunnel near Geneva. It also includes the design of a high-luminosity electron-positron collider (FCC-ee), which could be installed in the same tunnel as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb$_{3}$Sn superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton collider. The in...

  2. Event visualisation in ALICE - current status and strategy for Run 3

    Science.gov (United States)

    Niedziela, Jeremi; von Haller, Barthélémy

    2017-10-01

    A Large Ion Collider Experiment (ALICE) is one of the four big experiments running at the Large Hadron Collider (LHC), which focuses on the study of the Quark-Gluon Plasma (QGP) being produced in heavy-ion collisions. The ALICE Event Visualisation Environment (AliEve) is a tool providing an interactive 3D model of the detector’s geometry and a graphical representation of the data. Together with the online reconstruction module, it provides important quality monitoring of the recorded data. As a consequence it has been used in the ALICE Run Control Centre during all stages of Run 2. Static screenshots from the online visualisation are published on the public website - ALICE LIVE. Dedicated converters have been developed to provide geometry and data for external projects. An example of such project is the Total Event Display (TEV) - a visualisation tool recently developed by the CERN Media Lab based on the Unity game engine. It can be easily deployed on any platform, including web and mobile platforms. Another external project is More Than ALICE - an augmented reality application for visitors, overlaying detector descriptions and event visualisations on the camera’s picture. For the future Run 3 both AliEve and TEV will be adapted to fit the ALICE O2 project. Several changes are required due to the new data formats, especially so-called Compressed Time Frames.

  3. Electroweak physics at the Tevatron collider

    International Nuclear Information System (INIS)

    Aihara, H.

    1993-08-01

    Preliminary results on electroweak physics from the 1992--1993 run with the CDF and D0 detectors at the Tevatron collider are presented. New measurements of the ratio of the W and Z production cross sections times the branching fractions for subsequent decay into leptons are shown. The W width, Γ(W), and a limit on the top-quark mass independent of decay mode are extracted. The status of a measurement of the charge asymmetry of electrons from W decay is given. Also shown are a study of diboson (Wγ, Zγ and WZ) production and a search for a new neutral gauge boson (Z')

  4. Berkeley mini-collider

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1984-06-01

    The Berkeley Mini-Collider, a heavy-ion collider being planned to provide uranium-uranium collisions at T/sub cm/ less than or equal to 4 GeV/nucleon, is described. The central physics to be studied at these energies and our early ideas for a collider detector are presented

  5. High energy accelerator and colliding beam user group

    Energy Technology Data Exchange (ETDEWEB)

    1990-09-01

    This report discusses the following topics: OPAL experiment at LEP; D{phi} experiment at Fermilab; deep inelastic muon interactions at TEV II; CYGNUS experiment; final results from {nu}{sub e}{sup {minus}e} elastic scattering; physics with CLEO detector at CESR; results from JADE at PETRA; rare kaon-decay experiment at BNL; search for top quark; and super conducting super collider activities.

  6. Flavour and collider interplay for SUSY at LHC7

    International Nuclear Information System (INIS)

    Calibbi, L.; Hodgkinson, R.N.; Vives, O.; Jones Perez, J.; Masiero, A.

    2012-01-01

    The current 7 TeV run of the LHC experiment shall be able to probe gluino and squark masses up to values larger than 1 TeV. Assuming that hints for SUSY are found in the jets plus missing energy channel by the end of a 5 fb -1 run, we explore the flavour constraints on three models with a CMSSM-like spectrum: the CMSSM itself, a seesaw extension of the CMSSM, and Flavoured CMSSM. In particular, we focus on decays that might have been measured by the time the run is concluded, such as B s →μμ and μ→e γ. We also analyse constraints imposed by neutral meson bounds and electric dipole moments. The interplay between collider and flavour experiments is explored through the use of three benchmark scenarios, finding the flavour feedback useful in order to determine the model parameters and to test the consistency of the different models. (orig.)

  7. Prospects for colliders and collider physics to the 1 PeV energy scale

    Science.gov (United States)

    King, Bruce J.

    2000-08-01

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

  8. The ATLAS Muon Trigger Performance : Run 1 and initial Run 2.

    CERN Document Server

    Kasahara, Kota; The ATLAS collaboration

    2015-01-01

    Events with muons in the final state are an important signature for many physics topics at the Large Hadron Collider (LHC). An efficient trigger on muons and a detailed understanding of its performance are required. In 2012, the last year of Run 1, the instantaneous luminosity of the LHC reached 7.7x10^33 cm -2s-1 and the average number of events that occur in a same bunch crossing was 25. The ATLAS Muon trigger has successfully adapted to this changing environment by making use of isolation requirements, combined trigger signatures with electron and jet trigger objects, and by using so-called full-scan triggers, which make use of the full event information to search for di-lepton signatures, seeded by single lepton objects. A stable and highly efficient muon trigger was vital in the discovery of Higgs boson in 2012 and for many searches for new physics. 
The performance of muon triggers during the LHC Run 1 data-taking campaigns is presented, together with an overview and preliminary results of the new muo...

  9. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    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.

  10. Electron-cloud effects in high-luminosity colliders

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, F.

    1998-01-01

    Electron-cloud instabilities are expected to be important in most high-luminosity double-ring colliders. In this report, the author describes a few parameter regimes and some critical parameter dependences of this type of instability, and illustrate these with simulation results for the PEP-II and KEK B factories, the LHC, the VLHC, and DAPHNE. In addition, the author studies the possibility and the potential impact of an electron cloud in the interaction region.

  11. Measurement of the forward-backward asymmetry of top-quark and antiquark pairs using the full CDF Run II data set

    Science.gov (United States)

    Aaltonen, T.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Auerbach, B.; Aurisano, A.; Azfar, F.; Badgett, W.; Bae, T.; Barbaro-Galtieri, A.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartos, P.; Bauce, M.; Bedeschi, F.; Behari, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Bhatti, A.; Bland, K. R.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Bortoletto, D.; Boudreau, J.; Boveia, A.; Brigliadori, L.; Bromberg, C.; Brucken, E.; Budagov, J.; Budd, H. S.; Burkett, K.; Busetto, G.; Bussey, P.; Butti, P.; Buzatu, A.; Calamba, A.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Castro, A.; Catastini, P.; Cauz, D.; Cavaliere, V.; Cerri, A.; Cerrito, L.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Chokheli, D.; Clark, A.; Clarke, C.; Convery, M. E.; Conway, J.; Corbo, M.; Cordelli, M.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; d'Ascenzo, N.; Datta, M.; de Barbaro, P.; Demortier, L.; Deninno, M.; D'Errico, M.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Dittmann, J. R.; Donati, S.; D'Onofrio, M.; Dorigo, M.; Driutti, A.; Ebina, K.; Edgar, R.; Erbacher, R.; Errede, S.; Esham, B.; Farrington, S.; Fernández Ramos, J. P.; Field, R.; Flanagan, G.; Forrest, R.; Franklin, M.; Freeman, J. C.; Frisch, H.; Funakoshi, Y.; Galloni, C.; Garfinkel, A. F.; Garosi, P.; Gerberich, H.; Gerchtein, E.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Giokaris, N.; Giromini, P.; Glagolev, V.; Glenzinski, D.; Gold, M.; Goldin, D.; Golossanov, A.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grosso-Pilcher, C.; Guimaraes da Costa, J.; Hahn, S. R.; Han, J. Y.; Happacher, F.; Hara, K.; Hare, M.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hays, C.; Heinrich, J.; Herndon, M.; Hocker, A.; Hong, Z.; Hopkins, W.; Hou, S.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Introzzi, G.; Iori, M.; Ivanov, A.; James, E.; Jang, D.; Jayatilaka, B.; Jeon, E. J.; Jindariani, S.; Jones, M.; Joo, K. K.; Jun, S. Y.; Junk, T. R.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Kasmi, A.; Kato, Y.; Ketchum, W.; Keung, J.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. H.; Kim, S. B.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kurata, M.; Laasanen, A. T.; Lammel, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lee, H. S.; Lee, J. S.; Leo, S.; Leone, S.; Lewis, J. D.; Limosani, A.; Lipeles, E.; Lister, A.; Liu, Q.; Liu, T.; Lockwitz, S.; Loginov, A.; Lucchesi, D.; Lucà, A.; Lueck, J.; Lujan, P.; Lukens, P.; Lungu, G.; Lys, J.; Lysak, R.; Madrak, R.; Maestro, P.; Malik, S.; Manca, G.; Manousakis-Katsikakis, A.; Marchese, L.; Margaroli, F.; Marino, P.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McNulty, R.; Mehta, A.; Mehtala, P.; Mesropian, C.; Miao, T.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nakano, I.; Napier, A.; Nett, J.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Okusawa, T.; Orava, R.; Ortolan, L.; Pagliarone, C.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parker, W.; Pauletta, G.; Paulini, M.; Paus, C.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pondrom, L.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ristori, L.; Robson, A.; Rodriguez, T.; Rolli, S.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sakumoto, W. K.; Sakurai, Y.; Santi, L.; Sato, K.; Saveliev, V.; Savoy-Navarro, A.; Schlabach, P.; Schmidt, E. E.; Schwarz, T.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Semenov, A.; Sforza, F.; Shalhout, S. Z.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shochet, M.; Shreyber-Tecker, I.; Simonenko, A.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Song, H.; Sorin, V.; St. Denis, R.; Stancari, M.; Stentz, D.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Toback, D.; Tokar, S.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Ukegawa, F.; Uozumi, S.; Vázquez, F.; Velev, G.; Vellidis, C.; Vernieri, C.; Vidal, M.; Vilar, R.; Vizán, J.; Vogel, M.; Volpi, G.; Wagner, P.; Wallny, R.; Wang, S. M.; Waters, D.; Wester, W. C.; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wolbers, S.; Wolfe, H.; Wright, T.; Wu, X.; Wu, Z.; Yamamoto, K.; Yamato, D.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yeh, G. P.; Yi, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Yu, G. B.; Yu, I.; Zanetti, A. M.; Zeng, Y.; Zhou, C.; Zucchelli, S.; CDF Collaboration

    2016-06-01

    We measure the forward-backward asymmetry of the production of top-quark and antiquark pairs in proton-antiproton collisions at center-of-mass energy √{s }=1.96 TeV using the full data set collected by the Collider Detector at Fermilab (CDF) in Tevatron Run II corresponding to an integrated luminosity of 9.1 fb-1 . The asymmetry is characterized by the rapidity difference between top quarks and antiquarks (Δ y ) and measured in the final state with two charged leptons (electrons and muons). The inclusive asymmetry, corrected to the entire phase space at parton level, is measured to be AFBt t ¯=0.12 ±0.13 , consistent with the expectations from the standard model (SM) and previous CDF results in the final state with a single charged lepton. The combination of the CDF measurements of the inclusive AFBt t ¯ in both final states yields AFBt t ¯=0.160 ±0.045 , which is consistent with the SM predictions. We also measure the differential asymmetry as a function of Δ y . A linear fit to AFBt t ¯(|Δ y |), assuming zero asymmetry at Δ y =0 , yields a slope of α =0.14 ±0.15 , consistent with the SM prediction and the previous CDF determination in the final state with a single charged lepton. The combined slope of AFBt t ¯(|Δ y |) in the two final states is α =0.227 ±0.057 , which is 2.0 σ larger than the SM prediction.

  12. Status of the SLC: Developments in Linear Collider physics

    International Nuclear Information System (INIS)

    Krejcik, P.

    1994-11-01

    This paper reviews the performance of the SLAC Linear Collider, both from the perspective of a machine delivering high luminosity polarized beams for physics, and as a test for future linear colliders. The development of the SLC taken place over a number of years and the steady improvements have been documented in previous review papers. As a review paper, the list references also serves as a bibliography, pointing to the work of the many people contributing to the upgrades and commissioning of the various SLC systems. The major upgrades for this present run have been an improved final focus optics, new low impedance vacuum chambers for the damping rings and improved polarization from the electron source. The performance of the SLC is driven to some extent by its unique 3-beam operation in which the linac accelerates both the electron and positron bunches for collision, as well as the electron bunch to produce the positrons. The special attention required to maintain stable operation in the face of the interactions caused by beam loading from the bunches will (fortunately exclamation point) not be an issue in future linear colliders. They will deal instead with the problems associated with handling long bunch trains

  13. CERN looks to the long-term future: might a 100km circular collider follow the LHC around mid-century?

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Particle physics is a long-term field of research: the LHC was originally conceived in the 1980s, but did not start running until 25 years later. An accelerator unlike any other, it is now just at the start of a programme that is set to run for another 20 years. While the LHC programme is already well defined for the next two decades, it is now time to look even further ahead, and so CERN is initiating an exploratory study for a future long-term project centred on a next-generation circular collider with a circumference of 80 to 100 kilometres. A worthy successor to the LHC, whose collision energies will reach 13 TeV in 2015, such an accelerator would allow particle physicists to push the boundaries of knowledge even further. The Future Circular Collider (FCC) programme will focus on studies for a hadron collider, like the LHC, capable of reaching unprecedented energies in the region of 100 TeV. It will also study electron-positron and electron-proton options. Opening with an introduction to the LHC and its...

  14. Asymmetric collider

    International Nuclear Information System (INIS)

    Bharadwaj, V.; Colestock, P.; Goderre, G.; Johnson, D.; Martin, P.; Holt, J.; Kaplan, D.

    1993-01-01

    The study of CP violation in beauty decay is one of the key challenges facing high energy physics. Much work has not yielded a definitive answer how this study might best be performed. However, one clear conclusion is that new accelerator facilities are needed. Proposals include experiments at asymmetric electron-positron colliders and in fixed-target and collider modes at LHC and SSC. Fixed-target and collider experiments at existing accelerators, while they might succeed in a first observation of the effect, will not be adequate to study it thoroughly. Giomataris has emphasized the potential of a new approach to the study of beauty CP violation: the asymmetric proton collider. Such a collider might be realized by the construction of a small storage ring intersecting an existing or soon-to-exist large synchrotron, or by arranging collisions between a large synchrotron and its injector. An experiment at such a collider can combine the advantages of fixed-target-like spectrometer geometry, facilitating triggering, particle identification and the instrumentation of a large acceptance, while the increased √s can provide a factor > 100 increase in beauty-production cross section compared to Tevatron or HERA fixed-target. Beams crossing at a non-zero angle can provide a small interaction region, permitting a first-level decay-vertex trigger to be implemented. To achieve large √s with a large Lorentz boost and high luminosity, the most favorable venue is the high-energy booster (HEB) at the SSC Laboratory, though the CERN SPS and Fermilab Tevatron are also worth considering

  15. Novel real-time alignment and calibration of the LHCb detector in Run II

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z., E-mail: zhirui.xu@epfl.ch; Tobin, M.

    2016-07-11

    An automatic real-time alignment and calibration strategy of the LHCb detector was developed for the Run II. Thanks to the online calibration, tighter event selection criteria can be used in the trigger. Furthermore, the online calibration facilitates the use of hadronic particle identification using the Ring Imaging Cherenkov (RICH) detectors at the trigger level. The motivation for a real-time alignment and calibration of the LHCb detector is discussed from both the operational and physics performance points of view. Specific challenges of this novel configuration are discussed, as well as the working procedures of the framework and its performance.

  16. Novel real-time alignment and calibration of the LHCb detector in Run II

    CERN Document Server

    AUTHOR|(CDS)2086132; Tobin, Mark

    2016-01-01

    An automatic real-time alignment and calibration strategy of the LHCb detector was developed for the Run II. Thanks to the online calibration, tighter event selection criteria can be used in the trigger. Furthermore, the online calibration facilitates the use of hadronic particle identification using the Ring Imaging Cherenkov (RICH) detectors at the trigger level. The motivation for a real-time alignment and calibration of the LHCb detector is discussed from both the operational and physics performance points of view. Specific challenges of this novel configuration are discussed, as well as the working procedures of the framework and its performance.

  17. Pulse-by-pulse energy measurement at the Stanford Linear Collider

    International Nuclear Information System (INIS)

    Blaylock, G.; Briggs, D.; Collins, B.; Petree, M.

    1992-01-01

    The stanford Linear Collider (SLC) collides a beam of electrons and positrons at 92 GeV. It is the first colliding linac, and produces Z 0 particles for High-Energy Physics measurements. The energy of each beam must be measured to one part in 10 4 on every collision (120 Hz). An Energy Spectrometer in each beam line after collision produces two stripes of high-energy synchrotron radiation with critical energy of a few MeV. The distance between these two stripes at an imaging plane measures the beam energy. The Wire- Imaging Synchrotron Radiation Detector (WISRD) system comprises a novel detector, data acquisition electronics, readout and analysis. The detector comprises an array of wires for each synchrotron stripe. The electronics measure secondary emission charge on each wire of each array. A Macintosh II (using THINK C, THINK Class Library) and DSP coprocessor (using ANSI C) acquire and analyze the data, and display and report the results for SLC operation

  18. Pulse-by-pulse energy measurement at the Stanford Linear Collider

    Science.gov (United States)

    Blaylock, G.; Briggs, D.; Collins, B.; Petree, M.

    1992-01-01

    The Stanford Linear Collider (SLC) collides a beam of electrons and positrons at 92 GeV. It is the first colliding linac, and produces Z(sup 0) particles for High-Energy Physics measurements. The energy of each beam must be measured to one part in 10(exp 4) on every collision (120 Hz). An Energy Spectrometer in each beam line after the collision produces two stripes of high-energy synchrotron radiation with critical energy of a few MeV. The distance between these two stripes at an imaging plane measures the beam energy. The Wire-Imaging Synchrotron Radiation Detector (WISRD) system comprises a novel detector, data acquisition electronics, readout, and analysis. The detector comprises an array of wires for each synchrotron stripe. The electronics measure secondary emission charge on each wire of each array. A Macintosh II (using THINK C, THINK Class Library) and DSP coprocessor (using ANSI C) acquire and analyze the data, and display and report the results for SLC operation.

  19. The CMS Level-1 tau lepton and Vector Boson Fusion triggers for the LHC Run II

    CERN Document Server

    Amendola, Chiara

    2017-01-01

    The CMS experiment implements a sophisticated two-level triggering system composed of Level-1, instrumented by custom-design hardware boards, and a software High-Level-Trigger. A new Level-1 trigger architecture with improved performance is now being used to maintain the thresholds that were used in LHC Run I for the more challenging luminosity conditions experienced during Run II. The upgrades to the calorimetry trigger will be described along with performance data. The algorithms for the selection of final states with tau leptons, both for precision measurements and for searches of new physics beyond the Standard Model, will be described in detail. The implementation of the first dedicated Vector Boson Fusion trigger algorithm will be presented as well, along with its performance on benchmark physics signals.

  20. B-Physics at CMS with LHC Run-II and Beyond

    CERN Document Server

    Chen, Kai-Feng

    2015-01-01

    The LHC is entering into operation with an increased centre-of-mass energy of 13~TeV, and within the next 3 years of operations (Run-II) the foreseen integrated luminosity delivered to CMS will be about 100 fb$^{-1}$. The B hadron production cross section is expected to nearly double at this energy, thus potentially increasing by almost one order of magnitude the collected statistics relative to the previous operation period. This will enable CMS to perform enhanced measurements in the B-physics sector. A further increase in integrated luminosity is expected to occur in two more steps after the second LHC long shutdown (LS) in 2018 and the third LS in 2021, thus enabling to significantly improve the precision of several B-physics measurements, including $B_s(B_d)\\to\\mu^+\\mu^-$, and search for rarer decays. This proceeding reports on the prospects for B-physics measurements with high statistics data at CMS.

  1. Linear colliders - prospects 1985

    International Nuclear Information System (INIS)

    Rees, J.

    1985-06-01

    We discuss the scaling laws of linear colliders and their consequences for accelerator design. We then report on the SLAC Linear Collider project and comment on experience gained on that project and its application to future colliders. 9 refs., 2 figs

  2. Lecture | CERN prepares its long-term future: a 100-km circular collider to follow the LHC? | CERN Globe | 11 March

    CERN Multimedia

    2015-01-01

    Particle physics is a long-term field of research: the LHC was originally conceived in the 1980s, but did not start running until 25 years later. An accelerator unlike any other, it is now just at the start of a programme that is set to run for another 20 years.   Frédérick Bordry. While the LHC programme is already well defined for the next two decades, it is now time to look even further ahead, and so CERN is initiating an exploratory study for a future long-term project centred on a next-generation circular collider with a circumference of 80 to 100 kilometres. A worthy successor to the LHC, whose collision energies will reach 13 TeV in 2015, such an accelerator would allow particle physicists to push the boundaries of knowledge even further. The Future Circular Collider (FCC) programme will focus especially on studies for a hadron collider, like the LHC, capable of reaching unprecedented energies in the region of 100 TeV. Opening with an introduction to the LHC and...

  3. Design of a High Luminosity 100 TeV Proton Antiproton Collider

    Energy Technology Data Exchange (ETDEWEB)

    Oliveros Tuativa, Sandra Jimena [Univ. of Mississippi, Oxford, MS (United States)

    2017-04-01

    Currently new physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. A 10$^{\\,34}$ cm$^{-2}$ s$^{-1}$ luminosity 100 TeV proton-antiproton collider is explored with 7$\\times$ the energy of the LHC. The dipoles are 4.5\\,T to reduce cost. A proton-antiproton collider is selected as a future machine for several reasons. The cross section for many high mass states is 10 times higher in $p\\bar{p}$ than $pp$ collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per bunch crossing, because lower beam currents can produce the same rare event rates. Events are also more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller $\\beta^{*}$ for higher luminosity. To adjust to antiproton beam losses (burn rate), a Fermilab-like antiproton source would be adapted to disperse the beam into 12 different momentum channels, using electrostatic septa, to increase antiproton momentum capture 12 times. At Fermilab, antiprotons were stochastically cooled in one Debuncher and one Accumulator ring. Because the stochastic cooling time scales as the number of particles, two options of 12 independent cooling systems are presented. One electron cooling ring might follow the stochastic cooling rings for antiproton stacking. Finally antiprotons in the collider ring would be recycled during runs without leaving the collider ring, by joining them to new bunches with snap bunch coalescence and synchrotron damping. These basic ideas are explored in this work on a future 100 TeV proton-antiproton collider and the main parameters are presented.

  4. Design of a High Luminosity 100 TeV Proton-Antiproton Collider

    Science.gov (United States)

    Oliveros Tautiva, Sandra Jimena

    Currently new physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. A 10 34 cm-2 s-1 luminosity 100 TeV proton-antiproton collider is explored with 7x the energy of the LHC. The dipoles are 4.5 T to reduce cost. A proton-antiproton collider is selected as a future machine for several reasons. The cross section for many high mass states is 10 times higher in pp than pp collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per bunch crossing, because lower beam currents can produce the same rare event rates. Events are also more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller beta* for higher luminosity. To adjust to antiproton beam losses (burn rate), a Fermilab-like antiproton source would be adapted to disperse the beam into 12 different momentum channels, using electrostatic septa, to increase antiproton momentum capture 12 times. At Fermilab, antiprotons were stochastically cooled in one Debuncher and one Accumulator ring. Because the stochastic cooling time scales as the number of particles, two options of 12 independent cooling systems are presented. One electron cooling ring might follow the stochastic cooling rings for antiproton stacking. Finally antiprotons in the collider ring would be recycled during runs without leaving the collider ring, by joining them to new bunches with snap bunch coalescence and synchrotron damping. These basic ideas are explored in this work on a future 100 TeV proton-antiproton collider and the main parameters are presented.

  5. The International Linear Collider - Volume 1: Executive Summary

    CERN Document Server

    Brau, James E.; Foster, Brian; Fuster, Juan; Harrison, Mike; Paterson, James McEwan; Peskin, Michael; Stanitzki, Marcel; Walker, Nicholas; Yamamoto, Hitoshi

    2013-01-01

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to incr...

  6. Calorimeter based detectors for high energy hadron colliders

    International Nuclear Information System (INIS)

    1993-01-01

    The work was directed in two complementary directions, the D0 experiment at Fermilab, and the GEM detector for the SSC. Efforts have been towards the data taking and analysis with the newly commissioned D0 detector at Fermilab in the bar pp Collider run that started in May 1992 and ended on June 1, 1993. We involved running and calibration of the calorimeter and tracking chambers, the second level trigger development, and various parts of the data analysis, as well as studies for the D0 upgrade planned in the second half of this decade. Another major accomplishment was the ''delivery'' of the Technical Design Report for the GEM SSC detector. Efforts to the overall detector and magnet design, design of the facilities, installation studies, muon system coordination, muon chamber design and tests, muon system simulation studies, and physics simulation studies. In this document we describe these activities separately

  7. Photoproduction at collider energies: from RHIC and HERA to the LHC

    CERN Document Server

    Baltz, A; Brodsky, S J; D'Enterria, D G; Dreyer, U; Engel, R; Frankfurt, L; Gorbunov, Y; Guzey, V; Hamilton, A; Klasen, M; Klein, S R; Kowalski, H; Levonian, S; Lourenço, C; Machado, M V T; Nachtmann, O; Nagy, Z; Nystrand, J; Piotrzkowski, K; Ramalhete, P; Savin, A; Scapparone, E; Schicker, R; Silvermyr, D; Strikman, M I; Valkárová, A; Vogt, R; Yilmaz, M; Enterria, David d'

    2007-01-01

    We present the mini-proceedings of the workshop on "Photoproduction at collider energies: from RHIC and HERA to the LHC" held at the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*, Trento) from January 15 to 19, 2007. The workshop gathered both theorists and experimentalists to discuss the current status of investigations of high-energy photon-induced processes at different colliders (HERA, RHIC, and Tevatron) as well as preparations for extension of these studies at the LHC. The main physics topics covered were: (i) small-$x$ QCD in photoproduction studies with protons and in electromagnetic (aka. ultraperipheral) nucleus-nucleus collisions, (ii) hard diffraction physics at hadron colliders, and (iii) photon-photon collisions at very high energies: electroweak and beyond the Standard Model processes. These mini-proceedings consist of an introduction and short summaries of the talks presented at the meeting.

  8. The beam energy measurement system for the Beijing electron-positron collider

    International Nuclear Information System (INIS)

    Zhang, J.Y.; Abakumova, E.V.; Achasov, M.N.; Blinov, V.E.; Cai, X.; Dong, H.Y.; Fu, C.D.; Harris, F.A.; Kaminsky, V.V.; Krasnov, A.A.; Liu, Q.; Mo, X.H.; Muchnoi, N.Yu.; Nikolaev, I.B.; Qin, Q.; Qu, H.M.; Olsen, S.L.; Pyata, E.E.; Shamov, A.G.; Shen, C.P.

    2012-01-01

    The beam energy measurement system (BEMS) for the upgraded Beijing electron-positron collider BEPC-II is described. The system is based on measuring the energies of Compton back-scattered photons. The relative systematic uncertainty of the electron and positron beam energy determination is estimated as 2⋅10 -5 .

  9. Collide@CERN: sharing inspiration

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    Late last year, Julius von Bismarck was appointed to be CERN's first "artist in residence" after winning the Collide@CERN Digital Arts award. He’ll be spending two months at CERN starting this March but, to get a flavour of what’s in store, he visited the Organization last week for a crash course in its inspiring activities.   Julius von Bismarck, taking a closer look... When we arrive to interview German artist Julius von Bismarck, he’s being given a presentation about antiprotons’ ability to kill cancer cells. The whiteboard in the room contains graphs and equations that might easily send a non-scientist running, yet as Julius puts it, “if I weren’t interested, I’d be asleep”. Given his numerous questions, he must have been fascinated. “This ‘introduction’ week has been exhilarating,” says Julius. “I’ve been able to interact ...

  10. Towards a Muon Collider

    International Nuclear Information System (INIS)

    Eichten, E.

    2011-01-01

    A multi TeV Muon Collider is required for the full coverage of Terascale physics. The physics potential for a Muon Collider at ∼3 TeV and integrated luminosity of 1 ab -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 31 cm -2 s -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.

  11. CMS operations for Run II preparation and commissioning of the offline infrastructure

    CERN Document Server

    Cerminara, Gianluca

    2016-01-01

    The restart of the LHC coincided with an intense activity for the CMS experiment. Both at the beginning of Run II in 2015 and the restart of operations in 2016, the collaboration was engaged in an extensive re-commissioning of the CMS data-taking operations. After the long stop, the detector was fully aligned and calibrated. Data streams were redesigned, to fit the priorities dictated by the physics program for 2015 and 2016. A new reconstruction software (both online and offline) was commissioned with early collisions and further developed during the year. A massive campaign of Monte Carlo production was launched, to assist physics analyses. This presentation reviews the main event of this commissioning journey and describes the status of CMS physics performances for 2016.

  12. Performance of the CMS precision electromagnetic calorimeter at LHC Run II and prospects for High-Luminosity LHC

    CERN Document Server

    Zhang, Zhicai

    2017-01-01

    Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high-resolution electron and photon energy measurements. Following the excellent performance achieved during LHC Run I at center-of-mass energies of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) is operating at the LHC with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run II has achieved unprecedented levels. The average number of concurrent proton-proton collisions per bunch-crossing (pileup) has reached up to 40 interactions in 2016 and may increase further in 2017. These high pileup levels necessitate a retuning of the ECAL readout and trigger thresholds and reconstruction algorithms. In addition, the energy response of the detector must be precisely calibrated and monitored. We present new reconstruction algorithms and calibration strategies that were implemented to maintain the excellent performance of the CMS ECAL throughout Run...

  13. Towards future circular colliders

    Science.gov (United States)

    Benedikt, Michael; Zimmermann, Frank

    2016-09-01

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) presently provides proton-proton collisions at a center-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics program will extend through the second half of the 2030's. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ˜100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCCee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on Nb3 S n superconductor, for the FCC-hh hadron collider, and a highly-efficient superconducting radiofrequency system for the FCC-ee lepton collider. Following the FCC concept, the Institute of High Energy Physics (IHEP) in Beijing has initiated a parallel design study for an e + e - Higgs factory in China (CEPC), which is to be succeeded by a high-energy hadron collider (SPPC). At present a tunnel circumference of 54 km and a hadron collider c.m. energy of about 70 TeV are being considered. After a brief look at the LHC, this article reports the motivation and the present status of the FCC study, some of the primary design challenges and R&D subjects, as well as the emerging global collaboration.

  14. LHCb : First years of running for the LHCb calorimeter system and preparation for run 2

    CERN Multimedia

    Chefdeville, Maximilien

    2015-01-01

    The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). It comprises a calorimeter system composed of four subdetectors: a Scintillating Pad Detector (SPD) and a Pre-Shower detector (PS) in front of an electromagnetic calorimeter (ECAL) which is followed by a hadron calorimeter (HCAL). They are used to select transverse energy hadron, electron and photon candidates for the first trigger level and they provides the identification of electrons, photons and hadrons as well as the measurement of their energies and positions. The calorimeter has been pre-calibrated before its installation in the pit. The calibration techniques have been tested with data taken in 2010 and used regularly during run 1. For run 2, new calibration methods have been devised to follow and correct online the calorimeter detector response. The design and construction characteristics of the LHCb calorimeter will be recalled. Strategies for...

  15. Accelerator physics highlights in the 1997/98 SLC run

    International Nuclear Information System (INIS)

    Assmann, R.W.; Bane, K.L.F.; Barkow, T.

    1998-03-01

    The authors report various accelerator physics studies and improvements from the 1997/98 run at the Stanford Linear Collider (SLC). In particular, the authors discuss damping-ring lattice diagnostics, changes to the linac set up, fast control for linac rf phase stability, new emittance tuning strategies, wakefield reduction, modifications of the final-focus optics, longitudinal bunch shaping, and a novel spot-size control at the interaction point (IP)

  16. Very high energy colliders

    International Nuclear Information System (INIS)

    Richter, B.

    1986-03-01

    The luminosity and energy requirements are considered for both proton colliders and electron-positron colliders. Some of the basic design equations for high energy linear electron colliders are summarized, as well as design constraints. A few examples are given of parameters for very high energy machines. 4 refs., 6 figs

  17. ColliderBit. A GAMBIT module for the calculation of high-energy collider observables and likelihoods

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, Csaba [Monash University, School of Physics and Astronomy, Melbourne, VIC (Australia); Australian Research Council Centre of Excellence for Particle Physics at the Tera-scale (Australia); Buckley, Andy [University of Glasgow, SUPA, School of Physics and Astronomy, Glasgow (United Kingdom); Dal, Lars A.; Krislock, Abram; Raklev, Are [University of Oslo, Department of Physics, Oslo (Norway); Farmer, Ben [AlbaNova University Centre, Oskar Klein Centre for Cosmoparticle Physics, Stockholm (Sweden); Jackson, Paul; Murnane, Daniel; White, Martin [Australian Research Council Centre of Excellence for Particle Physics at the Tera-scale (Australia); University of Adelaide, Department of Physics, Adelaide, SA (Australia); Kvellestad, Anders [NORDITA, Stockholm (Sweden); Putze, Antje [Universite de Savoie, LAPTh, Annecy-le-Vieux (France); Rogan, Christopher [Harvard University, Department of Physics, Cambridge, MA (United States); Saavedra, Aldo [Australian Research Council Centre of Excellence for Particle Physics at the Tera-scale (Australia); The University of Sydney, Faculty of Engineering and Information Technologies, Centre for Translational Data Science, School of Physics, Sydney, NSW (Australia); Scott, Pat [Imperial College London, Blackett Laboratory, Department of Physics, London (United Kingdom); Weniger, Christoph [University of Amsterdam, GRAPPA, Institute of Physics, Amsterdam (Netherlands); Collaboration: The GAMBIT Scanner Workgroup

    2017-11-15

    We describe ColliderBit, a new code for the calculation of high energy collider observables in theories of physics beyond the Standard Model (BSM). ColliderBit features a generic interface to BSM models, a unique parallelised Monte Carlo event generation scheme suitable for large-scale supercomputer applications, and a number of LHC analyses, covering a reasonable range of the BSM signatures currently sought by ATLAS and CMS. ColliderBit also calculates likelihoods for Higgs sector observables, and LEP searches for BSM particles. These features are provided by a combination of new code unique toColliderBit, and interfaces to existing state-of-the-art public codes. ColliderBit is both an important part of the GAMBIT framework for BSM inference, and a standalone tool for efficiently applying collider constraints to theories of new physics. (orig.)

  18. FERMILAB: Call for physics

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    Several hundred physicists attended a special Fermilab 'All Experimenter's Meeting' on November 20 to hear Director John Peoples call for new Tevatron Collider proposals for the years 2000-2005, when the new Main Injector will be complete. At the Tevatron proton-antiproton collider, the CDF and DO experiments are currently completing improvements for Run II to use the Tevatron when the Main Injector is complete later in this decade. New proposals would be aimed at a Collider Run III to follow these CDF and DO efforts

  19. Collider Physics

    OpenAIRE

    Zeppenfeld, D.

    1999-01-01

    These lectures are intended as a pedagogical introduction to physics at $e^+e^-$ and hadron colliders. A selection of processes is used to illustrate the strengths and capabilities of the different machines. The discussion includes $W$ pair production and chargino searches at $e^+e^-$ colliders, Drell-Yan events and the top quark search at the Tevatron, and Higgs searches at the LHC.

  20. The D-Zero Run II Trigger

    International Nuclear Information System (INIS)

    Blazey, G. C.

    1997-01-01

    The general purpose D0 collider detector, located at Fermi National Accelerator Laboratory, requires significantly enhanced data acquisition and triggering to operate in the high luminosity (L = 2 x 10 32 cm -2 s -1 ), high rate environment (7 MHz or 132 ns beam crossings) of the upgraded TeVatron proton anti-proton accelerator. This article describes the three major levels and frameworks of the new trigger. Information from the first trigger stage (L1) which includes scintillating, tracking and calorimeter detectors will provide a deadtimeless, 4.2 (micro)s trigger decision with an accept rate of 10 kHz. The second stage (L2), comprised of hardware engines associated with specific detectors and a single global processor will test for correlations between L1 triggers. L2 will have an accept rate of 1 kHz at a maximum deadtime of 5% and require a 100 (micro)s decision time. The third and final stage (L3) will reconstruct events in a farm of processors for a final instantaneous accept rate of 50 Hz

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

    NARCIS (Netherlands)

    Rojo, Juan; Accardi, Alberto; Ball, Richard D.; Cooper-Sarkar, Amanda; Roeck, Albert de; Farry, Stephen; Ferrando, James; Forte, Stefano; Gao, Jun; Harland-Lang, Lucian; Huston, Joey; Glazov, Alexander; Gouzevitch, Maxime; Gwenlan, Claire; Lipka, Katerina; Lisovyi, Mykhailo; Mangano, Michelangelo L.; Nadolsky, Pavel; Perrozzi, Luca; Placakyte, Ringaile; Radescu, Voica; Salam, Gavin P.; Thorne, Robert S.

    2015-01-01

    The accurate determination of the Parton Distribution Functions (PDFs) of the proton is an essential ingredient of the Large Hadron Collider (LHC) program. PDF uncertainties impact a wide range of processes, from Higgs boson characterisation and precision Standard Model measurements to New Physics

  2. Towards Future Circular Colliders

    CERN Document Server

    AUTHOR|(CDS)2108454; Zimmermann, Frank

    2016-01-01

    The Large Hadron Collider (LHC) at CERN presently provides proton-proton collisions at a centre-of-mass (c.m.) energy of 13 TeV. The LHC design was started more than 30 years ago, and its physics programme will extend through the second half of the 2030’s. The global Future Circular Collider (FCC) study is now preparing for a post-LHC project. The FCC study focuses on the design of a 100-TeV hadron collider (FCC-hh) in a new ∼100 km tunnel. It also includes the design of a high-luminosity electron-positron collider (FCC-ee) as a potential intermediate step, and a lepton-hadron collider option (FCC-he). The scope of the FCC study comprises accelerators, technology, infrastructure, detectors, physics, concepts for worldwide data services, international governance models, and implementation scenarios. Among the FCC core technologies figure 16-T dipole magnets, based on $Nb_3Sn$ superconductor, for the FCC-hh hadron collider, and a highly efficient superconducting radiofrequency system for the FCC-ee lepton c...

  3. Online calculation of the Tevatron collider luminosity using accelerator instrumentation

    International Nuclear Information System (INIS)

    Hahn, A.A.

    1997-07-01

    The luminosity of a collision region may be calculated if one understands the lattice parameters and measures the beam intensities, the transverse and longitudinal emittances, and the individual proton and antiproton beam trajectories (space and time) through the collision region. This paper explores an attempt to make this calculation using beam instrumentation during Run 1b of the Tevatron. The instrumentation used is briefly described. The calculations and their uncertainties are compared to luminosities calculated independently by the Collider Experiments (CDF and D0)

  4. Photon-photon colliders

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1995-04-01

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy

  5. Evaluation report on CCTF Core-II reflood test C2-4 (Run 62)

    International Nuclear Information System (INIS)

    Okubo, Tsutomu; Iguchi, Tadashi; Sugimoto, Jun; Akimoto, Hajime; Murao, Yoshio; Okabe, Kazuharu.

    1985-03-01

    This report presents a data evaluation of the CCTF Core-II test C2-4 (Run 62), which was conducted on May 12, 1983. This test was conducted to investigate the reproducibility of tests in the CCTF Core-II test series. Therefore, the initial and boundary conditions of the present test were determined to be the same as those for the previously performed base case test (Test C2-SH1). Comparing the data of the present test with those of Test C2-SH1, the following results are obtained. (1) The initial and boundary conditions for the two tests were nearly identical except the temperature of the core barrel and the lower plenum fluid. The difference in the latter is considered to result in the difference in the core inlet subcooling of about 6 K at most. (2) The system behavior was almost identical. (3) The core cooling behavior was also nearly identical except a little difference in the rod surface temperature in the upper part of the high power region. (4) Taking account that the difference mentioned above in item (3) is small and can be explained qualitatively to be caused by the difference in the core inlet subcooling mentioned above in item (1), it is considered practically that there is the reproducibility of the thermo-hydrodynamic behavior in the CCTF Core-II tests. (author)

  6. Multi-TeV muon colliders

    International Nuclear Information System (INIS)

    Neuffer, D.

    1986-01-01

    The possibility that muons may be used in a future generation of high-energy high-luminosity μ + μ - and μ - p colliders is presented. The problem of collecting and cooling high-intensity muon bunches is discussed and ionization cooling is described. High-energy collider scenarios are outlined; muon colliders may become superior to electron colliders in the multi-TeV energy range

  7. The development of colliders

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1997-03-01

    During the period of the 50's and the 60's colliders were developed. Prior to that time there were no colliders, and by 1965 a number of small devices had worked, good understanding had been achieved, and one could speculate, as Gersh Budker did, that in a few years 20% of high energy physics would come from colliders. His estimate was an under-estimate, for now essentially all of high energy physics comes from colliders. The author presents a brief review of that history: sketching the development of the concepts, the experiments, and the technological advances which made it all possible

  8. The CMS calorimeter trigger upgrade for the LHC Run II

    CERN Document Server

    Zabi, Alexandre

    2014-01-01

    The CMS experiment implements a sophisticated two-level online selection system that achieves a rejection factor of nearly 10e5. The first level (L1) is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger combines fine-grain information from all sub-detectors. During Run II, the LHC will increase its centre of mass energy up to 13 TeV and progressively reach an instantaneous luminosity of 2e34 cm-2s-1. In order to guarantee a successful and ambitious physics program under this intense environment, the CMS Trigger and Data acquisition system must be consolidated. In particular the L1 calorimeter Trigger hardware and architecture will be modified. The goal is to maintain the current thresholds (e.g., for electrons and photons) and improve the performance for the selection of tau leptons. This can only be achieved by designing an updated trigger architecture based on the recent microTCA technology. Racks can be equipped with fast optical links and latest...

  9. RHIC PC CNI POLARIMETER:STATUS AND PERFORMANCE from THE FIRST COLLIDER RUN

    International Nuclear Information System (INIS)

    JINNOUCHI, O.; ALEKSEEV, I.G.; BLAND, L.C.; BRAVAR, A.; BUNCE, G.; CADMAN, R.; DESHPANDE, A.D.; HAWAN, S.; FIELDS, D.E.; HUANG, H.; HUGHES, V.; IGO, G.; IMAI, K.; KANAVETS, V.P.; KIRYLUK, J.; KURITA, K.; LI, Z.; LOZOWSKI, W.; MACKAY, W.W.; MAKDISI, Y.; OGAWA, A.; RESCIA, S.; ROSER, T.; SAITO, N.; SPINKA, H.; SURROW, B.; SVIRIDA, D.N.; TOJO, J.; UNDERWOOD, D.; WOOD, J.

    2002-01-01

    Polarimeters using the proton carbon elastic scattering process in Coulomb Nuclear Interference (CNI) region were installed in two RHIC rings. Polarization measurements were successfully carried out with the high energy polarized proton beams for the first polarized pp collision run. The physics principles, performance, and polarization measurements are presented

  10. $B$ physics at the Tevatron: Run II and beyond

    CERN Document Server

    Anikeev, K; Azfar, F.; Bailey, S.; Bauer, C.W.; Bell, W.; Bodwin, G.; Braaten, E.; Burdman, G.; Butler, J.N.; Byrum, K.; Cason, N.; Cerri, A.; Cheung, H.W.K.; Dighe, A.; Donati, S.; Ellis, R.K.; Falk, A.; Feild, G.; Fleming, S.; Furic, I.; Gardner, S.; Grossman, Y.; Gutierrez, G.; Hao, W; Harris, B.W.; Hewett, J.; Hiller, G.; Jesik, R.; Jones, M.; Kasper, P.A.; El-Khadra, A.; Kirk, M.; Kiselev, V.V.; Kroll, J.; Kronfeld, A.S.; Kutschke, R.; Kuznetsov, V.E.; Laenen, E.; Lee, J.; Leibovich, A.K.; Lewis, J.D.; Ligeti, Z.; Likhoded, A.K.; Logan, H.E.; Luke, M.; Maciel, A.; Majumder, G.; Maksimovic, P.; Martin, M.; Menary, S.; Nason, P.; Nierste, U.; Nir, Y.; Nogach, L.; Norrbin, E.; Oleari, C.; Papadimitriou, V.; Paulini, M.; Paus, C.; Petteni, M.; Poling, R.; Procario, M.; Punzi, G.; Quinn, H.; Rakitine, A.; Ridolfi, G.; Shestermanov, K.; Signorelli, G.; Silva, J.P.; Skwarnicki, T.; Smith, A.; Speakman, B.; Stenson, K.; Stichelbaut, F.; Stone, S.; Sumorok, K.; Tanaka, M.; Taylor, W.; Trischuk, W.; Tseng, J.; Van Kooten, R.; Vasiliev, A.; Voloshin, M.; Wang, J.C.; Wicklund, A.B.; Wurthwein, F.; Xuan, N.; Yarba, J.; Yip, K.; Zieminski, A.

    2002-01-01

    This report provides a comprehensive overview of the prospects for B physics at the Tevatron. The work was carried out during a series of workshops starting in September 1999. There were four working groups: 1) CP Violation, 2) Rare and Semileptonic Decays, 3) Mixing and Lifetimes, 4) Production, Fragmentation and Spectroscopy. The report also includes introductory chapters on theoretical and experimental tools emphasizing aspects of B physics specific to hadron colliders, as well as overviews of the CDF, D0, and BTeV detectors, and a Summary.

  11. Potential performance for Pb-Pb, p-Pb, and p-p collisions in a future circular collider

    Directory of Open Access Journals (Sweden)

    Michaela Schaumann

    2015-09-01

    Full Text Available The hadron collider studied in the future circular collider (FCC project could operate with protons and lead ions in similar operation modes as the LHC. In this paper the potential performances in lead-lead, proton-lead, and proton-proton collisions are investigated. Based on average lattice parameters, the strengths of intrabeam scattering and radiation damping are evaluated and their effect on the beam and luminosity evolution is presented. Estimates for the integrated luminosity per fill and per run are given, depending on the turnaround time. Moreover, the beam-beam tune shift and bound free pair production losses in heavy-ion operation are addressed.

  12. Stanford's linear collider

    International Nuclear Information System (INIS)

    Southworth, B.

    1985-01-01

    The peak of the construction phase of the Stanford Linear Collider, SLC, to achieve 50 GeV electron-positron collisions has now been passed. The work remains on schedule to attempt colliding beams, initially at comparatively low luminosity, early in 1987. (orig./HSI).

  13. Optimisation of the ATLAS Track Reconstruction Software for Run-2

    CERN Document Server

    Salzburger, Andreas; The ATLAS collaboration

    2015-01-01

    The reconstruction of particle trajectories in the tracking detectors of experiments at the Large Hadron Collider (LHC) is one of the most complex parts in analysing the collected data from beam-beam collisions. To achieve the desired integrated luminosity during Run-1 of the LHC data taking period, the number of simultaneous proton-proton interactions per beam crossing (pile-up) was steadily increased. The track reconstruction is the most time consuming reconstruction component and scales non-linear in high luminosity environments. Flat budget projections (at best) for computing resources during the upcoming Run-2 of the LHC together with the demands of reconstructing higher pile-up collision data at rates more than double compared to Run-1 have put pressure on the track reconstruction software to stay within the available computing resources. The ATLAS experiment has thus performed a two year long software campaign which led to a reduction of the reconstruction time for Run-2 conditions by a factor of four:...

  14. The dijet invariant mass at the Tevatron Collider

    International Nuclear Information System (INIS)

    Giannetti, P.

    1990-01-01

    The differential cross section of the process p + pbar → jet + jet + X as a function of the dijet invariant mass has been measured with the CDF detector at a center of mass energy of 1.8 TeV at the Tevatron Collider in Fermilab. The present analysis is based on the sample of events collected in the 1988/89 run, amounting to a total integrated luminosity of 4.2 pb -1 . A comparison to leading order QCD and quark compositeness predictions is presented as well as a study of the sensitivity of the mass spectrum to the gluon radiation. 10 refs., 6 figs

  15. Prospects of measuring general Higgs couplings at e{sup +}e{sup -} linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, K. [KEK, Ibaraki (Japan). Theory Group; Ishihara, S. [KEK, Ibaraki (Japan). Theory Group; Department of Physics, Hyogo University of Education, 941-1 Shimokume, Yashiro, Kato, Hyogo 673-1494 (Japan); Kamoshita, J. [Department of Physics, Ochanomizu University, 2-1-1 Otsuka, Bunkyo, Tokyo 112-8610 (Japan); Kniehl, B.A. [II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2000-06-01

    We examine how accurately the general HZV couplings, with V=Z{gamma}, may be determined by studying e{sup +}e{sup -}{yields}Hf anti f processes at future e{sup +}e{sup -} linear colliders. By using the optimal-observable method, which makes use of all available experimental information, we find out which combinations of the various HZV coupling terms may be constrained most efficiently with high luminosity. We also assess the benefits of measuring the tau-lepton helicities, identifying the bottom-hadron charges, polarizing the electron beam and running at two different collider energies. The HZZ couplings are generally found to be well constrained, even without these options, while the HZ{gamma} couplings are not. The constraints on the latter may be significantly improved by beam polarization. (orig.)

  16. SLAC linear collider

    International Nuclear Information System (INIS)

    Richter, B.; Bell, R.A.; Brown, K.L.

    1980-06-01

    The SLAC LINEAR COLLIDER is designed to achieve an energy of 100 GeV in the electron-positron center-of-mass system by accelerating intense bunches of particles in the SLAC linac and transporting the electron and positron bunches in a special magnet system to a point where they are focused to a radius of about 2 microns and made to collide head on. The rationale for this new type of colliding beam system is discussed, the project is described, some of the novel accelerator physics issues involved are discussed, and some of the critical technical components are described

  17. Heavy-ion performance of the LHC and future colliders

    Energy Technology Data Exchange (ETDEWEB)

    Schaumann, Michaela

    2015-04-29

    In 2008 the Large Hadron Collider (LHC) and its experiments started operation at the European Centre of Nuclear Research (CERN) in Geneva with the main aim of finding or excluding the Higgs boson. Only four years later, on the 4th of July 2012, the discovery of a Higgs-like particle was proven and first published by the two main experiments ATLAS and CMS. Even though proton-proton collisions are the main operation mode of the LHC, it also acts as an heavy-ion collider. Here, the term ''heavy-ion collisions'' refers to the collision between fully stripped nuclei. While the major hardware system of the LHC is compatible with heavy-ion operation, the beam dynamics and performance limits of ion beams are quite different from those of protons. Because of the higher mass and charge of the ions, beam dynamic effects like intra-beam scattering and radiation damping are stronger. Also the electromagnetic cross-sections in the collisions are larger, leading to significantly faster intensity decay and thus shorter luminosity lifetimes. As the production cross-sections for various physics processes under study of the experiments are still small at energies reachable with the LHC and because the heavy-ion run time is limited to a few days per year, it is essential to obtain the highest possible collision rate, i.e. maximise the instantaneous luminosity, in order to obtain enough events and therefore low statistical errors. Within this thesis, the past performance of the LHC in lead-lead (Pb-Pb) collisions, at a centre-of-mass energy of 2.76 TeV per colliding nucleon pair, is analysed and potential luminosity limitations are identified. Tools are developed to predict future performance and techniques are presented to further increase the luminosity. Finally, a perspective on the future of high energy heavy-ion colliders is given.

  18. Approximations for W-Pair Production at Linear-Collider Energies

    CERN Document Server

    Denner, A

    1997-01-01

    We determine the accuracy of various approximations to the O(alpha) corrections for on-shell W-pair production. While an approximation based on the universal corrections arising from initial-state radiation, from the running of alpha, and from corrections proportional to m_t^2 fails in the Linear-Collider energy range, a high-energy approximation improved by the exact universal corrections is sufficiently good above about 500GeV. These results indicate that in Monte Carlo event generators for off-shell W-pair production the incorporation of the universal corrections is not sufficient and more corrections should be included.

  19. Muon collider progress

    Energy Technology Data Exchange (ETDEWEB)

    Noble, Robert J. FNAL

    1998-08-01

    Recent progress in the study of muon colliders is presented. An international collaboration consisting of over 100 individuals is involved in calculations and experiments to demonstrate the feasibility of this new type of lepton collider. Theoretical efforts are now concentrated on low-energy colliders in the 100 to 500 GeV center-of-mass energy range. Credible machine designs are emerging for much of a hypothetical complex from proton source to the final collider. Ionization cooling has been the most difficult part of the concept, and more powerful simulation tools are now in place to develop workable schemes. A collaboration proposal for a muon cooling experiment has been presented to the Fermilab Physics Advisory Committee, and a proposal for a targetry and pion collection channel experiment at Brookhaven National Laboratory is in preparation. Initial proton bunching and space-charge compensation experiments at existing hadron facilities have occurred to demonstrate proton driver feasibility.

  20. A global view on the Higgs self-coupling at lepton colliders

    Energy Technology Data Exchange (ETDEWEB)

    Di Vita, Stefano [INFN Sezione di Milano (Italy); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Durieux, Gauthier [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Grojean, Christophe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Gu, Jiayin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chinese Academy of Sciences, Beijing (China). Center for Future High Energy Physics; Liu, Zhen [Fermi National Accelerator Laboratory, Batavia, IL (United States). Theoretical Physics Dept.; Panico, Giuliano [Univ. Autonoma de Barcelona (Spain). IFAE; Univ. Autonoma de Barcelona (Spain). BIST; Riembau, Marc; Vantalon, Thibaud [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Univ. Autonoma de Barcelona (Spain). IFAE; Univ. Autonoma de Barcelona (Spain). BIST

    2017-11-15

    We perform a global effective-field-theory analysis to assess the precision on the determination of the Higgs trilinear self-coupling at future lepton colliders. Two main scenarios are considered, depending on whether the center-of-mass energy of the colliders is sufficient or not to access Higgs pair production processes. Low-energy machines allow for ∝40% precision on the extraction of the Higgs trilinear coupling through the exploitation of next-to-leading-order effects in single Higgs measurements, provided that runs at both 240/250 GeV and 350 GeV are available with luminosities in the few attobarns range. A global fit, including possible deviations in other SM couplings, is essential in this case to obtain a robust determination of the Higgs self-coupling. High-energy machines can easily achieve a ∝20% precision through Higgs pair production processes. In this case, the impact of additional coupling modifications is milder, although not completely negligible.

  1. A global view on the Higgs self-coupling at lepton colliders

    International Nuclear Information System (INIS)

    Di Vita, Stefano; Durieux, Gauthier; Grojean, Christophe; Humboldt-Universitaet, Berlin; Gu, Jiayin; Chinese Academy of Sciences, Beijing; Liu, Zhen; Panico, Giuliano; Univ. Autonoma de Barcelona; Riembau, Marc; Vantalon, Thibaud; Univ. Autonoma de Barcelona; Univ. Autonoma de Barcelona

    2017-11-01

    We perform a global effective-field-theory analysis to assess the precision on the determination of the Higgs trilinear self-coupling at future lepton colliders. Two main scenarios are considered, depending on whether the center-of-mass energy of the colliders is sufficient or not to access Higgs pair production processes. Low-energy machines allow for ∝40% precision on the extraction of the Higgs trilinear coupling through the exploitation of next-to-leading-order effects in single Higgs measurements, provided that runs at both 240/250 GeV and 350 GeV are available with luminosities in the few attobarns range. A global fit, including possible deviations in other SM couplings, is essential in this case to obtain a robust determination of the Higgs self-coupling. High-energy machines can easily achieve a ∝20% precision through Higgs pair production processes. In this case, the impact of additional coupling modifications is milder, although not completely negligible.

  2. Linear Colliders

    International Nuclear Information System (INIS)

    Alcaraz, J.

    2001-01-01

    After several years of study e''+ e''- linear colliders in the TeV range have emerged as the major and optimal high-energy physics projects for the post-LHC era. These notes summarize the present status form the main accelerator and detector features to their physics potential. The LHC era. These notes summarize the present status, from the main accelerator and detector features to their physics potential. The LHC is expected to provide first discoveries in the new energy domain, whereas an e''+ e''- linear collider in the 500 GeV-1 TeV will be able to complement it to an unprecedented level of precision in any possible areas: Higgs, signals beyond the SM and electroweak measurements. It is evident that the Linear Collider program will constitute a major step in the understanding of the nature of the new physics beyond the Standard Model. (Author) 22 refs

  3. Status of the calibration and alignment framework at the Belle II experiment

    Science.gov (United States)

    Dossett, D.; Sevior, M.; Ritter, M.; Kuhr, T.; Bilka, T.; Yaschenko, S.; Belle Software Group, II

    2017-10-01

    The Belle II detector at the Super KEKB e+e-collider plans to take first collision data in 2018. The monetary and CPU time costs associated with storing and processing the data mean that it is crucial for the detector components at Belle II to be calibrated quickly and accurately. A fast and accurate calibration system would allow the high level trigger to increase the efficiency of event selection, and can give users analysis-quality reconstruction promptly. A flexible framework to automate the fast production of calibration constants is being developed in the Belle II Analysis Software Framework (basf2). Detector experts only need to create two components from C++ base classes in order to use the automation system. The first collects data from Belle II event data files and outputs much smaller files to pass to the second component. This runs the main calibration algorithm to produce calibration constants ready for upload into the conditions database. A Python framework coordinates the input files, order of processing, and submission of jobs. Splitting the operation into collection and algorithm processing stages allows the framework to optionally parallelize the collection stage on a batch system.

  4. Hadron collider tests of neutrino mass-generating mechanisms

    Science.gov (United States)

    Ruiz, Richard Efrain

    The Standard Model of particle physics (SM) is presently the best description of nature at small distances and high energies. However, with tiny but nonzero neutrino masses, a Higgs boson mass unstable under radiative corrections, and little guidance on understanding the hierarchy of fermion masses, the SM remains an unsatisfactory description of nature. Well-motivated scenarios that resolve these issues exist but also predict extended gauge (e.g., Left-Right Symmetric Models), scalar (e.g., Supersymmetry), and/or fermion sectors (e.g., Seesaw Models). Hence, discovering such new states would have far-reaching implications. After reviewing basic tenets of the SM and collider physics, several beyond the SM (BSM) scenarios that alleviate these shortcomings are investigated. Emphasis is placed on the production of a heavy Majorana neutrinos at hadron colliders in the context of low-energy, effective theories that simultaneously explain the origin of neutrino masses and their smallness compared to other elementary fermions, the so-called Seesaw Mechanisms. As probes of new physics, rare top quark decays to Higgs bosons in the context of the SM, the Types I and II Two Higgs Doublet Model (2HDM), and the semi-model independent framework of Effective Field Theory (EFT) have also been investigated. Observation prospects and discovery potentials of these models at current and future collider experiments are quantified.

  5. Higgs self-coupling in the MSSM and NMSSM after the LHC Run 1

    Directory of Open Access Journals (Sweden)

    Lei Wu

    2015-07-01

    Full Text Available Measuring the Higgs self-coupling is one of the crucial physics goals at the LHC Run-2 and other future colliders. In this work, we attempt to figure out the size of SUSY effects on the trilinear self-coupling of the 125 GeV Higgs boson in the MSSM and NMSSM after the LHC Run-1. Taking account of current experimental constraints, such as the Higgs data, flavor constraints, electroweak precision observables and dark matter detections, we obtain the observations: (1 In the MSSM, the ratio λ3hMSSM/λ3hSM has been tightly constrained by the LHC data, which can be only slightly smaller than 1 and minimally reach 97%; (2 In the NMSSM with λ0.7, a large enhancement or reduction −1.1<λ3h1NMSSM/λ3h1SM<2 can occur, which is accompanied by a sizable change of h1τ+τ− coupling. The future colliders, such as the HL-LHC and ILC, will have the capacity to test these large deviations in the NMSSM.

  6. Generation and diagnostics of uncaptured beam in the Fermilab Tevatron and its control by electron lenses

    Directory of Open Access Journals (Sweden)

    Xiao-Long Zhang

    2008-05-01

    Full Text Available In the collider run II, the Tevatron operates with 36 high intensity bunches of 980 GeV protons and antiprotons. Particles not captured by the Tevatron rf system pose a threat since they can quench the superconducting magnets during acceleration or at beam abort. We describe the main mechanisms for the origination of this uncaptured beam, and present measurements of its main parameters by means of a newly developed diagnostics system. The Tevatron electron lens is effectively used in the collider run II operation to remove uncaptured beam and keep its intensity in the abort gaps at a safe level.

  7. Breached fuel pin contamination from Run Beyond Cladding Breach (RBCB) tests in EBR-II

    International Nuclear Information System (INIS)

    Colburn, R.P.; Strain, R.V.; Lambert, J.D.B.; Ukai, S.; Shibahara, I.

    1988-09-01

    Studies indicate there may be a large economic incentive to permit some continued reactor operation with breached fuel pin cladding. A major concern for this type of operation is the potential spread of contamination in the primary coolant system and its impact on plant maintenance. A study of the release and transport of contamination from naturally breached mixed oxide Liquid Metal Reactor (LMR) fuel pins was performed as part of the US Department of Energy/Power Reactor and Nuclear Fuel Development Corporation (DOE/PNC) Run Beyond Cladding Breach (RBCB) Program at EBR-II. The measurements were made using the Breached Fuel Test Facility (BFTF) at EBR-II with replaceable deposition samplers located approximately 1.5 meters from the breached fuel test assemblies. The effluent from the test assemblies containing the breached fuel pins was routed up through the samplers and past dedicated instrumentation in the BFTF before mixing with the main coolant flow stream. This paper discusses the first three contamination tests in this program. 2 refs., 5 figs., 2 tabs

  8. Measurement of the inclusive jet cross section using the midpoint algorithm in Run II at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Group, Robert Craig [Univ. of Florida, Gainesville, FL (United States)

    2006-01-01

    A measurement is presented of the inclusive jet cross section using the Midpoint jet clustering algorithm in five different rapidity regions. This is the first analysis which measures the inclusive jet cross section using the Midpoint algorithm in the forward region of the detector. The measurement is based on more than 1 fb-1 of integrated luminosity of Run II data taken by the CDF experiment at the Fermi National Accelerator Laboratory. The results are consistent with the predictions of perturbative quantum chromodynamics.

  9. Performance of the ATLAS Level-1 muon barrel trigger during the Run 2 data taking

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00404546; The ATLAS collaboration

    2018-01-01

    The Level-1 Muon Barrel Trigger is one of the main elements of the event selection of the ATLAS experiment at the Large Hadron Collider. It exploits the Resistive Plate Chambers (RPC) detectors to generate the trigger signal. The RPCs are placed in the barrel region of the ATLAS experiment: they are arranged in three concentric double layers and operate in a strong magnetic toroidal field. RPC detectors cover the pseudo-rapidity range |η| < 1.05 for a total surface of more than 4000 m 2 and about 3600 gas volumes. The Level-1 Muon Trigger in the barrel region allows to select muon candidates according to their transverse momentum and associates them with the correct bunch-crossing. The trigger system is able to take a decision within a latency of about 2 μs. The measurement of the RPC detector efficiencies and the trigger performance during the ATLAS Run-II data taking are here presented.

  10. The beam energy measurement system for the Beijing electron-positron collider

    International Nuclear Information System (INIS)

    Abakumova, E.V.; Achasov, M.N.; Blinov, V.E.; Cai, X.; Dong, H.Y.; Fu, C.D.; Harris, F.A.; Kaminsky, V.V.; Krasnov, A.A.; Liu, Q.; Mo, X.H.; Muchnoi, N.Yu.; Nikolaev, I.B.; Qin, Q.; Qu, H.M.; Olsen, S.L.; Pyata, E.E.; Shamov, A.G.; Shen, C.P.; Todyshev, K.Yu.

    2011-01-01

    The beam energy measurement system (BEMS) for the upgraded Beijing electron-positron collider BEPC-II is described. The system is based on measuring the energies of Compton back-scattered photons. The relative systematic uncertainty of the electron and positron beam energy determination is estimated as 2×10 -5 . The relative uncertainty of the beam's energy spread is about 6%.

  11. Long-lived sleptons at the LHC and a 100 TeV proton collider

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  12. The LHC cryogenic operation for first collisions and physics run

    CERN Document Server

    Brodzinski, K; Benda, V; Bremer, J; Casas-Cubillos, J; Claudet, S; Delikaris, D; Ferlin, G; Fernandez Penacoba, G; Perin, A; Pirotte, O; Soubiran, M; Tavian, L; van Weelderen, R; Wagner, U

    2011-01-01

    The Large Hadron Collider (LHC) cryogenic system was progressively and successfully run for the LHC accelerator operation period starting from autumn 2009. The paper recalls the cryogenic system architecture and main operation principles. The system stability during magnets powering and availability periods for high energy beams with first collisions at 3.5 TeV are presented. Treatment of typical problems, weak points of the system and foreseen future consolidations will be discussed.

  13. Photon collider at TESLA

    International Nuclear Information System (INIS)

    Telnov, Valery

    2001-01-01

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

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

    CERN Document Server

    Barklow, Tim; Fujii, Keisuke; Gao, Yuanning; Hoang, Andre; Kanemura, Shinya; List, Jenny; Logan, Heather E; Nomerotski, Andrei; Perelstein, Maxim; Peskin, Michael E; Pöschl, Roman; Reuter, Jürgen; Riemann, Sabine; Savoy-Navarro, Aurore; Servant, Geraldine; Tait, Tim M P

    2013-01-01

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to incr...

  15. The International Linear Collider Technical Design Report - Volume 4: Detectors

    CERN Document Server

    Behnke, Ties; Burrows, Philip N.; Fuster, Juan; Peskin, Michael; Stanitzki, Marcel; Sugimoto, Yasuhiro; Yamada, Sakue; Yamamoto, Hitoshi

    2013-01-01

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to incr...

  16. "Towards a Future Linear Collider" and "The Linear Collider Studies at CERN"

    CERN Document Server

    CERN. Geneva

    2010-01-01

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

  17. The ATLAS Tile Calorimeter DCS for Run 2

    CERN Document Server

    Pedro Martins, Filipe Manuel; The ATLAS collaboration

    2016-01-01

    TileCal is one of the ATLAS sub-detectors operating at the Large Hadron Collider (LHC), which is taking data since 2010. The Detector Control System (DCS) was developed to ensure the coherent and safe operation of the whole ATLAS detector. Seventy thousand (70000) parameters are used for control and monitoring purposes of TileCal, requiring an automated system. The TileCal DCS is mainly responsible for the control and monitoring of the high and low voltage systems but it also supervises the detector infrastructure (cooling and racks), calibration systems, data acquisition and safety. During the first period of data taking (Run 1, 2010-12) the TileCal DCS allowed a smooth detector operation and should continue to do so for the second period (Run 2) that started in 2015. The TileCal DCS was updated in order to cope with the hardware and software requirements for Run 2 operation. These updates followed the general ATLAS guidelines on the software and hardware upgrade but also the new requirements from the TileCa...

  18. The ATLAS Tile Calorimeter DCS for Run 2

    CERN Document Server

    Pedro Martins, Filipe Manuel; The ATLAS collaboration

    2016-01-01

    TileCal is one of the ATLAS subdetectors operating at the Large Hadron Collider (LHC), which is taking data since 2010. Seventy thousand (70000) parameters are used for control and monitoring purposes, requiring an automated system. The Detector Control System (DCS) was developed to ensure the coherent and safe operation of the whole ATLAS detector. The TileCal DCS is mainly responsible for the control and monitoring of the high and low voltage systems but it also supervises the detector infrastructure (cooling and racks), calibration systems, data acquisition and safety. During the first period of data taking (Run 1, 2010-12) the TileCal DCS allowed a smooth detector operation and should continue to do so for the second period (Run 2) that started in 2015. The TileCal DCS was updated in order to cope with the hardware and software requirements for Run 2 operation. These updates followed the general ATLAS guidelines on the software and hardware upgrade but also the new requirements from the TileCal detector. ...

  19. SPEAR II performance

    International Nuclear Information System (INIS)

    Paterson, J.M.

    1975-01-01

    The single beam and colliding beam performance of the SLAC electron-positron storage ring SPEAR II is described. The sevenfold increase in harmonic number in SPEAR II in comparison to SPEAR I has made significant changes in single beam behavior. Strong synchrobetatron resonances and a new transverse instability are observed, and our first studies of these phenomena are described. Measurements on current dependent bunch lengthening are presented. (auth)

  20. ALICE Diffractive Detector Control System for RUN-II in the ALICE Experiment

    CERN Document Server

    INSPIRE-00522336; Martinez, M.I.; Monzon, I. Leon

    2016-01-01

    This paper describes general characteristics of the deployment and commissioned of the Detector Control System (DCS) AD0 for the second phase of the Large Hadron Collider (LHC). The AD0 detector is installed in the ALICE experiment to provide a better selection of diffractive events.

  1. LHCb's Time-Real Alignment in RunII

    CERN Multimedia

    Batozskaya, Varvara

    2015-01-01

    LHCb has introduced a novel real-time detector alignment and calibration strategy for LHC Run 2. Data collected at the start of the fill will be processed in a few minutes and used to update the alignment, while the calibration constants will be evaluated for each run. This procedure will improve the quality of the online alignment. Critically, this new real-time alignment and calibration procedure allows identical constants to be used in the online and offline reconstruction, thus improving the correlation between triggered and offline selected events. This offers the opportunity to optimise the event selection in the trigger by applying stronger constraints. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. The motivation for a real-time alignment and calibration of the LHCb detector is discussed from both the operational and physics performance points of view. Specific challenges of this novel configur...

  2. The Run-2 ATLAS Trigger System: Design, Performance and Plan

    CERN Document Server

    zur Nedden, Martin; The ATLAS collaboration

    2016-01-01

    In high-energy physics experiments, online selection is crucial to select interesting collisions from the large data volume. The ATLAS experiment at the Large Hadron Collider (LHC) utilizes the trigger system that consists of a hardware Level-1 (L1) and a software based high-level trigger (HLT), reducing the event rate from the design bunch-crossing rate of 40 MHz to an average recording rate of about 1000 Hz. The ATLAS trigger has been successfully collecting collision data during the first run of the LHC (Run-1) between 2009-2013 at a centre-of-mass energy between 900 GeV and 8 TeV. In the second run of LHC (Run-2) starting from 2015, the LHC operates at centre-of-mass energy of 13 TeV and provides a higher luminosity of collisions. Also, the number of collisions occurring in a same bunch crossing increases. The ATLAS trigger system has to cope with these challenges, while maintaining or even improving the efficiency to select relevant physics processes. In this talk, first we will review the ATLAS trigger ...

  3. eγ and γγ colliders

    International Nuclear Information System (INIS)

    Watanabe, Isamu

    1994-01-01

    The results that can be expected by eγ and γγ colliders in future are summarized. eγ and γγ colliders have many fine possibilities, and are the economical selection for utilizing future e + e - colliders more effectively. eγ and γγ colliders were proposed by former USSR researchers at the beginning of 1980s, but recently, the prospect of realizing future e + e - collision type linear accelerator projects has become high, they have become to be considered seriously as the option of remodeling them. The high energy photon beam of eγ and γγ colliders is obtained by causing Compton reverse scattering, irradiating laser beam to the electron beam of e + e - accelerators. The production of γ-beam is explained. As for the physics noteworthy in eγ colliders, abnormal gauge coupling, the formation of Higgs particles, excited leptons, lepto-quark, supersymmetric particles and top quark are explained. As the physics noteworthy in γγ colliders, the formation of Higgs particles which is most interesting in γγ colliders, abnormal gauge coupling, top quark, Yukawa coupling, Higgs pair formation and other particles are enumerated. The linear e + e - accelerators of TeV range including JLC have the performance to be remodeled to eγ and γγ colliders, and the prospect of realizing them has become high. Their possibility of realization is discussed. (K.I.)

  4. Superconducting linear colliders

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The advantages of superconducting radiofrequency (SRF) for particle accelerators have been demonstrated by successful operation of systems in the TRISTAN and LEP electron-positron collider rings respectively at the Japanese KEK Laboratory and at CERN. If performance continues to improve and costs can be lowered, this would open an attractive option for a high luminosity TeV (1000 GeV) linear collider

  5. The development of colliders

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1993-02-01

    Don Kerst, Gersh Budker, and Bruno Touschek were the individuals, and the motivating force, which brought about the development of colliders, while the laboratories at which it happened were Stanford, MURA, the Cambridge Electron Accelerator, Orsay, Frascati, CERN, and Novosibirsk. These laboratories supported, during many years, this rather speculative activity. Of course, many hundreds of physicists contributed to the development of colliders but the men who started it, set it in the right direction, and forcefully made it happen, were Don, Gersh, and Bruno. Don was instrumental in the development of proton-proton colliders, while Bruno and Gersh spearheaded the development of electron-positron colliders. In this brief review of the history, I will sketch the development of the concepts, the experiments, and the technological developments which made possible the development of colliders. It may look as if the emphasis is on theoretical concepts, but that is really not the case, for in this field -- the physics of beams -- the theory and experiment go hand in hand; theoretical understanding and advances are almost always motivated by the need to explain experimental results or the desire to construct better experimental devices

  6. Alignment of the CMS Tracker: Latest results from LHC Run-II

    CERN Document Server

    Mittag, Gregor

    2017-01-01

    The all-silicon design of the tracking system of the CMS experiment provides excellent measurements of charged-particle tracks and an efficient tagging of jets. Conditions of the CMS tracker changed repeatedly during the 2015/2016 shutdown and the 2016 data-taking period. Still the true position and orientation of each of the 15 148 silicon strip and 1440 silicon pixel modules need to be known with high precision for all intervals. The alignment constants also need to be promptly re-adjusted each time the state of the CMS magnet is changed between 0T and 3.8 T. Latest Run-II results of the CMS tracker alignment and resolution performance are presented, which are obtained using several millions of reconstructed tracks from collision and cosmic-ray data of 2016. The geometries and the resulting performance of physics observables are carefully validated. In addition to the offline alignment, an online procedure has been put in place which continuously monitors movements of the pixel high-level structures and tri...

  7. Modelling Energy Loss Mechanisms and a Determination of the Electron Energy Scale for the CDF Run II W Mass Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Riddick, Thomas [Univ. College London, Bloomsbury (United Kingdom)

    2012-06-15

    The calibration of the calorimeter energy scale is vital to measuring the mass of the W boson at CDF Run II. For the second measurement of the W boson mass at CDF Run II, two independent simulations were developed. This thesis presents a detailed description of the modification and validation of Bremsstrahlung and pair production modelling in one of these simulations, UCL Fast Simulation, comparing to both geant4 and real data where appropriate. The total systematic uncertainty on the measurement of the W boson mass in the W → eve channel from residual inaccuracies in Bremsstrahlung modelling is estimated as 6.2 ±3.2 MeV/c2 and the total systematic uncertainty from residual inaccuracies in pair production modelling is estimated as 2.8± 2.7 MeV=c2. Two independent methods are used to calibrate the calorimeter energy scale in UCL Fast Simulation; the results of these two methods are compared to produce a measurement of the Z boson mass as a cross-check on the accuracy of the simulation.

  8. Exploration of a High Luminosity 100 TeV Proton Antiproton Collider

    Energy Technology Data Exchange (ETDEWEB)

    Oliveros, Sandra J. [Univ. of Mississippi, Oxford, MS (United States); Summers, Don [Univ. of Mississippi, Oxford, MS (United States); Cremaldi, Lucien [Univ. of Mississippi, Oxford, MS (United States); Acosta, John [Univ. of Mississippi, Oxford, MS (United States); Neuffer, David [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2017-04-12

    New physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. We explore a 10$^{\\,34}$ cm$^{-2}$ s$^{-1}$ luminosity, 100 TeV $p\\bar{p}$ collider with 7$\\times$ the energy of the LHC but only 2$\\times$ as much NbTi superconductor, motivating the choice of 4.5 T single bore dipoles. The cross section for many high mass states is 10 times higher in $p\\bar{p}$ than $pp$ collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per beam crossing, because lower beam currents can produce the same rare event rates. Events are more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller $\\beta^{*}$ for higher luminosity. A Fermilab-like $\\bar p$ source would disperse the beam into 12 momentum channels to capture more antiprotons. Because stochastic cooling time scales as the number of particles, 12 cooling ring sets would be used. Each set would include phase rotation to lower momentum spreads, equalize all momentum channels, and stochastically cool. One electron cooling ring would follow the stochastic cooling rings. Finally antiprotons would be recycled during runs without leaving the collider ring by joining them to new bunches with synchrotron damping.

  9. Scaling behavior of circular colliders dominated by synchrotron radiation

    Science.gov (United States)

    Talman, Richard

    2015-08-01

    The scaling formulas in this paper — many of which involve approximation — apply primarily to electron colliders like CEPC or FCC-ee. The more abstract “radiation dominated” phrase in the title is intended to encourage use of the formulas — though admittedly less precisely — to proton colliders like SPPC, for which synchrotron radiation begins to dominate the design in spite of the large proton mass. Optimizing a facility having an electron-positron Higgs factory, followed decades later by a p, p collider in the same tunnel, is a formidable task. The CEPC design study constitutes an initial “constrained parameter” collider design. Here the constrained parameters include tunnel circumference, cell lengths, phase advance per cell, etc. This approach is valuable, if the constrained parameters are self-consistent and close to optimal. Jumping directly to detailed design makes it possible to develop reliable, objective cost estimates on a rapid time scale. A scaling law formulation is intended to contribute to a “ground-up” stage in the design of future circular colliders. In this more abstract approach, scaling formulas can be used to investigate ways in which the design can be better optimized. Equally important, by solving the lattice matching equations in closed form, as contrasted with running computer programs such as MAD, one can obtain better intuition concerning the fundamental parametric dependencies. The ground-up approach is made especially appropriate by the seemingly impossible task of simultaneous optimization of tunnel circumference for both electrons and protons. The fact that both colliders will be radiation dominated actually simplifies the simultaneous optimization task. All GeV scale electron accelerators are “synchrotron radiation dominated”, meaning that all beam distributions evolve within a fraction of a second to an equilibrium state in which “heating” due to radiation fluctuations is canceled by the “cooling” in

  10. RHIC pC CNI Polarimeter: Status and Performance from the First Collider Run

    International Nuclear Information System (INIS)

    Jinnouchi, O.; Tojo, J.; Alekseev, I.G.; Kanavets, V.P.; Svirida, D.N.; Bland, L.C.; Bravar, A.; Huang, H.; Li, Z.; MacKay, W.W.; Makdisi, Y.; Ogawa, A.; Rescia, S.; Roser, T.; Surrow, B.; Bunce, G.; Cadman, R.; Spinka, H.; Underwood, D.; Deshpande, A.

    2003-01-01

    Polarimeters using the proton carbon elastic scattering process in Coulomb Nuclear Interference (CNI) region were installed in two RHIC rings. Polarization measurements were successfully carried out with the high energy polarized proton beams for the first polarized pp collision run. The physics principles, performance, and polarization measurements are presented

  11. The rise of colliding beams

    International Nuclear Information System (INIS)

    Richter, B.

    1992-06-01

    It is a particular pleasure for me to have this opportunity to review for you the rise of colliding beams as the standard technology for high-energy-physics accelerators. My own career in science has been intimately tied up in the transition from the old fixed-target technique to colliding-beam work. I have led a kind of double life both as a machine builder and as an experimenter, taking part in building and using the first of the colliding-beam machines, the Princeton-Stanford Electron-Electron Collider, and building the most recent advance in the technology, the Stanford Linear Collider. The beginning was in 1958, and in the 34 years since there has been a succession of both electron and proton colliders that have increased the available center-of-mass energy for hard collisions by more than a factor of 1000. For the historians here, I regret to say that very little of this story can be found in the conventional literature. Standard operating procedure for the accelerator physics community has been publication in conference proceedings, which can be obtained with some difficulty, but even more of the critical papers are in internal laboratory reports that were circulated informally and that may not even have been preserved. In this presentation I shall review what happened based on my personal experiences and what literature is available. I can speak from considerable experience on the electron colliders, for that is the topic in which I was most intimately involved. On proton colliders my perspective is more than of an observer than of a participant, but I have dug into the literature and have been close to many of the participants

  12. Differential satellite cell density of type I and II fibres with lifelong endurance running in old men

    DEFF Research Database (Denmark)

    Mackey, Abigail; Karlsen, A; Couppé, C

    2014-01-01

    AIM: To investigate the influence of lifelong endurance running on the satellite cell pool of type I and type II fibres in healthy human skeletal muscle. METHODS: Muscle biopsies were collected from 15 healthy old trained men (O-Tr) who had been running 43 ± 16 (mean ± SD) kilometres a week for 28...... ± 9 years. Twelve age-matched untrained men (O-Un) and a group of young trained and young untrained men were recruited for comparison. Frozen sections were immunohistochemically stained for Pax7, type I myosin and laminin, from which fibre area, the number of satellite cells, and the relationship......-Un. A strong positive relationship between fibre size and satellite cell content was detected in trained individuals. In line with a history of myofibre repair, a greater number of fibres with centrally located myonuclei were detected in O-Tr. CONCLUSION: Lifelong endurance training (i) does not deplete...

  13. Dedicating Fermilab's Collider

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1986-01-15

    It was a bold move to have a fullscale dedication ceremony for the new proton-antiproton Collider at the Fermilab Tevatron on 13 October, two days before the first collisions were seen. However the particles dutifully behaved as required, and over the following weekend the Collider delivered its goods at a total energy of 1600 GeV, significantly boosting the world record for laboratory collisions.

  14. Towards the International Linear Collider

    International Nuclear Information System (INIS)

    Lopez-Fernandez, Ricardo

    2006-01-01

    The broad physics potential of e+e- linear colliders was recognized by the high energy physics community right after the end of LEP in 2000. In 2007, the Large Hadron Collider (LHC) now under construction at CERN will obtain its first collisions. The LHC, colliding protons with protons at 14 TeV, will discover a standard model Higgs boson over the full potential mass range, and should be sensitive to new physics into the several TeV range. The program for the Linear Collider (LC) will be set in the context of the discoveries made at the LHC. All the proposals for a Linear Collider will extend the discoveries and provide a wealth of measurements that are essential for giving deeper understanding of their meaning, and pointing the way to further evolution of particle physics in the future. For the mexican groups is the right time to join such an effort

  15. SLAC-Linac-Collider (SLC) Project

    International Nuclear Information System (INIS)

    Wiedemann, H.

    1981-02-01

    The proposed SLAC Linear Collider Project (SLC) and its features are described in this paper. In times of ever increasing costs for energy the electron storage ring principle is about to reach its practical limit. A new class of colliding beam beam facilities, the Linear Colliders, are getting more and more attractive and affordable at very high center-of-mass energies. The SLC is designed to be a poineer of this new class of colliding beam facilities and at the same time will serve as a valuable tool to explore the high energy physics at the level of 100 GeV in the center-of-mass system

  16. BES-II fast data reconstruction

    International Nuclear Information System (INIS)

    Rong Gang; Zhang Jiawen; Guo Yiqing; Zhang Shaoqiang; Zhao Dixin

    2002-01-01

    The BES-II fast data reconstruction is reported. Based on PC FARM and/or a 'Distributed Clustered Linux PC System', BES-II fast data reconstruction system is set up. With this system the BES-II data can be fully reconstructed in about 20 minutes after data collection. It takes only 12 minutes to fully reconstruct 30000 events, collected with BES-II detector at BEPC Collider, with a P III-800 PC. The detector performance can be examined based on fully reconstructed data in about 20 minutes after data taking in the BES-II experiment

  17. CERN balances linear collider studies

    CERN Multimedia

    ILC Newsline

    2011-01-01

    The forces behind the two most mature proposals for a next-generation collider, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) study, have been steadily coming together, with scientists from both communities sharing ideas and information across the technology divide. In a support of cooperation between the two, CERN in Switzerland, where most CLIC research takes place, recently converted the project-specific position of CLIC Study Leader to the concept-based Linear Collider Study Leader.   The scientist who now holds this position, Steinar Stapnes, is charged with making the linear collider a viable option for CERN’s future, one that could include either CLIC or the ILC. The transition to more involve the ILC must be gradual, he said, and the redefinition of his post is a good start. Though not very much involved with superconducting radiofrequency (SRF) technology, where ILC researchers have made significant advances, CERN participates in many aspect...

  18. SAMGrid experiences with the Condor technology in Run II computing

    International Nuclear Information System (INIS)

    Baranovski, A.; Loebel-Carpenter, L.; Garzoglio, G.; Herber, R.; Illingworth, R.; Kennedy, R.; Kreymer, A.; Kumar, A.; Lueking, L.; Lyon, A.; Merritt, W.; Terekhov, I.; Trumbo, J.; Veseli, S.; White, S.; St. Denis, R.; Jain, S.; Nishandar, A.

    2004-01-01

    SAMGrid is a globally distributed system for data handling and job management, developed at Fermilab for the D0 and CDF experiments in Run II. The Condor system is being developed at the University of Wisconsin for management of distributed resources, computational and otherwise. We briefly review the SAMGrid architecture and its interaction with Condor, which was presented earlier. We then present our experiences using the system in production, which have two distinct aspects. At the global level, we deployed Condor-G, the Grid-extended Condor, for the resource brokering and global scheduling of our jobs. At the heart of the system is Condor's Matchmaking Service. As a more recent work at the computing element level, we have been benefiting from the large computing cluster at the University of Wisconsin campus. The architecture of the computing facility and the philosophy of Condor's resource management have prompted us to improve the application infrastructure for D0 and CDF, in aspects such as parting with the shared file system or reliance on resources being dedicated. As a result, we have increased productivity and made our applications more portable and Grid-ready. Our fruitful collaboration with the Condor team has been made possible by the Particle Physics Data Grid

  19. Muon colliders and neutrino factories

    Energy Technology Data Exchange (ETDEWEB)

    Geer, S.; /Fermilab

    2010-09-01

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

  20. The future e+e- colliders

    International Nuclear Information System (INIS)

    Voss, G.A.

    1990-01-01

    At present, the highest energy e + e - colliders are the SLC and LEP. In this paper their future improvement programs for increasing luminosity and/or energy, and the use of longitudinally polarized beams at the interaction point (IP) are discussed. An e + e - collider in the SSC tunnel does not seem to be an attractive option, on both technical and economical grounds, and with LEP, circular colliders have reached the sensible limit of size and cost. Linear colliders which have, in principle, no high energy limit, must overcome a new set of technical problems having to do with beam power limitations, emittance control, superstrong focusing at the IP, strong bunch-bunch interactions at the IP and related backgrounds

  1. Linear collider: a preview

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, H.

    1981-11-01

    Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.

  2. Linear collider: a preview

    International Nuclear Information System (INIS)

    Wiedemann, H.

    1981-11-01

    Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center

  3. Muon muon collider: Feasibility study

    International Nuclear Information System (INIS)

    1996-01-01

    A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10 35 cm -2 s -1 . The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice--the authors believe--to allow them 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 which 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

  4. Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

    Science.gov (United States)

    Infantino, Angelo; Alía, Rubén García; Besana, Maria Ilaria; Brugger, Markus; Cerutti, Francesco

    2017-09-01

    As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh), running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee) as well as a lepton-hadron option (FCC-he). In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

  5. Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

    Directory of Open Access Journals (Sweden)

    Infantino Angelo

    2017-01-01

    Full Text Available As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh, running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee as well as a lepton-hadron option (FCC-he. In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

  6. Superconducting super collider

    International Nuclear Information System (INIS)

    Limon, P.J.

    1987-01-01

    The Superconducting Super Collider is to be a 20 TeV per beam proton-proton accelerator and collider. Physically the SCC will be 52 miles in circumference and slightly oval in shape. The use of superconducting magnets instead of conventional cuts the circumference from 180 miles to the 52 miles. The operating cost of the SCC per year is estimated to be about $200-250 million. A detailed cost estimate of the project is roughly $3 billion in 1986 dollars. For the big collider ring, the technical cost are dominated by the magnet system. That is why one must focus on the cost and design of the magnets. Presently, the process of site selection is underway. The major R and D efforts concern superconducting dipoles. The magnets use niobium-titanium as a conductor stabilized in a copper matrix. 10 figures

  7. Heavy leptons at hadron colliders

    International Nuclear Information System (INIS)

    Ohnemus, J.E.

    1987-01-01

    The recent advent of high energy hadron colliders capable of producing weak bosons has opened new vistas for particle physics research, including the search for a possible fourth generation heavy charged lepton, which is the primary topic of the thesis. Signals for identifying a new heavy lepton have been calculated and compared to Standard Model backgrounds. Results are presented for signals at the CERN collider, the Fermilab collider, and the proposed Superconducting Supercollider

  8. Luminosity upgrade possibilities for the PEP-II B-Factory

    CERN Document Server

    Sullivan, M

    2003-01-01

    PEP-II is an asymmetric e sup + e sup - collider being constructed in the SLAC PEP tunnel by SLAC, LBNL, and LLNL. The two beams have energies of 3.1 GeV and 9.0 GeV and are made to collide at a single interaction point. PEP-II has a 2200 m circumference. The nominal parameters for PEP-II are listed in Table 1. The High Energy Ring (HER) of PEP-II started commissioning in 1997. The Low Energy Ring (LER) will be commissioned in the summer of 1998. The BaBar detector is to be installed starting January 1999. Studies for increasing the luminosity in PEP-II beyond the design are underway. A brief summary of the possibilities are presented here. Improvements to the integrated luminosity will be implemented gradually. Major luminosity improvements will likely come in two phased upgrades. Several of these possibilities are summarized in Table 1.

  9. LUMINOSITY UPGRADE POSSIBILITIES FOR THE PEP-II B-FACTORY

    International Nuclear Information System (INIS)

    Sullivan, Michael K

    2003-01-01

    PEP-II is an asymmetric e + e - collider being constructed in the SLAC PEP tunnel by SLAC, LBNL, and LLNL. The two beams have energies of 3.1 GeV and 9.0 GeV and are made to collide at a single interaction point. PEP-II has a 2200 m circumference. The nominal parameters for PEP-II are listed in Table 1. The High Energy Ring (HER) of PEP-II started commissioning in 1997. The Low Energy Ring (LER) will be commissioned in the summer of 1998. The BaBar detector is to be installed starting January 1999. Studies for increasing the luminosity in PEP-II beyond the design are underway. A brief summary of the possibilities are presented here. Improvements to the integrated luminosity will be implemented gradually. Major luminosity improvements will likely come in two phased upgrades. Several of these possibilities are summarized in Table 1

  10. Computing and data handling requirements for SSC [Superconducting Super Collider] and LHC [Large Hadron Collider] experiments

    International Nuclear Information System (INIS)

    Lankford, A.J.

    1990-05-01

    A number of issues for computing and data handling in the online in environment at future high-luminosity, high-energy colliders, such as the Superconducting Super Collider (SSC) and Large Hadron Collider (LHC), are outlined. Requirements for trigger processing, data acquisition, and online processing are discussed. Some aspects of possible solutions are sketched. 6 refs., 3 figs

  11. Final Focus Systems in Linear Colliders

    International Nuclear Information System (INIS)

    Raubenheimer, Tor

    1998-01-01

    In colliding beam facilities, the ''final focus system'' must demagnify the beams to attain the very small spot sizes required at the interaction points. The first final focus system with local chromatic correction was developed for the Stanford Linear Collider where very large demagnifications were desired. This same conceptual design has been adopted by all the future linear collider designs as well as the SuperConducting Supercollider, the Stanford and KEK B-Factories, and the proposed Muon Collider. In this paper, the over-all layout, physics constraints, and optimization techniques relevant to the design of final focus systems for high-energy electron-positron linear colliders are reviewed. Finally, advanced concepts to avoid some of the limitations of these systems are discussed

  12. Searching for light Higgs scalar boson in the next generation of electron-positron collider at LEP

    International Nuclear Information System (INIS)

    Chukwumah, G.C.

    1985-11-01

    The e + e - -collider facilities at LEP II, with the cm energy √S in the range 100-170 GeV may be able to detect ''light'' Higgs bosons, assuming a high luminosity. In this paper, we have calculated production cross-sections of a light Higgs boson H 0 in association with the neutral gauge boson Z 0 , for varying ranges of the cm energy expected to be available to LEP II and VLEEP (Novosibirsk) and for various values of the light Higgs mass. It is found out that production cross-sections are sizeable in comparison with those for the very massive Higgs bosons in proton-anti(proton) super-colliders, Tevatron, Spp-barS and SSC, respectively. The implication of this feature is pointed out. Further, prospects for light Higgs production in association with the charged gauge boson, W - in ultra energetic neutrino beams are examined. (author)

  13. Production and decay of Z bosons at the SLC [SLAC Linear Collider

    International Nuclear Information System (INIS)

    Feldman, G.J.

    1989-12-01

    My lectures at Cargese covered the very first physics results from the SLAC Linear Collider (SLC). At the time of this writing (December 1989), it seems most sensible to present a review of the results that were presented at the school in an updated form. The organization of this report will be to give a brief introduction to linear colliders and the SLC, then to describe the MARK II detector, and finally to review the current status of the three major physics topics discussed at Cargese: the Z line shape, from which we deduce the Z mass and width, and the number of neutrino species, the partonic structure of hadronic decays and a measurement of α s , and searches for new quarks and leptons. 39 refs., 27 figs., 3 tabs

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

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Howard [Univ. of Oklahoma, Norman, OK (United States); Barklow, Tim [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fujii, Keisuke [National Lab. for High Energy Physics (KEK), Tokai (Japan); Gao, Yuanning [Unlisted; Hoang, Andre [Univ. of Vienna (Austria); Kanemura, Shinya [Univ. of Toyama (Japan); List, Jenny [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Logan, Heather E. [Carleton Univ., Ottawa, ON (Canada); Nomerotski, Andrei [Univ. of Oxford (United Kingdom); Perelstein, Maxim [Cornell Univ., Ithaca, NY (United States); Peskin, Michael E. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Pöschl, Roman [Univ. Paris-Sud, Orsay (France). Linear Accelerator Lab. (LAL); Reuter, Jürgen [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Riemann, Sabine [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Savoy-Navarro, Aurore [CNRS/IN2P3. Univ. Paris (France). Observatoire de Paris. AstroParticule et Cosmologie (APC); Servant, Geraldine [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Tait, Tim P. [Univ. of California, Los Angeles, CA (United States); Yu, Jaehoon [Univ. of Science and Technology of China, Hefei (China)

    2013-06-26

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

  15. The International Linear Collider Technical Design Report - Volume 4: Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Ties [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2013-06-26

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

  16. SLAC linear collider and a few ideas on future linear colliders

    International Nuclear Information System (INIS)

    Loew, G.A.

    1984-04-01

    This paper comes in two parts. The first part is a progress report on the SLAC Linear Collider (SLC) with emphasis on those systems which are of special interest to linear accelerator designers; it sets the stage for a number of contributed papers on specific topics which are also presented at this conference. The second part presents some ideas which are of interest to the design of future linear colliders of higher energies

  17. A study of tau decays of the W boson at CDF [Collider Detector at Fermilab

    International Nuclear Information System (INIS)

    Gladney, L.D.

    1990-01-01

    A report is given of a search for tau decays of the W boson in p bar p collisions at √s = 1.8 TeV using the Collider Detector at Fermilab (CDF). A description of a hardware trigger specifically designed to enhance the number of events with tau decays is presented along with the results of a preliminary analysis of data taken during the 1988--89 run of CDF. 10 refs., 4 figs

  18. Evolution of online algorithms in ATLAS and CMS in Run2

    CERN Document Server

    Tomei, Thiago R. F. P.

    2017-01-01

    The Large Hadron Collider has entered a new era in Run~2, with centre-of-mass energy of 13~TeV and instantaneous luminosity reaching $\\mathcal{L}_\\textrm{inst} = 1.4\\times$10\\textsuperscript{34}~cm\\textsuperscript{-2}~s\\textsuperscript{-1} for pp collisions. In order to cope with those harsher conditions, the ATLAS and CMS collaborations have improved their online selection infrastructure to keep a high efficiency for important physics processes -- like W, Z and Higgs bosons in their leptonic and diphoton modes -- whilst keeping the size of data stream compatible with the bandwidth and disk resources available. In this note, we describe some of the trigger improvements implemented for Run~2, including algorithms for selection of electrons, photons, muons and hadronic final states.

  19. Muon muon collider: Feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-18

    A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10{sup 35} cm{sup {minus}2} s{sup {minus}1}. The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice--the authors believe--to allow them 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 which 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.

  20. Searching for R-parity violation at run-II of the tevatron

    International Nuclear Information System (INIS)

    Allanach, B.; Banerjee, S.; Berger, E. L.; Chertok, M.; Diaz, M. A.; Dreiner, H.; Eboli, O. J. P.; Harris, B. W.; Hewett, J.; Magro, M. B.; Mondal, N. K.; Narasimham, V. S.; Navarro, L.; Parua, N.; Porod, W.; Restrepo, D. A.; Richardson, P.; Rizzo, T.; Seymour, M. H.; Sullivan, Z.; Valle, J. W. F.; Campos, F. de

    1999-01-01

    The authors present an outlook for possible discovery of supersymmetry with broken R-parity at Run II of the Tevatron. They first present a review of the literature and an update of the experimental bounds. In turn they then discuss the following processes: (1) resonant slepton production followed by R P decay, (a) via LQD c and (b) via LLE c ; (2) how to distinguish resonant slepton production from Zprime or Wprime production; (3) resonant slepton production followed by the decay to neutralino LSP, which decays via LQD c ; (4) resonant stop production followed by the decay to a chargino, which cascades to the neutralino LSP; (5) gluino pair production followed by the cascade decay to charm squarks which decay directly via L 1 Q 2 D 1 c ; (6) squark pair production followed by the cascade decay to the neutralino LSP which decays via L 1 Q 2 D 1 c ; (7) MSSM pair production followed by the cascade decay to the LSP which decays (a) via LLE c , (b) via LQD c , and (c) via U c D c D c , respectively; and (8) top quark and top squark decays in spontaneous R P

  1. NOVOSIBIRSK/STANFORD: colliding linac beams

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Plans to use colliding beams from linear accelerators are being considered at Novosibirsk and Stanford. The VLEPP scheme proposed for Novosibirsk and the Stanford single pass collider scheme are described. (W.D.L.).

  2. Superconducting magnets for a muon collider

    International Nuclear Information System (INIS)

    Green, M.A.

    1996-01-01

    The existence of a muon collider will be dependent on the use of superconducting magnets. Superconducting magnets for the μ - μ + collider will be found in the following locations: the π - π + capture system, the muon phase rotation system, the muon cooling system, the recirculating acceleration system, the collider ring, and the collider detector system. This report describes superconducting magnets for each of these sections except the detector. In addition to superconducting magnets, superconducting RF cavities will be found in the recirculating accelerator sections and the collider ring. The use of superconducting magnets is dictated by the need for high magnetic fields in order to reduce the length of various machine components. The performance of all of the superconducting magnets will be affected the energy deposited from muon decay products. (orig.)

  3. Progress in the NNPDF global analysis and the impact of the legacy HERA combination

    NARCIS (Netherlands)

    Rojo, Juan

    2015-01-01

    The H1 and ZEUS collaborations have recently presented their final results for the combination of inclusive cross-section measurements taken during Run I and Run II at the HERA collider. In this contribution, following an overview of recent progress in the NNPDF framework, we quantify the impact of

  4. Hadron collider physics at UCR

    International Nuclear Information System (INIS)

    Kernan, A.; Shen, B.C.

    1997-01-01

    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 + -e - 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/2γ at PEP and the OPAL detector at LEP, as well as efforts on hadron machines

  5. Physics at a future collider beyond the LHC and a TeV class linear collider

    CERN Multimedia

    CERN. Geneva

    2003-01-01

    After the LHC will have probed the physics at the TeV frontier, new generations of colliders capable of reaching into the multi-TeV energy domain will need to be considered. Concepts for both high energy e+e- linear colliders and muon storage rings have been proposed as well as hadron colliders. Highly challenging R&D programs are presently pursued to demonstrate their principles. The definition of a physics programme in the multi-TeV range still requires essential data that is likely to become available only after the first years of LHC operation and, possibly, also the results from a TeV-class linear collider. At present we have to envisage several possible scenarios for the fundamental questions to be addressed by collider experiments in the next decade, to guide the choices in the accelerator designs and parameters. After a brief review of the main accelerator projects and the present status of their R&D, I shall discuss the main signatures of the physics of possible relevance in relation to the e...

  6. Stable massive particles at colliders

    Energy Technology Data Exchange (ETDEWEB)

    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.

    2006-11-01

    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.

  7. Summary of the half-day internal review of LHC performance limitations (linked to transverse collective effects) during run II (CERN, 29/11/2016)

    CERN Document Server

    Metral, Elias; Biancacci, Nicolo; Buffat, Xavier; Carver, Lee Robert; Iadarola, Giovanni; Li, Kevin Shing Bruce; Persson, Tobias Hakan Bjorn; Romano, Annalisa; Schenk, Michael; Tambasco, Claudia; CERN. Geneva. ATS Department

    2017-01-01

    In this note the half-day internal review of LHC performance limitations (linked to transverse collective effects) during run II (2015-2016), which took place at CERN on 29/11/2016 (https://indico.cern.ch/event/589625/), is summarised and the next steps are discussed.

  8. TeV e+e- linear colliders

    International Nuclear Information System (INIS)

    Le Duff, J.

    1987-12-01

    The basic philosophy and performance and technical constraints of linear e + e - colliders at TeV energies are summarized. Collider luminosity, pinch effects due to beam interaction, beam-beam bremsstrahlung, and typical parameters for an e + e - linear collider are discussed. Accelerating structures, HF power sources, electron guns, positron production, and storage rings are considered [fr

  9. The SLAC linear collider

    International Nuclear Information System (INIS)

    Richter, B.

    1985-01-01

    A report is given on the goals and progress of the SLAC Linear Collider. The author discusses the status of the machine and the detectors and give an overview of the physics which can be done at this new facility. He also gives some ideas on how (and why) large linear colliders of the future should be built

  10. LHC Report: Tests of new LHC running modes

    CERN Document Server

    Verena Kain for the LHC team

    2012-01-01

    On 13 September, the LHC collided lead ions with protons for the first time. This outstanding achievement was key preparation for the planned 2013 operation in this mode. Outside of two special physics runs, the LHC has continued productive proton-proton luminosity operation.   Celebrating proton-ion collisions. The first week of September added another 1 fb-1 of integrated luminosity to ATLAS’s and CMS’s proton-proton data set. It was a week of good and steady production mixed with the usual collection of minor equipment faults. The peak performance was slightly degraded at the start of the week but thanks to the work of the teams in the LHC injectors the beam brightness – and thus the LHC peak performance – were restored to previous levels by the weekend. The LHC then switched to new running modes and spectacularly proved its potential as a multi-purpose machine. This is due in large part to the LHC equipment and controls, which have been designed wi...

  11. Hadron collider physics at UCR

    Energy Technology Data Exchange (ETDEWEB)

    Kernan, A.; Shen, B.C.

    1997-07-01

    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.

  12. Energy determination at BEPC-II

    International Nuclear Information System (INIS)

    Achasov, M.N.; Blinov, V.E.; Bogomyagkov, A.V.; Fu ChengDong; Harris, F.A.; Kaminsky, V.V.; Liu, Q.; Mo Xiaohu; Muchnoi, N.Yu.; Nikitin, S.A.; Nikolaev, I.B.; Qin Qing; Qu Huamin; Olsen, S.L.; Pyata, E.E.; Shamov, A.G.; Shen, C.P.; Varner, G.S.; Wang Yifang; Xu Jinqiang

    2009-01-01

    The BEPC-II collider beam energy calibration system is discussed. The system is based on the Compton backscattering method. The expected precision of the electron and positron beam energy ε determination is δε/ε∼3.10 -5 .

  13. The Higgs and Supersymmetry at Run II of the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Shih, David [Rutgers Univ., Piscataway, NJ (United States)

    2016-04-14

    Prof. David Shih was supported by DOE grant DE-SC0013678 from April 2015 to April 2016. His research during this year focused on the phenomenology of super-symmetry (SUSY) and maximizing its future discovery potential at Run II of the LHC. SUSY is one of the most well-motivated frameworks for physics beyond the Standard Model. It solves the "naturalness" or "hierarchy" problem by stabilizing the Higgs mass against otherwise uncontrolled quantum corrections, predicts "grand unification" of the fundamental forces, and provides many potential candidates for dark matter. However, after decades of null results from direct and indirect searches, the viable parameter space for SUSY is increasingly constrained. Also, the discovery of a Standard Model-like Higgs with a mass at 125 GeV places a stringent constraint on SUSY models. In the work supported on this grant, Shih has worked on four different projects motivated by these issues. He has built natural SUSY models that explain the Higgs mass and provide viable dark matter; he has studied the parameter space of "gauge mediated supersymmetry breaking" (GMSB) that satisfies the Higgs mass constraint; he has developed new tools for the precision calculation of flavor and CP observables in general SUSY models; and he has studied new techniques for discovery of supersymmetric partners of the top quark.

  14. The Higgs and Supersymmetry at Run II of the LHC

    International Nuclear Information System (INIS)

    Shih, David

    2016-01-01

    Prof. David Shih was supported by DOE grant DE-SC0013678 from April 2015 to April 2016. His research during this year focused on the phenomenology of super-symmetry (SUSY) and maximizing its future discovery potential at Run II of the LHC. SUSY is one of the most well-motivated frameworks for physics beyond the Standard Model. It solves the 'naturalness' or 'hierarchy' problem by stabilizing the Higgs mass against otherwise uncontrolled quantum corrections, predicts 'grand unification' of the fundamental forces, and provides many potential candidates for dark matter. However, after decades of null results from direct and indirect searches, the viable parameter space for SUSY is increasingly constrained. Also, the discovery of a Standard Model-like Higgs with a mass at 125 GeV places a stringent constraint on SUSY models. In the work supported on this grant, Shih has worked on four different projects motivated by these issues. He has built natural SUSY models that explain the Higgs mass and provide viable dark matter; he has studied the parameter space of 'gauge mediated supersymmetry breaking' (GMSB) that satisfies the Higgs mass constraint; he has developed new tools for the precision calculation of flavor and CP observables in general SUSY models; and he has studied new techniques for discovery of supersymmetric partners of the top quark.

  15. B factory with hadron colliders

    International Nuclear Information System (INIS)

    Lockyer, N.S.

    1990-01-01

    The opportunities to study B physics in a hadron collider are discussed. Emphasis is placed on the technological developments necessary for these experiments. The R and D program of the Bottom Collider Detector group is reviewed. (author)

  16. Status Report and Future Plans for the PEP-II B Factory

    International Nuclear Information System (INIS)

    Fisher, Alan S.

    2001-01-01

    The PEP-II B Factory at SLAC has been in operation with the BABAR detector since the summer of 1999. The peak currents and luminosity steadily increased through the end of the 2000 run on October 31. By that time, 0.75 A of electrons (the design current) routinely collided with 1.4 A of positrons in 657 bunches, to give a peak luminosity of 2.6 x 10 33 cm -2 s -1 . We delivered an integrated luminosity of up to 184 pb -1 per day and 1033 per week; BABAR logged a total of 25 fb -1 . Three days of machine development at the end of the run raised the peak luminosity to 3.29 x 10 33 , exceeding the design goal of 3.0. BABAR then logged data for an hour, starting with a peak of 3.20. Next, we achieved the design value for positron current, 2.14 A, operating without collisions. The major limitation has been growth in the size of the positron beam in the low-energy ring (LER) due to electron clouds and multipacting. Since the arcs benefit from antechambers and a TiN coating with low secondary emission, our efforts have concentrated on the straights, where we added solenoid windings. Each straight wound allowed higher LER current without blow-up, and a consequent increase in luminosity. Measurements of the bunch-by-bunch luminosity showed that the effect becomes significant by about the tenth bunch in a train, but clears after a short gap. Careful control of the fill pattern has thus been essential in raising luminosity. For the 2001 run, which began in February, we added a third LER RF station, to collide with more LER current and more bunches, and also tried reducing β* x from 50 to 35 cm, with the goal of reaching a luminosity of 5 x 10 33 by year's end. In 2003, we plan to add a fourth LER and sixth HER RF station to reach 1 x 10 34

  17. The Large Hadron Collider of CERN and the roadmap toward higher performance

    CERN Document Server

    Rossi, L

    2012-01-01

    The Large Hadron Collider is exploring the new frontier of particle physics. It is the largest and most ambitious scientific instrument ever built and 100 years after the Rutherford experiment it continues that tradition of “smashing atoms” to unveil the secret of the infinitely small. LHC makes use of all what we learnt in 40 years of hadron colliders, in particular of ISR and Sp-pbarS at CERN and Tevatron at Fermilab, and it is based on Superconductivity, discovered also 100 years ago. Designing, developing the technology, building and finally commissioning the LHC took more than twenty years. While LHC is now successfully running, we are already preparing the future for the next step. First, by increasing of a factor five the LHC luminosity in ten years from now, and then by increasing its energy by a factor two or more, on the horizon of the next twenty years. These LHC upgrades, in luminosity and energy, will be the super-exploitation of the CERN infrastructure and is the best investment that the HEP...

  18. Vector-like quarks coupling discrimination at the LHC and future hadron colliders

    Science.gov (United States)

    Barducci, D.; Panizzi, L.

    2017-12-01

    The existence of new coloured states with spin one-half, i.e. extra-quarks, is a striking prediction of various classes of new physics models. Should one of these states be discovered during the 13 TeV runs of the LHC or at future high energy hadron colliders, understanding its properties will be crucial in order to shed light on the underlying model structure. Depending on the extra-quarks quantum number under SU(2) L , their coupling to Standard Model quarks and bosons have either a dominant left- or right-handed chiral component. By exploiting the polarisation properties of the top quarks arising from the decay of pair-produced extra quarks, we show how it is possible to discriminate among the two hypothesis in the whole discovery range currently accessible at the LHC, thus effectively narrowing down the possible interpretations of a discovered state in terms of new physics scenarios. Moreover, we estimate the discovery and discrimination power of future prototype hadron colliders with centre of mass energies of 33 and 100 TeV.

  19. Physics at Future Hadron Colliders

    CERN Document Server

    Baur, U.; Parsons, J.; Albrow, M.; Denisov, D.; Han, T.; Kotwal, A.; Olness, F.; Qian, J.; Belyaev, S.; Bosman, M.; Brooijmans, G.; Gaines, I.; Godfrey, S.; Hansen, J.B.; Hauser, J.; Heintz, U.; Hinchliffe, I.; Kao, C.; Landsberg, G.; Maltoni, F.; Oleari, C.; Pagliarone, C.; Paige, F.; Plehn, T.; Rainwater, D.; Reina, L.; Rizzo, T.; Su, S.; Tait, T.; Wackeroth, D.; Vataga, E.; Zeppenfeld, D.

    2001-01-01

    We discuss the physics opportunities and detector challenges at future hadron colliders. As guidelines for energies and luminosities we use the proposed luminosity and/or energy upgrade of the LHC (SLHC), and the Fermilab design of a Very Large Hadron Collider (VLHC). We illustrate the physics capabilities of future hadron colliders for a variety of new physics scenarios (supersymmetry, strong electroweak symmetry breaking, new gauge bosons, compositeness and extra dimensions). We also investigate the prospects of doing precision Higgs physics studies at such a machine, and list selected Standard Model physics rates.

  20. HIGH ENERGY PHYSICS POTENTIAL AT MUON COLLIDERS

    International Nuclear Information System (INIS)

    PARSA, Z.

    2000-01-01

    In this paper, high energy physics possibilities and future colliders are discussed. The μ + μ - collider and experiments with high intensity muon beams as the stepping phase towards building Higher Energy Muon Colliders (HEMC) are briefly reviewed and encouraged

  1. Performance of the ATLAS Muon Trigger in Run 2

    CERN Document Server

    Morgenstern, Marcus; The ATLAS collaboration

    2018-01-01

    Events containing muons in the final state are an important signature for many analyses being carried out at the Large Hadron Collider (LHC), including both standard model measurements and searches for new physics. To be able to study such events, it is required to have an efficient and well-understood muon trigger. The ATLAS muon trigger consists of a hardware based system (Level 1), as well as a software based reconstruction (High Level Trigger). Due to high luminosity and pile up conditions in Run 2, several improvements have been implemented to keep the trigger rate low while still maintaining a high efficiency. Some examples of recent improvements include requiring coincidence hits between different layers of the muon spectrometer, improvements for handling overlapping muons, and optimised muon isolation. We will present an overview of how we trigger on muons, recent improvements, and the performance of the muon trigger in Run 2 data.

  2. ATLAS Metadata Infrastructure Evolution for Run 2 and Beyond

    CERN Document Server

    van Gemmeren, Peter; The ATLAS collaboration; Malon, David; Vaniachine, Alexandre

    2015-01-01

    ATLAS developed and employed for Run 1 of the Large Hadron Collider a sophisticated infrastructure for metadata handling in event processing jobs. This infrastructure profits from a rich feature set provided by the ATLAS execution control framework, including standardized interfaces and invocation mechanisms for tools and services, segregation of transient data stores with concomitant object lifetime management, and mechanisms for handling occurrences asynchronous to the control framework’s state machine transitions. This metadata infrastructure is evolving and being extended for Run 2 to allow its use and reuse in downstream physics analyses, analyses that may or may not utilize the ATLAS control framework. At the same time, multiprocessing versions of the control framework and the requirements of future multithreaded frameworks are leading to redesign of components that use an incident-handling approach to asynchrony. The increased use of scatter-gather architectures, both local and distributed, requires ...

  3. Muon Muon Collider: Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    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

    2012-04-05

    A feasibility study is presented of a 2 + 2 TeV muon collider with a luminosity of L = 10{sup 35} cm{sup -2}s{sup -1}. The resulting design is not optimized for performance, and certainly not for cost; however, it does suffice - we believe - to allow us to make a credible case, that a muon collider is a serious possibility for particle physics and, therefore, worthy of R and D support so that the reality of, and interest in, a muon collider can be better assayed. The goal of this support would be to completely assess the physics potential and to evaluate the cost and development of the necessary technology. The muon collider complex consists of components which first produce copious pions, then capture the pions and the resulting muons from their decay; this is followed by an ionization cooling channel to reduce the longitudinal and transverse emittance of the muon beam. The next stage is to accelerate the muons and, finally, inject them into a collider ring wich has a small beta function at the colliding point. This is the first attempt at a point design and it will require further study and optimization. Experimental work will be needed to verify the validity of diverse crucial elements in the design. Muons because of their large mass compared to an electron, do not produce significant synchrotron radiation. As a result there is negligible beamstrahlung and high energy collisions are not limited by this phenomena. In addition, muons can be accelerated in circular devices which will be considerably smaller than two full-energy linacs as required in an e{sup +} - e{sup -} collider. A hadron collider would require a CM energy 5 to 10 times higher than 4 TeV to have an equivalent energy reach. Since the accelerator size is limited by the strength of bending magnets, the hadron collider for the same physics reach would have to be much larger than the muon collider. In addition, muon collisions should be cleaner than hadron collisions. There are many detailed particle

  4. Prospettive per il Run 2 ad LHC

    CERN Document Server

    Ciulli, Vitaliano

    2015-01-01

    With the approach of resumption of the activity of the Large Hadron Collider at the CERN, scheduled for the spring of 2015, the physicists of the ATLAS and CMS experiments are pondering the prospects that will be opened up by the increase of centre-of-mass energy from 8 to 13 TeV, after the discovery of the Higgs boson. However the results from Run 2 go, they will mark an important new chapter in the physics of fundamental interactions, making it possible to explore the region up to around 1 TeV of mass in the search for new particles that can explain dark matter and the other unresolved questions of the Standard Model.

  5. Beam-beam observations in the Relativistic Heavy Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States); White, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  6. Variable millimetre radiation from the colliding-wind binary Cygnus OB2 #8A

    Science.gov (United States)

    Blomme, R.; Fenech, D. M.; Prinja, R. K.; Pittard, J. M.; Morford, J. C.

    2017-12-01

    Context. Massive binaries have stellar winds that collide. In the colliding-wind region, various physically interesting processes occur, leading to enhanced X-ray emission, non-thermal radio emission, as well as non-thermal X-rays and gamma-rays. Non-thermal radio emission (due to synchrotron radiation) has so far been observed at centimetre wavelengths. At millimetre wavelengths, the stellar winds and the colliding-wind region emit more thermal free-free radiation, and it is expected that any non-thermal contribution will be difficult or impossible to detect. Aims: We aim to determine if the material in the colliding-wind region contributes substantially to the observed millimetre fluxes of a colliding-wind binary. We also try to distinguish the synchrotron emission from the free-free emission. Methods: We monitored the massive binary Cyg OB2 #8A at 3 mm with the NOrthern Extended Millimeter Array (NOEMA) interferometer of the Institut de Radioastronomie Millimétrique (IRAM). The data were collected in 14 separate observing runs (in 2014 and 2016), and provide good coverage of the orbital period. Results: The observed millimetre fluxes range between 1.1 and 2.3 mJy, and show phase-locked variability, clearly indicating that a large part of the emission is due to the colliding-wind region. A simple synchrotron model gives fluxes with the correct order of magnitude, but with a maximum that is phase-shifted with respect to the observations. Qualitatively this phase shift can be explained by our neglect of orbital motion on the shape of the colliding-wind region. A model using only free-free emission results in only a slightly worse explanation of the observations. Additionally, on the map of our observations we also detect the O6.5 III star Cyg OB2 #8B, for which we determine a 3 mm flux of 0.21 ± 0.033 mJy. Conclusions: The question of whether synchrotron radiation or free-free emission dominates the millimetre fluxes of Cyg OB2 #8A remains open. More detailed

  7. Collide@CERN Geneva

    CERN Multimedia

    CERN. Geneva; Kieffer, Robert; Blas Temino, Diego; Bertolucci, Sergio; Mr. Decelière, Rudy; Mr. Hänni, Vincent

    2014-01-01

    CERN, the Republic and Canton of Geneva, and the City of Geneva are delighted to invite you to “Collide@CERN Geneva Music”. Come to the public lecture about collisions between music and particle physics by the third winners of Collide@CERN Geneva, Vincent Hänni & Rudy Decelière, and their scientific inspiration partners, Diego Blas and Robert Kieffer. The event marks the beginning of their residency at CERN, and will be held at the CERN Globe of Science and Innovation on 16 October 2014 at 19.00. Doors will open at 18.30.

  8. The MARX Modulator Development Program for the International Linear Collider

    International Nuclear Information System (INIS)

    Leyh, G.E.

    2006-01-01

    The International Linear Collider (ILC) Marx Modulator Development Program at SLAC is working towards developing a full-scale ILC Marx ''Reference Design'' modulator prototype, with the goal of significantly reducing the size and cost of the ILC modulator while improving overall modulator efficiency and availability. The ILC Reference Design prototype will provide a proof-of-concept model to industry in advance of Phase II SBIR funding, and also allow operation of the new 10MW L-Band Klystron prototypes immediately upon their arrival at SLAC

  9. Novel methods and expected run II performance of ATLAS track reconstruction in dense environments

    CERN Document Server

    Jansky, Roland Wolfgang; The ATLAS collaboration

    2015-01-01

    Detailed understanding and optimal track reconstruction performance of ATLAS in the core of high pT objects is paramount for a number of techniques such as jet energy and mass calibration, jet flavour tagging, and hadronic tau identification as well as measurements of physics quantities like jet fragmentation functions. These dense environments are characterized by charged particle separations on the order of the granularity of ATLAS’s inner detector. With the insertion of a new innermost layer in this tracking detector, which allows measurements closer to the interaction point, and an increase in the centre of mass energy, these difficult environments will become even more relevant in Run II, such as in searches for heavy resonances. Novel algorithmic developments to the ATLAS track reconstruction software targeting these topologies as well as the expected improved performance will be presented.

  10. Characterising the Decays of High-pt Top Quarks and Addressing Naturalness with Jet Substructure in ATLAS Runs I and II

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00397460

    The coupling of the Standard Model top quark to the Higgs boson is O(1), which leads to large quantum corrections in the perturbative expansion of the Higgs boson mass. Possible solutions to this so-called naturalness problem include supersymmetric models with gluinos and stop squarks whose masses are at the electroweak scale, O(1 TeV). If supersymmetry is realised in nature at this scale, these particles are expected to be accessible with the Large Hadron Collider at CERN. A search for gluino pair production with decays mediated by stop- and sbottom-squark loops in the initial 14.8 ifb of the ATLAS run 2 dataset is presented in terms of a pair of simplified models, which targets extreme regions of phase space using jet substructure techniques. No excess is observed and limits are set which greatly extend the previous exclusion region of this search, up to 1.9 TeV (1.95 TeV) for gluinos decaying through light stop (sbottom) squarks to the lightest neutralinos. A performance study of top tagging algorithms in ...

  11. FERMILAB: Collider detectors -2

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Last month's edition (April, page 12) included a status report on data collection and preliminary physics results from the 'newcomer' DO detector at Fermilab's Tevatron proton-antiproton collider. This time the spotlight falls in the Veteran' CDF detector, in action since 1985 and meanwhile significantly upgraded. Meanwhile the Tevatron collider continues to improve, with record collision rates

  12. Recent results from E-735 at the Fermilab tevatron proton-antiproton collider with √s=1.8 TeV

    International Nuclear Information System (INIS)

    Alexopoulos, T.; Erwin, A.; Findeisen, C.; Nelson, K.; Thompson, M.; Banerjee, S.; Beery, P.D.; Biswas, N.N.; DeBonte, R.; Kenney, V.P.; LoSecco, J.M.; McManus, A.P.; Piekarz, J.; Stampke, S.R.; Carter, T.; Goshaw, A.T.; Oh, S.A.; Walker, W.D.; Wesson, D.K.

    1989-01-01

    E-735 is searching for signs of the quark-gluon-plasma phase transition in minimum bias proton-antiproton events. Results from the 1987 run at the Tevatron Collider at √s=1.8 TeV are presented. Included are distributions of the average p t versus multiplicity dependence for charged particles, and preliminary particle identification analysis using time of flight. (orig.)

  13. Colliding almost-plane gravitational waves: Colliding plane waves and general properties of almost-plane-wave spacetimes

    International Nuclear Information System (INIS)

    Yurtsever, U.

    1988-01-01

    It is well known that when two precisely plane-symmetric gravitational waves propagating in an otherwise flat background collide, they focus each other so strongly as to produce a curvature singularity. This paper is the first of several devoted to almost-plane gravitational waves and their collisions. Such waves are more realistic than plane waves in having a finite but very large transverse size. In this paper we review some crucial features of the well-known exact solutions for colliding plane waves and we argue that one of these features, the breakdown of ''local inextendibility'' can be regarded as nongeneric. We then introduce a new framework for analyzing general colliding plane-wave spacetimes; we give an alternative proof of a theorem due to Tipler implying the existence of singularities in all generic colliding plane-wave solutions; and we discuss the fact that the recently constructed Chandrasekhar-Xanthopoulos colliding plane-wave solutions are not strictly plane symmetric and thus do not satisfy the conditions and the conclusion of Tipler's theorem

  14. Progress on $e^{+}e^{-}$ linear colliders

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Siemann, Peter

    2002-01-01

    Physics issues. The physics program will be reviewed for e+e- linear colliders in the TeV energy range. At these prospective facilities central issues of particle physics can be addressed, the problem of mass, unification and structure of space-time. In this context the two lectures will focus on analyses of the Higgs mechanism, supersymmetry and extra space dimensions. Moreover, high-precision studies of the top-quark and the gauge boson sector will be discussed. Combined with LHC results, a comprehensive picture can be developed of physics at the electroweak scale and beyond. Designs and technologies (R. Siemann - 29, 30, 31 May) The physics and technologies of high energy linear colliders will be reviewed. Fundamental concepts of linear colliders will be introduced. They will be discussed in: the context of the Stanford Linear Collider where many ideas changed and new ones were developed in response to operational experience. the requirements for future linear colliders. The different approaches for reac...

  15. The International Linear Collider Technical Design Report - Volume 1: Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    Behnke, Ties [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brau, James E. [Univ. of Oregon, Eugene, OR (United States); Foster, Brian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fuster, Juan [Univ. of Valencia (Spain); Harrison, Mike [Brookhaven National Lab. (BNL), Upton, NY (United States); Paterson, James McEwan [SLAC National Accelerator Lab., Menlo Park, CA (United States); Peskin, Michael [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanitzki, Marcel [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Walker, Nicholas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yamamoto, Hitoshi [Tohoku Univ., Sendai (Japan)

    2013-06-26

    The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

  16. Physics at Hadronic Colliders (4/4)

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

  17. Physics at Hadronic Colliders (1/4)

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

  18. Physics at Hadronic Colliders (2/4)

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

  19. Physics at Hadronic Colliders (3/4)

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    Hadron colliders are often called "discovery machines" since they produce the highest mass particles and thus give often the best chance to discover new high mass particles. Currently they are particularly topical since the Large Hadron Collider will start operating later this year, increasing the centre-of-mass energy by a factor of seven compared to the current highest energy collider, the Tevatron. I will review the benefits and challenges of hadron colliders and review some of the current physics results from the Tevatron and give an outlook to the future results we are hoping for at the LHC. Prerequisite knowledge: Introduction to Particle Physics (F. Close), Detectors (W. Riegler, at least mostly) and The Standard Model (A. Pich)

  20. Constraining Dark Matter Interactions with Pseudoscalar and Scalar Mediators Using Collider Searches for Multijets plus Missing Transverse Energy.

    Science.gov (United States)

    Buchmueller, Oliver; Malik, Sarah A; McCabe, Christopher; Penning, Bjoern

    2015-10-30

    The monojet search, looking for events involving missing transverse energy (E_{T}) plus one or two jets, is the most prominent collider dark matter search. We show that multijet searches, which look for E_{T} plus two or more jets, are significantly more sensitive than the monojet search for pseudoscalar- and scalar-mediated interactions. We demonstrate this in the context of a simplified model with a pseudoscalar interaction that explains the excess in GeV energy gamma rays observed by the Fermi Large Area Telescope. We show that multijet searches already constrain a pseudoscalar interpretation of the excess in much of the parameter space where the mass of the mediator M_{A} is more than twice the dark matter mass m_{DM}. With the forthcoming run of the Large Hadron Collider at higher energies, the remaining regions of the parameter space where M_{A}>2m_{DM} will be fully explored. Furthermore, we highlight the importance of complementing the monojet final state with multijet final states to maximize the sensitivity of the search for the production of dark matter at colliders.

  1. ATLAS LAr calorimeter performance and LHC Run-2 commissioning

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00366625; The ATLAS collaboration

    2016-01-01

    The ATLAS detector was built to study proton-proton collisions produced by the Large Hadron Collider (LHC) at a center of mass energy of up to 14 TeV. The Liquid Argon (LAr) calorimeters are used for all electromagnetic calorimetry as well as the hadronic calorimetry in the endcap and forward regions. They have shown excellent performance during the first LHC data taking campaign, from 2010 to 2012, so-called Run 1, at a peak luminosity of $8 \\times 10^{33} \\text{cm}^{-2}\\text{s}^{-1}$. During the next run, peak luminosities of $1.5 \\times 10^{34} \\text{cm}^{-2}\\text{s}^{-1}$ and even higher are expected at a 25ns bunch spacing. Such a high collision rate may have an impact on the quality of the energy reconstruction which is attempted to be maintained at a high level using a calibration procedure described in this contribution. It also poses major challenges to the first level of the trigger system which is constrained to a maximal rate of 100 kHz. For Run-3, scheduled to start in 2019, instantaneous luminos...

  2. The upgraded Pixel Detector of the ATLAS experiment for Run-2 at the Large Hadron Collider

    CERN Document Server

    Giordani, MarioPaolo; The ATLAS collaboration

    2016-01-01

    Run-2 of the LHC is providing new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. Therefore the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). IBL is a fourth layer of pixel detectors, and has been installed in May 2014 at a radius of 3.3 cm between the existing Pixel Detector and a new smaller radius beam-pipe. The new detector, built to cope with high radiation and expected occupancy, is the first large scale application of 3D detectors and CMOS 130nm technology. In addition the Pixel detector was refurbished with a new service quarter panel to recover about 3% of defective modules lost during run-1 and a new optical readout system to readout the data at higher speed while reducing the occupancy when running with increased luminosity. The commissioning and performance of the 4-layer Pixel Detector, in particular the IBL, will be presented, using collision data.

  3. The track finding algorithm of the Belle II vertex detectors

    Directory of Open Access Journals (Sweden)

    Bilka Tadeas

    2017-01-01

    Full Text Available The Belle II experiment is a high energy multi purpose particle detector operated at the asymmetric e+e− - collider SuperKEKB in Tsukuba (Japan. In this work we describe the algorithm performing the pattern recognition for inner tracking detector which consists of two layers of pixel detectors and four layers of double sided silicon strip detectors arranged around the interaction region. The track finding algorithm will be used both during the High Level Trigger on-line track reconstruction and during the off-line full reconstruction. It must provide good efficiency down to momenta as low as 50 MeV/c where material effects are sizeable even in an extremely thin detector as the VXD. In addition it has to be able to cope with the high occupancy of the Belle II detectors due to the background. The underlying concept of the track finding algorithm, as well as details of the implementation are outlined. The algorithm is proven to run with good performance on simulated ϒ(4S → BB̄ events with an efficiency for reconstructing tracks of above 90% over a wide range of momentum.

  4. Experimental particle physics at the University of Pittsburgh. Progress report, November 1, 1995--October 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Boudreau, J.F.; Engels, E. Jr.; Shepard, P.F.; Thompson, J.A.

    1996-05-01

    This report covers the progress on two different tasks, Task A and Task B. Task A focuses on rare and semi-rare decays of {phi} and of the short-lived kaon with emphasis on those aspects needed in preparation for the proposed {Phi}-Factory measurements of CPT violation and {epsilon}{prime}/{epsilon} from the CP-violating decays of the K{sub L}K{sub S} final state. The second aspect of the kaon decay work is participation in the so-called rare kaon decay experiments, E865, at BNL. The major goals of Task B, Fermilab program, are as follows: (1) participation in the analysis of the E706 data taken during the 1990--1991 fixed target run at Fermilab and (2) the continuation of the work with the CDF collaboration particularly the SVX II upgrade. The E706 part of the program involves the completion of publications reporting the results of the 1990--91 data run. The analysis of these data is now mature and physics results are emerging. The CDF program involves a dedicated effort to the design of a silicon vertex detector upgrade, SVX II, to be accomplished by the time Fermilab run II collider run (1999). In addition they are participating in the 1993--1995 collide run Ib and actively analyzing the data from both runs Ia and Ib.

  5. Design of a Multi-Bunch BPM for the Next Linear Collider

    International Nuclear Information System (INIS)

    Young, Andrew

    2003-01-01

    The Next Linear Collider (NLC) design requires precise control of colliding trains of high-intensity (1.4 x 10 10 particles/bunch) and low-emittance beams. High-resolution multi-bunch beam position monitors (BPMs) are required to ensure uniformity across the bunch trains with bunch spacing of 1.4ns. A high bandwidth (∼350 MHz) multi-bunch BPM has been designed based on a custom-made stripline sum and difference hybrid on a Teflon-based material. High bandwidth RF couplers were included to allow injection of a calibration tone. Three prototype BPMs were fabricated at SLAC and tested in the Accelerator Test Facility at KEK and in the PEP-II ring at SLAC. Tone calibration data and single-bunch and multi-bunch beam data were taken with high-speed (5Gsa/s) digitizers. Offline analysis determined the deconvolution of individual bunches in the multi-bunch mode by using the measured single bunch response. The results of these measurements are presented in this paper

  6. Review of Physics Results from the Tevatron: Top Quark Physics

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Cecilia E.; Vellidis, Costas

    2014-09-17

    We present results on top quark physics from the CDF and D0 collaborations at the Fermilab Tevatron proton anti-proton collider. These include legacy results from Run II that were published or submitted for publication before mid-2014, as well as a summary of Run I results. The historical perspective of the discovery of the top quark in Run I is also described.

  7. Model independent Z' constraints at future e+e- colliders

    International Nuclear Information System (INIS)

    Leike, A.

    1993-11-01

    Model independent constraints on the mass of extra neutral gauge bosons and their couplings to charged leptons are given for LEP II and a 500 GeV e + e - collider. Analytical exclusion limits are derived in the Born approximation. The Z' limits obtained with radiative corrections are always worse than those calculated at the Born level. Polarized beams are only useful for degrees of polarization essentially larger than 50%. Known discovery limits on extra Z bosons predicted by popular Z' models are reproduced as special cases. The Z' constraints are compared to those predicted by four fermion contact interactions. (orig.)

  8. The photon collider at TESLA

    Czech Academy of Sciences Publication Activity Database

    Badelek, B.; Bloechinger, C.; Blümlein, J.; Boos, E.; Brinkman, R.; Burkhardt, H.; Bussey, P.; Carimalo, C.; Chýla, Jiří; Ciftci, A.K.

    2004-01-01

    Roč. 19, č. 30 (2004), s. 5097-5186 ISSN 0217-751X Institutional research plan: CEZ:AV0Z1010920 Keywords : photon collider * linear collider * gamma-gamma * photon-photon * photon electron * Compton scattering Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.054, year: 2004

  9. Direct Searches for Scalar Leptoquarks at the Run II Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Daniel Edward [Tufts Univ., Medford, MA (United States)

    2004-08-01

    This dissertation sets new limits on the mass of the scalar leptoquark from direct searches carried out at the Run II CDF detector using data from March 2001 to October 2003. The data analyzed has a total time-integrated measured luminosity of 198 pb-1 of p$\\bar{p}$ collisions with √s = 1.96 TeV. Leptoquarks are assumed to be pair-produced and to decay into a lepton and a quark of the same generation. They consider two possible leptoquark decays: (1) β = BR(LQ → μq) = 1.0, and (2) β = BR(LQ → μq) = 0.5. For the β = 1 channel, they focus on the signature represented by two isolated high-pT muons and two isolated high-pT jets. For the β = 1/2 channel, they focus on the signature represented by one isolated high-pT muon, large missing transverse energy, and two isolated high-pT jets. No leptoquark signal is experimentally detected for either signature. Using the next to leading order theoretical cross section for scalar leptoquark production in p$\\bar{p}$ collisions [1], they set new mass limits on second generation scalar leptoquarks. They exclude the existence of second generation scalar leptoquarks with masses below 221(175) GeV/c2 for the β = 1(1/2) channels.

  10. Single-top-squark production via baryon-number-violating couplings at the Fermilab Tevatron Collider

    International Nuclear Information System (INIS)

    Berger, E. L.; Harris, B. W.; Sullivan, Z.

    1999-01-01

    We consider the s-channel R-parity-violating production of a single light top squark tilde t 1 and its subsequent R-parity-conserving decay. For masses in the range 180-325 GeV, and R-parity-violating couplings λ 3ij double p rime > 0.02-0.05, we show that discovery of the top squark is possible with 2 fb -1 of integrated luminosity at run II. If no evidence for the top squark is found, the bound on λ 3ij '' can be reduced by up to an order of magnitude with existing data from run I, and by two orders of magnitude at run II

  11. Search for the decays B_{(s)};{0} --> e;{+} micro;{-} and B_{(s)};{0} --> e;{+} e;{-} in CDF run II.

    Science.gov (United States)

    Aaltonen, T; Adelman, J; Akimoto, T; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzurri, P; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burke, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Chwalek, T; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cordelli, M; Cortiana, G; Cox, C A; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hays, C; Heck, M; Heijboer, A; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C-S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lucchesi, D; Luci, C; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Nett, J; Neu, C; Neubauer, M S; Neubauer, S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Osterberg, K; Griso, S Pagan; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Peiffer, T; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Renz, M; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Rutherford, B; Saarikko, H; Safonov, A; Sakumoto, W K; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Stuart, D; Suh, J S; Sukhanov, A; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Tourneur, S; Trovato, M; Tsai, S-Y; Tu, Y; Turini, N; Ukegawa, F; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wagner-Kuhr, J; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Weinelt, J; Wenzel, H; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Würthwein, F; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zhang, X; Zheng, Y; Zucchelli, S

    2009-05-22

    We report results from a search for the lepton flavor violating decays B_{s};{0} --> e;{+} micro;{-} and B;{0} --> e;{+} micro;{-}, and the flavor-changing neutral-current decays B_{s};{0} --> e;{+} e;{-} and B;{0} --> e;{+} e;{-}. The analysis uses data corresponding to 2 fb;{-1} of integrated luminosity of pp[over ] collisions at sqrt[s] = 1.96 TeV collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron. The observed number of B0 and B_{s};{0} candidates is consistent with background expectations. The resulting Bayesian upper limits on the branching ratios at 90% credibility level are B(B_{s};{0} --> e;{+} micro;{-}) e;{+} micro;{-}) e;{+} e;{-}) e;{+} e;{-}) e;{+} micro;{-}), the following lower bounds on the Pati-Salam leptoquark masses are also derived: M_{LQ}(B_{s};{0} --> e;{+} micro;{-}) > 47.8 TeV/c;{2}, and M_{LQ}(B;{0} --> e;{+} micro;{-}) > 59.3 TeV / c;{2}, at 90% credibility level.

  12. International Workshop on Linear Colliders 2010

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    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

  13. Estimates of Fermilab Tevatron collider performance

    International Nuclear Information System (INIS)

    Dugan, G.

    1991-09-01

    This paper describes a model which has been used to estimate the average luminosity performance of the Tevatron collider. In the model, the average luminosity is related quantitatively to various performance parameters of the Fermilab Tevatron collider complex. The model is useful in allowing estimates to be developed for the improvements in average collider luminosity to be expected from changes in the fundamental performance parameters as a result of upgrades to various parts of the accelerator complex

  14. Strings and superstrings. Electron linear colliders

    International Nuclear Information System (INIS)

    Alessandrini, V.; Bambade, P.; Binetruy, P.; Kounnas, C.; Le Duff, J.; Schwimmer, A.

    1989-01-01

    Basic string theory; strings in interaction; construction of strings and superstrings in arbitrary space-time dimensions; compactification and phenomenology; linear e+e- colliders; and the Stanford linear collider were discussed [fr

  15. The standard model and colliders

    International Nuclear Information System (INIS)

    Hinchliffe, I.

    1987-03-01

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

  16. Hadron collider physics 2005. Proceedings

    International Nuclear Information System (INIS)

    Campanelli, M.; Clark, A.; Wu, X.

    2006-01-01

    The Hadron Collider Physics Symposia (HCP) are a new series of conferences that follow the merger of the Hadron Collider Conferences with the LHC Symposia series, with the goal of maximizing the shared experience of the Tevatron and LHC communities. This book gathers the proceedings of the first symposium, HCP2005, and reviews the state of the art in the key physics directions of experimental hadron collider research: - QCD physics - precision electroweak physics - c-, b-, and t-quark physics - physics beyond the Standard Model - heavy ion physics The present volume will serve as a reference for everyone working in the field of accelerator-based high-energy physics. (orig.)

  17. Prospects for next-generation e+e- linear colliders

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1990-02-01

    The purpose of this paper is to review progress in the US towards a next generation linear collider. During 1988, there were three workshops held on linear colliders: ''Physics of Linear Colliders,'' in Capri, Italy, June 14--18, 1988; Snowmass 88 (Linear Collider subsection) June 27--July 15, 1988; and SLAC International Workshop on Next Generation Linear Colliders, November 28--December 9, 1988. In this paper, I focus on reviewing the issues and progress on a next generation linear collider. The energy range is dictated by physics with a mass reach well beyond LEP, although somewhat short of SSC. The luminosity is that required to obtain 10 3 --10 4 units of R 0 per year. The length is consistent with a site on Stanford land with collision occurring on the SLAC site; the power was determined by economic considerations. Finally, the technology as limited by the desire to have a next generation linear collider by the next century. 37 refs., 3 figs., 6 tabs

  18. Vanilla Technicolor at Linear Colliders

    DEFF Research Database (Denmark)

    T. Frandsen, Mads; Jarvinen, Matti; Sannino, Francesco

    2011-01-01

    We analyze the reach of Linear Colliders (LC)s for models of dynamical electroweak symmetry breaking. We show that LCs can efficiently test the compositeness scale, identified with the mass of the new spin-one resonances, till the maximum energy in the center-of-mass of the colliding leptons. In ...

  19. CLIC e+e- Linear Collider Studies

    CERN Document Server

    Dannheim, Dominik; Linssen, Lucie; Schulte, Daniel; Simon, Frank; Stapnes, Steinar; Toge, Nobukazu; Weerts, Harry; Wells, James

    2012-01-01

    This document provides input from the CLIC e+e- linear collider studies to the update process of the European Strategy for Particle Physics. It is submitted on behalf of the CLIC/CTF3 collaboration and the CLIC physics and detector study. It describes the exploration of fundamental questions in particle physics at the energy frontier with a future TeV-scale e+e- linear collider based on the Compact Linear Collider (CLIC) two-beam acceleration technique. A high-luminosity high-energy e+e- collider allows for the exploration of Standard Model physics, such as precise measurements of the Higgs, top and gauge sectors, as well as for a multitude of searches for New Physics, either through direct discovery or indirectly, via high-precision observables. Given the current state of knowledge, following the observation of a \\sim125 GeV Higgs-like particle at the LHC, and pending further LHC results at 8 TeV and 14 TeV, a linear e+e- collider built and operated in centre-of-mass energy stages from a few-hundred GeV up t...

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

    CERN Document Server

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

    2014-08-21

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

  1. Fault Tracking of the Superconducting Magnet System at the CERN Large Hadron Collider

    CERN Document Server

    Griesemer, Tobias

    2016-03-25

    The Large Hadron Collider (LHC) at CERN is one of the most complex machines ever built. It is used to explore the mysteries of the universe by reproducing conditions of the big bang. High energy particles are collide in particle detectors and as a result of the collision process secondary particles are created. New particles could be discovered during this process. The operation of such a machine is not straightforward and is subject to many different types of failures. A model of LHC operation needs to be defined in order to understand the impact of the various failures on availability. As an example a typical operational cycle is described: the beams are first injected, then accelerated, and finally brought into collisions. Under nominal conditions, beams should be in collision (so-called ‘stable beams’ period) for about 10 hours and then extracted onto a beam dump block. In case of a failure, the Machine Protection Systems ensure safe extraction of the beams. From the experience in LHC Run 1 (2009 - 20...

  2. Searches for the Standard Model Higgs boson at the Tevatron collider

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Wade C. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Junk, Thomas R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-01-01

    During Run II of the Tevatron collider, which took place from 2001 until 2011, the CDF and D0 detectors each collected approximately 10 fb -1 of collision data at a center-of-mass energy of . This dataset allowed for tests for the presence of the SM Higgs boson in the mass range 90-200 GeV in the production modes gg → H, W/ZH, vector-boson fusion, and H, with H decay modes H → , H → W+W-, H →

  3. Optimisation of the level-1 calorimeter trigger at ATLAS for Run II

    Energy Technology Data Exchange (ETDEWEB)

    Suchek, Stanislav [Kirchhoff-Institute for Physics, Im Neuenheimer Feld 227, 69120 Heidelberg (Germany); Collaboration: ATLAS-Collaboration

    2015-07-01

    The Level-1 Calorimeter Trigger (L1Calo) is a central part of the ATLAS Level-1 Trigger system, designed to identify jet, electron, photon, and hadronic tau candidates, and to measure their transverse energies, as well total transverse energy and missing transverse energy. The optimisation of the jet energy resolution is an important part of the L1Calo upgrade for Run II. A Look-Up Table (LUT) is used to translate the electronic signal from each trigger tower to its transverse energy. By optimising the LUT calibration we can achieve better jet energy resolution and better performance of the jet transverse energy triggers, which are vital for many physics analyses. In addition, the improved energy calibration leads to significant improvements of the missing transverse energy resolution. A new Multi-Chip Module (MCM), as a part of the L1Calo upgrade, provides two separate LUTs for jets and electrons/photons/taus, allowing to optimise jet transverse energy and missing transverse energy separately from the electromagnetic objects. The optimisation is validated using jet transverse energy and missing transverse energy triggers turn-on curves and rates.

  4. The effect of photoionizing feedback on star formation in isolated and colliding clouds

    Science.gov (United States)

    Shima, Kazuhiro; Tasker, Elizabeth J.; Federrath, Christoph; Habe, Asao

    2018-05-01

    We investigate star formation occurring in idealized giant molecular clouds, comparing structures that evolve in isolation versus those undergoing a collision. Two different collision speeds are investigated and the impact of photoionizing radiation from the stars is determined. We find that a colliding system leads to more massive star formation both with and without the addition of feedback, raising overall star formation efficiencies (SFE) by a factor of 10 and steepening the high-mass end of the stellar mass function. This rise in SFE is due to increased turbulent compression during the cloud collision. While feedback can both promote and hinder star formation in an isolated system, it increases the SFE by approximately 1.5 times in the colliding case when the thermal speed of the resulting H II regions matches the shock propagation speed in the collision.

  5. SLAC linear collider conceptual design report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    The linear collider system is described in detail, including the transport system, the collider lattice, final focusing system, positron production, beam damping and compression, high current electron source, instrumentation and control, and the beam luminosity. The experimental facilities and the experimental uses are discussed along with the construction schedule and estimated costs. Appendices include a discussion of space charge effects in the linear accelerator, emittance growth in the collider, the final focus system, beam-beam instabilities and pinch effects, and detector backgrounds. (GHT)

  6. SLAC linear collider conceptual design report

    International Nuclear Information System (INIS)

    1980-06-01

    The linear collider system is described in detail, including the transport system, the collider lattice, final focusing system, positron production, beam damping and compression, high current electron source, instrumentation and control, and the beam luminosity. The experimental facilities and the experimental uses are discussed along with the construction schedule and estimated costs. Appendices include a discussion of space charge effects in the linear accelerator, emittance growth in the collider, the final focus system, beam-beam instabilities and pinch effects, and detector backgrounds

  7. Colliding druthers

    International Nuclear Information System (INIS)

    Ankenbrandt, C.; Johnson, R.P.

    1977-01-01

    Recommendations are made to maximize the usefulness of the colliding beam facility of the Main Ring and Energy Doubler at the Fermilab accelerator. The advantages of the transposed crossing geometry over the kissing geometry are pointed out

  8. Test facilities for future linear colliders

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1995-12-01

    During the past several years there has been a tremendous amount of progress on Linear Collider technology world wide. This research has led to the construction of the test facilities described in this report. Some of the facilities will be complete as early as the end of 1996, while others will be finishing up around the end 1997. Even now there are extensive tests ongoing for the enabling technologies for all of the test facilities. At the same time the Linear Collider designs are quite mature now and the SLC is providing the key experience base that can only come from a working collider. All this taken together indicates that the technology and accelerator physics will be ready for a future Linear Collider project to begin in the last half of the 1990s

  9. A Large Hadron Electron Collider at CERN

    CERN Document Server

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

    2012-01-01

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

  10. Status of the relativistic heavy ion collider

    International Nuclear Information System (INIS)

    Karl, F.

    1999-01-01

    At the present time, commissioning of the 3.8 kilometer Relativistic Heavy Ion Collider (RHIC) is in full swing. On July 16, 1999, the commissioners were successful in circulating a Gold Ion Beam for the first time, in the Blue Ring, as power supplies were being checked out for beam into the Yellow Ring. The commissioning schedule is to accelerate beam in the Blue Ring, then spiral and accelerate beam in the Yellow Ring, then if all goes well, obtain some collisions, all before a fast approaching shutdown in mid-August. The four experimental regions, Star, Phenix, Brahms and Phobos are gearing up for their maiden beam runs and much effort is being spent to make the thirst glimpse of the beam an exciting one. Our Alignment Group has been working closely with the experimenters in these areas, mostly with MANCAT type component pre-surveys and in the near future installing and locating these various components relative to the RHIC Beam Line. (author)

  11. Muon collider interaction region design

    Directory of Open Access Journals (Sweden)

    Y. I. Alexahin

    2011-06-01

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

  12. Lasers and future high energy colliders

    International Nuclear Information System (INIS)

    Parsa, Z.

    1998-02-01

    Future high energy colliders, directions for particle physics and relationship to new technology such as lasers are discussed. Experimental approaches to explore New Physics with emphasis on the utility of high energy colliders are also discussed

  13. Physics at hadron colliders: Experimental view

    International Nuclear Information System (INIS)

    Siegrist, J.L.

    1987-08-01

    The physics of the hadron-hadron collider experiment is considered from an experimental point of view. The problems encountered in determination of how well the standard model describes collider results are discussed. 53 refs., 58 figs

  14. Linear Colliders TESLA

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The aim of the TESLA (TeV Superconducting Linear Accelerator) collaboration (at present 19 institutions from seven countries) is to establish the technology for a high energy electron-positron linear collider using superconducting radiofrequency cavities to accelerate its beams. Another basic goal is to demonstrate that such a collider can meet its performance goals in a cost effective manner. For this the TESLA collaboration is preparing a 500 MeV superconducting linear test accelerator at the DESY Laboratory in Hamburg. This TTF (TESLA Test Facility) consists of four cryomodules, each approximately 12 m long and containing eight 9-cell solid niobium cavities operating at a frequency of 1.3 GHz

  15. Operations and Performance of RHIC as a Cu-Cu Collider

    CERN Document Server

    Pilat, Fulvia Caterina; Bai, Mei; Barton, Donald; Beebe-Wang, Joanne; Blaskiewicz, Michael; Brennan, Joseph M; Bruno, Donald; Cameron, Peter; Connolly, Roger; De Long, Joseph; Drees, Angelika; Fischer, Wolfram; Ganetis, George; Gardner, Chris J; Glenn, Joseph; Harvey, Margaret; Hayes, Thomas; Hseuh Hsiao Chaun; Huang, Haixin; Ingrassia, Peter; Iriso, Ubaldo; Lee, Roger C; Litvinenko, Vladimir N; Luo, Yun; MacKay, William W; Marr, Gregory J; Marusic, Al; Michnoff, Robert; Montag, Christoph; Morris, John; Nicoletti, Tony; Oerter, Brian; Ptitsyn, Vadim; Roser, Thomas; Russo, Thomas; Sandberg, Jon; Satogata, Todd; Schultheiss, Carl; Tepikian, Steven; Tomas, Rogelio; Trbojevic, Dejan; Tsoupas, Nicholaos; Tuozzolo, Joseph; Vetter, Kurt; Zaltsman, Alex; Zeno, Keith; Zhang, S Y; Zhang, Wu

    2005-01-01

    The 5th year of RHIC operations, started in November 2004 and expected to last till June 2005, consists of a physics run with Cu-Cu collisions at 100 GeV/u followed by one with polarized protons at 100 GeV. We will address here overall performance of the RHIC complex used for the first time as a Cu-Cu collider, and compare it with previous operational experience with Au, PP and asymmetric d-Au collisions. We will also discuss operational improvements, such as a ?* squeeze to 85cm in the high luminosity interaction regions from the design value of 1m, system improvements and machine performance limitations, such as vacuum pressure rise, intra-beam scattering, and beam beam interaction.

  16. Improvements in emittance wake field optimization for the SLAC Linear Collider

    CERN Document Server

    Decker, Franz Josef

    2003-01-01

    The transverse emittances in the SLAC Linear Collider can be severely diluted by collective wakefield effects and dispersion. For the 1997/98 SLC/SLD run important changes were implemented in the way the emittance is optimized. Early in the linac, where the energy spread is large due to BNS damping, the emittance growth is dominated by dispersion. In this regime emittance tuning bumps may introduce additional wakefield tails and their use is now avoided. At the end of the linac the energy spread is minimal and the emittance measurement is most sensitive to wakefield emittance dilution. In previous years, the emittances were tuned on wire scanners located near but not at the end of the linac (after about 90% of its length). Simulations show that emittance growth of up to 100% can occur in the remaining 10%. In this run wire scanners at the entrance of the Final Focus, the last place where the emittances can be measured, were used for the optimization. Screens at the end of the linac allow additional real time ...

  17. Linear colliders for photon collisions

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    The enthusiasm of the first international workshop on photonphoton colliders and associated physics, held at the Lawrence Berkeley Laboratory from 28 March - 1 April, could have set a ball rolling. According to proponents of this physics, the particle physics one can study with a high energy linear collider is special and complements that of a hadron supercollider

  18. Overview of colliding beam facilities

    International Nuclear Information System (INIS)

    Herrera, J.C.; Month, M.

    1979-01-01

    A review is presented of the colliding beam facilities in existence today. The major high energy physics facilities around the world are described, and a view is presented of the beam collisions in which the instruments used to make the beams collide and those used to detect the products of particle interactions in the beam overlap region are described

  19. String Resonances at Hadron Colliders

    CERN Document Server

    Anchordoqui, Luis A; Dai, De-Chang; Feng, Wan-Zhe; Goldberg, Haim; Huang, Xing; Lust, Dieter; Stojkovic, Dejan; Taylor, Tomasz R

    2014-01-01

    [Abridged] We consider extensions of the standard model based on open strings ending on D-branes. Assuming that the fundamental string mass scale M_s is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (3000 fb^{-1}) with \\sqrt{s} = 14 TeV, and at potential future pp colliders, HE-LHC and VLHC, operating at \\sqrt{s} = 33 and 100 TeV, respectively. In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and \\gamma + jet are completely independent of the details of compactification, and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV), lowest massive Regge exc...

  20. Search for the neutral MSSM Higgs bosons in the ditau decay channels at CDF Run II

    Energy Technology Data Exchange (ETDEWEB)

    Almenar, Cristobal Cuenca [Univ. of Valencia (Spain)

    2008-04-01

    This thesis presents the results on a search for the neutral MSSM Higgs bosons decaying to tau pairs, with least one of these taus decays leptonically. The search was performed with a sample of 1.8 fb-1 of proton-antiproton collisions at √s = 1.96 TeV provided by the Tevatron and collected by CDF Run II. No significant excess over the Standard Model prediction was found and a 95% confidence level exclusion limit have been set on the cross section times branching ratio as a function of the Higgs boson mass. This limit has been translated into the MSSM Higgs sector parameter plane, tanβ vs. MA, for the four different benchmark scenarios.

  1. Beyond the Large Hadron Collider: A First Look at Cryogenics for CERN Future Circular Colliders

    Science.gov (United States)

    Lebrun, Philippe; Tavian, Laurent

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

  2. Superphysics at UNK collider

    International Nuclear Information System (INIS)

    Kereselidze, A.R.; Liparteliani, A.G.; Sokolov, A.A.; Volkov, G.G.

    1988-01-01

    The theoretical incompleteness of standard model and the way of going beyond frames on the basis of supersymmetry are considered. The most important directions of experimental researches at the colliders of a new generation are given. Theoretical estimates of masses of supersymmetrical particles in the framework of N=1 supergravity obtained from compactification of the popular E 8 xE 8 superstring theories are presented. The experimental search for supersymmetrical particles at the UNK pp-collider (√s=6 TeV) is performed

  3. Final focus systems for linear colliders

    International Nuclear Information System (INIS)

    Erickson, R.A.

    1987-11-01

    The final focus system of a linear collider must perform two primary functions, it must focus the two opposing beams so that their transverse dimensions at the interaction point are small enough to yield acceptable luminosity, and it must steer the beams together to maintain collisions. In addition, the final focus system must transport the outgoing beams to a location where they can be recycled or safely dumped. Elementary optical considerations for linear collider final focus systems are discussed, followed by chromatic aberrations. The design of the final focus system of the SLAC Linear Collider (SLC) is described. Tuning and diagnostics and steering to collision are discussed. Most of the examples illustrating the concepts covered are drawn from the SLC, but the principles and conclusions are said to be generally applicable to other linear collider designs as well. 26 refs., 17 figs

  4. Considerations on Energy Frontier Colliders after LHC

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2016-11-15

    Since 1960’s, particle colliders have been in the forefront of particle physics, 29 total have been built and operated, 7 are in operation now. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosity and feasibility of cost. Here we overview all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC) and discuss major challenges and accelerator R&D required to demonstrate feasibility of an energy frontier accelerator facility following the LHC. We conclude by taking a look into ultimate energy reach accelerators based on plasmas and crystals, and discussion on the perspectives for the far future of the accelerator-based particle physics. This paper largely follows previous study [1] and the presenta ion given at the ICHEP’2016 conference in Chicago [2].

  5. Level-1 trigger selection of electrons and photons with CMS for LHC Run-II.

    CERN Document Server

    AUTHOR|(CDS)2088114

    2016-01-01

    The CMS experiment has a sophisticated two-level online selection system that achieves a rejection factor of nearly $10^5$. The first, hardware-level trigger (L1) is based on coarse information coming from the calorimeters and the muon detectors while the High-Level Trigger combines fine-grain information from all subdetectors. During Run II, the LHC will increase its center of mass energy to 13 or 14 TeV, and progressively reach an instantaneous luminosity of $2\\times10^{34} \\mathrm{cm}^{-2}\\mathrm{s}^{-1}$. In order to guarantee a successful and ambitious physics programme in this intense environment, the CMS trigger and data acquisition system must be upgraded. The L1 calorimeter trigger hardware and architecture in particular has been redesigned to maintain the current thresholds even in presence of more demanding conditions (e.g., for electrons and photons) and improve the performance for the selection of $\\tau$ leptons. This design benefits from recent $\\mu$TCA technology, allowing sophisticated algorit...

  6. STAR FORMATION IN TURBULENT MOLECULAR CLOUDS WITH COLLIDING FLOW

    International Nuclear Information System (INIS)

    Matsumoto, Tomoaki; Dobashi, Kazuhito; Shimoikura, Tomomi

    2015-01-01

    Using self-gravitational hydrodynamical numerical simulations, we investigated the evolution of high-density turbulent molecular clouds swept by a colliding flow. The interaction of shock waves due to turbulence produces networks of thin filamentary clouds with a sub-parsec width. The colliding flow accumulates the filamentary clouds into a sheet cloud and promotes active star formation for initially high-density clouds. Clouds with a colliding flow exhibit a finer filamentary network than clouds without a colliding flow. The probability distribution functions (PDFs) for the density and column density can be fitted by lognormal functions for clouds without colliding flow. When the initial turbulence is weak, the column density PDF has a power-law wing at high column densities. The colliding flow considerably deforms the PDF, such that the PDF exhibits a double peak. The stellar mass distributions reproduced here are consistent with the classical initial mass function with a power-law index of –1.35 when the initial clouds have a high density. The distribution of stellar velocities agrees with the gas velocity distribution, which can be fitted by Gaussian functions for clouds without colliding flow. For clouds with colliding flow, the velocity dispersion of gas tends to be larger than the stellar velocity dispersion. The signatures of colliding flows and turbulence appear in channel maps reconstructed from the simulation data. Clouds without colliding flow exhibit a cloud-scale velocity shear due to the turbulence. In contrast, clouds with colliding flow show a prominent anti-correlated distribution of thin filaments between the different velocity channels, suggesting collisions between the filamentary clouds

  7. STAR FORMATION IN TURBULENT MOLECULAR CLOUDS WITH COLLIDING FLOW

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Tomoaki [Faculty of Humanity and Environment, Hosei University, Fujimi, Chiyoda-ku, Tokyo 102-8160 (Japan); Dobashi, Kazuhito; Shimoikura, Tomomi, E-mail: matsu@hosei.ac.jp [Department of Astronomy and Earth Sciences, Tokyo Gakugei University, Koganei, Tokyo 184-8501 (Japan)

    2015-03-10

    Using self-gravitational hydrodynamical numerical simulations, we investigated the evolution of high-density turbulent molecular clouds swept by a colliding flow. The interaction of shock waves due to turbulence produces networks of thin filamentary clouds with a sub-parsec width. The colliding flow accumulates the filamentary clouds into a sheet cloud and promotes active star formation for initially high-density clouds. Clouds with a colliding flow exhibit a finer filamentary network than clouds without a colliding flow. The probability distribution functions (PDFs) for the density and column density can be fitted by lognormal functions for clouds without colliding flow. When the initial turbulence is weak, the column density PDF has a power-law wing at high column densities. The colliding flow considerably deforms the PDF, such that the PDF exhibits a double peak. The stellar mass distributions reproduced here are consistent with the classical initial mass function with a power-law index of –1.35 when the initial clouds have a high density. The distribution of stellar velocities agrees with the gas velocity distribution, which can be fitted by Gaussian functions for clouds without colliding flow. For clouds with colliding flow, the velocity dispersion of gas tends to be larger than the stellar velocity dispersion. The signatures of colliding flows and turbulence appear in channel maps reconstructed from the simulation data. Clouds without colliding flow exhibit a cloud-scale velocity shear due to the turbulence. In contrast, clouds with colliding flow show a prominent anti-correlated distribution of thin filaments between the different velocity channels, suggesting collisions between the filamentary clouds.

  8. Future prospects for electron colliders

    CERN Document Server

    Toge, N

    2001-01-01

    An overview on the future prospects for electron colliders is presented. In the first part of this paper we will walk through the status of current development of next-generation electron linear colliders of sub-TeV to TeV energy range. Then we will visit recent results from technological developments which aim at longer term future for higher energy accelerators.

  9. Design Studies for a 1036 SuperB-Factory

    International Nuclear Information System (INIS)

    Seeman, J

    2003-01-01

    A Super B Factory, an asymmetric e + e - collider with a luminosity of 10 36 cm -2 s -1 , can provide a sensitive probe of new physics in the flavor sector of the Standard Model. The success of PEP-II and KEKB in producing unprecedented luminosity with unprecedented short commissioning time has taught us about the accelerator physics of asymmetric e + e - colliders in a new parameter regime. It appears to be possible to build on this success to advance the state of the accelerator art by building a collider at a luminosity approaching 10 36 cm -2 s -1 . Such a collider would produce an integrated luminosity of 10,000 fb -1 (10 ab -1 ) in a running year. Design studies are underway to arrive at a complete parameter set based on a collider in the PEP-II tunnel but with an upgraded RF system (perhaps a higher frequency) and an upgraded interaction region [1-6

  10. Role of ionization fronts in the colliding wind model of planetary nebulae

    International Nuclear Information System (INIS)

    Giuliani, J.L. Jr.

    1981-01-01

    A similarity transformation is used to study the expansion of a planetary nebula which is driven by a fast stellar wind as well as an expanding H II region. The undisturbed gas is taken to be the remnant of a slow, red giant wind. The present analysis improves upon Kwok, Purton, and FitzGerald's colliding wind model for the formation of planetary nebulae since it includes the dynamical influence of ionization fronts, and calculates the variation of velocity and density within the flow

  11. The International Linear Collider Progress Report 2015

    Energy Technology Data Exchange (ETDEWEB)

    Evans, L. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yamamoto, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-07-15

    The International Committee for Future Accelerators (ICFA) set up the Global Design Effort (GDE) for the design of the International Linear Collider (ILC) in 2005. Drawing on the resources of over 300 national laboratories, universities and institutes worldwide, the GDE produced a Reference Design Report in 2007, followed by a more detailed Technical Design Report (TDR) in 2013. Following this report, the GDE was disbanded. A compact core team, the Linear Collider Collaboration (LCC), replaced it. This is still under the auspices of ICFA and is directly overseen by the Linear Collider Board, which reports to ICFA. The LCC is charged with continuing the design effort on a much-reduced scale until the Project is approved for construction. An additional mandate of the LCC was to bring together all linear collider work, including the CERN-based Compact Linear Collider (CLIC) under one structure in order to exploit synergies between the two studies.

  12. Status of the SLAC Linear Collider Project

    International Nuclear Information System (INIS)

    Stiening, R.

    1983-01-01

    The SLAC Linear Collider Project has two principal goals. The first is to serve as a prototype for a future very high energy linear electron-positron collider. The second is to quickly, at low cost, achieve sufficient luminosity at 100 GeV center-of-mass energy to explore the physics of the Z 0 . The first goal is important to the future of electron-positron physics because the rapid increase of synchrotron radiation with energy causes the cost of circular storage ring colliders to whereas the cost of linear colliders increases only in proportion to the center-of-mass energy. The second is important because the existance at SLAC of a linear accelerator which can be converted at low cost to collider operation makes possible a unique opportunity to quickly achieve 100 GeV center-of-mass collisions. At the design luminosity of 6.0 x 10 30 many thousands of Z 0 decays should be observed in each day of operation

  13. Habilitation thesis on STT and Higgs searches in WH production

    Energy Technology Data Exchange (ETDEWEB)

    Sonnenschein, Lars [Univ. Pierre et Marie Curie, Paris (France)

    2006-12-15

    The detector of the D0 experiment at the proton anti-proton collider Tevatron in Run II is discussed in detail. The performance of the collider and the experiment is presented. Standard model Higgs searches with integrated luminosities between 260 pb-1 and 950 pb-1 and their combination are performed. No deviation from SM background expectation has been observed. Sensitivity prospects at the Tevatron are shown.

  14. Magnet R and D for future colliders

    International Nuclear Information System (INIS)

    Sabbi, Gian Luca

    2001-01-01

    High-energy colliders complementing and expanding the physics reach of LHC are presently under study in the United States, Europe and Japan. The magnet system is a major cost driver for hadron colliders at the energy frontier, and critical to the successful operation of muon colliders. Under most scenarios, magnet design as well as vacuum and cryogenic systems are complicated by high radiation loads. Magnet R and D programs are underway worldwide to take advantage of new developments in superconducting materials, achieve higher efficiency and simplify fabrication while preserving accelerator-class field quality. A review of recent progress in magnet technology for future colliders is presented, with emphasis on the most innovative design concepts and fabrication techniques

  15. Parameters of the SLAC Next Linear Collider

    International Nuclear Information System (INIS)

    Raubenheimer, T.; Adolphsen, C.; Burke, D.

    1995-05-01

    In this paper, the authors present the parameters and layout of the Next Linear Collider (NLC). The NLC is the SLAC design of a future linear collider using X-band RF technology in the main linacs. The collider would have an initial center-of-mass energy of 0.5 TeV which would be upgraded to 1 TeV and then 1.5 TeV in two stages. The design luminosity is > 5 x 10 33 cm -2 sec -1 at 0.5 TeV and > 10 34 cm -2 sec -1 at 1.0 and 1.5 TeV. They briefly describe the components of the collider and the proposed energy upgrade scenario

  16. RHIC spin: The first polarized proton collider

    International Nuclear Information System (INIS)

    Roser, T.

    1994-01-01

    The very successful program of QCD and electroweak tests at the high energy hadron colliders have shown that the perturbative QCD has progressed towards becoming a ''precision'' theory. At the same time, it has been shown that with the help of Siberian Snakes it is feasible to accelerate polarized protons to high enough energies where the proven methods of collider physics can be used to probe the spin content of the proton but also where fundamental tests of the spin effects in the standard model are possible. With Siberian Snakes the Relativistic Heavy Ion Collider (RHIC) will be the first collider to allow for 250 GeV on 250 GeV polarized proton collisions

  17. Proton-Proton and Proton-Antiproton Colliders

    CERN Document Server

    Scandale, Walter

    2014-01-01

    In the last five decades, proton–proton and proton–antiproton colliders have been the most powerful tools for high energy physics investigations. They have also deeply catalyzed innovation in accelerator physics and technology. Among the large number of proposed colliders, only four have really succeeded in becoming operational: the ISR, the SppbarS, the Tevatron and the LHC. Another hadron collider, RHIC, originally conceived for ion–ion collisions, has also been operated part-time with polarized protons. Although a vast literature documenting them is available, this paper is intended to provide a quick synthesis of their main features and key performance.

  18. Dedicating Fermilab's Collider

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    It was a bold move to have a fullscale dedication ceremony for the new proton-antiproton Collider at the Fermilab Tevatron on 13 October, two days before the first collisions were seen. However the particles dutifully behaved as required, and over the following weekend the Collider delivered its goods at a total energy of 1600 GeV, significantly boosting the world record for laboratory collisions

  19. Particle physics experiments at high energy colliders

    International Nuclear Information System (INIS)

    Hauptman, John

    2011-01-01

    Written by one of the detector developers for the International Linear Collider, this is the first textbook for graduate students dedicated to the complexities and the simplicities of high energy collider detectors. It is intended as a specialized reference for a standard course in particle physics, and as a principal text for a special topics course focused on large collider experiments. Equally useful as a general guide for physicists designing big detectors. (orig.)

  20. Zeroth-order design report for the next linear collider. Volume 2

    International Nuclear Information System (INIS)

    Raubenheimer, T.O.

    1996-05-01

    This Zeroth-Order Design Report (ZDR) for the Next Linear Collider (NLC) has been completed as a feasibility study for a TeV-scale linear collider that incorporates a room-temperature accelerator powered by rf microwaves at 11.424 GHz--similar to that presently used in the SLC, but at four times the rf frequency. The purpose of this study is to examine the complete systems of such a collider, to understand how the parts fit together, and to make certain that every required piece has been included. The ''design'' presented here is not fully engineered in any sense, but to be assured that the NLC can be built, attention has been given to a number of critical components and issues that present special challenges. More engineering and development of a number of mechanical and electrical systems remain to be done, but the conclusion of this study is that indeed the NLC is technically feasible and can be expected to reach the performance levels required to perform research at the TeV energy scale. Volume II covers the following: collimation systems; IP switch and big bend; final focus; the interaction region; multiple bunch issues; control systems; instrumentation; machine protection systems; NLC reliability considerations; NLC conventional facilities. Also included are four appendices on the following topics: An RF power source upgrade to the NLC; a second interaction region for gamma-gamma, gamma-electron; ground motion: theory and measurement; and beam-based feedback: theory and implementation

  1. Zeroth-order design report for the next linear collider. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Raubenheimer, T.O. [ed.

    1996-05-01

    This Zeroth-Order Design Report (ZDR) for the Next Linear Collider (NLC) has been completed as a feasibility study for a TeV-scale linear collider that incorporates a room-temperature accelerator powered by rf microwaves at 11.424 GHz--similar to that presently used in the SLC, but at four times the rf frequency. The purpose of this study is to examine the complete systems of such a collider, to understand how the parts fit together, and to make certain that every required piece has been included. The ``design`` presented here is not fully engineered in any sense, but to be assured that the NLC can be built, attention has been given to a number of critical components and issues that present special challenges. More engineering and development of a number of mechanical and electrical systems remain to be done, but the conclusion of this study is that indeed the NLC is technically feasible and can be expected to reach the performance levels required to perform research at the TeV energy scale. Volume II covers the following: collimation systems; IP switch and big bend; final focus; the interaction region; multiple bunch issues; control systems; instrumentation; machine protection systems; NLC reliability considerations; NLC conventional facilities. Also included are four appendices on the following topics: An RF power source upgrade to the NLC; a second interaction region for gamma-gamma, gamma-electron; ground motion: theory and measurement; and beam-based feedback: theory and implementation.

  2. Status of the Future Circular Collider Study

    Science.gov (United States)

    Benedikt, Michael

    2016-03-01

    Following the 2013 update of the European Strategy for Particle Physics, the international Future Circular Collider (FCC) Study has been launched by CERN as host institute, to design an energy frontier hadron collider (FCC-hh) in a new 80-100 km tunnel with a centre-of-mass energy of about 100 TeV, an order of magnitude beyond the LHC's, as a long-term goal. The FCC study also includes the design of a 90-350 GeV high-luminosity lepton collider (FCC-ee) installed in the same tunnel, serving as Higgs, top and Z factory, as a potential intermediate step, as well as an electron-proton collider option (FCC-he). The physics cases for such machines will be assessed and concepts for experiments will be developed in time for the next update of the European Strategy for Particle Physics by the end of 2018. The presentation will summarize the status of machine designs and parameters and discuss the essential technical components to be developed in the frame of the FCC study. Key elements are superconducting accelerator-dipole magnets with a field of 16 T for the hadron collider and high-power, high-efficiency RF systems for the lepton collider. In addition the unprecedented beam power presents special challenges for the hadron collider for all aspects of beam handling and machine protection. First conclusions of geological investigations and implementation studies will be presented. The status of the FCC collaboration and the further planning for the study will be outlined.

  3. Calculations of safe collimator settings and β^{*} at the CERN Large Hadron Collider

    Directory of Open Access Journals (Sweden)

    R. Bruce

    2015-06-01

    Full Text Available The first run of the Large Hadron Collider (LHC at CERN was very successful and resulted in important physics discoveries. One way of increasing the luminosity in a collider, which gave a very significant contribution to the LHC performance in the first run and can be used even if the beam intensity cannot be increased, is to decrease the transverse beam size at the interaction points by reducing the optical function β^{*}. However, when doing so, the beam becomes larger in the final focusing system, which could expose its aperture to beam losses. For the LHC, which is designed to store beams with a total energy of 362 MJ, this is critical, since the loss of even a small fraction of the beam could cause a magnet quench or even damage. Therefore, the machine aperture has to be protected by the collimation system. The settings of the collimators constrain the maximum beam size that can be tolerated and therefore impose a lower limit on β^{*}. In this paper, we present calculations to determine safe collimator settings and the resulting limit on β^{*}, based on available aperture and operational stability of the machine. Our model was used to determine the LHC configurations in 2011 and 2012 and it was found that β^{*} could be decreased significantly compared to the conservative model used in 2010. The gain in luminosity resulting from the decreased margins between collimators was more than a factor 2, and a further contribution from the use of realistic aperture estimates based on measurements was almost as large. This has played an essential role in the rapid and successful accumulation of experimental data in the LHC.

  4. Calculations of safe collimator settings and β* at the CERN Large Hadron Collider

    Science.gov (United States)

    Bruce, R.; Assmann, R. W.; Redaelli, S.

    2015-06-01

    The first run of the Large Hadron Collider (LHC) at CERN was very successful and resulted in important physics discoveries. One way of increasing the luminosity in a collider, which gave a very significant contribution to the LHC performance in the first run and can be used even if the beam intensity cannot be increased, is to decrease the transverse beam size at the interaction points by reducing the optical function β*. However, when doing so, the beam becomes larger in the final focusing system, which could expose its aperture to beam losses. For the LHC, which is designed to store beams with a total energy of 362 MJ, this is critical, since the loss of even a small fraction of the beam could cause a magnet quench or even damage. Therefore, the machine aperture has to be protected by the collimation system. The settings of the collimators constrain the maximum beam size that can be tolerated and therefore impose a lower limit on β*. In this paper, we present calculations to determine safe collimator settings and the resulting limit on β*, based on available aperture and operational stability of the machine. Our model was used to determine the LHC configurations in 2011 and 2012 and it was found that β* could be decreased significantly compared to the conservative model used in 2010. The gain in luminosity resulting from the decreased margins between collimators was more than a factor 2, and a further contribution from the use of realistic aperture estimates based on measurements was almost as large. This has played an essential role in the rapid and successful accumulation of experimental data in the LHC.

  5. Challenges for highest energy circular colliders

    CERN Document Server

    Benedikt, M; Wenninger, J; Zimmermann, F

    2014-01-01

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

  6. Super High Energy Colliding Beam Accelerators

    International Nuclear Information System (INIS)

    Abdelaziz, M.E.

    2009-01-01

    This lecture presents a review of cyclic accelerators and their energy limitations. A description is given of the phase stability principle and evolution of the synchrotron, an accelerator without energy limitation. Then the concept of colliding beams emerged to yield doubling of the beam energy as in the Tevatron 2 trillion electron volts (TeV) proton collider at Fermilab and the Large Hadron Collider (LHC) which is now planned as a 14-TeV machine in the 27 kilometer tunnel of the Large Electron Positron (LEP) collider at CERN. Then presentation is given of the Superconducting Supercollider (SSC), a giant accelerator complex with energy 40-TeV in a tunnel 87 kilometers in circumference under the country surrounding Waxahachie in Texas, U.S.A. These superhigh energy accelerators are intended to smash protons against protons at energy sufficient to reveal the nature of matter and to consolidate the prevailing general theory of elementary particle.

  7. An Afterburner at the ILC: The Collider Viewpoint

    International Nuclear Information System (INIS)

    Raubenheimer, T

    2004-01-01

    The concept of a high-gradient plasma wakefield accelerator is considered as an upgrade path for the International Linear Collider, a future linear collider. Basic parameters are presented based on those developed for the SLC ''Afterburner.'' Basic layout considerations are described and the primary concerns related to the collider operation are discussed

  8. Tau physics at p bar p colliders

    International Nuclear Information System (INIS)

    Konigsberg, J.

    1993-01-01

    Tau detection techniques in hadron colliders are discussed together with the measurements and searches performed so far. We also underline the importance tau physics has in present and future collider experiments

  9. World lays groundwork for future linear collider

    CERN Multimedia

    Feder, Toni

    2010-01-01

    "New physics from the Large Hadron Collider can best be explored with a large lepton collider; realizing one will require mobilizing accelerator and particle physicists, funding agencies, and politicians" (3 pages)

  10. Crystal Ball: On the Future High Energy Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2015-09-20

    High energy particle colliders have been in the forefront of particle physics for more than three decades. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). A number of next generation collider facilities have been proposed and are currently under consideration for the medium- and far-future of the accelerator-based high energy physics. In this paper we offer a uniform approach to evaluation of various accelerators based on the feasibility of their energy reach, performance reach and cost range. We briefly review such post-LHC options as linear e+e- colliders in Japan (ILC) or at CERN (CLIC), muon collider, and circular lepton or hadron colliders in China (CepC/SppC) and Europe (FCC). We conclude with a look into ultimate energy reach accelerators based on plasmas and crystals, and some perspectives for the far future of accelerator-based particle physics.

  11. Beam-strahlung effects in e-p collider

    International Nuclear Information System (INIS)

    Cho, Y.

    1982-09-01

    The electromagnetic fields produced by one beam in an interaction point of a colliding-beam facility cause to the emission of synchrotron radiation by the other beam. This effect, the beam strahlung, for the e+e - colliders has been considered by several authors, and they have pointed out that the effect is very important consideration at very-high-energy e+e - colliders. At the first glance, the beam-strahlung effect can play an important role in the e-p collision due to the fact that the circulating currents in the collider are much higher than those of the e+e - machine. However the detailed study shows that is not the case because of the collision geometry involved. What follows in this note is the beam-strahlung derivations using the method previously used by Hofmann and Keil. The difference between this note and that of Hofman and Keil is that in the case of e+e - collider, equal mass particles are involved in the consideration and, in the e-p case, the electrons radiate and the protons provide the electromagnetic fields

  12. Evaluating results from the Relativistic Heavy Ion Collider with perturbative QCD and hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fries, R.J.; Nonaka, C.

    2011-07-01

    We review the basic concepts of perturbative quantum chromodynamics (QCD) and relativistic hydrodynamics, and their applications to hadron production in high energy nuclear collisions. We discuss results from the Relativistic Heavy Ion Collider (RHIC) in light of these theoretical approaches. Perturbative QCD and hydrodynamics together explain a large amount of experimental data gathered during the first decade of RHIC running, although some questions remain open. We focus primarily on practical aspects of the calculations, covering basic topics like perturbation theory, initial state nuclear effects, jet quenching models, ideal hydrodynamics, dissipative corrections, freeze-out and initial conditions. We conclude by comparing key results from RHIC to calculations.

  13. ATLAS inner detector: the Run 1 to Run 2 transition, and first experience from Run 2

    CERN Document Server

    Dobos, Daniel; The ATLAS collaboration

    2015-01-01

    The ATLAS experiment is equipped with a tracking system, the Inner Detector, built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded; taking advantage of the long showdown, the Pixel Detector was extracted from the experiment and brought to surface, to equip it with new service quarter panels, to repair modules and to ease installation of the Insertable B-Layer (IBL), a fourth layer of pixel detectors, installed in May 2014 between the existing Pixel Detector and a new smaller radius beam-pipe at a radius of 3.3 cm from the beam axis. To cope with the high radiation and pixel occupancy due to the proximity to the interaction point and the increase of Luminosity that LHC will face in Run-2, a new read-out chip within CMOS 130nm and two different silicon sensor pixel technologies (planar and 3D) have been developed. SCT and TRT systems consolidation was also carri...

  14. Future colliders

    International Nuclear Information System (INIS)

    Palmer, R.B.; Gallardo, J.C.

    1996-10-01

    The high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, pp), of lepton (e + e - , μ + μ - ) and photon-photon colliders are considered. Technical arguments for increased energy in each type of machine are presented. Their relative size, and the implications of size on cost are discussed

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

    CERN Document Server

    Leyton, M

    2009-01-01

    The Large Hadron Collider (LHC) at CERN will collide bunches of protons (p) at a center-of-mass energy of sqrt(s) = 14 TeV and a rate of 40 MHz. The unprecedented collision energy and interaction rate at the LHC will allow us to explore the TeV mass scale and take a major step forward in our understanding of the fundamental nature of matter. The initial physics run of the LHC is expected to start in November 2009 and continue until the end of 2010, with collisions at sqrt(s) = 900 GeV, 7 TeV and 10 TeV. ATLAS (A Toroidal LHC ApparatuS) is a 4pi general-purpose detector designed for studying LHC collisions at the particle level. The design and layout of ATLAS are intended to cover the wide spectrum of physics signatures that are possible at the TeV mass scale. Construction and installation of the ATLAS detector at CERN are now complete. This dissertation focuses on measuring the properties of inelastic pp interactions at the LHC with the ATLAS detector. A method for measuring the central pseudorapidity den...

  16. On the Future High Energy Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2015-09-28

    High energy particle colliders have been in the forefront of particle physics for more than three decades. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). A number of the next generation collider facilities have been proposed and are currently under consideration for the medium and far-future of accelerator-based high energy physics. In this paper we offer a uniform approach to evaluation of various accelerators based on the feasibility of their energy reach, performance potential and cost range.

  17. Polarized electron sources for linear colliders

    International Nuclear Information System (INIS)

    Clendenin, J.E.; Ecklund, S.D.; Miller, R.H.; Schultz, D.C.; Sheppard, J.C.

    1992-07-01

    Linear colliders require high peak current beams with low duty factors. Several methods to produce polarized e - beams for accelerators have been developed. The SLC, the first linear collider, utilizes a photocathode gun with a GaAs cathode. Although photocathode sources are probably the only practical alternative for the next generation of linear colliders, several problems remain to be solved, including high voltage breakdown which poisons the cathode, charge limitations that are associated with the condition of the semiconductor cathode, and a relatively low polarization of ≤5O%. Methods to solve or at least greatly reduce the impact of each of these problems are at hand

  18. Standard model Higgs physics at colliders

    International Nuclear Information System (INIS)

    Rosca, A.

    2007-01-01

    In this report we briefly review the experimental status and prospects to verify the Higgs mechanism of spontaneous symmetry breaking. The focus is on the most relevant aspects of the phenomenology of the Standard Model Higgs boson at current (Tevatron) and future (Large Hadron Collider, LHC and International Linear Collider, ILC) particle colliders. We review the Standard Model searches: searches at the Tevatron, the program planned at the LHC and prospects at the ILC. Emphasis is put on what follows after a candidate discovery at the LHC: the various measurements which are necessary to precisely determine what the properties of this Higgs candidate are. (author)

  19. Physics at high luminosity muon colliders and a facility overview

    International Nuclear Information System (INIS)

    Parsa, Z.

    2001-01-01

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

  20. Overview of a high luminosity μ+μ- collider

    International Nuclear Information System (INIS)

    Palmer, R.B.; Gallardo, J.C.

    1997-03-01

    Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should be regarded as complementary. Parameters are given of a 4 TeV high luminosity μ + μ - collider, and of a 0.5 TeV lower luminosity demonstration machine. The authors discuss the various systems in such muon colliders

  1. Linear collider systems and costs

    International Nuclear Information System (INIS)

    Loew, G.A.

    1993-05-01

    The purpose of this paper is to examine some of the systems and sub-systems involved in so-called ''conventional'' e + e - linear colliders and to study how their design affects the overall cost of these machines. There are presently a total of at least six 500 GeV c. of m. linear collider projects under study in the world. Aside from TESLA (superconducting linac at 1.3 GHz) and CLIC (two-beam accelerator with main linac at 30GHz), the other four proposed e + e - linear colliders can be considered ''conventional'' in that their main linacs use the proven technique of driving room temperature accelerator sections with pulsed klystrons and modulators. The centrally distinguishing feature between these projects is their main linac rf frequency: 3 GHz for the DESY machine, 11.424 GHz for the SLAC and JLC machines, and 14 GHz for the VLEPP machine. The other systems, namely the electron and positron sources, preaccelerators, compressors, damping rings and final foci, are fairly similar from project to project. Probably more than 80% of the cost of these linear colliders will be incurred in the two main linacs facing each other and it is therefore in their design and construction that major savings or extra costs may be found

  2. Muon Collider Progress: Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Zisman, Michael S.

    2011-09-10

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

  3. RHIC FY15 pp Run RHIC and AGS polarization analysis

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H. [Brookhaven National Lab. (BNL), Upton, NY (United States); Adams, P. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-02-20

    The polarization information is important for the spin physics program in Relativistic Heavy Ion Collider (RHIC). There are discrepancies between AGS and RHIC polarization measurements. First, the face value of AGS polarization is higher than RHIC ones in general. Second, the measured polarization profile (described by the profile ratio R) is stronger in AGS than in RHIC. This note analyzes the polarization data from FY15 pp run period. The results show that the differences between AGS and RHIC polarization measurements are reasonable, but the R value difference is puzzling. The difference between blue and yellow ring is worth of spin simulation to explain.

  4. B-physics at CDF and prospects for the next run

    International Nuclear Information System (INIS)

    Wenzel, H.

    1991-09-01

    Current CDF b-physics results are presented. The analysis is based on data corresponding to an integrated luminosity of 4.4 pb -1 recorded with the CDF detector in 88--89 at the Fermilab Tevatron p bar p collider (√ bar s = 1.8 TeV). Preliminary results include the differential cross section dPt / dσ(b) , some reconstructed exclusive B-decays, a limit for the rare decay B 0 → μ + μ - and a measurement of B bar B-mixing parameters. Finally we will discuss the prospects concerning b-physics for the next data run which will start in February 1992. 12 refs., 8 figs

  5. Kinematics and resolution at future ep colliders

    International Nuclear Information System (INIS)

    Bluemlein, J.; Klein, M.

    1992-01-01

    Limitations due to resolution and kinematics are discussed of the (Q 2 , x) range accessible with electron-proton colliders after HERA. For the time after HERA one may think of two electron-proton colliders: an asymmetric energy machine and a rather symmetric one. Both colliders are compared here in order to study the influence of the different E l /E p ratios on the accessible kinematic range which is restricted due to angular coverage, finite detector resolution and calibration uncertainties

  6. RNA polymerase II collision interrupts convergent transcription

    DEFF Research Database (Denmark)

    Hobson, David J; Wei, Wu; Steinmetz, Lars M

    2012-01-01

    Antisense noncoding transcripts, genes-within-genes, and convergent gene pairs are prevalent among eukaryotes. The existence of such transcription units raises the question of what happens when RNA polymerase II (RNAPII) molecules collide head-to-head. Here we use a combination of biochemical...

  7. Polarized Electrons for Linear Colliders

    International Nuclear Information System (INIS)

    Clendenin, J.

    2004-01-01

    Future electron-positron linear colliders require a highly polarized electron beam with a pulse structure that depends primarily on whether the acceleration utilizes warm or superconducting rf structures. The International Linear Collider (ILC) will use cold structures for the main linac. It is shown that a dc-biased polarized photoelectron source such as successfully used for the SLC can meet the charge requirements for the ILC micropulse with a polarization approaching 90%

  8. Photon Collider Physics with Real Photon Beams

    International Nuclear Information System (INIS)

    Gronberg, J; Asztalos, S

    2005-01-01

    Photon-photon interactions have been an important probe into fundamental particle physics. Until recently, the only way to produce photon-photon collisions was parasitically in the collision of charged particles. Recent advances in short-pulse laser technology have made it possible to consider producing high intensity, tightly focused beams of real photons through Compton scattering. A linear e + e - collider could thus be transformed into a photon-photon collider with the addition of high power lasers. In this paper they show that it is possible to make a competitive photon-photon collider experiment using the currently mothballed Stanford Linear Collider. This would produce photon-photon collisions in the GeV energy range which would allow the discovery and study of exotic heavy mesons with spin states of zero and two

  9. Collider Interplay for Supersymmetry, Higgs and Dark Matter

    CERN Document Server

    Buchmueller, O.; Ellis, J.; Guha, S.; Marrouche, J.; Olive, K.A.; de Vries, K.; Zheng, Jiaming

    2016-01-01

    We discuss the potential impacts on the CMSSM of future LHC runs and possible electron-positron and higher-energy proton-proton colliders, considering searches for supersymmetry via MET events, precision electroweak physics, Higgs measurements and dark matter searches. We validate and present estimates of the physics reach for exclusion or discovery of supersymmetry via MET searches at the LHC, which should cover the low-mass regions of the CMSSM parameter space favoured in a recent global analysis. As we illustrate with a low-mass benchmark point, a discovery would make possible accurate LHC measurements of sparticle masses using the MT2 variable, which could be combined with cross-section and other measurements to constrain the gluino, squark and stop masses and hence the soft supersymmetry-breaking parameters m_0, m_{1/2} and A_0 of the CMSSM. Slepton measurements at CLIC would enable m_0 and m_{1/2} to be determined with high precision. If supersymmetry is indeed discovered in the low-mass region, precisi...

  10. B factory at RHIC [Relativistic Heavy Ion Collider]?

    International Nuclear Information System (INIS)

    Lockyer, N.S.; Van Berg, R.; Newcomer, F.M.

    1988-01-01

    A dedicated B physics experiment located in the proposed Relativistic Heavy Ion Collider at Brookhaven (RHIC) is considered. The machine may operate in a p-p mode with a luminosity in excess of 10 32 cm/sup /minus/2/ sec/sup /minus/1/ at 250 /times/ 250 GeV. The estimated B/bar B/ cross section at these energies is about 10 μbarns and a run of 10 7 sec would produce roughly 10 10 B/bar B/ pairs. A comparison to similar ideas proposed for the Fermilab Tevatron Upgrade and the SSC are discussed. The most ambitious physics objective of such an experiment would be the study of CP nonconservation. Particular emphasis at this workshop was given to the self tagging mode B → K + π/sup /minus//. Experimental techniques developed during this experiment would be extremely useful for more ambitious projects anticipated at the SSC. 36 refs., 10 figs

  11. Polarization Effects at a Muon Collider

    International Nuclear Information System (INIS)

    Parsa, Z.

    1998-01-01

    For Muon Colliders, Polarization will be a useful tool if high polarization is achievable with little luminosity loss. Formulation and effects of beam polarization and luminosity including polarization effects in Higgs resonance studies are discussed for improving precision measurements and Higgs resonance ''discovery'' capability e.g. at the First Muon Collider (FMC)

  12. Summary of exotic collider concepts group

    International Nuclear Information System (INIS)

    Pellegrini, C.

    1995-01-01

    We present a summary of the discussions in the Exotic Collider Concepts Group. Most of the discussions were centered around the status and open problems for muon-muon and gamma-gamma colliders. In addition the group discussed some general problems and new results of accelerator physics. copyright 1995 American Institute of Physics

  13. Analysis of the beam induced heat loads on the LHC arc beam screens during Run 2

    CERN Document Server

    Iadarola, Giovanni; Dijkstal, Philipp; Mether, Lotta; CERN. Geneva. ATS Department

    2017-01-01

    During Run 2 the Large Hadron Collider (LHC) has been routinely operated with 25 ns bunch spacing. In these conditions large heat loads have been measured on the beam screens of the superconducting magnets, together with other observations indicating that an electron cloud develops in the beam chambers. The analysis of these heat loads has revealed several interesting features allowing to pinpoint peculiar characteristics of the observed beam-induced heating. This document describes the main findings of this analysis including the evolution taking place during the run, the observed dependence on the beam conditions and the results from special tests and dedicated instrumentation. The differences observed in the behavior of the eight LHC arcs are also discussed.

  14. Physics with W's, Z's and leptons at the Tevatron collider

    International Nuclear Information System (INIS)

    Bodek, A.

    1996-10-01

    Recent data from proton-antiproton collisions at high energy provide information on the masses of the Top quark and W boson. The W asymmetry data constrains the slope of the d/u quark distributions and significantly reduces the systematic error on the extracted value of the W mass. Drell-Yan dilepton production at high invariant mass yield limits on extra Z' bosons, and place strong limits on quark substructure. Compositeness limits from CDF Run 1, and expected sensitivity in Run II and TEV33 are presented

  15. Progression in Running Intensity or Running Volume and the Development of Specific Injuries in Recreational Runners: Run Clever, a Randomized Trial Using Competing Risks.

    Science.gov (United States)

    Ramskov, Daniel; Rasmussen, Sten; Sørensen, Henrik; Parner, Erik Thorlund; Lind, Martin; Nielsen, Rasmus

    2018-06-12

    Study Design Randomized clinical trial, etiology. Background Training intensity and volume have been proposed to be associated with specific running-related injuries. If such an association exists, secondary preventive measures could be initiated by clinicians based on symptoms of a specific injury diagnosis. Objectives To test the following hypotheses: (i) A running schedule focusing on intensity will increase the risk of sustaining Achilles tendinopathy, gastrocnemius injuries and plantar fasciitis compared with hypothesized volume-related injuries. (ii) A running schedule focusing on running volume will increase the risk of sustaining patellofemoral pain syndrome, iliotibial band syndrome and patellar tendinopathy compared with hypothesized intensity-related injuries. Methods Healthy recreational runners were included in a 24-week follow-up, divided into 8-week preconditioning and 16-week specific focus-training. Participants were randomized to one of two running schedules: Schedule Intensity(Sch-I) or Schedule Volume(Sch-V). Sch-I progressed the amount of high intensity running (≥88% VO2max) each week. Sch-V progressed total weekly running volume. Global positioning system watch or smartphone collected data on running. Running-related injuries were diagnosed based on a clinical examination. Estimates were risk difference (RD) and 95%CI. Results Of 447 runners, a total of 80 sustained an injury (Sch-I n=36; Sch-V n=44). Risk of intensity injuries in Sch-I were: RD 2-weeks =-0.8%[-5.0;3.4]; RD 4-weeks =-0.8%[-6.7;5.1]; RD 8-weeks =-2.0%[-9.2;5.1]; RD 16-weeks =-5.1%[-16.5;6.3]. Risk of volume injuries in Sch-V were: RD 2-weeks =-0.9%[-5.0;3.2]; RD 4-weeks =-2.0%[-7.5;3.5]; RD 8-weeks =-3.2%[-9.1;2.7]; RD 16-weeks =-3.4%[-13.2;6.2]. Conclusion No difference in risk of hypothesized intensity and volume specific running-related injuries exist between running schedules focused on progression in either running intensity or volume. Level of Evidence Etiology, level 1

  16. International linear collider reference design report

    Energy Technology Data Exchange (ETDEWEB)

    Aarons, G.

    2007-06-22

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

  17. Possible limits of plasma linear colliders

    Science.gov (United States)

    Zimmermann, F.

    2017-07-01

    Plasma linear colliders have been proposed as next or next-next generation energy-frontier machines for high-energy physics. I investigate possible fundamental limits on energy and luminosity of such type of colliders, considering acceleration, multiple scattering off plasma ions, intrabeam scattering, bremsstrahlung, and betatron radiation. The question of energy efficiency is also addressed.

  18. Polarized proton colliders

    International Nuclear Information System (INIS)

    Roser, T.

    1995-01-01

    High energy polarized beam collisions will open up the unique physics opportunities of studying spin effects in hard processes. This will allow the study of the spin structure of the proton and also the verification of the many well documented expectations of spin effects in perturbative QCD and parity violation in W and Z production. Proposals for polarized proton acceleration for several high energy colliders have been developed. A partial Siberian Snake in the AGS has recently been successfully tested and full Siberian Snakes, spin rotators, and polarimeters for RHIC are being developed to make the acceleration of polarized beams to 250 GeV possible. This allows for the unique possibility of colliding two 250 GeV polarized proton beams at luminosities of up to 2 x 10 32 cm -2 s -1

  19. Druid, displaying root module used for linear collider detectors

    International Nuclear Information System (INIS)

    Ruan, M

    2012-01-01

    Based on the ROOT TEve/TGeo classes and the standard linear collider data structure, a dedicated linear collider event display has been developed. It supports the latest detector models for both International Linear Collider and Compact Linear Collider as well as the CALICE test beam prototypes. It can be used to visualise event information at the generation, simulation and reconstruction levels. Many options are provided in an intuitive interface. It has been heavily employed in a variety of analyses.

  20. Collider Physics

    Indian Academy of Sciences (India)

    This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology (WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these problems by the subgroups formed during the workshop is ...

  1. Muon colliders, frictional cooling and universal extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Greenwald, Daniel E.

    2011-07-20

    A muon collider combines the advantages of proton-proton and electron-positron colliders, sidestepping many of their disadvantages, and has the potential to make discoveries and precision measurements at high energies. However, muons bring their own technical challenges, largely relating to their instability. We present a summary of the motivations and R and D efforts for a muon collider. We detail a scheme for preparing high-luminosity muon beams on timescales shorter than the muon lifetime, and an experiment to demonstrate aspects of this scheme at the Max Planck Institute for Physics. We also investigate the potentials to discover physics beyond the standard model at a muon collider. (orig.)

  2. Muon colliders, frictional cooling and universal extra dimensions

    International Nuclear Information System (INIS)

    Greenwald, Daniel E.

    2011-01-01

    A muon collider combines the advantages of proton-proton and electron-positron colliders, sidestepping many of their disadvantages, and has the potential to make discoveries and precision measurements at high energies. However, muons bring their own technical challenges, largely relating to their instability. We present a summary of the motivations and R and D efforts for a muon collider. We detail a scheme for preparing high-luminosity muon beams on timescales shorter than the muon lifetime, and an experiment to demonstrate aspects of this scheme at the Max Planck Institute for Physics. We also investigate the potentials to discover physics beyond the standard model at a muon collider. (orig.)

  3. Summary of the Linear Collider Working Group

    International Nuclear Information System (INIS)

    Ruth, R.D.

    1989-01-01

    The focus of the Linear Collider Working Group was on a next generation linear collider. Topics discussed are: parameters; damping rings; bunch compression and pre-acceleration; linac; final focus; and multibunch effects. 8 refs., 3 figs., 7 tabs

  4. Siting the superconducting super collider

    International Nuclear Information System (INIS)

    Price, R.; Rooney, R.C.

    1988-01-01

    At the request of the Department of Energy, the National Academy of Sciences and the National Academy of Engineering established the Super Collider Site Evaluation Committee to evaluate the suitability of proposed sites for the Superconducting Super Collider. Thirty-six proposals were examined by the committee. Using the set of criteria announced by DOE in its Invitation for Site Proposals, the committee identified eight sites that merited inclusion on a ''best qualified list.'' The list represents the best collective judgment of 21 individuals, carefully chosen for their expertise and impartiality, after a detailed assessment of the proposals using 19 technical subcriteria and DOE's life cycle cost estimates. The sites, in alphabetical order, are: Arizona/Maricopa; Colorado; Illinois; Michigan/Stockbridge; New York/Rochester; North Carolina; Tennessee; and Texas/Dallas-Fort Worth. The evaluation of these sites and the Superconducting Super Collider are discussed in this book

  5. Dark Matter Benchmark Models for Early LHC Run-2 Searches. Report of the ATLAS/CMS Dark Matter Forum

    Energy Technology Data Exchange (ETDEWEB)

    Abercrombie, Daniel [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). et al.

    2015-07-06

    One of the guiding principles of this report is to channel the efforts of the ATLAS and CMS collaborations towards a minimal basis of dark matter models that should influence the design of the early Run-2 searches. At the same time, a thorough survey of realistic collider signals of Dark Matter is a crucial input to the overall design of the search program.

  6. Developments in the ATLAS Tracking Software ahead of LHC Run 2

    CERN Document Server

    Styles, N; The ATLAS collaboration

    2014-01-01

    After a hugely successful first run, the Large Hadron Collider (LHC) is currently in a shut-down period, during which essential maintenance and upgrades are being performed on the accelerator. The ATLAS experiment, one of the four large LHC experiments has also used this period for consolidation and further developments of the detector and of its software framework, ahead of the new challenges that will be brought by the increased centre-of-mass energy and instantaneous luminosity in the next run period. This is of particular relevance for the ATLAS Tracking software, responsible for reconstructing the trajectory of charged particles through the detector, which faces a steep increase in CPU consumption due to the additional combinatorics of the high-multiplicity environment. The steps taken to mitigate this increase and stay within the available computing resources while maintaining the excellent performance of the tracking software in terms of the information provided to the physics analyses will be presente...

  7. Developments in the ATLAS Tracking Software ahead of LHC Run 2

    CERN Document Server

    Styles, N; The ATLAS collaboration; Salzburger, A

    2015-01-01

    After a hugely successful first run, the Large Hadron Collider (LHC) is currently in a shut-down period, during which essential maintenance and upgrades are being performed on the accelerator. The ATLAS experiment, one of the four large LHC experiments has also used this period for consolidation and further developments of the detector and of its software framework, ahead of the new challenges that will be brought by the increased centre-of-mass energy and instantaneous luminosity in the next run period. This is of particular relevance for the ATLAS Tracking software, responsible for reconstructing the trajectory of charged particles through the detector, which faces a steep increase in CPU consumption due to the additional combinatorics of the high-multiplicity environment. The steps taken to mitigate this increase and stay within the available computing resources while maintaining the excellent performance of the tracking software in terms of the information provided to the physics analyses will be presente...

  8. Physicist pins hopes on particle collider

    CERN Multimedia

    2007-01-01

    Physicist pins hopes on particle collider By Deseret Morning News Published: Monday, Dec. 31, 27 12:4 a.m. MST FONT Scott Thomas, a 187 State University graduate, is working at the frontiers of science. The theoretical physicist is crafting ways to extract fundamental secrets that seem certain to be uncovered by the Large Hadron Collider.

  9. Measurement of the Top Quark Mass at D0 Run II with the Matrix Element Method in the Lepton+Jets Final State

    Energy Technology Data Exchange (ETDEWEB)

    Schieferdecker, Philipp [Ludwig Maximilian Univ. of Munich (Germany)

    2005-08-05

    The mass of the top quark is a fundamental parameter of the Standard Model. Its precise knowledge yields valuable insights into unresolved phenomena in and beyond the Standard Model. A measurement of the top quark mass with the matrix element method in the lepton+jets final state in D0 Run II is presented. Events are selected requiring an isolated energetic charged lepton (electron or muon), significant missing transverse energy, and exactly four calorimeter jets. For each event, the probabilities to originate from the signal and background processes are calculated based on the measured kinematics, the object resolutions and the respective matrix elements. The jet energy scale is known to be the dominant source of systematic uncertainty. The reference scale for the mass measurement is derived from Monte Carlo events. The matrix element likelihood is defined as a function of both, m{sub top} and jet energy scale JES, where the latter represents a scale factor with respect to the reference scale. The top mass is obtained from a two-dimensional correlated fit, and the likelihood yields both the statistical and jet energy scale uncertainty. Using a dataset of 320 pb-1 of D0 Run II data, the mass of the top quark is measured to be: m$ℓ+jets\\atop{top}$ = 169.5 ± 4.4(stat. + JES)$+1.7\\atop{-1.6}$(syst.) GeV; m$e+jets\\atop{top}$ = 168.8 ± 6.0(stat. + JES)$+1.9\\atop{-1.9}$(syst.) GeV; m$μ+jets\\atop{top}$ = 172.3 ± 9.6(stat.+JES)$+3.4\\atop{-3.3}$(syst.) GeV. The jet energy scale measurement in the ℓ+jets sample yields JES = 1.034 ± 0.034, suggesting good consistency of the data with the simulation. The measurement forecasts significant improvements to the total top mass uncertainty during Run II before the startup of the LHC, as the data sample will grow by a factor of ten and D0's tracking capabilities will be employed in jet energy reconstruction and flavor identification.

  10. Measurement of the Inclusive Jet Cross Section using the k(T) algorithm in p anti-p collisions at s**(1/2) = 1.96-TeV with the CDF II Detector

    Energy Technology Data Exchange (ETDEWEB)

    Abulencia, A.; /Illinois U., Urbana; Adelman, J.; /Chicago U., EFI; Affolder, Anthony Allen; /UC, Santa Barbara; Akimoto, T.; /Tsukuba U.; Albrow, Michael G.; /Fermilab; Ambrose, D.; /Fermilab; Amerio, S.; /Padua U.; Amidei, Dante E.; /Michigan U.; Anastassov, A.; /Rutgers U., Piscataway; Anikeev, Konstantin; /Fermilab; Annovi, A.; /Frascati /Comenius U.

    2007-01-01

    The authors report on measurements of the inclusive jet production cross section as a function of the jet transverse momentum in p{bar p} collisions at {radical}s = 1.96 TeV, using the k{sub T} algorithm and a data sample corresponding to 1.0 fb{sup -1} collected with the Collider Detector at Fermilab in Run II. The measurements are carried out in five different jet rapidity regions with |y{sup jet}| < 2.1 and transverse momentum in the range 54 < p{sub T}{sup jet} < 700 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.

  11. Beamstrahlung spectra in next generation linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Barklow, T.; Chen, P. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)); Kozanecki, W. (DAPNIA-SPP, CEN-Saclay (France))

    1992-04-01

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

  12. The principles and construction of linear colliders

    International Nuclear Information System (INIS)

    Rees, J.

    1986-09-01

    The problems posed to the designers and builders of high-energy linear colliders are discussed. Scaling laws of linear colliders are considered. The problem of attainment of small interaction areas is addressed. The physics of damping rings, which are designed to condense beam bunches in phase space, is discussed. The effect of wake fields on a particle bunch in a linac, particularly the conventional disk-loaded microwave linac structures, are discussed, as well as ways of dealing with those effects. Finally, the SLAC Linear Collider is described. 18 refs., 17 figs

  13. Physics at high energy photon photon colliders

    International Nuclear Information System (INIS)

    Chanowitz, M.S.

    1994-06-01

    I review the physic prospects for high energy photon photon colliders, emphasizing results presented at the LBL Gamma Gamma Collider Workshop. Advantages and difficulties are reported for studies of QCD, the electroweak gauge sector, supersymmetry, and electroweak symmetry breaking

  14. LHC Report: special run with de-squeezed beams for ATLAS/ALFA and TOTEM

    CERN Multimedia

    Helmut Burkhardt for the LHC team

    2015-01-01

    The main high-luminosity proton-proton run of the LHC is complemented by one week per year of special proton-proton runs. The special runs are performed with larger beam sizes at the interaction points to allow the forward physics experiments, TOTEM and ATLAS/ALFA, the chance to make precise measurements of protons as they emerge from collisions at small angles.   In standard high-luminosity operation, the beams are squeezed to give small beam sizes at the interaction points to maximise the collision rates. The “squeeze” takes place at top energy and the beam size at the centre of ATLAS (IP1) and CMS (IP5) is reduced from 66 micrometres at the top of the ramp to 18 micrometres before colliding beams are established. Protons that avoid the fate of an inelastic collision but yet still interact – in elastic or diffractive events – are scattered and emerge in the forward direction. The reduction in beam size has a side effect of increasing the an...

  15. ERL-BASED LEPTON-HADRON COLLIDERS: eRHIC AND LHeC

    CERN Document Server

    Zimmermann, F

    2013-01-01

    Two hadron-ERL colliders are being proposed. The Large Hadron electron Collider (LHeC) plans to collide the high-energy protons and heavy ions in the Large Hadron Collider (LHC) at CERN with 60-GeV polarized electrons or positrons. The baseline scheme for this facility adds to the LHC a separate recirculating superconducting (SC) lepton linac with energy recovery, delivering a lepton current of 6.4mA. The electron-hadron collider project eRHIC aims to collide polarized (and unpolarized) electrons with a current of 50 (220) mA and energies in the range 5–30 GeV with a variety of hadron beams— heavy ions as well as polarized light ions— stored in the existing Relativistic Heavy Ion Collider (RHIC) at BNL. The eRHIC electron beam will be generated in an energy recovery linac (ERL) installed inside the RHIC tunnel.

  16. Hadron collider luminosity limitations

    CERN Document Server

    Evans, Lyndon R

    1992-01-01

    The three colliders operated to date have taught us a great deal about the behaviour of both bunched and debunched beams in storage rings. The main luminosity limitations are now well enough understood that most of them can be stronglu attenuated or eliminated by approriate design precautions. Experience with the beam-beam interaction in both the SPS and the Tevatron allow us to predict the performance of the new generation of colliders with some degree of confidence. One of the main challenges that the accelerator physicist faces is the problem of the dynamic aperture limitations due to the lower field quality expected, imposed by economic and other constraints.

  17. Future Circular Collider Study FCC-he Baseline Parameters

    CERN Document Server

    Bruning, Oliver; Klein, Max; Pellegrini, Dario; Schulte, Daniel; Zimmermann, Frank

    2017-01-01

    Initial considerations are presented on the FCC-he, the electron-hadron collider con guration within the Future Circular Collider study. This note considers arguments for the choice of the electron beam energy based on physics, ep scattering kinematics and cost. The default con guration for the electron accelerator, as for the LHeC, is chosen to be a multi-turn energy recovery linac external to the proton beam tunnel. The main accelerator parameters of the FCC-he are discussed, assuming the concurrent operation of ep with the 100TeV cms energy pp collider. These are compared with the LHeC design concept, for increased performance as for a Higgs facility using the HL-LHC, and also the high energy HE-LHC ep collider configuration. Initial estimates are also provided for the luminosity performance of electron-ion colliders for the 60 GeV electron ERL when combined with the LHC, the HE-LHC and the FCC ion beams.

  18. The silicon strip detector at the Mark 2

    International Nuclear Information System (INIS)

    Jacobsen, R.; Golubev, V.; Lueth, V.; Barnett, B.; Dauncey, P.; Matthews, J.; Adolphsen, C.; Burchat, P.; Gratta, G.; King, M.; Labarga, L.; Litke, A.; Turala, M.; Zaccardelli, C.

    1990-04-01

    We have installed a Silicon Strip Vertex Detector in the Mark II detector at the Stanford Linear Collider. We report on the performance of the detector during a recent test run, including backgrounds, stability and charged particle tracking. 10 refs., 9 figs

  19. Study of Collective Effects in the FCC-ee Collider

    OpenAIRE

    Zobov, Mikhail; Belli, Eleonora; Castorina, Giovanni; Migliorati, Mauro; Persichelli, Serena; Rumolo, Giovanni; Spataro, Bruno

    2018-01-01

    The Future Circular Collider (FCC) study aims at designing different options of a post-LHC collider. The high luminosity electron-positron collider FCC-ee based on the crab waist concept is considered as an intermediate step on the way towards FCC-hh, a 100 TeV hadron collider using the same tunnel of about 100 km. Due to a high intensity of circulating beams the impact of collective effects on FCC-ee performance has to be carefully analyzed. In this paper we evaluate beam coupling impedance ...

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

    Science.gov (United States)

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

    2014-08-01

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