1,592 research outputs found
GEANT4 : a simulation toolkit
No full textAbstract Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics. PACS: 07.05.Tp; 13; 2
First look at the physics case of TLEP
No full textThe discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model at the TeV scale, has triggered interest in ideas for future Higgs factories. A new circular e+e− collider hosted in a 80 to 100 km tunnel, TLEP, is among the most attractive solutions proposed so far. It has a clean experimental environment, produces high luminosity for top-quark, Higgs boson, W and Z studies, accommodates multiple detectors, and can reach energies up to the tt¯ threshold and beyond. It will enable measurements of the Higgs boson properties and of Electroweak Symmetry-Breaking (EWSB) parameters with unequalled precision, offering exploration of physics beyond the Standard Model in the multi-TeV range. Moreover, being the natural precursor of the VHE-LHC, a 100 TeV hadron machine in the same tunnel, it builds up a long-term vision for particle physics. Altogether, the combination of TLEP and the VHE-LHC offers, for a great cost effectiveness, the best precision and the best search reach of all options presently on the market. This paper presents a first appraisal of the salient features of the TLEP physics potential, to serve as a baseline for a more extensive design study
Measurement of the Ds ± lifetime
No full textWe report a precise measurement of the Ds± meson lifetime. The data were taken by the SELEX experiment (E781) spectrometer using 600 GeV/c ∑-, π- and p beams. The measurement has been done using 918 reconstructed Ds±. The lifetime of the Ds± is measured to be 472.5 ± 17.2 ± 6.6 fs, using K*(892)0K± and φπ± decay modes. The lifetime ratio of Ds± to D0 is 1.145 ± 0.049. © 2001 Elsevier Science B.V. All rights reserved.Ball State University, Muncie, IN 47306Bogazici University, Bebek 80815 IstanbulCarnegie-Mellon University, Pittsburgh, PA 15213Centro Brasileiro de Pesquisas F�sicas, Rio de JaneiroFermilab, Batavia, IL 60510Institute for High Energy Physics, ProtvinoInstitute of High Energy Physics, BeijingInstitute of Theoretical and Experimental Physics, MoscowMax-Planck-Institut für Kernphysik, 69117 HeidelbergMoscow State University, MoscowPetersburg Nuclear Physics Institute, St. PetersburgTel Aviv University, 69978 Ramat AvivUniversidad Autónoma de San Luis Potosí, San Luis PotosíUniversidade Federal da Paraíba, ParaíbaUniversity of Bristol, Bristol BS8 1TLUniversity of Iowa, Iowa City, IA 52242University of Michigan-Flint, Flint, MI 48502University of Rome “La Sapienza” and INFN, RomeUniversity of São Paulo, São PauloUniversity of Trieste and INFN, TriesteInfinion, MünchenImperial College, London SW7 2BZInstituto de F�sica da Universidade Estadual de Campinas UNICAMP, SPPhysik-Department Technische Universität München, 85748 GarchingThe Boston Consulting Group, MünchenLucent Technologies, Naperville, ILInstituto de Física Teórica da Universidade Estadual Paulista, São PauloSPSS Inc, Chicago, ILUniversity of Alabama at Birmingham, Birmingham AL 35294DOE, Germantown, MDSiemens Medizintechnik, ErlangenDeutsche Bank AG, EschbornInstituto de Física Teórica da Universidade Estadual Paulista, São Paul
Development of a tracking system of exotic nuclear beams for FAIR
No full textNew accelerators like SPIRAL2 (GANIL, France) or FAIR (GSI, Germany) will be
soon constructed, and they will be able to produce radioactive ion beams (RIB) with high
intensities of current (≥106pps). These beams, at low energy, lower than 20 MeV/n, usually have
high emittance, which imposes the use of tracking detectors before the target in order to
reconstruct the trajectory of the ions. The group of Nuclear Physics at CNA (Centro Nacional de
Aceleradores), is in charge of developing a tracking system for the low energy branch of FAIR
(the HISPEC/DESPEC project). A collaboration with CEA-SACLAY was established, with the
aim of developing, building and testing low pressure Secondary electron Detectors (SeD).
Within this proposal we have projected and constructed a new Nuclear Physics Line in the CNA
in order to be able to receive any kind of detector tests and the associated nuclear instruments
Measurement of the σ- charge radius by σ--electron elastic scattering
No full textThe σ- mean squared charge radius has been measured in the space-like Q2 range 0.035-0.105 GeV2/c2 by elastic scattering of a σ- beam off atomic electrons. The measurement was performed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c. We obtain (rch2σ- = (0.61 ± 0.12(stat.) ± 0.09(syst.)) fm2. The proton and π- charge radii were measured as well and are consistent with results of other experiments. Our result agrees with the recently measured strong interaction radius of the σ-. © 2001 Elsevier Science B.V. All rights reserved.Ball State University, Muncie, IN 47306Bogazici University, Bebek 80815 IstanbulCarnegie-Mellon University, Pittsburgh, PA 15213Centro Brasiliero de Pesquisas Físicas, Rio de JaneiroFermilab, Batavia, IL 60510Institute for High Energy Physics, ProtvinoInstitute of High Energy Physics, BeijingInstitute of Theoretical and Experimental Physics, MoscowMax-Planck-Institut für Kernphysik, 69117 HeidelbergMoscow State University, MoscowPetersburg Nuclear Physics Institute, St. PetersburgTel Aviv University, 69978 Ramat AvivUniversidad Autónoma de San Luis Potosó, San Luis PotosiUniversidade Federal da Paraiba, ParaíbaUniversity of Bristol, Bristol BS8 1TLUniversity of Iowa, IA City, IA 52242University of Michigan-Flint, Flint, MI 48502University of Rome 'La Sapienza' and INFN, RomeUniversity of SãoPaulo, São PauloUniversity of Trieste and INFN, TriesteImperial College, London SW7 2BZBoston Consulting Group, MunchenSiemens Medizintechnik, ErlangenDeutsche Bank AG, EschbornInfineon Technologies AG, MünchenUniversity of Karlsruhe, KarlsruheInstituto de Fisica da Universidade Estadual de Campinas UNICAMP, SPUniversität Freiburg, FreiburgPhysik-Department Technische Universität München, GarchingLucent Technologies, Naperville, ILInstituto de Física Teórica da Universidade Estadual Paulista, São PauloMax-Planck-Institut fur Physik, MunchenSPSS Inc., Chicago, ILUniversity of Alabama at Birmingham, Birmingham, AL 35294, LondonDOE, Germantown, MDInstituto de Física Teórica da Universidade Estadual Paulista, São Paul
Production asymmetry of Ds from 600 GeV/c σ- and π- beam
No full textThe production of Ds- relative to Ds+ as a function of xF with 600 GeV/c Σ- beam is measured in the interval 0.15 < xF < 0.7 by the SELEX (E781) experiment at Fermilab. The integrated charge asymmetries with 600 GeV/c Σ- beam (0.53 ± 0.06) and π- beam (0.06 ± 0.11) are also compared. The results show the Σ- beam fragments play a role in the production of Ds-, as suggested by the leading quark model. © 2003 Elsevier Science B.V. All rights reserved.Ball State University, Muncie, IN 47306Bogazici University, Bebek 80815 IstanbulCarnegie-Mellon University, Pittsburgh, PA 15213Centro Brasileiro de Pesquisas Físicas, Rio de JaneiroFermi National Accelerator Laboratory, Batavia, IL 60510Institute for High Energy Physics, ProtvinoInstitute of High Energy Physics, BeijingInstitute of Theoretical and Experimental Physics, MoscowMax-Planck-Institut für Kernphysik, 69117 HeidelbergMoscow State University, MoscowPetersburg Nuclear Physics Institute, St. PetersburgTel Aviv University, 69978 Ramat AvivUniversidad Autónoma de San Luis Potosí, San Luis PotosíUniversidade Federal da Paraíba, ParaíbaUniversity of Bristol, Bristol BS8 1TLUniversity of Iowa, Iowa City, IA 52242University of Michigan-Flint, Flint, MI 48502University of Rome 'La Sapienza' and INFN, RomeUniversity of São Paulo, São PauloUniversity of Trieste and INFN, TriesteInfinion, MünchenImperial College, London SW7 2BZInstituto de Física da Universidade Estadual de Campinas UNICAMP, SPKafkas University, KarsPhysik-Department Technische Universität München, 85748 GarchingThe Boston Consulting Group, MünchenInstituto de Física Teórica da Universidade Estadual Paulista, São PauloLucent Technologies, Naperville, ILSPSS Inc., Chicago, ILUniversity of Alabama at Birmingham, Birmingham, AL 35294DOE, Germantown, MDSolidum, Ottawa, ONSiemens Medizintechnik, ErlangenDeutsche Bank AG, EschbornInstituto de Física Teórica da Universidade Estadual Paulista, São Paul
Search for new physics in events with photons, jets, and missing transverse energy in pp collisions at s√ = 7 TeV
No full textA search for physics beyond the standard model involving events with one or more photons, jets, and missing transverse energy has been performed by the CMS experiment. The data sample corresponds to an integrated luminosity of 4.93 inverse femtobarns of proton-proton collisions at s√ = 7 TeV, produced at the Large Hadron Collider. No excess of events with large missing transverse energy is observed beyond expectations from standard model processes, and upper limits on the signal production cross sections for new physics processes are set at the 95% confidence level. The results of this search are interpreted in the context of three models of new physics: a general model of gauge-mediated supersymmetry breaking, Simplified Models, and a theory involving universal extra dimensions. In the absence of evidence for new physics, exclusion regions are derived in the parameter spaces of the respective models
The Strong and Weak Senses of Theory-Ladenness of Experimentation: Theory-Driven versus Exploratory Experiments in the History of High-Energy Particle Physics
No full textIn the theory-dominated view of scientific experimentation, all relations of theory and experiment are taken on a par; namely, that experiments are performed solely to ascertain the conclusions of scientific theories. As a result, different aspects of experimentation and of the relation of theory to experiment remain undifferentiated. This in turn fosters a notion of theory-ladenness of experimentation (TLE) that is too coarse-grained to accurately describe the relations of theory and experiment in scientific practice. By contrast, in this article, I suggest that TLE should be understood as an umbrella concept that has different senses. To this end, I introduce a three-fold distinction among the theories of high-energy particle physics (HEP) as background theories, model theories and phenomenological models. Drawing on this categorization, I contrast two types of experimentation, namely, “theory-driven” and “exploratory” experiments, and I distinguish between the “weak” and “strong” senses of TLE in the context of scattering experiments from the history of HEP. This distinction enables to identify the exploratory character of the deep-inelastic electron-proton scattering experiments—performed at the Stanford Linear Accelerator Center (SLAC) between the years 1967 and 1973—thereby shedding light on a crucial phase of the history of HEP, namely, the discovery of “scaling”, which was the decisive step towards the construction of quantum chromo-dynamics (QCD) as a gauge theory of strong interactions
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Compilation of current high energy physics experiments, 1981
No full textThis is the fourth edition of our compilation of current high energy physics experiments. It is a collaborative effort of the Berkeley Particle Data Group, the SLAC library, and nine participating laboratories: Argonne (ANL), Brookhaven (BNL), CERN, DESY, Fermilab (FNAL), the Institute for Nuclear Study, Tokyo (INS), KEK, Serpukhov (SERP), and SLAC. The compilation includes summaries of all high energy physics experiments at the above laboratories that (1) were approved (and not subsequently withdrawn) before about April 1981, and (2) had not completed taking of data by 1 January 1977. We emphasize that only approved experiments are included
The Forward Physics Facility at the High-Luminosity LHC
No full textHigh energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential.</p
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