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154 records · Page 9

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DOE OSTI2011

On the interaction of high-energy cosmic leptons with neutralino dark matter

The interaction of neutralino cold dark matter with cosmic-ray electrons is considered in terms of the supersymmetric Standard Model. The production of heavy supersymmetric particles in collisions and their decay are shown to give rise to leptons and neutrinos with certain energies and to relativistic neutralinos. The possibility of detecting dark matter through its interaction with cosmic rays is discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Muon anomalous magnetic moment in the supersymmetric economical 3-3-1 model

We investigate the muon anomalous magnetic moment in the context of a supersymmetric version of the economical 3-3-1 model. We compute the 1-loop contribution of superpartner particles. We show that the contribution of superparticle loops become significant when tanγ is large. We investigate the cases of both small and large values of tanγ. We find the region of the parameter space where the slepton masses of a few hundred GeV are favored by the muon g–2 for small tanγ (tanγ ≈ 5). Numerical estimation gives the mass of supersymmetric particles, the mass of gauginos m{sub G} ≈ 700 GeV, and the light slepton mass m{sub L̃} of the order of O (100) GeV. When tanγ is large (tanγ ≈ 60), the charged slepton mass m{sub L̃} and the gaugino mass m{sub G} are O(1) TeV, while the sneutrino mass ≈450 GeV is in the reach of the LHC.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2011

Searches for new physics at Tevatron: Most recent results

The most recent results obtained from searches of particles and phenomena beyond the Standard Model (new physics) in the D0 and CDF experiments at the Tevatron accelerator (FNAL, USA) on the basis of statistics corresponding to the integrated luminosity of up to 4 fb{sup -1} in 2009 are considered. Particular attention is given to the most recent results on searches for a supersymmetric Higgs boson.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Constrained Sypersymmetric Flipped SU (5) GUT Phenomenology

We explore the phenomenology of the minimal supersymmetric flipped SU(5) GUT model (CFSU(5)), whose soft supersymmetry-breaking (SSB) mass parameters are constrained to be universal at some input scale, Min, above the GUT scale, M{sub GUT}. We analyze the parameter space of CFSU(5) assuming that the lightest supersymmetric particle (LSP) provides the cosmological cold dark matter, paying careful attention to the matching of parameters at the GUT scale. We first display some specific examples of the evolutions of the SSB parameters that exhibit some generic features. Specifically, we note that the relationship between the masses of the lightest neutralino {chi} and the lighter stau {tilde {tau}}{sub 1} is sensitive to M{sub in}, as is the relationship between m{sub {chi}} and the masses of the heavier Higgs bosons A,H. For these reasons, prominent features in generic (m{sub 1/2}, m{sub 0}) planes such as coannihilation strips and rapid-annihilation funnels are also sensitive to Min, as we illustrate for several cases with tan {beta} = 10 and 55. However, these features do not necessarily disappear at large Min, unlike the case in the minimal conventional SU(5) GUT. Our results are relatively insensitive to neutrino masses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Enhancing the CDF's B physics program with a faster data acquisition system.

The physics program of Run II at the Tevatron includes precision electroweak measurements such as the determination of the top quark and W boson masses; bottom and charm physics including the determination of the B{sub s} and D{sup 0} mixing parameters; studies of the strong interaction; and searches for the Higgs particle, supersymmetric particles, hidden space-time dimensions and quark substructure. All of these measurements benefit from a high-resolution tracking detector. Most of them rely heavily on the efficient identification of heavy flavored B hadrons by detection of displaced secondary vertices, and are enhanced by the capability to trigger on tracks not coming from the primary vertex. This is uniquely provided by CDF's finely-segmented silicon detectors surrounding the interaction region. Thus CDF experiment's physics potential critically depends on the performance of its silicon detectors. The CDF silicon detectors were designed to operate up to 2-3 fb{sup -1} of accumulated pji collisions, with an upgrade planned thereafter. However, the upgrade project was canceled in 2003 and Run II has been extended through 2011, with an expected total delivered integrated luminosity of 12 fb{sup -1} or more. Several preventive measures were taken to keep the original detector operational and maintain its performance. The most important of these are the decrease in the operating temperature of the detector, which reduces the impact of radiation exposure, and measures to minimize damage due to integrated radiation dose, thermal cycles, and wire bond resonance conditions. Despite these measures the detectors operating conditions continue to change with issues arising from radiation damage to the sensors, aging infrastructure and electronics. These, together with the basic challenges posed by the inaccessibility of the detector volume and large number (about 750 thousand) of readout channels, make the silicon detector operations the single most complex and high priority job in the CDF experiment.

43 PARTICLE ACCELERATORS↗

DOE OSTI2018

Particle Physics Booklet 2018

This Booklet is extracted from the Review of Particle Physics, Physical Review D, 98, 030001 (2018). This Particle Physics Booklet includes the Summary Tables plus essential tables, figures, and equations from selected review articles. The table of contents, on the following pages, lists also additional material available in the full Review.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Electroweak Physics at the Tevatron

The most recent Electroweak results from the Tevatron are presented. The importance of precise Standard Model measurements in the Higgs sector, quantum chromodynamics and searches for new physics is emphasized. Analyzed data correspond to 1-7 fb{sup -1} of integrated luminosity recorded by the CDF and D0 detectors at the Tevatron Collider at {radical}s = 1.96 TeV during the period between 2002-2010. The main goal of the Electroweak (EW) physics is to probe the mechanism of the EW symmetry breaking. An important aspect of these studies is related to precise measurements of the Standard Model (SM) parameters and tests of the SU(2) x U(1) gauge symmetry. Deviations from the SM may be indicative of new physics. Thus, the interplay between the tests of the 'standard' physics and searches for a 'nonstandard' physics is an important aspect of the EW measurements. The observables commonly used in these measurements are cross sections, gauge boson couplings, differential distributions, asymmetries, etc. Besides, many EW processes represent a non-negligible background in a Higgs boson and top quark production, and production of supersymmetric particles. Therefore, the complete and detailed understanding of EW processes is a mandatory precondition for early discoveries of very small new physics signals. Furthermore, several EW analyses represent a proving ground for analysis techniques and statistical treatments used in the Tevatron Higgs searches.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

SUSY Searches at the Tevatron

In this article results from supersymmetry searches at D0 and CDF are reported. Searches for third generation squarks, searches for gauginos, and searches for models with R-parity violation are described. As no signs of supersymmetry for these models are observed, the most stringent limits to date are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Search for Chargino-Neutralino Associated Production in Dilepton Final States with Tau Leptons

We present a search for chargino and neutralino supersymmetric particles yielding same signed dilepton final states including one hadronically decaying tau lepton using 6.0 fb{sup -1} of data collected by the the CDF II detector. This signature is important in SUSY models where, at high tan {beta}, the branching ratio of charginos and neutralinos to tau leptons becomes dominant. We study event acceptance, lepton identification cuts, and efficiencies. We set limits on the production cross section as a function of SUSY particle mass for certain generic models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2011

Identifying sneutrino dark matter: Interplay between the LHC and direct search

Under R parity, the lightest supersymmetric particle (LSP) is stable and may serve as a good dark matter candidate. The R parity can be naturally introduced with a gauge origin at the TeV scale. We go over why a TeV scale B-L gauge extension of the minimal supersymmetric standard model is one of the most natural, if not demanded, low energy supersymmetric models. In the presence of a TeV scale Abelian gauge symmetry, the (predominantly) right-handed sneutrino LSP can be a good dark matter candidate. Its identification at the LHC is challenging because it does not carry any standard model charge. We show how we can use the correlation between the LHC experiments (dilepton resonance signals) and the direct dark matter search experiments (such as CDMS and XENON) to identify the right-handed sneutrino LSP dark matter in the B-L extended minimal supersymmetric standard model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗