5,151 research outputs found

    Mixing and CP Violation at the Tevatron

    Get PDF
    Measurements of meson mixing and CP violation parameters obtained by the CDF and D0 experiments at the Fermilab Tevatron are presented. These include results on BsB_s and DD meson mixing, and searches for CP violation in the decay B+→J/ψK+B^+ \to J/\psi K^+, in mixing through semileptonic BsB_s meson decays, and in the interference between mixing and decay in the process Bs→J/ψϕB_s \to J/\psi \phi.Comment: 9 pages, Proceedings of the Hadron Collider Physics Symposium (HCP2008),Galena, Illinois, US

    Top Quark Mass Measurements at the Tevatron

    Get PDF
    The general strategy, as well as channel-specific details, applied to the measurement of the top quark mass at the Tevatron in Run I are reviewed, and the combination of the results obtained by the CDF and DO collaborations presented. The accelerator and detector upgrades for Run II are described, and expected improvements in the systematic uncertainties on the measurement evaluated.Comment: Latex (Frascati.sty), 11 pages, 3 figs. Talk given at the 14th Rencontres de Physique de la Vallee d'Aoste, La Thuile, Aosta Valley, Italy, February 200

    Determination of Scanning Efficiencies in Experiments Using Nuclear Emulsion Sheets

    Get PDF
    During their exposure, nuclear emulsion sheets detect both tracks from experiment-related particles, as well as a considerable amount of background tracks, mainly due to cosmic rays. Unless the exposure has been fairly short, it is therefore fairly likely that a fraction of the tracks that have been identified as belonging to the particles the experiment is interested in, are really due to background. A method, which allows to measure this fraction reliably directly from the data, is described.Comment: 7 pages, uses elsart, to be published in NIMA 450, p 44

    High pT Hadronic Top Quark Identification

    Get PDF
    At the LHC objects with masses at the electroweak scale will for the first time be produced with very large transverse momenta. In many cases, these objects decay hadronically, producing a set of collimated jets. This interesting new experimental phenomenology requires the development and tuning of new tools, since the usual reconstruction methods would simply reconstruct a single jet. This note describes the application of the YSplitter algorithm in conjunction with the jet mass to identify high transverse momentum top quarks decaying hadronically

    A Supersymmetric Solution to the Solar and Atmospheric Neutrino Anomalies

    Get PDF
    The formalism for neutrino flavor change induced by lepton family number violating interactions is developed for the three-neutrino case, and used to derive the corresponding flavor change probabilities in matter. Applied to the solar and atmospheric neutrino fluxes, it is argued that the observed anomalies, including the zenith dependence for the atmospheric case, could be due to such interactions.Comment: 6 pages, 1 figure Modifications: include limit from tau -> rho mu (leads to somewhat different conclusions) and a change to the figur

    After the Standard Model: New Resonances at the LHC

    Full text link
    Experiments will soon start taking data at CERN's Large Hadron Collider (LHC) with high expectations for discovery of new physics phenomena. Indeed, the LHC's unprecedented center-of-mass energy will allow the experiments to probe an energy regime where the standard model is known to break down. In this article, the experiments' capability to observe new resonances in various channels is reviewed.Comment: Preprint version of a Brief Review for Modern Physics Letters A. Changes w.r.t. the fully corrected version are smal

    General bounds on non-standard neutrino interactions

    Full text link
    We derive model-independent bounds on production and detection non-standard neutrino interactions (NSI). We find that the constraints for NSI parameters are around O(10^{-2}) to O(10^{-1}). Furthermore, we review and update the constraints on matter NSI. We conclude that the bounds on production and detection NSI are generally one order of magnitude stronger than their matter counterparts.Comment: 18 pages, revtex4, 1 axodraw figure. Minor changes, matches published versio

    Loop bounds on non-standard neutrino interactions

    Full text link
    We reconsider the bounds on non-standard neutrino interactions with matter which can be derived by constraining the four-charged-lepton operators induced at the loop level. We find that these bounds are model dependent. Naturalness arguments can lead to much stronger constraints than those presented in previous studies, while no completely model-independent bounds can be derived. We will illustrate how large loop-contributions to four-charged-lepton operators are induced within a particular model that realizes gauge invariant non-standard interactions and discuss conditions to avoid these bounds. These considerations mainly affect the O(10−4)\mathcal O(10^{-4}) constraint on the non-standard coupling strength \eps_{e\mu}, which is lost. The only model-independent constraints that can be derived are O(10−1)\mathcal O(10^{-1}). However, significant cancellations are required in order to saturate this bound.Comment: Minor changes, version to be published in JHEP. 17 pages, 3 Axodraw figures, REVTeX
    • …
    corecore