The ATLAS Inner Detector commissioning and calibration
European Physical Journal C 70:3 (2010) 787-821
Abstract:
The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7. 6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22. 1±0. 9 μm and a relative momentum resolution σp/p=(4. 83±0. 16)×10-4 GeV-1×pT have been measured for high momentum tracks. © 2010 CERN for the benefit of the ATLAS collaboration.Search for dijet resonances in 7 TeV pp collisions at CMS
Physical Review Letters 105:21 (2010)
Abstract:
A search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9pb⊃-1 collected by the CMS experiment at the Large Hadron Collider. Upper limits at the 95% confidence level are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% confidence level: string resonances, with mass less than 2.50 TeV, excited quarks, with mass less than 1.58 TeV, and axigluons, colorons, and E6 diquarks, in specific mass intervals. This extends previously published limits on these models. Copyright © 2010 American Physical Society.Updated search for the flavor-changing neutral-current decay D0→μ⊃+μ⊃- in pp̄ collisions at √s=1.96 TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:9 (2010)
Abstract:
We report on a search for the flavor-changing neutral-current decay D0→μ⊃+μ⊃- in pp̄ collisions at √s=1.96TeV using 360pb⊃-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. A displaced vertex trigger selects long-lived D0 candidates in the μ⊃+μ⊃-, π⊃+π⊃-, and K⊃-π⊃+ decay modes. We use the Cabibbo-favored D0→K⊃- π⊃+ channel to optimize the selection criteria in an unbiased manner, and the kinematically similar D0→π⊃+π⊃- channel for normalization. We set an upper limit on the branching fraction B(D0→μ⊃+μ⊃-)<2.1×10⊃-7(3.0×10⊃-7) at the 90% (95%) confidence level. © 2010 The American Physical Society.Search for R-parity violating decays of sneutrinos to eμ, μτ, and eτ pairs in pp collisions at square root s = 1.96 TeV.
Phys Rev Lett 105:19 (2010) 191801
Abstract:
We present a search for supersymmetric neutrino ν production using the Tevatron pp collision data collected with the CDF II detector and corresponding to an integrated luminosity of 1 fb-1. We focus on the scenarios predicted by the R-parity violating (RPV) supersymmetric models in which sneutrinos decay to two charged leptons of different flavor. With the data consistent with the standard model expectations, we set upper limits on σ(pp→ν)×BR(ν→eμ,μτ,eτ) and use these results to constrain the RPV couplings as a function of the sneutrino mass.Search for the supersymmetric partner of the top quark in pp̄ collisions at √s=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:9 (2010)