Measurement of the cross section for the production of a W boson in association with b-jets in pp collisions at 鈭歴=7TeV with the ATLAS detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:5 (2012) 438-458
Abstract:
A measurement is presented of the cross section for the production of a W boson with one or two jets, of which at least one must be a b-jet, in pp collisions at s=7TeV. Production via top decay is not included in the signal definition. The measurement is based on 35pb -1 of data collected with the ATLAS detector at the LHC. The W+b-jet cross section is defined for jets reconstructed with the anti-k t clustering algorithm with transverse momentum above 25 GeV and rapidity within 卤2.1. The b-jets are identified by reconstructing secondary vertices. The fiducial cross section is measured both for the electron and muon decay channel of the W boson and is found to be 10.2卤1.9(stat)卤2.6(syst)pb for one lepton flavour. The results are compared with next-to-leading order QCD calculations, which predict a cross section smaller than, though consistent with, the measured value. 漏 2011 CERN.Measurement of the top quark pair production cross section in pp collisions at 鈭歴=7TeV in dilepton final states with ATLAS
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:5 (2012) 459-477
Abstract:
A measurement of the production cross section of top quark pairs (tt虅) in proton-proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider is reported. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. Using a data sample corresponding to an integrated luminosity of 35pb-1, a tt虅 production cross section 蟽tt虅=177卤20(stat.)卤14(syst.)卤7(lum.)pb is measured for an assumed top quark mass of mt=172.5GeV. A second measurement requiring at least one jet identified as coming from a b quark yields a comparable result, demonstrating that the dilepton final states are consistent with being accompanied by b-quark jets. These measurements are in good agreement with Standard Model predictions. 漏 2011 CERN.Measurements of the electron and muon inclusive cross-sections in proton-proton collisions at 鈭歴=7TeV with the ATLAS detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:5 (2012) 438-458
Abstract:
This Letter presents measurements of the differential cross-sections for inclusive electron and muon production in proton-proton collisions at a centre-of-mass energy of s=7TeV, using data collected by the ATLAS detector at the LHC. The muon cross-section is measured as a function of pT in the range 4Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:5 (2012) 478-496
Abstract:
We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models. 漏 2011 CERN.Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead-lead collisions at sNN=2.76 TeV with the ATLAS detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:3-4 (2012) 330-348