Searches for supersymmetry with the ATLAS detector using final states with two leptons and missing transverse momentum in s=7TeV proton-proton collisions
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 709:3 (2012) 137-157
Abstract:
Results of three searches are presented for the production of supersymmetric particles decaying into final states with missing transverse momentum and exactly two isolated leptons, e or μ. The analysis uses a data sample collected during the first half of 2011 that corresponds to a total integrated luminosity of 1fb-1 of s=7TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Opposite-sign and same-sign dilepton events are separately studied, with no deviations from the Standard Model expectation observed. Additionally, in opposite-sign events, a search is made for an excess of same-flavour over different-flavour lepton pairs. Effective production cross sections in excess of 9.9 fb for opposite-sign events containing supersymmetric particles with missing transverse momentum greater than 250 GeV are excluded at 95% CL. For same-sign events containing supersymmetric particles with missing transverse momentum greater than 100 GeV, effective production cross sections in excess of 14.8 fb are excluded at 95% CL. The latter limit is interpreted in a simplified electroweak gaugino production model excluding chargino masses up to 200 GeV, under the assumption that slepton decay is dominant. © 2012 CERN.Search for the Higgs Boson in the H→WW(*)→l +νl-ν̄ Decay Channel in pp Collisions at √s=7TeV with the ATLAS Detector
Physical Review Letters 108:11 (2012)
Abstract:
A search for the Higgs boson has been performed in the H→WW( *)→+ν-ν̄ channel (=e/μ) with an integrated luminosity of 2.05fb-1 of pp collisions at √s=7TeV collected with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 110GeVSearch for the standard model Higgs boson in the diphoton decay channel with 4.9fb-1 of pp collision data at √s=7TeV with atlas
Physical Review Letters 108:11 (2012)
Abstract:
A search for the standard model Higgs boson is performed in the diphoton decay channel. The data used correspond to an integrated luminosity of 4.9fb-1 collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of √s=7TeV. In the diphoton mass range 110-150GeV, the largest excess with respect to the background-only hypothesis is observed at 126.5GeV, with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account in the range 110-150GeV, this significance becomes 1.5 standard deviations. The standard model Higgs boson is excluded at 95% confidence level in the mass ranges of 113-115GeV and 134.5-136GeV. © 2012 CERN.A measurement of the ratio of the W and Z cross sections with exactly one associated jet in pp collisions at s=7TeV with ATLAS
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 708:3-5 (2012) 221-240
Abstract:
The ratio of production cross sections of the W and Z bosons with exactly one associated jet is presented as a function of jet transverse momentum threshold. The measurement has been designed to maximise cancellation of experimental and theoretical uncertainties, and is reported both within a particle-level kinematic range corresponding to the detector acceptance and as a total cross-section ratio. Results are obtained with the ATLAS detector at the LHC in pp collisions at a centre-of-mass energy of 7 TeV using an integrated luminosity of 33 pb-1. The results are compared with perturbative leading-order, leading-log, and next-to-leading-order QCD predictions, and are found to agree within experimental and theoretical uncertainties. The ratio is measured for events with a single jet with pT>30 GeV to be 8.73±0.30(stat)±0.40(syst) in the electron channel, and 8.49±0.23(stat)±0.33(syst) in the muon channel. © 2012 CERN.Measurement of the production cross section for Z/γ* in association with jets in pp collisions at √s=7TeV with the ATLAS detector
Physical Review D - Particles, Fields, Gravitation and Cosmology 85:3 (2012)