Combined search for the Standard Model Higgs boson using up to 4.9 fb-1 of pp collision data at s=7TeV with the ATLAS detector at the LHC
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 710:1 (2012) 49-66
Abstract:
A combined search for the Standard Model Higgs boson with the ATLAS experiment at the LHC using datasets corresponding to integrated luminosities from 1.04 fb-1 to 4.9 fb-1 of pp collisions collected at s=7TeV is presented. The Higgs boson mass ranges 112.9-115.5 GeV, 131-238 GeV and 251-466 GeV are excluded at the 95% confidence level (CL), while the range 124-519 GeV is expected to be excluded in the absence of a signal. An excess of events is observed around mH~126GeV with a local significance of 3.5 standard deviations (σ). The local significances of H→γγ, H→ZZ(z.ast;)→ℓ+ℓ-ℓ'+ℓ'- and H→WW(z.ast;)→ℓ+νℓ'-ν- the three most sensitive channels in this mass range, are 2.8σ, 2.1σ and 1.4σ, respectively. The global probability for the background to produce such a fluctuation anywhere in the explored Higgs boson mass range 110-600 GeV is estimated to be ~1.4% or, equivalently, 2.2σ. © 2012 CERN.Measurement of the W ±Z production cross section and limits on anomalous triple gauge couplings in proton-proton collisions at s=7 TeV with the ATLAS detector
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 709:4-5 (2012) 341-357
Abstract:
This Letter presents a measurement of W ±Z production in 1.02 fb -1 of pp collision data at s=7 TeV collected by the ATLAS experiment in 2011. Doubly leptonic decay events are selected with electrons, muons and missing transverse momentum in the final state. In total 71 candidates are observed, with a background expectation of 12.1±1.4(stat.)-2.0+4.1(syst.) events. The total cross section for W ±Z production for Z/γ * masses within the range 66 GeV to 116 GeV is determined to be σWZtot=20.5-2.8+3.1(stat.)-1.3+1.4(syst.)-0.8+0.9(lumi.) pb, which is consistent with the Standard Model expectation of 17.30.8+1.3 pb. Limits on anomalous triple gauge boson couplings are extracted. © 2012 CERN.Measurement of D *± meson production in jets from pp collisions at √s=7TeV with the ATLAS detector
Physical Review D - Particles, Fields, Gravitation and Cosmology 85:5 (2012)
Abstract:
This paper reports a measurement of D *± meson production in jets from proton-proton collisions at a center-of-mass energy of √s=7TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30pb -1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |η|<2.5. D *± mesons found in jets are fully reconstructed in the decay chain: D *+→D0π +, D0→K -π +, and its charge conjugate. The production rate is found to be N(D *±)/N(jet)=0.025±0. 001(stat.)±0.004(syst.) for D *± mesons that carry a fraction z of the jet momentum in the range 0.3Searches 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 +ν±ô-ν̄ Decay Channel in pp Collisions at √s=7TeV with the ATLAS Detector
Physical Review Letters 108:11 (2012)