Search for Higgs bosons produced in association with b quarks
Physical Review D - Particles, Fields, Gravitation and Cosmology 85:3 (2012)
Abstract:
We present a search for neutral Higgs bosons decaying into bb̄, produced in association with b quarks in pp̄ collisions. This process could be observable in supersymmetric models with high values of tanβ. The event sample corresponds to 2.6fb -1 of integrated luminosity collected with the CDF II detector at the Fermilab Tevatron collider. We search for an enhancement in the mass of the two leading jets in events with three jets identified as coming from b quarks using a displaced vertex algorithm. A data-driven procedure is used to estimate the dijet mass spectrum of the nonresonant multijet background. The contributions of backgrounds and a possible Higgs boson signal are determined by a two-dimensional fit of the data, using the dijet mass together with an additional variable which is sensitive to the flavor composition of the three tagged jets. We set mass-dependent limits on σ(pp̄→)×B(→bb̄) which are applicable for a narrow scalar particle produced in association with b quarks. We also set limits on tanβ in supersymmetric Higgs models including the effects of the Higgs boson width. © 2012 American Physical Society.An improved measurement of muon antineutrino disappearance in MINOS
(2012)
Measurement of the branching fraction B(Λb0→Λc+π -π +π -) at CDF
Physical Review D - Particles, Fields, Gravitation and Cosmology 85:3 (2012)
Abstract:
We report an analysis of the Λb0→Λc+π -π +π - decay in a data sample collected by the CDF II detector at the Fermilab Tevatron corresponding to 2.4fb -1 of integrated luminosity. We reconstruct the currently largest samples of the decay modes Λb0→Λ c(2595) +π - (with Λ c(2595) +→Λc+π +π -), Λb0→Λ c(2625) +π - (with Λ c(2625) +→Λc+π +π -), Λb0→Σ c(2455) ++π -π - (with Σ c(2455) ++→Λc+π +), and Λb0→Σ c(2455)0π +π - (with Σ c(2455)0→Λc+π -) and measure the branching fractions relative to the Λb0→Λc+π - branching fraction. We measure the ratio B(Λb0→Λc+π -π +π -)/B(Λb0→Λc+π -)=3.04±0.33(stat)-0.55+0.70(syst) which is used to derive B(Λb0→Λc+π -π +π -)= (26.8-11.2+11.9)×10 -3. © 2012 American Physical Society.Measurement of the cross section for the production of a W boson in association with b-jets in pp collisions at √s=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 ±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±1.9(stat)±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. © 2011 CERN.Measurement of the top quark pair production cross section in pp collisions at √s=7TeV in dilepton final states with ATLAS
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 707:5 (2012) 459-477