Measurement of Zγ production in pp̄ collisions at √s=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:3 (2010)
Abstract:
The production rate and kinematics of photons produced in association with Z bosons are studied using 2fb-1 of pp̄ collision data collected at the Collider Detector at Fermilab. The cross section for pp̄→"+-γ+X (where the leptons " are either muons or electrons with dilepton mass M>40GeV/c2, and where the photon has transverse energy ETγ>7GeV and is well separated from the leptons) is 4.6±0.2(stat)±0.3(syst)±0.3(lum)pb, which is consistent with standard model expectations. We use the photon ET distribution from Zγ events where the Z has decayed to μ+μ -, e+e-, or νν̄ to set limits on anomalous (non standard model) trilinear couplings between photons and Z bosons. © 2010 The American Physical Society.Search for the production of scalar bottom quarks in pp̄ collisions at √s=1.96TeV
Physical Review Letters 105:8 (2010)
Abstract:
We report on a search for direct scalar bottom quark (sbottom) pair production in pp̄ collisions at √s=1.96TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65fb-1 of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70GeV/c2, sbottom masses up to 230GeV/c2 are excluded at 95% confidence level. © 2010 The American Physical Society.Search for new color-octet vector particle decaying to tT{topbar} in pP{topbar} collisions at √s=1.96 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 691:4 (2010) 183-190
Abstract:
We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb-1 of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study tT{topbar} events in the lepton. +. jets channel with at least one b-tagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV/c2 and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space. © 2010 Elsevier B.V.Search for the production of scalar bottom quarks in pp collisions at square root(s) = 1.96 TeV.
Physical review letters 105:8 (2010) 081802
Abstract:
We report on a search for direct scalar bottom quark (sbottom) pair production in pp collisions at square root(s) = 1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65 fb(-1) of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70 GeV/c2, sbottom masses up to 230 GeV/c2 are excluded at 95% confidence level.Measurement of W-boson polarization in Top-Quark Decay in pp collisions at sqrt[s]=1.96 TeV.
Phys Rev Lett 105:4 (2010) 042002