ATLAS search for a heavy gauge boson decaying to a charged lepton and a neutrino in pp collisions at √s =7 TeV
European Physical Journal C 72:12 (2012)
Abstract:
The ATLAS detector at the LHC is used to search for high-mass states, such as heavy charged gauge bosons (Wʹ), decaying to a charged lepton (electron or muon) and a neutrino. Results are presented based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.7 fb−1. No excess beyond Standard Model expectations is observed. AWʹ with Sequential Standard Model couplings is excluded at the 95% credibility level for masses up to 2.55 TeV. Excited chiral bosons (W*) with equivalent coupling strength are excluded for masses up to 2.42 TeV.Measurement of CP-violating asymmetries in D0→π+π- and D0→K+K- decays at CDF
Physical Review D American Physical Society (APS) 85:1 (2012) 012009
Measurement of the W boson polarization in top quark decays with the ATLAS detector
Journal of High Energy Physics 2012:6 (2012)
Abstract:
This paper presents measurements of the polarization ofW bosons in top quark decays, derived from tt̄ events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data from pp collisions at a centre-of-mass energy of 7 TeV were collected with the ATLAS experiment at the LHC and correspond to an integrated luminosity of 1.04 fb-1. The measured fractions of longitudinally, left- and right-handed polarization are F0 = 0.67 ± 0.07, FL = 0.32 ± 0.04 and FR = 0.01 ± 0.05, in agreement with the Standard Model predictions. As the polarization of the W bosons in top quark decays is sensitive to the Wtb vertex Lorentz structure and couplings, the measurements were used to set limits on anomalous contributions to the Wtb couplings. © CERN.Measurements of the tt¯ forward-backward asymmetry at CDF
Proceedings of Science 2012-July (2012)
Abstract:
At next-to-leading order in QCD, the tt¯ forward-backward asymmetry in s = 1.96 TeV pp¯ collisions receives non-zero contributions from interference between leading-order and next-to-leading order exclusive tt¯ production, and interference between the leading-order diagrams of tt¯ production with a radiated gluon. CDF measurements of the asymmetry differ from the predictions at the ˜ 2s level, with maximum deviations at high tt¯ invariant mass. The measurements are performed in the tt¯ semileptonic decay using the full CDF data set, and in the tt¯ fully leptonic decay using data corresponding to 5.1 fb-1 of integrated luminosity.Search for heavy metastable particles decaying to jet pairs in pp¯ collisions at s=1.96 TeV
Physical Review D American Physical Society (APS) 85:1 (2012) 012007