Measurement of W-boson polarization in top-quark decay using the full CDF Run II data set
Physical Review D - Particles, Fields, Gravitation and Cosmology 87:3 (2013)
Abstract:
We measure the polarization of W bosons from top-quark (t) decays into final states with a charged lepton and jets, tt̄→W+bW -b̄→ℓνbqq̄′b̄, using the full Run II data set collected by the CDF II detector, corresponding to an integrated luminosity of 8.7 fb-1. A model-independent method simultaneously determines the fraction of longitudinal (f0) and right-handed (f+) W bosons to yield f0=0.726±0. 066(stat)±0.067(syst) and f+=-0.045±0.044(stat) ±0.058(syst) with a correlation coefficient of -0.69. Additional results are presented under various standard model assumptions. No significant discrepancies with the standard model are observed. © 2013 American Physical Society.Observation of the production of a W boson in association with a single charm quark
Physical Review Letters 110:7 (2013)
Abstract:
The first observation of the production of a W boson with a single charm quark (c) jet in pp̄ collisions at √s=1.96 TeV is reported. The analysis uses data corresponding to 4.3 fb-1, recorded with the CDF II detector at the Fermilab Tevatron. Charm quark candidates are selected through the identification of an electron or muon from charm-hadron semileptonic decay within a hadronic jet, and a Wc signal is observed with a significance of 5.7 standard deviations. The production cross section σ Wc(pTc>20 GeV/c,|ηc|<1.5) ×B(W→ℓν) is measured to be 13.6-3.1+3.4 pb and is in agreement with theoretical expectations. From this result the magnitude of the quark-mixing matrix element Vcs is derived, |Vcs|=1. 08±0.16 along with a lower limit of |Vcs|>0.71 at the 95% confidence level, assuming that the Wc production through c to s quark coupling is dominant. © 2013 American Physical Society.Updated search for the standard model Higgs boson in events with jets and missing transverse energy using the full CDF data set
(2013)
Updated search for the standard model Higgs boson in events with jets and missing transverse energy using the full CDF data set
ArXiv 1301.444 (2013)
Abstract:
We present an updated search for the Higgs boson produced in association with a vector boson in the final state with missing transverse energy and two jets. We use the full CDF data set corresponding to an integrated luminosity of 9.45 fb${}^{-1}$ at a proton-antiproton center-of-mass energy of $\sqrt{s}=1.96$ TeV. New to this analysis is the inclusion of a $b$-jet identification algorithm specifically optimized for $H\to b\bar{b}$ searches. Across the Higgs boson mass range $90 \le m_H \le 150$ GeV$/c^2$, the expected 95% credibility level upper limits on the $V H$ production cross section times the $H\to b\bar{b}$ branching fraction are improved by an average of 14% relative to the previous analysis. At a Higgs boson mass of 125 GeV$/c^2$, the observed (expected) limit is 3.06 (3.33) times the standard model prediction, corresponding to one of the most sensitive searches to date in this final state.Measurement of the Bc-meson lifetime in the decay Bc-→J/ψπ
Physical Review D - Particles, Fields, Gravitation and Cosmology 87:1 (2013)