Measurements of direct CP violating asymmetries in charmless decays of strange bottom mesons and bottom baryons.
Phys Rev Lett 106:18 (2011) 181802
Abstract:
We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb(-1) of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, A(CP)(B(s)(0)→K(-)π(+))=+0.39±0.15(stat)±0.08(syst), and bottom baryons, A(CP)(Λ(b)(0)→pπ(-))=+0.03±0.17(stat)±0.05(syst) and A(CP)(Λ(b)(0)→pK(-))=+0.37±0.17(stat)±0.03(syst). In addition, we measure CP violation in B(0)→K(+)π(-) decays with 3.5σ significance, A(CP)(B(0)→K(+)π(-))=-0.086±0.023(stat)±0.009(syst), in agreement with the current world average. Measurements of branching fractions of B(s)(0)→K(+)K(-) and B(0)→π(+)π(-) decays are also updated.Invariant mass distribution of jet pairs produced in association with a W boson in pp collisions at sqrt[s]=1.96 TeV.
Phys Rev Lett 106:17 (2011) 171801
Abstract:
We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 fb(-1). The observed distribution has an excess in the 120-160 GeV/c(2) mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this Letter, we report studies of the properties of this excess.Measurement of the top quark mass in the lepton+jets channel using the lepton transverse momentum
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 698:5 (2011) 371-379
Abstract:
This Letter reports a measurement of the top quark mass, Mtop, in data from pp- collisions at s=1.96 TeV corresponding to 2.7 fb-1 of integrated luminosity at the Fermilab Tevatron using the CDF II detector. Events with the lepton+jets topology are selected. An unbinned likelihood is constructed based on the dependence of the lepton transverse momentum, PT, on Mtop. A maximum likelihood fit to the data yields a measured mass Mtop=176.9±8.0stat±2.7syst GeV/c2. In this measurement, the contribution by the jet energy scale uncertainty to the systematic error is negligible. The result provides an important consistency test for other Mtop measurements where explicit use of the jet energy is made for deriving the top quark mass. © 2011 Elsevier B.V.Measurement of the forward-backward asymmetry in the B→K(*) μ+μ- decay and first observation of the Bs0→μ+μ- decay
Physical Review Letters 106:16 (2011)
Abstract:
We reconstruct the rare decays B+→K+μ +μ-, B0→K*(892)0μ +μ-, and Bs0→(1020)μ+μ - in a data sample corresponding to 4.4fb-1 collected in pp̄ collisions at √s=1.96TeV by the CDF II detector at the Tevatron Collider. Using 121±16 B+→K+μ +μ- and 101±12 B0→K*0μ +μ- decays we report the branching ratios. In addition, we report the differential branching ratio and the muon forward-backward asymmetry in the B+ and B0 decay modes, and the K*0 longitudinal polarization fraction in the B0 decay mode with respect to the squared dimuon mass. These are consistent with the predictions, and most recent determinations from other experiments and of comparable accuracy. We also report the first observation of the Bs0→μ+μ- decay and measure its branching ratio BR(Bs0→μ+μ-)= [1.44±0.33±0.46]×10-6 using 27±6 signal events. This is currently the most rare Bs0 decay observed. © 2011 American Physical Society.Measurement of the mass difference between t and t quarks.
Phys Rev Lett 106:15 (2011) 152001