We present a search for a Higgs boson decaying to two W bosons in pp collisions at √ s = 1.96TeV center-of-mass energy. The data sample corresponds to an integrated luminosity of 3.0 fb −1 collected with the CDF II detector. We find no evidence for production of a Higgs boson with mass between 110 and 200 GeV/c 2 , and determine upper limits on the production cross section. For the mass of 160 GeV/c 2 , where the analysis is most sensitive, the observed (expected) limit is 0.7 pb (0.9 pb) at 95% Bayesian credibility level which is 1.7 (2.2) times the standard model cross section.

We present a new measurement of the inclusive forward-backward tt production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb −1 of pp collisions at √ s = 1.96 TeV, recorded with the CDF II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the tt rest frame, and in both cases are found to be consistent with CP conservation under interchange of t andt. In the tt rest frame, the asymmetry is observed to increase with the tt rapidity difference, ∆y, and with the invariant mass M tt of the tt system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large ∆y and M tt . For M tt ≥ 450 GeV/c 2 , the parton-level asymmetry in the tt rest frame is A tt = 0.475 ± 0.114 compared to a next-to-leading order QCD prediction of 0.088 ± 0.013.

We have measured the W -boson mass MW using data corresponding to 2.2 fb −1 of integrated luminosity collected in pp collisions at √ s = 1.96 TeV with the CDF II detector at the Fermilab Tevatron collider. Samples consisting of 470 126 W → eν candidates and 624 708 W → µν candidates yield the measurement MW = 80 387 ± 12stat ± 15syst = 80 387 ± 19 MeV/c 2 . This is the most precise measurement of the W -boson mass to date and significantly exceeds the precision of all previous measurements combined. PACS numbers: 13.38.Be, 14.70.Fm, 12.15.Ji, 13.85.Qk The mass of the W boson, M W , is an important parameter of the standard model (SM) of particle physics. Precise measurements of M W and of other electroweak observables significantly constrain the mass of the as-yet * Deceased † With visitors from

We report the first observation of single top quark production using 3.2 fb −1 of pp collision data with √ s = 1.96 TeV collected by the Collider Detector at Fermilab. The significance of the observed data is 5.0 standard deviations, and the expected sensitivity for standard model production and decay is in excess of 5.9 standard deviations. Assuming mt = 175 GeV/c 2 , we measure a cross section of 2.3 +0.6 −0.5 (stat + syst) pb, extract the CKM matrix element value |V tb | = 0.91 ± 0.11(stat + syst) ± 0.07(theory), and set the limit |V tb | > 0.71 at the 95% C.L.

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