94,473 research outputs found

    2012 Update of the Combination of CDF and D0 Results for the Mass of the W Boson

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    We summarize and combine the results on the direct measurements of the mass of the W boson in data collected by the Tevatron experiments CDF and D0 at Fermilab. Earlier results from CDF Run-0 (1988--1989), D0 and CDF Run-I (1992--1995) and D0 results from 1/fb (2002--2006) of Run-II data are now combined with two new, high statistics Run-II measurements: a CDF measurement in both electron and muon channels using 2.2/fb of integrated luminosity collected between 2002 and 2007, and a D0 measurement in the electron channel using 4.3/fb collected between 2006 and 2009. As in previous combinations, the results are corrected for inconsistencies in parton distribution functions and assumptions about electroweak parameters used in the different analyses. The resulting Tevatron average for the mass of the W boson is Mw = 80387 +- 16 MeV and a new world average including data from LEP II is Mw = 80385+- 15 MeV.Comment: 11 pages, 1 figur

    Precision Electroweak Measurements and Constraints on the Standard Model

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    This note presents constraints on Standard Model parameters using published and preliminary precision electroweak results measured at the electron-positron colliders LEP and SLC. The results are compared with precise electroweak measurements from other experiments, notably CDF and D{\O}at the Tevatron. Constraints on the input parameters of the Standard Model are derived from the combined set of results obtained in high-Q2Q^2 interactions, and used to predict results in low-Q2Q^2 experiments, such as atomic parity violation, M{\o}ller scattering, and neutrino-nucleon scattering. The main changes with respect to the experimental results presented in 2008 are new combinations of results on the W-boson mass and the mass of the top quark.Comment: 18 page