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Register a new userCombination of CDF and D0 Limits on a Gauge Mediated SUSY Model Using Diphoton and Missing Transverse Energy Channel
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We combine the results of the CDF and D0 searches for chargino and neutralino production in Gauge-Mediated SUSY using the two-photon and missing Et channel. The data are p-pbar collisions produced at the Tevatron with sqrt(s)=1.96 TeV, with 202 pb^-1 collected at CDF and 263 pb^-1 collected at D0. The combined limit excludes a chargino mass less than 209 GeV/c^2. This result significantly extends the individual experimental limits.
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We summarize and combine direct measurements of the mass of the $W$ boson in $sqrt{s} = 1.96 text{TeV}$ proton-antiproton collision data collected by CDF and D0 experiments at the Fermilab Tevatron Collider. Earlier measurements from CDF and D0 are combined with the two latest, more precise measurements: a CDF measurement in the electron and muon channels using data corresponding to $2.2 mathrm{fb}^{-1}$ of integrated luminosity, and a D0 measurement in the electron channel using data corresponding to $4.3 mathrm{fb}^{-1}$ of integrated luminosity. The resulting Tevatron average for the mass of the $W$ boson is $MW = 80,387 pm 16 text{MeV}$. Including measurements obtained in electron-positron collisions at LEP yields the most precise value of $MW = 80,385 pm 15 text{MeV}$.
We report the combination of recent measurements of the helicity of the W boson from top quark decay by the CDF and D0 collaborations, based on data samples corresponding to integrated luminosities of 2.7 - 5.4 fb^-1 of ppbar collisions collected during Run II of the Fermilab Tevatron Collider. Combining measurements that simultaneously determine the fractions of W bosons with longitudinal (f0) and right-handed (f+) helicities, we find f0 = 0.722 pm 0.081 [pm 0.062 (stat.) pm 0.052 (syst.)] and f+ = -0.033 pm 0.046 [pm 0.034 (stat.) pm 0.031 (syst.)]. Combining measurements where one of the helicity fractions is fixed to the value expected in the standard model, we find f0 = 0.682 pm 0.057 [pm 0.035 (stat.) pm 0.046 (syst.)] and f+ = -0.015pm0.035 [pm 0.018 (stat.) pm 0.030 (syst.)]. The results are consistent with standard model expectations.
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 $Hto bbar{b}$ 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 $Hto bbar{b}$ 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.
We summarize the current top quark mass ($m_t$) measurements from the CDF and D0 experiments at Fermilab. We combine published results from Run I (1992--1996) with the most precise published and preliminary Run II (2001--2011) measurements based on $pbar{p}$ data corresponding to up to $9.7:{rm fb}^{-1}$ of $pbar{p}$ collisions. Taking correlations of uncertainties into account, and combining the statistical and systematic contributions in quadrature, the preliminary Tevatron average mass value for the top quark is $m_t = 174.30 pm 0.65:mathrm{GeV}/c^{2}$, corresponding to a relative precision of $0.37%$
We combine the results of CDF and DO searches for the rare decays B_s to mu+ mu- and B_d to mu+ mu-. The experiments use 364 pb-1 and 300 pb-1 of data respectively. The limits on the branching ratios are obtained by normalizing the estimated sensitivity to the decay B+ to J/psi K+, taking into account the fragmentation ratios f_u/f_s(d). The combined results exclude branching ratios of BR(B_s to mu+ mu-) > 1.5x10-7 and BR(B_d to mu+ mu- > 4.0x10-8 at 95% confidence level. These are the most stringent limits on these decays at the present time.
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