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Abstract:

We measure the ratio of cross section times branching fraction, Rp=σχc2B(χc2→J/ψγ)/σχc1B(χc1→J/ ψγ), in 1.1fb-1 of pp̄ collisions at s=1.96TeV. This measurement covers the kinematic range pT(J/ψ)>4.0GeV/c, η(J/ψ)<1.0, and pT(γ)>1.0GeV/c. For events due to prompt processes, we find Rp=0.395±0.016(stat)±0.015(syst). This result represents a significant improvement in precision over previous measurements of prompt χc1,2 hadro production. © 2007 The American Physical Society.

Abstract:

We describe a search for anomalous production of events with two leptons (e or μ) of the same electric charge in pp̄ collisions at a center-of-mass energy of 1.96 TeV. Many extensions to the standard model predict the production of two leptons of the same electric charge. This search has a significant increase in sensitivity compared to earlier searches. Using a data sample corresponding to 1fb-1 of integrated luminosity recorded by the CDF II detector, we observe no significant excess in an inclusive selection (expect 33.2±4.7 events, observe 44) or in a supersymmetry-optimized selection (expect 7.8±1.1 events, observe 13.) © 2007 The American Physical Society.

Abstract:

We present a measurement of the inclusive production cross section for Z bosons decaying to tau leptons in pp̄ collisions at s=1.96TeV. We use a channel with one hadronically-decaying and one electronically-decaying tau. This measurement is based on 350pb-1 of CDF Run II data. Using a sample of 504 opposite sign eτ events with a total expected background of 190 events, we obtain σ(pp̄→4Z)•B(Z→ττ)=264±23(stat) ±14(syst)±15(lumi)pb, in agreement with the next-to-next-to- leading order QCD prediction. This is the first CDF cross section measurement using hadronically-decaying taus in Run II. © 2007 The American Physical Society.

Abstract:

We present the results of a search for W′ boson decaying to electron-neutrino pairs in pp̄ collisions at a center-of-mass energy of 1.96 TeV, using a data sample corresponding to 205pb-1 of integrated luminosity collected by the CDF II detector at Fermilab. We observe no evidence for this decay mode and set limits on the production cross section times branching fraction, assuming the neutrinos from W′ boson decays to be light. If we assume the manifest left-right symmetric model, we exclude a W′ boson with mass less than 788GeV/c2 at the 95% confidence level. © 2007 The American Physical Society.