• Energy Research

We report first evidence for a fully reconstructed decay mode of the B_c^{\pm} meson in the channel B_c^{\pm} \to J/psi ��^{\pm}, with J/psi \to mu^+mu^-. The analysis is based on an integrated luminosity of 360 pb$^{-1} in p\bar{p} collisions at 1.96 TeV center of mass energy collected by the Collider Detector at Fermilab. We observe 14.6 \pm 4.6 signal events with a background of 7.1 \pm 0.9 events, and a fit to the J/psi pi^{\pm} mass spectrum yields a B_c^{\pm} mass of 6285.7 \pm 5.3(stat) \pm 1.2(syst) MeV/c^2. The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%. 7 pages, 3 figures. Version 3, accepted by PRL

We describe a search for anomalous production of events with two leptons ($e$ or $��$) of the same electric charge in \ppbar 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 1 \invfb of integrated luminosity recorded by the CDF II detector, we observe no significant excess in an inclusive selection (expect $33.2\pm4.7$ events, observe 44) or in a SUSY-optimized selection (expect $7.8\pm1.1$ events, observe 13.) replaced with published version

We describe a general search for resonances decaying to a neutral e{mu} final state in p{bar p} collisions at a center-of-mass energy of 1.96 TeV. Using a data sample representing 344 pb{sup -1} of integrated luminosity recorded by the CDF II experiment, we compare Standard Model predictions with the number of observed events for invariant masses between 50 and 800 GeV/c{sup 2}. Finding no significant excess (5 events observed vs. 7.7 {+-} 0.8 expected for M{sub e{mu}} > 100 GeV/c{sup 2}), we set limits on sneutrino and Z' masses as functions of lepton family number violating couplings.

The Tevatron energy scan will present unique operational challenges for the CDF detector as a whole and the CLC luminosity detector in particular. The primary concern for CLC operations is the energy dependence of the p{bar p} cross section. In this note, values for the hadronic p{bar p} cross section at the center-of-mass energies to be visited during the scan are tabulated.