Production of the Upsilon (1S) meson in association with a vector boson is a rare process in the standard model with a cross section predicted to be below the sensitivity of the Tevatron. Observation ...of this process could signify contributions not described by the standard model or reveal limitations with the current nonrelativistic quantum-chromodynamic models used to calculate the cross section. We perform a search for this process using the full Run II data set collected by the CDF II detector corresponding to an integrated luminosity of 9.4 fb super(-1). The search considers the Upsilon arrow right mu mu decay and the decay of the W and Z bosons into muons and electrons. In these purely leptonic decay channels, we observe one Upsilon W candidate with an expected background of 1.2 + or - 0.5 events, and one Upsilon Z candidate with an expected background of 0.1 + or - 0.1 events. Both observations are consistent with the predicted background contributions. The resulting upper limits on the cross section for Upsilon + W/Z production are the most sensitive reported from a single experiment and place restrictions on potential contributions from non-standard-model physics.
If the technicolor omegasub T particle exists, a likely decay mode is omegasub Tr arrowgammapisub T , followed by pisub Tr arrowbbar b , yielding the signature gammabbar b . We have searched 85 pbsup ...minus1 of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result as an exclusion region in the Msub omegasub T-Msub pisub T mass plane. copyright ital 1999 ital The American Physical Society
We report on a search for the flavor-changing neutral current decays Bsup +r arrowmusup +musup minusKsup + and Bsup 0r arrowmusup +musup minusKsup *0 using 88 pbsup minus1 of data from bar pp ...collisions at radical (s) =1.8 TeV , collected with the Collider Detector at Fermilab. Finding no evidence for these decays, we set upper limits on the branching fractions B(Bsup +r arrowmusup +musup minusKsup +)lt5.2times10sup minus6 and B(Bsup 0r arrowmusup +musup minusKsup *0)lt4.0times10sup minus6 at the 90percent confidence level. copyright ital 1999 ital The American Physical Society
We present a search for like-sign dielectron plus multijet events using 107 pbsup minus1 of data in povr p collisions at radical (s) =1.8 TeV collected in 1992endash1995 by the CDF experiment. ...Finding no events that pass our selection, we set sigmatimesBR limits on two supersymmetric processes that can produce this experimental signature: gluino-gluino or squark-antisquark production with R -parity violating decays of the charm squark or lightest neutralino via a nonzero lambdasup primesub 121 coupling. We compare our results to the next-to-leading order calculations for gluino and squark production cross sections and set lower limits on M(tilde g) , M(tilde tsub 1) , and M(tilde q) . copyright ital 1999 ital The American Physical Society
A search is performed for heavy metastable particles that decay into jet pairs with a macroscopic lifetime (cτ˜1cm) in pp¯ collisions at s=1.96TeV using data from the CDF II detector at Fermilab ...corresponding to an integrated luminosity of 3.2fb-1. To estimate the standard model background, a data-driven approach is used. Probability-density functions are constructed to model secondary vertices from known processes. No statistically significant excess is observed above the background. Limits on the production cross section in a hidden valley benchmark phenomenology are set for various Higgs boson masses as well as metastable particle masses and lifetimes.
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