A prompt photon cross section measurement from the Collider Detector at Fermilab experiment is presented. Detector and trigger upgrades, as well as six times the integrated luminosity compared with ...our previous publication, have contributed to a much more precise measurement and extended ital Psub ital T range. As before, QCD calculations agree qualitatively with the measured cross section, but the data has a steeper slope than the calculations.
The ital W+jet angular distribution is measured using ital Wminusgtital enu events recorded with the Collider Detector at Fermilab (CDF) during 1988--89 and 1992--93 Tevatron runs. The data agree ...well with both a leading order and a next-to-leading order theoretical prediction. The shape of the angular distribution is similar to that observed in photon+jet data, and significantly different from that observed in dijet data.
We present a measurement of the ratio sigmaital B(ital Wr arrowital ev)/sigmaital B(ital Zsup 0r arrowital esup +ital esup minus) in ital bar pp collisions at radicalital s =1.8 TeV. The data ...represent an integrated luminosity of 21.7 pbsup minus1 from the 1992--1993 run of the Collider Detector at Fermilab. We find sigmaital B(ital Wr arrowital eV)/sigmaital B(ital Zsup 0r arrowital esup +ital esup minus)=10.90plus minus0.32(stat)plus minus0.29(sys t). From this value, we extract a value for the ital W width, Gamma(ital W)=2.064plus minus0.061(stat)plus minus0.059(syst) GeV, and the branching ratio, Gamma(ital Wr arrowital eV)/Gamma(ital W)=0.1094plus minus0.0033(stat)plus minus0.0031(syst), and we set a decay-mode-independent limit on the top quark mass ital msub topgt62 GeV/ital csup 2 at the 95% C.L.
We summarize a search for the top quark with the Collider Detector at Fermilab (CDF) in a sample of ital bar pp collisions at radicalital s =1.8 TeV with an integrated luminosity of 19.3 pbsup ...minus1. We find 12 events consistent with either two ital W bosons, or a ital W boson and at least one ital b jet. The probability that the measured yield is consistent with the background is 0.26%. Though the statistics are too limited to establish firmly the existence of the top quark, a natural interpretation of the excess is that it is due to ital tbar t production. Under this assumption, constrained fits to individual events yield a top quark mass of 174plus minus10sub minus12sup +13 GeV/ital csup 2. The ital tbar t production cross section is measured to be 13.9sub minus4.8sup +6.1 pb.
The lifetimes of the ital Bsup + and ital Bsup 0 mesons have been measured using fully reconstructed decays. In a sample of similar to49 600ital J/psir arrowmusup +musup minus decays recorded with ...the Collider Detector at Fermilab, 148plus minus16 ital Bsup + and 121plus minus16ital Bsup 0 mesons have been reconstructed using the silicon vertex detector. Unbinned likelihood fits to the proper lifetime distributions of these ital B mesons give tausup +=1.61plus minus0.16 (stat)plus minus0.05 (syst) ps, tausup 0=1.57plus minus0.18 (stat) plus minus0.08 (syst) ps, and tausup +/tausup 0=1.02plus minus0.16 (stat) plus minus0.05 (syst).
If quarks are composite particles then excited states are expected. We have searched in ital pbar p collisions for excited quarks (ital qsup *) which decay to common quarks by emitting a ital W boson ...(ital qsup *r arrowital qW) or a photon (ital qsup *r arrowital qgamma). The simplest model of excited quarks has been excluded for mass ital Msup *lt540 GeV/ital csup 2 at 95% confidence level.
The dijet invariant mass distribution has been measured in the region between 140 and 1000 GeV/ital csup 2, in 1.8 TeV ital p bar p collisions. Data collected with the Collider Detector at Fermilab ...show agreement with QCD calculations. A limit on quark compositeness of Lambdasub ital cgt1.3 TeV is obtained. Axigluons with masses between 240 and 640 GeV/ital csup 2 are excluded at 95% C.L. if we assume ten open decay channels. Model-independent limits on the production of heavy particles decaying into two jets are also presented.
The average ital b-hadron lifetime has been measured using a high statistics sample of ital Br arrowital J/psi ital X decays recorded with the Collider Detector at Fermilab. The decay vertices of ...5344 inclusive ital J/psir arrowmusup +musup minus candidates have been reconstructed using information from a silicon vertex detector. The measured ital B lifetime, which is the average over all ital b hadrons produced in ital pbar p collisions at radicalital s =1.8 TeV weighted by their branching ratios into ital J/psi, is 1.46plus minus0.06(stat)plus minus0.06(syst) ps.
This Letter reports the observation and mass measurement of fully reconstructed ital Bsub ital ssup 0 mesons through the decay chain ital Bsub ital ssup 0r arrowital J/psi psi, ital J/psir arrowmusup ...+musup minus, phir arrowital Ksup +ital Kminus using data obtained at the Collider Detector at Fermilab in ital bar pp collisions at radicalital s =1.8 TeV. A signal of 14.0plus minus4.7 events is observed. Comparison of the ital Bsub ital ssup 0 signal with the kinematically similar decays ital Bsup +r arrowital J/psi ital Ksup + and ital Bsup 0r arrowital J/psi Ksup *(892)sup 0 is presented. The mass of the ital Bsub ital ssup 0 meson is determined to be 5383.3plus minus4.5(stat)plus minus5.0(syst) MeV/ital csup 2.
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