Search for scalar top and scalar bottom quarks in p anti-p collisions at S**(1/2) = 1.8-TeV

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top quark decays to a charm quark and a neutralino, or scalar bottom quark decays to a bottom quark and a neutralino. The numbers of events that pass our selection for each process show no deviation from Standard Model expectations. We compare our results to next-to-leading order calculations for the scalar quark production cross sections to exclude regions in scalar quark-neutralino parameter space

Search for scalar top quark production in anti-p p collisions at S**(1/2) = 1.8-TeV

We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb-1 of p anti-p collisions at s**(1/2) = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c2 and scalar neutrino masses of at least 40 GeV/c2, we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios.We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb-1 of p anti-p collisions at s**(1/2) = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a scalar neutrino. The event signature for both decay scenarios is a lepton, missing transverse energy, and at least two b-quark jets. For a chargino mass of 90 GeV/c2 and scalar neutrino masses of at least 40 GeV/c2, we find no evidence for scalar top production and present upper limits on the production cross section in both decay scenarios

Search for the flavor changing neutral current decays B+ ---> muon+ muon- K+ and B0 ---> muon+ muon- K*0

We report on a search for the flavor-changing neutral current decays B^+ -> mu^+ mu^- K^+ and B^0 -> mu^+ mu^- K^{*0} using 88 pb^{-1} of data from p-pbar collisions at \sqrt{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(B^+ -> mu^+ mu^- K^+) mu^+ mu^-K^{*0}) < 4.0x10^{-6} at the 90% confidence level

Search for neutral supersymmetric Higgs bosons in p anti-p collisions at s**(1/2) = 1.8-TeV

We present the results of a search for neutral Higgs bosons produced in association with $b$ quarks in $p\bar{p}\to b\bar{b} \phi\to b\bar{b}b\bar{b}$ final states with $91 \pm 7$ pb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV recorded by the Collider Detector at Fermilab. We find no evidence of such a signal and the data is interpreted in the context of the neutral Higgs sector of the Minimal Supersymmetric extension of the Standard Model. With basic parameter choices for the supersymmetric scale and the stop quark mixing, we derive 95% C.L. lower mass limits for neutral Higgs bosons for \tb values in excess of 35

Direct measurement of the W boson width in p anti-p collisions at S**(1/2) = 1.8-TeV

This Letter describes a direct measurement of the $W$ boson total decay width, \gw, using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of 90\invpb, collected during the 1994--1995 run of the Fermilab Tevatron p\pbar collider. The width is determined by normalizing predicted signal and background distributions to 49844 \wenu candidates and 21806 \wmunu candidates in the transverse-mass region M_T<200\gev and then fitting the predicted shape to the 438 electron events and 196 muon events in the high-$M_T$ region, 100. The result is $\Gamma_W=2.04\pm0.11$(stat)$\pm0.09$(syst)GeV

Measurement of the top quark mass with the Collider Detector at Fermilab

This report describes a measurement of the top quark mass in \ppbar collisions at a center of mass energy of 1.8 TeV. The data sample was collected with the CDF detector during the 1992--95 collider run at the Fermilab Tevatron, and corresponds to an integrated luminosity of 106 \pb. Candidate $t\bar{t}$ events in the ``lepton+jets'' decay channel provide our most precise measurement of the top quark mass. For each event a top mass is determined by using energy and momentum constraints on the production of the \ttbar pair and its subsequent decay. A likelihood fit to the distribution of reconstructed masses in the data sample gives a top mass in the lepton+jets channel of 176.1\pm 5.1 (stat.)\pm 5.3 (syst.) \gevcc. Combining this result with measurements from the ``all-hadronic'' and ``dilepton'' decay topologies yields a top mass of 176.1\pm 6.6 \gevcc

Measurement of the inclusive jet cross-section in anti-p p collisions at s**(1/2) = 1.8-TeV

We present results from the measurement of the inclusive jet cross section for jet transverse energies from 40 to 465 GeV in the pseudo-rapidity range $0.1<|\eta|<0.7$. The results are based on 87 $pb^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron Collider. The data are consistent with previously published results. The data are also consistent with QCD predictions given the flexibility allowed from current knowledge of the proton parton distributions. We develop a new procedure for ranking the agreement of the parton distributions with data and find that the data are best described by QCD predictions using the parton distribution functions which have a large gluon contribution at high $E_T$ (CTEQ4HJ)