We describe a general search for resonances decaying to a neutral e{mu} final state in pp 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 Collider Detector at Fermilab 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{sup '} masses as functions of lepton family number violating couplings.
We present a measurement of the tt production cross section in pp collisions at {radical}(s)=1.96 TeV which uses events with an inclusive signature of significant missing transverse energy and jets. ...This is the first measurement which makes no explicit lepton identification requirements, so that sensitivity to W{yields}{tau}{nu} decays is maintained. Heavy flavor jets from top quark decay are identified with a secondary vertex tagging algorithm. From 311 pb{sup -1} of data collected by the Collider Detector at Fermilab, we measure a production cross section of 5.8{+-}1.2(stat){sub -0.7}{sup +0.9}(syst) pb for a top quark mass of 178 GeV/c{sup 2}, in agreement with previous determinations and standard model predictions.
We search for pair-produced Dirac magnetic monopoles in 35.7 pb{sup -1} of proton-antiproton collisions at {radical}(s)=1.96 TeV with the Collider Detector at Fermilab (CDF). We find no monopole ...candidates corresponding to a 95% confidence-level cross-section limit {sigma}<0.2 pb for a monopole with mass between 200 and 700 GeV/c{sup 2}. Assuming a Drell-Yan pair-production mechanism, we set a mass limit m>360 GeV/c{sup 2}.
We searched for scalar bottom quarks in 156 pb{sup -1} of pp collisions at {radical}(s)=1.96 TeV recorded by the Collider Detector at Fermilab II experiment at the Tevatron. Scalar bottom quarks can ...be produced from gluino decays in R-parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar bottom quark. Then, a scalar bottom quark can decay into a bottom quark and a neutralino. To search for this scenario, we investigated events with large missing transverse energy and at least three jets, two or more of which were identified as containing a secondary vertex from the hadronization of b quarks. We found four candidate events, where 2.6{+-}0.7 are expected from standard model processes, and placed 95% confidence level lower limits on gluino and scalar bottom quark masses of up to 280 and 240 GeV/c{sup 2}, respectively.
We report a search for the anomalous production of events with multiple charged leptons in pp collisions at {radical}(s)=1.96 TeV using a data sample corresponding to an integrated luminosity of 346 ...pb{sup -1} collected by the CDF II detector at the Fermilab Tevatron. The search is divided into three-lepton and four-or-more-lepton data samples. We observe six events in the three-lepton sample and zero events in the {>=}4-lepton sample. Both numbers of events are consistent with standard model background expectations. Within the framework of an R-parity-violating supergravity model, the results are interpreted as mass limits on the lightest neutralino ({chi}-tilde{sub 1}{sup 0}) and chargino ({chi}-tilde{sub 1}{sup {+-}}) particles. For one particular choice of model parameters, the limits are M({chi}-tilde{sub 1}{sup 0})>110 GeV/c{sup 2} and M({chi}-tilde{sub 1}{sup {+-}})>203 GeV/c{sup 2} at 95% confidence level; the variation of these mass limits with model parameters is presented.
We present the first observation of the baryon decay {lambda}{sub b}{sup 0}{yields}{lambda}{sub c}{sup +}{pi}{sup -} followed by {lambda}{sub c}{sup +}{yields}pK{sup -}{pi}{sup +} in 106 pb{sup -1} ...pp collisions at {radical}(s)=1.96 TeV in the CDF experiment. In order to reduce systematic error, the measured rate for {lambda}{sub b}{sup 0} decay is normalized to the kinematically similar meson decay B{sup 0}{yields}D{sup +}{pi}{sup -} followed by D{sup +}{yields}{pi}{sup +}K{sup -}{pi}{sup +}. We report the ratio of production cross sections ({sigma}) times the ratio of branching fractions (B) for the momentum region integrated above p{sub T}>6 GeV/c and pseudorapidity range |{eta}|<1.3: {sigma}(pp{yields}{lambda}{sub b}{sup 0}X)/{sigma}(pp{yields}B{sup 0}X)xB({lambda}{sub b}{sup 0}{yields}{lambda}{sub c}{sup =} +{pi}{sup -})/B(B{sup 0}{yields}D{sup +}{pi}{sup -})=0.82{+-} 0.08(stat){+-}0.11(syst){+-}0.22B({lambda}{sub c}{sup +}{yields}pK{sup -}{pi}{sup +}).
We report a measurement of the {lambda}{sub b}{sup 0} lifetime in the exclusive decay {lambda}{sub b}{sup 0}{yields}J/{psi}{lambda}{sup 0} in pp collisions at {radical}(s)=1.96 TeV using an ...integrated luminosity of 1.0 fb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. Using fully reconstructed decays, we measure {tau}({lambda}{sub b}{sup 0})=1.593{sub -0.078}{sup +0.083}(stat){+-}0.033(syst) ps. This is the single most precise measurement of {tau}({lambda}{sub b}{sup 0}) and is 3.2{sigma} higher than the current world average.
We report on a measurement of the inclusive jet production cross section as a function of the jet transverse momentum in pp collisions at {radical}(s)=1.96 TeV using data collected with the upgraded ...Collider Detector at Fermilab in run II, corresponding to an integrated luminosity of 385 pb{sup -1}. The measurement is carried out for jets with rapidity 0.1< vertical bar y{sup jet} vertical bar<0.7 and transverse momentum in the range 54<p{sub T}{sup jet}<700 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross section after the necessary nonperturbative parton-to-hadron corrections are included.
We measure the dipion mass spectrum in X(3872){yields}J/{psi}{pi}{sup +}{pi}{sup -} decays using 360 pb{sup -1} of pp collisions at {radical}(s)=1.96 TeV collected with the CDF II detector. The ...spectrum is fit with predictions for odd C-parity ({sup 3}S{sub 1}, {sup 1}P{sub 1}, and {sup 3}D{sub J}) charmonia decaying to J/{psi}{pi}{sup +}{pi}{sup -}, as well as even C-parity states in which the pions are from {rho}{sup 0} decay. The latter case also encompasses exotic interpretations, such as a D{sup 0}D*{sup 0} molecule. Only the {sup 3}S{sub 1} and J/{psi}{rho} hypotheses are compatible with our data. Since {sup 3}S{sub 1} is untenable on other grounds, decay via J/{psi}{rho} is favored, which implies C=+1 for the X(3872). Models for different J/{psi}-{rho} angular momenta L are considered. Flexibility in the models, especially the introduction of {rho}-{omega} interference, enables good descriptions of our data for both L=0 and 1.
We report an upper limit on the fraction of V+A current, f{sub V+A}, in top-quark decays, using approximately 700 pb{sup -1} of pp collisions at {radical}(s)=1.96 TeV acquired by the upgraded ...Collider Detector at Fermilab. For the decay t{yields}Wb{yields}l{nu}b (where l=e or {mu}), the invariant mass of the charged lepton and the bottom quark jet is sensitive to the polarization of the W boson. We determine f{sub V+A}=-0.06{+-}0.25 given a top-quark mass of 175 GeV/c{sup 2}. We set an upper limit on f{sub V+A} of 0.29 at the 95% confidence level, an improvement by a factor of 2 on the previous best direct limit.
PDF