Search results for "COLLIDER DETECTOR"
showing 10 items of 24 documents
Direct Bound on the Total Decay Width of the Top Quark inpp¯Collisions ats=1.96 TeV
2009
We present the first direct experimental bound on the total decay width of the top quark, Gamma(t), using 955 pb(-1) of the Tevatron's p (p) over bar collisions recorded by the Collider Detector at Fermilab. We identify 253 top-antitop pair candidate events. The distribution of reconstructed top quark mass from these events is fitted to templates representing different values of the top quark width. Using a confidence interval based on likelihood-ratio ordering, we extract an upper limit at 95% C.L. of Gamma(t) < 13.1 GeV for an assumed top quark mass of 175 GeV/c(2).
Measurement ofCP-violating asymmetries inB0→(ρπ)0decays using a time-dependent Dalitz plot analysis
2012
We report on a measurement of CP-violating asymmetries (A{sub CP}) in the Cabibbo-suppressed D{sup 0} {yields} {pi}{sup +}{pi}{sup -} and D{sup 0} {yields} K{sup +}K{sup -} decays reconstructed in a data sample corresponding to 5.9 fb{sup -1} of integrated luminosity collected by the upgraded Collider Detector at Fermilab. We use the strong decay D*{sup +} {yields} D{sup 0}{pi}{sup +} to identify the flavor of the charmed meson at production and exploit CP-conserving strong c{bar c} pair-production in p{bar p} collisions. High-statistics samples of Cabibbo-favored D{sup 0} {yields} K{sup -}{pi}{sup +} decays with and without a D*{sup {+-}} tag are used to correct for instrumental effects an…
Measurement of theWW+WZProduction Cross Section Using thelepton+jetsFinal State at CDF II
2010
We report two complementary measurements of the diboson (WW + WZ) cross section in the final state consisting of an electron or muon, missing transverse energy, and jets, performed using p{bar p} collision data at {radical}s = 1.96 TeV collected by the Collider Detector at Fermilab. The first method uses the dijet invariant mass distribution while the second method uses more of the kinematic information in the event through matrix-element calculations of the signal and background processes and has a higher sensitivity. The result from the second method has a signal significance of 5.4{sigma} and is the first observation of WW + WZ production using this signature. Combining the results from …
Measurement of Inclusive Jet Cross Sections inZ/γ*(→e+e−)+jetsProduction inpp¯Collisions ats=1.96 TeV
2008
Inclusive jet cross sections in Z/{gamma}* events, with Z/{gamma}* decaying into an electron-positron pair, are measured as a function of jet transverse momentum and jet multiplicity in p{bar p} collisions at {radical}s - 1.96 TeV with the upgraded Collider Detector at Fermilab in Run II, based on an integrated luminosity of 1.7 fb{sup -1}. The measurements cover the rapidity region |y{sup jet}| 30 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.
Measurement of thett¯production cross section with anin situcalibration ofb-jet identification efficiency
2011
A measurement of the top-quark pair-production cross section in ppbar collisions at sqrt{s}=1.96 TeV using data corresponding to an integrated luminosity of 1.12/fb collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states e nu + jets and mu nu + jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires that the measured cross sections with exactly one and multiple identified b-quarks from the top-quark decays agree. Assuming a top-quark mass of 175 GeV/c^2, a cross section of 8.5+/-0.6(stat.)+/-0.7(syst.) pb is measured.
Search for the supersymmetric partner of the top quark inpp¯collisions ats=1.96 TeV
2010
We present a search for the lightest supersymmetric partner of the top quark in proton-antiproton collisions at a center-of-mass energy root s = 1: 96 TeV. This search was conducted within the framework of the R parity conserving minimal supersymmetric extension of the standard model, assuming the stop decays dominantly to a lepton, a sneutrino, and a bottom quark. We searched for events with two oppositely-charged leptons, at least one jet, and missing transverse energy in a data sample corresponding to an integrated luminosity of 1 fb(-1) collected by the Collider Detector at Fermilab experiment. No significant evidence of a stop quark signal was found. Exclusion limits at 95% confidence …
Observation of Orbitally Excited Bs Mesons
2007
We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.
Search for Large Extra Dimensions in Final States Containing One Photon or Jet and Large Missing Transverse Energy Produced inpp¯Collisions ats=1.96 …
2008
We present the results of searches for large extra dimensions in samples of events with large missing transverse energy E_{T} and either a photon or a jet produced in pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II. For gamma+E_{T} and jet+E_{T} candidate samples corresponding to 2.0 and 1.1 fb;{-1} of integrated luminosity, respectively, we observe good agreement with standard model expectations and obtain a combined lower limit on the fundamental parameter of the large extra dimensions model M_{D} as a function of the number of extra dimensions in the model.
Search for anomalous production of events with two photons and additional energetic objects at CDF
2010
27 páginas, 17 figuras, 5 tablas.-- CDF Collaboration: et al.
Search for the Production of Scalar Bottom Quarks inpp¯Collisions ats=1.96 TeV
2010
We report on a search for direct scalar bottom quark (sbottom) pair production in pp collisions at {radical}(s)=1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a collider detector at Fermilab Run II data sample corresponding to 2.65 fb{sup -1} of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross se…