Search for narrow resonances lighter than Υ mesons
European Physical Journal C 62:2 (2009) 319-326
Abstract:
We report a search for narrow resonances, produced in p p̄ collisions at √ s=1.96 TeV, that decay into muon pairs with invariant mass between 6.3 and 9.0 GeV/c 2. The data, collected with the CDF II detector at the Fermilab Tevatron collider, correspond to an integrated luminosity of 630 pb -1. We use the dimuon invariant mass distribution to set 90% upper credible limits of about 1% to the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the Υ(1S) meson. © 2009 Springer-Verlag.Search for WW and WZ production in lepton plus jets final state at CDF
Physical Review D - Particles, Fields, Gravitation and Cosmology 79:11 (2009)
Abstract:
We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in s=1.96TeV pp̄ collisions at the Fermilab Tevatron, using data corresponding to 1.2fb-1 of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of σWW×BR(W→ν,W→jets)+σWZ×BR(W→ ν ,Z→jets)<2.88pb, which is consistent with the standard model next-to-leading-order cross section calculation for this decay channel of 2.09±0.12pb. © 2009 The American Physical Society.Evidence for a narrow near-threshold structure in the J/psivarphi mass spectrum in B;{+} --> J/psivarphiK;{+} decays.
Phys Rev Lett 102:24 (2009) 242002
Abstract:
Evidence is reported for a narrow structure near the J/psivarphi threshold in exclusive B;{+} --> J/psivarphiK;{+} decays produced in p[over]p collisions at sqrt[s] = 1.96 TeV. A signal of 14 +/- 5 events, with statistical significance in excess of 3.8 standard deviations, is observed in a data sample corresponding to an integrated luminosity of 2.7 fb;{-1}, collected by the CDF II detector. The mass and natural width of the structure are measured to be 4143.0 +/- 2.9(stat) +/- 1.2(syst) MeV/c;{2} and 11.7_{-5.0};{+8.3}(stat) +/- 3.7(syst) MeV/c;{2}.Measurement of particle production and inclusive differential cross sections in pp̄ collisions at s=1.96TeV
Physical Review D - Particles, Fields, Gravitation and Cosmology 79:11 (2009)
Abstract:
We report a set of measurements of particle production in inelastic pp̄ collisions collected with a minimum-bias trigger at the Tevatron Collider with the CDF II experiment. The inclusive charged particle transverse momentum differential cross section is measured, with improved precision, over a range about ten times wider than in previous measurements. The former modeling of the spectrum appears to be incompatible with the high particle momenta observed. The dependence of the charged particle transverse momentum on the event particle multiplicity is analyzed to study the various components of hadron interactions. This is one of the observable variables most poorly reproduced by the available Monte Carlo generators. A first measurement of the event transverse energy sum differential cross section is also reported. A comparison with a pythia prediction at the hadron level is performed. The inclusive charged-particle differential production cross section is fairly well reproduced only in the transverse momentum range available from previous measurements. At higher momentum the agreement is poor. The transverse energy sum is poorly reproduced over the whole spectrum. The dependence of the charged particle transverse momentum on the particle multiplicity needs the introduction of more sophisticated particle production mechanisms, such as multiple parton interactions, in order to be better explained. © 2009 The American Physical Society.Measurement of the k(T) distribution of particles in jets produced in pp collisions at sqrt(s)=1.96 TeV.
Phys Rev Lett 102:23 (2009) 232002