Dr Farrukh Azfar

Abstract:

We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon + muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV pp̄ collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to the Compton scattering process cg→cγ, with the final-state charm quark producing a muon. The cross section for events with a photon transverse momentum between 12 and 40 GeV/c is measured to be 46.8±6.3±7.5 pb, which is two standard deviations below the most recent theoretical calculation. A significant fraction of the events in the sample contain a final-state bottom quark. The ratio of charm to bottom production is measured to be 2.4±1.2, in good agreement with QCD models.

Abstract:

The inclusive cross section for J/Ψ production times the branching ratio B(J/Ψ→μ + μ - ) has been measured in the forward pseudorapidity region: B×dσ[p - +p→J/Ψ(p T >10 GeV/c,2.1<|η|<2.6)+X]/dη = 192±9(stat) ±29(syst) pb. The results are based on 74.1±5.2 pb -1 of data collected by the CDF Collaboration at the Fermilab Tevatron Collider. The measurements extend earlier measurements of the D0 Collaboration to higher p TJ/Ψ . In the kinematic range where the experiments partially overlap, these data are in good agreement with previous measurements.

Abstract:

We present measurements of the B+meson total cross section and differential cross section dσ/dpT. The measurements use a 98±4 pb-1sample of pp̄ collisions at √s=1.8 TeV collected by the CDF detector. Charged B meson candidates are reconstructed through the decay B±→J|ψ±with J|ψ→µ+µ-. The total cross section, measured in the central rapidity region |y|<1.0 for pT(B)>6.0 GeV/c, is 3.6±0.6(stat ⊕ syst) µb. The measured differential cross section is substantially larger than typical QCD predictions calculated to next-to-leading order.

Abstract:

We report a measurement of the ratio of the bottom quark production cross section in antiproton-proton collisions at (Formula Presented)=630 GeV to 1800 GeV using bottom quarks with transverse momenta greater than 10.75 GeV identified through their semileptonic decays and long lifetimes. The measured ratio σ(630)/ σ(1800) 50.171±.024±.012 is in good agreement with next-to-leading order quantum chromodynamics.

Abstract:

We have performed a search for radiative 6-hadron decays using events produced in pp̅ collisions at √s=1.8TeV and collected by the Collider Detector at Fermilab. The decays we considered were B0̅d→K*0(→K-π+γ, B0̅s→φ(→K+K-)γ,0b→γ(→p03C0-)γ), and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified by an electron-positron pair produced through the external photon conversion before the tracking detector volume. By combining the two methods we obtain upper limits on the branching fractions for the B0̅d, B0̅s and γ,0b radiative decays which, at the 95% confidence level, are found to be B(B0̅d→K*0γ<1.4×-4,B(B0̅d→φγ)<1.6×-4,and (γ,0b→γγ)<1.9×-3.