Dr Farrukh Azfar

Abstract:

We present a measurement of the inclusive jet cross section in pp̄ interactions at s=1.96TeV using 385pb-1 of data collected with the CDF II detector at the Fermilab Tevatron. The results are obtained using an improved cone-based jet algorithm (Midpoint). The data cover the jet transverse momentum range from 61 to 620GeV/c, extending the reach by almost 150GeV/c compared with previous measurements at the Tevatron. The results are in good agreement with next-to-leading order perturbative QCD predictions using the CTEQ6.1M parton distribution functions. © 2006 The American Physical Society.

Abstract:

We present the results of a search for new physics in the jets plus missing transverse energy data sample collected from 368pb-1 of pp̄ collisions at s=1.96TeV recorded by the Collider Detector at Fermilab. We compare the number of events observed in the data with a data-based estimate of the standard model backgrounds contributing to this signature. We observe no significant excess of events, and we interpret this null result in terms of lower limits on the fundamental Planck scale for a large extra dimensions scenario. © 2006 The American Physical Society.

Abstract:

We present a measurement of the tt̄ production cross section using events with one charged lepton and jets from pp̄ collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks coming from the event interaction vertex is applied to identify b quarks from top decay. Using 318pb-1 of data collected with the CDF II detector, we measure the tt̄ production cross section in events with at least one restrictive (tight) b-tagged jet and obtain 8.9-1.0+1.0(stat)-1.0+1.1(syst)pb. The cross section value assumes a top quark mass of mt=178GeV/c2 in the acceptance corrections. The dependence of the cross section on mt is presented in the paper. This result is consistent with other CDF measurements of the tt̄ cross section using different samples and analysis techniques, and has similar systematic uncertainties. We have also performed consistency checks by using the b-tagging probability function to vary the signal-to-background ratio and also using events that have at least two b-tagged jets. © 2006 The American Physical Society.

Abstract:

We report a measurement of the tt̄ production cross section using the CDF II detector at the Fermilab Tevatron. The analysis is performed using 311pb-1 of pp̄ collisions at s=1.96TeV. The data consist of events selected with six or more hadronic jets with additional kinematic requirements. At least one of these jets must be identified as a b-quark jet by the reconstruction of a secondary vertex. The cross section is measured to be σtt̄=7. 5±2.1(stat.)-2.2+3.3(syst.)-0.4+0.5(lumi.)pb, which is consistent with the standard model prediction. © 2006 The American Physical Society.

Abstract:

We present a measurement of RB, the ratio of the branching fraction for the rare decay D0→K+π- to that for the Cabibbo-favored decay D0→K-π+. Charge-conjugate decays are implicitly included. A signal of 2005±104 events for the decay D0→K+π- is obtained using the CDF II detector at the Fermilab Tevatron collider. The data set corresponds to an integrated luminosity of 0.35fb-1 produced in p̄p collisions at s=1.96TeV. Assuming no mixing, we find RB=[4.05±0.21(stat)±0.11(syst)] ×10-3. This measurement is consistent with the world average, and comparable in accuracy with the best measurements from other experiments. © 2006 The American Physical Society.