Measurement of the b jet cross section in events with a Z boson in pp̄ collisions at s=1.96TeV
Physical Review D Particles Fields Gravitation and Cosmology 74:3 (2006)
Abstract:
A measurement of the inclusive bottom jet cross section is presented for events containing a Z boson in pp̄ collisions at s=1.96TeV using the Collider Detector at Fermilab. Z bosons are identified in their electron and muon decay modes, and b jets with ET>20GeV and |η|<1.5 are identified by reconstructing a secondary decay vertex. The measurement is based on an integrated luminosity of about 330pb-1. A cross section times branching ratio of σ(Z+bjets)×B(Z→ℓ+ℓ-)=0.93±0.36pb is found, where B(Z→ℓ+ℓ-) is the branching ratio of the Z boson or γ* into a single flavor dilepton pair (e or μ) in the mass range between 66 and 116GeV/c2. The ratio of b jets to the total number of jets of any flavor in the Z sample, within the same kinematic range as the b jets, is 2.36±0.92%. Here, the uncertainties are the quadratic sum of statistical and systematic uncertainties. Predictions made with next-to-leading order QCD agree, within experimental and theoretical uncertainties, with these measurements. © 2006 The American Physical Society.Measurement of B (t → W b) / B (t → W q) at sqrt(s) = 1.96 TeV
Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 639:6 (2006) 616-622
Abstract:
We present the measurement of R = B (t → W b) / B (t → W q) in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV, using 230 pb-1 of data collected by the DØ experiment at the Fermilab Tevatron Collider. We fit simultaneously R and the number (NMeasurement of the Bs0-B̄s0 oscillation frequency
Physical Review Letters 97:6 (2006)
Abstract:
We present the first precise measurement of the Bs0-B̄s0 oscillation frequency Δms. We use 1fb-1 of data from pp̄ collisions at s=1.96TeV collected with the CDF II detector at the Fermilab Tevatron. The sample contains signals of 3600 fully reconstructed hadronic Bs decays and 37000 partially reconstructed semileptonic Bs decays. We measure the probability as a function of proper decay time that the Bs decays with the same, or opposite, flavor as the flavor at production, and we find a signal consistent with Bs0-B̄s0 oscillations. The probability that random fluctuations could produce a comparable signal is 0.2%. Under the hypothesis that the signal is due to Bs0-B̄s0 oscillations, we measure Δms=17.31-0.18+0.33(stat)±0. 07(syst)ps-1 and determine |Vtd/Vts|=0.208-0.002+0.001(expt)-0.006+0.008(theor). © 2006 The American Physical Society.Measurement of the isolated photon cross section in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 639:3-4 (2006) 151-158
Abstract:
The cross section for the inclusive production of isolated photons has been measured in p over(p, ̄) collisions at sqrt(s) = 1.96 TeV with the DØ detector at the Fermilab Tevatron Collider. The photons span transverse momenta 23 to 300 GeV and have pseudorapidity | η | < 0.9. The cross section is compared with the results from two next-to-leading order perturbative QCD calculations. The theoretical predictions agree with the measurement within uncertainties. © 2006 Elsevier B.V. All rights reserved.A search for t → τ ν q in t t ¯ production
Physics Letters B Elsevier BV 639:3-4 (2006) 172-178