A measurement of the b quark cross section in pp collisions is presented for b quarks with PT above 11.5 GeV/c and rapidity [parallel]y[parallel]

A measurement of the b quark cross section in pp collisions is presented for b quarks with PT above 11.5 GeV/c and rapidity [parallel]y[parallel]

The study of b quarks at high energy hadron colliders tests the Standard Model in regions of small [chi] and high transverse momentum. The method used to measure the b quark cross section using the semileptonic decay to muons is outlined. A preliminary CDF muon cross section is given using data from the 88--89 run, and a plot of the measured b quark cross section compared to other CDF preliminary results is shown.

We present the measurement of the top quark pair production cross section in p{bar p} collisions at √s = 1.96 TeV using 318 pb−1 of data collected by the CDF detector at the Fermilab Tevatron. We measure the cross section in events with one high transverse momentum electron or muon, large missing transverse energy and three or more jets, where at least one bottom quarks from the top quark decay is identified via a secondary vertex tagging algorithm. The measured t{bar t} cross section is 8.7{sub -0.9}{sup +0.9}(stat){sub -0.9}{sup +1.2}(syst) pb, assuming a top quark mass of 178 GeV. The cross section measurement in the subsample in which both b-quark jets are identified gives 10.1{sub -1.4}{sup +1.6}(stat){sub -1.4}{sup +2.1}(syst) pb. We present one additional measurement of the t{bar t} cross section in the same dataset but without the b-tagging requirement. Top quark events are distinguished from the primary background of W boson production with associated jets using an artificial neural network method with a variety of kinematic quantities. This measurement uses a larger dataset albeit with a smaller t{bar t} fraction. The t{bar t} cross section without b-tagging is measured to be 6.0 ± 0.8(stat) ± 1.0(syst) pb.

The BABAR experiment at SLAC provides an opportunity for measurement of CP violation in B decays. A measurement of time-dependent CP violating asymmetries using exclusive B meson decays where the b quark decays to c[bar c]d (including B[sup 0][yields] D*[sup+]D*[sup -] and B[sup 0][yields] D*[sup[+-]]D[sup[-+]] decays) is presented here. This is the first measurement of CP violation in a mode sensitive to the Unitarity Triangle parameter sin2[beta] outside of decays containing charmonium. It provides a comparison to measurements of sin2[beta] using b[yields] c[bar c]s, and permits an observation into potential new physics sources of CP violation, such as supersymmetry, via differences between these measurements and those of B[sup 0][yields] J/[psi] K[sub S][sup 0] as statistics of reconstructed neutral B decays to D[sup (*)+] D[sup (*)-] increase. The measured value of the time-dependent CP violating asymmetries are: S= 0.38[+-] 0.88(stat)[+-] 0.12(syst) and C= -0.30[+-] 0.50(stat)[+-] 0.13(syst) for B[sup 0][yields] D*[sup -] D[sup+]; S= -0.43[+-] 1.41(stat)[+-] 0.23(syst) and C= 0.53[+-] 0.74(stat)[+-] 0.15(syst) for B[sup 0][yields] D*[sup+] D[sup -]; and S= -0.05[+-] 0.45(stat)[+-] 0.05(syst) and C= 0.12[+-] 0.30(stat)[+-] 0.05(syst) for B[sup 0][yields] D*[sup -] D[sup+]; where S corresponds to CP violation in the interference of mixing and decay and C corresponds to CP violation in decay.

We present the measurement of the top quark pair production cross section in p{bar p} collisions at √s = 1.96 TeV using 318 pb−1 of data collected by the CDF detector at the Fermilab Tevatron. We measure the cross section in events with one high transverse momentum electron or muon, large missing transverse energy and three or more jets, where at least one bottom quarks from the top quark decay is identified via a secondary vertex tagging algorithm. The measured t{bar t} cross section is 8.7{sub -0.9}{sup +0.9}(stat){sub -0.9}{sup +1.2}(syst) pb, assuming a top quark mass of 178 GeV. The cross section measurement in the subsample in which both b-quark jets are identified gives 10.1{sub -1.4}{sup +1.6}(stat){sub -1.4}{sup +2.1}(syst) pb. We present one additional measurement of the t{bar t} cross section in the same dataset but without the b-tagging requirement. Top quark events are distinguished from the primary background of W boson production with associated jets using an artificial neural network method with a variety of kinematic quantities. This measurement uses a larger dataset albeit with a smaller t{bar t} fraction. The t{bar t} cross section without b-tagging is measured to be 6.0 ± 0.8(stat) ± 1.0(syst) pb.