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Abstract:

We present a measurement of the forward-backward charge asymmetry of the process pp¯ → Z0/γ + X, Z0/γ → e+e− at Mee > MZ using 110 pb−1 of data at √ s = 1.8 TeV collected at the Collider Detector at Fermilab. The measured charge asymmetries are 0.43 ± 0.10 in the invariant mass region Mee > 105 GeV/c2, and 0.070 ± 0.016 in the region 75 < Mee < 105 GeV/c2. These results are consistent with the standard model values of 0.528 ± 0.009 and 0.052 ± 0.002, respectively. © 1996 The American Physical Society.

Abstract:

The properties of high-mass multijet events produced at the Fermilab proton-antiproton collider are compared with leading order QCD matrix element predictions, QCD parton shower Monte Carlo predictions, and the predictions from a model in which events are distributed uniformly over the available multibody phase space. Multijet distributions corresponding to ([Formula presented]) variables that span the [Formula presented]-body parameter space are found to be well described by the QCD calculations for inclusive three-jet, four-jet, and five-jet events. The agreement between data, QCD matrix element calculations, and QCD parton shower Monte Carlo predictions suggests that 2→2 scattering plus gluon radiation provides a good first approximation to the full LO QCD matrix element for events with three, four, or even five jets in the final state. © 1996 The American Physical Society.

Abstract:

The lifetimes of the B- and B−0 mesons are measured using the partially reconstructed semileptonic decays B−→D1-v−X, where D is either a D0 or D*+ meson. The data were collected by the CDF detector at the Fermilab Tevatron collider during 1992-1993 and correspond to 19.3 pb−1 of p−p collisions at s = 1.8 TeV. We measure the decay length distributions and find the lifetimes to be τ(B−) = 1.56±0.13±0.06 ps and τ(B−0) = 1.54±0.08±0.06 ps, and the ratio of lifetimes to be τ(B−)/τ(B−0) = 1.01±0.11±0.02, where the first uncertainties are statistical and the second are systematic. © 1996 The American Physical Society.

Abstract:

We report on a measurement of the branching fraction of the Cabibbo-suppressed decay B⁺u→J/ψπ⁺, where J/ψJ/ψμ⁺μ^-. The data were collected by the Collider Detector at Fermilab during 1992–1995 and correspond to an integrated luminosity of 110pb^-1 in pp collisions at √s=1.8TeV. A signal of 28⁺¹⁰-9 events is observed and we determine the ratio of branching fractions B(B⁺u→J/ψπ⁺)/B(B⁺u→J/ψ°­⁺) to be [5.0^+1.9-1.7(stat)±0.1(syst)]%. Using the world average value for B(B⁺u→J/ψπ⁺), we calculate the branching fraction B(B⁺u→J/ψπ⁺) to be (5.0^+2.1-1.9)×10^-5. We also search for the decay B⁺c→J/ψπ⁺ and report a 95% confidence level limit on σ(B⁺c)B⁺c→J/ψπ⁺/σ(µþ⁺u)B(B⁺u→J/ψ°­⁺) as a function of the B+c lifetime. © 1996 The American Physical Society.

Abstract:

We measure the mass of the B0s meson by reconstructing the decay chain B0s→J/ψφ, J/ψ→µ+µ-, and φ→K+K-. The data are obtained from 19.3 pb-1 of integrated luminosity of pp collisions at √s=1.8 TeV using the Collider Detector at Fermilab. A sample of 80 000 inclusive J/ψ→µ+µ- events is used to study systematic biases in track reconstruction and to calibrate the momentum scale. We reconstruct the kinematically similar decays B+→J/ψ°­+ and B0→J/ψ°­*0 to study the mass measurement technique used for the B0s meson. Based on the observation of 32 ± 6 candidates, the mass of the B0s meson is measured to be 5369.9 ± 2.3 ± 1.3 MeV/c2 and the mass difference between B0s and the average mass of B+ and B0 is determined to be 89.7 ± 2.7 ± 1.2 MeV/c2. © 1996 The American Physical Society.