Accelerator Neutrinos

Abstract:

A measurement of the mass of the W boson is presented based on a sample of 5982 W → eν decays observed in pp^¯ collisions at √s = 1.8 TeV with the D0 detector during the 1992-1993 run. From a fit to the transverse mass spectrum, combined with measurements of the Z boson mass, the W boson mass is measured to be MW = 80.350 ± 0.140(stat) ± 0.165(syst) ± 0.160(scale) GeV/c². © 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/ψK⁺) 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(B⁺u)B(B⁺u→J/ψK⁺) 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/ψK+ and B0→J/ψK*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.

Abstract:

We present a study of events with Z bosons and hadronic jets produced in ¯p p collisions at a center-of-mass energy of 1.8 TeV. The data consist of 6708 Z → e⁺e^- decays from 106pb^-1 of integrated luminosity collected using the CDF detector at the Fermilab Tevatron Collider. The Z+ ≥ n jet cross sections and jet production properties have been measured for n = 1 to 4. The data are compared to predictions of leading-order QCD matrix element calculations with added gluon radiation and simulated parton fragmentation. © 1996 The American Physical Society.

Abstract:

We report a measurement of the ratios of the decay rates of the B+, B0, and B0s mesons into exclusive final states containing a J/Ψ meson. The final states were selected from 19.6 pb-1 of pp collisions recorded by the Collider Detector at Fermilab. These data are interpreted to determine the b quark fragmentation fractions fu, fd, and fs. We also determine the branching fractions for the decay modes (formula presented). We discuss the implications of these measurements to B meson decay models. © 1996 The American Physical Society.