Measurement of the mass of the Bs0 meson

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.