Observation of the B0d and B0s mesons in the decays B0d → J/ψK∗0 and B0s → J/ψφ in ATLAS

The production of B0d and B0s mesons is observed in ATLAS through their decays B0d → J/ψ K∗0 and B0s→J/ψφ . Presented results are based on the analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 40.3 pb−1. A total of 2340 ± 80 (stat) B0d signal decays are observed after subtracting the background, with a fitted mass of 5279.6 ± 0.9 (stat) MeV. For the B0s signal 358 ± 22 (stat) decays are observed, with a fitted mass of 5364.0 ± 1.4 (stat) MeV. Within the statistical uncertainties, the fitted masses of both B mesons are consistent with the world average values.