First observation of the decay Bbar0s->D0K*0 and a measurement of the ratio of branching fractions Br(Bbar0s->D0K*0) / Br(Bbar0s->D0 rho0)

Abstract

The first observation of the decay B0s →D0K∗0 using pp data collected by the LHCb detector at a centreof- mass energy of 7 TeV, corresponding to an integrated luminosity of 36 pb−1, is reported. A signal of 34.4 ± 6.8 events is obtained and the absence of signal is rejected with a statistical significance of more than nine standard deviations. The B0s → D0K∗0 branching fraction is measured relative to that of B0→D0ρ0: B(B0s →D0 K∗0) B(B0→D0ρ0) = 1.48±0.34±0.15±0.12, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the ratio of the B0 and B0s hadronisation fractions