Measurement of the B0s→J/ψK0S branching fraction

Abstract

The B0s→J/ψK0S branching fraction is measured in a data sample corresponding to 0.41 fb−1 of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive tothe penguin contributions affecting the sin 2β measurement from B0→J/ψK0S. The time-integrated branching fraction is measured to be B(B0s→J/ψK0S)=(1.83±0.28)×10−5. This is the most precise measurement to date.