Measurement of the Bs0→J/ψKS0 branching fraction

The Bs0→J/ψKS0 branching fraction is measured in a data sample corresponding to 0.41fb−1 of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2β measurement from B0→J/ψKS0. The time-integrated branching fraction is measured to be B(Bs0→J/ψKS0)=(1.83±0.28)×10−5. This is the most precise measurement to date.