Abstract

The decay of B_s → D_s has long been assumed to be flavour-specific, that is the contribution from B_s → D_s⁺ + π^- is negligible or zero. The Standard Model predicts only a tiny contribution. To date, this assumption has never been explicitly tested despite the fact that many precision measurement at LHCb and elsewhere are based upon it. An analysis of the decay using the 2011 data from LHCb is presented.