Observation of the suppressed Lambda 0 b rightarrow DpK - decay with D rightarrow K + pi - and measurement of its CP asymmetry
A study of baryon decays to the Dp\Km final state is presented based on a proton-proton collision data sample corresponding to an integrated luminosity of 9\invfb collected with the LHCb detector. Two decays are considered, \Lb→D\proton\Km with D→\Km\pip and D→\Kp\pim, where D represents a superposition of and states. The latter process is expected to be suppressed relative to the former, and is observed for the first time. The ratio of branching fractions of the two decays is measured, and the asymmetry of the suppressed mode, which is sensitive to the CKM angle γ, is also reported.