Observation of and evidence for decays

Measurements of the branching fractions of and decays are performed using a data sample corresponding to of proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of , where the mesons are econstructed in the final state. The first observation of the decay and the first evidence for the decay are reported with branching fractions where the first uncertainties are statistical and the second are systematic. In addition, an upper limit of is set at confidence level.