Observation of B0 s→K 7 K ∓ and evidence for B0 s→K − π + decays

Abstract

Measurements of the branching fractions of → ± ∓ B KK * s 0 and → π± ∓ B K* s 0 decays are performed using a data sample corresponding to − 1.0 fb 1 of protonproton collision data collected with the LHCb detector at a centre-of-mass energy of 7 TeV, where the ± K* mesons are reconstructed in the π± KS 0 final state. The first observation of the → ± ∓ B KK * s 0 decay and the first evidence for the → π− + B K* s 0 decay are reported with branching fractions   π → = ±± × → = ±± × ±∓ − − + − ( ) ( ) B KK B K * (12.7 1.9 1.9) 10 , * (3.3 1.1 0.5) 10 , s s 0 6 0 6 where the first uncertainties are statistical and the second are systematic. In addition, an upper limit of  →<× ±∓ − ( ) B KK * 0.4 (0.5) 10 0 6 is set at 90% (95%) confidence level.