Branching fraction and CP asymmetry of the decays B+→KS0π+ and B+→KS0K+

Abstract

An analysis of B+→KS0π+ and B+→KS0K+ decays is performed with the LHCb experiment. The pp collision data used correspond to integrated luminosities of 1fb-1 and 2fb-1 collected at centre-of-mass energies of √s=7TeV and √s=8TeV, respectively. The ratio of branching fractions and the direct CP asymmetries are measured to be B(B+→KS0K+)/B(B+→KS0π+)=0.064±0.009 (stat.)±0.004(syst.), ACP(B+→KS0π+)=-0.022±0.025(stat.)±0.010 (syst.) and ACP(B+→KS0K+)=-0.21±0.14 (stat.)±0.01 (syst.). The data sample taken at √s=7 TeV is used to search for Bc+→KS0K+ decays and results in the upper limit (fc{dot operator}B(Bc+→KS0K+))/(fu{dot operator}B(B+→KS0π+))<5.8×10-2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a b- quark into a Bc+ or a B+ meson, respectively. © 2013 CERN.