Measurement of CP asymmetries in two-body B0(s)-meson decays to charged pions and kaons

摘要

The time-dependent CP asymmetries in B~0→π~+π~- and B_s~0→K~+K~- decays are measured using adata sample of p p collisions corresponding to an integrated luminosity of 3.0 fb~-1, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The same data sample is used to measure the time-integrated CP asymmetries in B~0→K~+π~- and B_s~0→π~+K~-decays. The results are C_π+_π-=-0.34±0.06±0.01,S_π+_π-=-0.63±0.05±0.01,C_(K+K-)=0.20±0.06±0.02, S_(K+K-)=0.18±0.06±0.02,A_(K~+K~-)~(ΔΓ)=-0.79±0.07±0.10,A_(CP)~(B~0)=-0.084±0.004±0.003,and A_(CP)~(B_s~0)=0.213±0.015±0.007,where the first uncertainties are statistical and the second systematic. Evidence for CP violation is found in the B_s~0→K+K- decay for the first time.