$\bar{B}^0_s \to Kπ,KK$ decays and effects of the next-to-leading order contribution

Abstract

By employing the perturbative QCD(pQCD) factorization approach, we calculate the branching ratios and CP violating asymmetries of the four $\bar{B}_s^0 \to Kπ$ and $K K $ decays, with the inclusion of all known next-to-leading order (NLO) contributions. We find numerically that (a) the NLO contribution can interfere with the LO part constructively or destructively for different decay modes; (b) the NLO contribution leads to a $22\%$ decrease for $Br(\bar{B}^0_s \to K^+ π^-)$, but $\sim 50\%$ enhancements to other three considered $\bar{B}_s$ decays, and therefore play an important role in interpreting the measured values of the branching ratios; and (c) for both $\bar{B}_s^0 \to K^+ π^-$ and $\bar{B}_s^0 \to K^+K^- $ decays, the NLO pQCD predictions for the direct and mixing induced CP-violating asymmetries agree very well with the measured values in both the sign and the magnitude.