Phenomenological analysis of charmless decays $B_s\to PP,PV$ with QCD factorization

We calculate the CP-averaged branching ratios and CP-violating asymmetries of two-body charmless hadronic decays of $B_s\to PP,PV$ with the QCD factorization approach (here P and V denote pseudoscalar and vector mesons, respectively), including contributions from the chirally enhanced power corrections and weak annihilations. Only several decay modes, such as $B_s\to K^{\left(*\right)}K,$ $K^{\left(*\right)\pm }{\pi }^{\mp },$ $K^{\pm }{\rho }^{\mp },$ ${\eta }^{(\prime )}{\eta }^{(\prime )},$ have large branching ratios, which may be observed in the near future. We also discuss $B_s\to K^{+}{K}^{-},$ $K^0{K}^0$ decays which could overconstrain the penguin-to-tree ratio $|P_{\pi \pi }{/T}_{\pi \pi }|$ of $\overrightarrow{B}{\pi }^{+}{\pi }^{-}$ decays and give a bound on the Cabibbo-Kobayashi-Maskawa angle $\gamma .$