Branching fractions and $CP$-violating asymmetries of charmless ${\overline{B}}_s\to PP$, $VP$, $VV$ decays ($P$ and $V$ denoting pseudoscalar and vector mesons, respectively) are reexamined in the framework of QCD factorization (QCDF). We take into account subleading power corrections to the penguin annihilation topology and to color-suppressed tree amplitudes that are crucial for resolving the $CP$ puzzles and rate deficit problems with penguin-dominated two-body decays and color-suppressed tree-dominated ${\pi }^0{\pi }^0$ and ${\rho }^0{\pi }^0$ modes in the $B_{u,d}$ sector. Many of the $B_s\to h_1{h}_2$ decays can be related to $B_d\to h_1{h}_2$ ones via $U$-spin or SU(3) symmetry. Some useful model-independent relations can be derived and tested. Mixing-induced $CP$ asymmetries for many of the penguin-dominated decays are predicted to be very small in the standard model. They are sensitive to new physics and offer rich possibilities of new discoveries. Measurements of direct $CP$-violating asymmetries can be used to discriminate QCDF from other competing approaches such as pQCD and soft-collinear effective theory.

• Received 29 October 2009

DOI:https://doi.org/10.1103/PhysRevD.80.114026