Charmless two-body B meson decays in the perturbative QCD factorization approach* *Supported by the National Science Foundation of China (11805060, 11975112, 12105028, 12070131001, 11775117), the Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1932110), the Natural Science Foundation of Jiangsu Province (BK20200980) and the National Key Research and Development Program of China (2020YFA0406400)

Abstract

The perturbative quantum chromodynamics (PQCD) approach based on factorization has resulted in great achievements in the QCD calculation of hadronic B decays. By regulating the endpoint divergence by the transverse momentum of quarks in the propagators, one can perform the perturbation calculation for various diagrams, including annihilation type diagrams. In this paper, we review the current status of the PQCD factorization calculation of two-body charmless U decays up to next-to-leading order (NLO) QCD corrections. Two new power suppressed terms in the decaying amplitudes are also considered. Using universal input (non-perturbative) parameters, we collect the branching ratios and asymmetry parameters of all charmless two body B decays, which are calculated in the PQCD approach up to NLO. The results are compared with those of the QCD factorization approach, soft-collinear effective theory approach, and current experimental measurements. For most of the considered B meson decays, the PQCD results for branching ratios agree well with those of other approaches and experimental data. The PQCD predictions for the asymmetry parameters of many of the decay channels do not agree with those of other approaches but have better agreement with experimental data. The longstanding puzzle regarding the pattern of the direct CP asymmetries of penguin-dominated decays can be understood after the inclusion of NLO contributions in PQCD. The NLO corrections and power suppressed terms play an important role in color suppressed and pure annihilation type B decay modes. These rare decays are more sensitive to different types of corrections, providing an opportunity to examine the factorization approach with more precise experimental measurements.