Cover Story (Issue 12, 2022) | Charmless two-body B meson decays in theperturbative QCD factorization approach

Authors: Jian Chai，Shan Cheng，Yao-hui Ju，Da-Cheng Yan，Cai-Dian Lü，Zhen-Jun Xiao

Abstract：The perturbative quantum chromodynamics(PQCD) approach based on kT factorization has resultedin 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 B→PP, PV, VVU decays up to next-to-leading order (NLO) QCD corrections. Two new power suppressed terms in the decaying amplitudes arealso considered. Using universal input (non-perturbative) parameters, wecollect the branching ratios and CP 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 the oryapproach, 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 CP asymmetry parameters of many ofthe decay channels do not agree with those of other approaches but have better agreement with experimental data. The longstanding kπ puzzleregarding the pattern of the direct CP asymmetries of penguin-dominated B→kπ 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 decaymodes. These rare decays are more sensitive to different types of corrections, providing an opportunity to examine the factorization approach with moreprecise experimental measurements.

Keywords: B decays, CP violation,pQCD approach