The PQCD approach towards to next-to-leading order: a short review

Abstract

In this short review we elaborate the significance of resummation in $k_T$ factorization theorem, and summarize the recent progresses in the calculations of the next-to-leading order contributions to B meson decays from the perturbative QCD (PQCD) approach. We also comment on the current status of the PQCD approach and highlight some key issues to develop it in the near future for more phenomenological applications.

Comments: Typos corrected. Matches the version published on Frontiers of Physics