k_T factorization of exclusive B decays

Abstract

I compare collinear and $k_T$ factorization theorems in perturbative QCD, and discuss their application to exclusive $B$ meson decays. Especially, I concentrate on the recently measured time-dependent CP asymmetry of the $B_d^0\to {\pi }^{+}{\pi }^{-}$ modes, from which the unitarity angle can be extracted.

Comments: 4 pages, talk presented at the XXXVIIIth Rencontres de Moriond session on QCD And High Energy Hadronic Interactions, Les Arcs 1800, France, Mar. 22-29, 2003