Abstract
The procedure of k_T factorization proof in PQCD method is shown, by considering the radiative corrections to πγ*→γ. In this report, the proof of the k_T factorization is demonstrated at O(α_s) diagrams as a simple example. This demonstration supplies us, however, the key points toward the all-order proof of k_T factorization theorem for exclusive B meson decays.
