$B\to \pi \rho$, $\pi \omega$ Decays in Perturbative QCD Approach

Abstract

We calculate the branching ratios and CP asymmetries for $B^0\to {\pi }^{+}{\rho }^{-}$, $B^0\to {\rho }^{+}{\pi }^{-}$, $B^{+}\to {\rho }^{+}{\pi }^0$, $B^{+}\to {\pi }^{+}{\rho }^0$, $B^0\to {\pi }^0{\rho }^0$, $B^{+}\to {\pi }^{+}\omega$ and $B^0\to {\pi }^0\omega$ decays, in a perturbative QCD approach. In this approach, we calculate non-factorizable and annihilation type contributions, in addition to the usual factorizable contributions. Our result is in agreement with the measured branching ratio of $B^0/{\bar{B}}^0\to {\pi }^{\pm }{\rho }^{\mp }$, $B^{\pm }\to {\pi }^{\pm }{\rho }^0$, ${\pi }^{\pm }\omega$ by CLEO and BABAR collaboration. We also predict large CP asymmetries in these decays. These channels are useful to determine the CKM angle ${\varphi }_2$.

Comments: 29 pages, Latex, higher twist wave functions are included