$B\to \pi \rho, \pi \omega$ 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 the 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 branching ratio of $B^0/\bar B^0 \to \pi^\pm\rho^\mp, B^\pm \to \pi^\pm\rho^0$, $\pi^\pm \omega$ measured by the CLEO and BABAR collaborations. We also predict large CP-asymmetries in these decays. These channels are useful to determine the CKM angle $\phi_2$.