Revisiting B- K ∗ π and B- Kρ decays using the modified perturbative QCD approach

We revisit B- K*pi and B- K rho decay processes using the modified perturbative QCD approach, which is developed based on the perturbative QCD approach with a few improvements. A critical infrared cutoff scale mu cis introduced to separate hard and soft contributions in the decay process. Hard contributions with scale mu larger than mu care calculated with perturbative QCD, and soft contributions with mu < mu(c) are described in terms of soft transition and production form factors. In addition, color-octet contributions are considered phenomenologically. The branching fractions and CP violations of B- K*pi, K rho decays are calculated. With appropriate parameter inputs, the theoretical results can be in good agreement with experimental data.