Branching Ratio and CP Asymmetry of $B \to \rho \eta^{(\prime)}$ Decays in the Perturbative QCD Approach

In this paper, we calculate the branching ratios and CP-violating asymmetries for B-0->rho(0)eta((')) and B+->rho(+)eta((')) decays in the perturbative QCD factorization approach. In this approach, we not only calculate the usual factorizable contributions, but also evaluate the nonfactorizable and annihilation type contributions. Besides the current-current operators, the contributions from the QCD and electroweak penguin operators are also taken into account. The theoretical predictions for the branching ratios are Br(B+->rho(+)eta((')))approximate to 9x10(-6) and Br(B-0->rho(0)eta((')))approximate to 5x10(-8), which agree well with the measured values and currently available experimental upper limits. We also predict large CP-violating asymmetries in these decays: A(CP)(dir)(rho(+/-)eta)approximate to-13%, A(CP)(dir)(rho(+/-)eta('))approximate to-18%, A(CP)(dir)(rho(0)eta)approximate to-41%, A(CP)(dir)(rho(0)eta('))approximate to-27%, A(CP)(mix)(rho(0)eta)approximate to+25%, and A(CP)(mix)(rho(0)eta('))approximate to+11%, which can be tested by the current or future B factory experiments.