Branching Ratio and CP Asymmetry of $B^0 \to η^{(\prime)} η^{(\prime)}$ Decays in the Perturbative QCD Approach

Abstract

We calculate the CP averaged branching ratios and CP-violating asymmetries for $B^0 \to ηη, ηη^\prime$ and $η^\prime η^\prime$ decays by employing the perturbative QCD (pQCD) factorization approach. The pQCD predictions for the CP-averaged branching ratios are $Br(B^0 \to ηη) \approx 0.67 \times 10^{-7}$, $Br(B^0 \to ηη^\prime) \approx 0.18 \times 10^{-7}$, and $Br(B^0 \to η^{\prime} η^{\prime}) \approx 0.11 \times 10^{-7}$, which are consistent with currently available experimental upper limits. We also predict large CP-violating asymmetries for the considered three decay modes, which can be tested by the future B meson experiments.