$B\to K{K}^{\ast }$ Decays in the Perturbative QCD Approach

Abstract

We calculate the branching ratios and CP-violating asymmetries for $B^0\to K^0\text{ov}{K}^{\ast 0}$, $\text{ov}{K}^0{K}^{\ast 0}$, $K^{+}{K}^{\ast -}$, $K^{-}{K}^{\ast +}$, and $B^{+}\to K^{+}\text{ov}{K}^{\ast 0}$ and $\text{ov}{K}^0{K}^{\ast +}$ decays by employing the low energy effective Hamiltonian and the perturbative QCD (pQCD) factorization approach. The theoretical predictions for the branching ratios are $Br(B^0/\text{ov}{B}^0\to K^{\pm }{K}^{\ast \mp })\approx 7.4\times 10^{-8}$, $Br(B^0/\text{ov}{B}^0\to K^0\text{ov}{K}^{\ast 0}(\text{ov}{K}^0{K}^{\ast 0}))\approx 19.6\times 10^{-7}$, $Br(B^{+}\to K^{+}\text{ov}{K}^{\ast 0})\approx 3\times 10^{-7}$ and $Br(B^{+}\to K^{\ast +}\text{ov}{K}^0)\approx 18.3\times 10^{-7}$, which are consistent with currently available experimental upper limits. We also predict large CP-violating asymmetries in these decays: $A_{CP}^{dir}(K^{\pm }\text{ov}{K}^{\ast 0})\approx -20$, $A_{CP}^{dir}(K^{\ast \pm }\text{ov}{K}^0)\approx -49$, which can be tested by the forthcoming B meson experiments.

Comments: 25 pages, 7 figures, RevTex, some corrections on the numerical results and contents, typos removed, new references added