$B\to a_1(1260)a_1(1260)$ and $b_1(1235)b_1(1235)$ decays in the perturbative QCD approach

Abstract

In this work, we study six tree-dominated $B\to a_1(1260)a_1(1260)$ and $b_1(1235)b_1(1235)$ decays in the perturbative QCD(pQCD) approach, where $a_1$($b_1$) is a ${}^3{P}_1$(${}^1{P}_1$) axial-vector meson. Based on the perturbative calculations and phenomenological analysis, we find that: (a) the CP-averaged branching ratio of $B^0\to a_1^{+}{a}_1^{-}$ decay in the pQCD approach is $54.7\times 10^{-6}$, which agrees well with the current data and the predictions given in the QCD factorization approach within errors; (b) the numerical results for the decay rates of other five channels are found to be in the order of $10^{-6}\sim 10^{-5}$, which could be accessed at B factories and Large Hadron Collider(LHC) experiments; (c) other physical observables such as polarization fractions and direct CP-violating asymmetries are also investigated with the pQCD approach in the present work and the predictions can be confronted with the relevant experiments in the near future; (d) the different phenomenologies shown between $B\to a_1{a}_1$ and $B\to b_1{b}_1$ decays are expected to be tested by the ongoing LHC and forthcoming Super-B experiments, which could shed light on the typical QCD dynamics involved in these decay modes, as well as in ${}^3{P}_1$ meson $a_1$ and ${}^1{P}_1$ meson $b_1$.

Comments: 1 figure, 27 pages, references added, improved version. Accepted for publication in Phys. Rev. D