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

TL;DR

This paper analyzes six B meson decay modes involving axial-vector mesons using the perturbative QCD approach, providing predictions for branching ratios, polarization, and CP asymmetries, with results comparable to current data and future experimental accessibility.

Contribution

It offers the first detailed pQCD-based predictions for these specific B decay channels, including polarization and CP violation observables, and compares them with other theoretical approaches.

Findings

The branching ratio for $B^0 o a_1^+ a_1^-$ matches experimental data.

Other decay channels have predicted rates of $10^{-6}$ to $10^{-5}$.

Predictions for polarization and CP asymmetries can be tested in upcoming experiments.

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 $^3P_1$($^1P_1$) 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 $^3P_1$ meson $a_1$ and $^1P_1$ meson $b_1$.