Branching ratios of $B_c \to A P $ decays in the perturbative QCD approach

TL;DR

This paper calculates the branching ratios of 32 charmless $B_c o A P$ decays using the perturbative QCD approach, revealing their ranges, dependencies, and differences based on meson types and CKM factors.

Contribution

First calculation of $B_c o A P$ decay branching ratios via pQCD, analyzing their magnitudes, dependencies, and meson type effects within the standard model.

Findings

BRs range from 10^{-6} to 10^{-8}

BRs of $ riangle S=0$ decays are larger than $ riangle S=1$

BRs for $^1P_1$ mesons are generally larger than for $^3P_1$

Abstract

In this paper we calculate the branching ratios (BRs) of the 32 charmless hadronic $B_c \to A P$ decays ($A=a_1(1260),b_1(1235),K_1(1270),K_1(1400), f_1(1285),f_1(1420),h_1(1170),h_1(1380)$) by employing the perturbative QCD(pQCD) factorization approach. These considered decay channels can only occur via annihilation type diagrams in the standard model. From the numerical calculations and phenomenological analysis, we found the following results: (a) the pQCD predictions for the BRs of the considered $B_c$ decays are in the range of $10^{-6}$ to $10^{-8}$, while the CP-violating asymmetries are absent because only one type tree operator is involved here; (b) the BRs of $\Delta S= 0$ processes are generally much larger than those of $\Delta S =1$ ones due to the large CKM factor of $|V_{ud}/V_{us}|^2\sim 19$; (c) since the behavior for $^1P_1$ meson is much different from that of $^3P_1$ meson, the BRs of $B_c \to A(^1P_1) P$ decays are generally larger than that of $B_c \to A(^3P_1) P$ decays; (d) the pQCD predictions for the BRs of $B_c \to (K_1(1270), K_1(1400)) \etap $ and $(K_1(1270), K_1(1400)) K$ decays are rather sensitive to the value of the mixing angle $\theta_K$.