Investigations on the light hadron decays of $Z_b(10610)$ and $Z_b(10650)$

TL;DR

This study calculates the decay rates of $Z_b(10610)$ and $Z_b(10650)$ into light mesons using an effective Lagrangian, providing predictions that can be tested in future experiments to understand their nature.

Contribution

It introduces a molecular state model for $Z_b$ states and evaluates their light hadron decay branching ratios considering intermediate meson loops.

Findings

Branching ratios for $Z_b(10610)$ decays are around 10^{-2}.

Branching ratios for $Z_b(10650)$ decays are around 10^{-3}.

Decay ratios depend on the $ heta_P$ mixing angle, offering experimental testability.

Abstract

The light hadron decay processes of $Z_b(10610)/Z_b(10650)$ provide us a way to study their nature and decay mechanism. In this work, we evaluate the branching ratios of $Z_b(10610)/Z_b(10650) \to VP$ ($V$ and $P$ stand for light vector and pseudoscalar mesons, respectively) using an effective Lagrangian approach, in which the contributions of intermediate bottomed meson triangle loops are considered. In our calculations, the $Z_b(10610)$ and $Z_b(10650)$ are regarded as $B\bar{B}^*+c.c.$ and $B^*\bar{B}^*$ molecular states, respectively. The predicted branching ratios of $Z_b(10610)\rightarrow VP$ are about in the order of $10^{-2}$, while the branching ratios of $Z_b(10650)\rightarrow VP$ are in the order of $10^{-3}$. Furthermore, the dependence of these ratios between different decay modes of $Z_b(10610)/Z_b(10650)$ on the mixing $\eta-\eta^\prime$ angle $\theta_P$ is investigated, which may be a good quantity for the experiments. It is hoped that the calculations here could be tested by future experiments.