Eur. Phys. J. C (2023) 83: 186
https://doi.org/10.1140/epjc/s10052-023-11333-0

Regular Article - Theoretical Physics

Production of $X_b$ via $\mathrm{{\rm Y}}(5S,6S)$ radiative decays

¹ School of Physics and Physical Engineering, Qufu Normal University, 273165, Qufu, China
² School of Physical Science and Technology, Southwest University, 400715, Chongqing, China
³ Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China
⁴ School of Nuclear Science and Technology, University of Chinese Academy of Sciences, 101408, Beijing, China
⁵ Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, 516000, Huizhou, Guangdong, China

^c gli@qfnu.edu.cn

Received: 13 January 2023
Accepted: 12 February 2023
Published online: 1 March 2023

Abstract

We investigate the production of $X_b$ in the process $\mathrm{{\rm Y}}(5S,6S)\to \gamma X_b$, where $X_b$ is assumed to be a $B{\overline{B}}^{\ast }$ molecular state. Two kinds of meson loops of $B^{(\ast )}{\overline{B}}^{(\ast )}$ and $B_1^{\prime }{\overline{B}}^{(\ast )}$ were considered. To explore the rescattering mechanism, we calculated the relevant branching ratios using the effective Lagrangian based on the heavy quark symmetry. The branching ratios for the $\mathrm{{\rm Y}}(5S,6S)\to \gamma X_b$ were found to be at the orders of ${10}^{-7}\sim {10}^{-6}$. Such sizeable branching ratios might be accessible at BelleII, which would provide important clues to the inner structures of the exotic state $X_b$.