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

Abstract

We investigate the production of $X_b$ in the process ${\rm Y}(5S,6S)\to \gamma X_b$, where $X_b$ is assumed to be a $B{\bar{B}}^{\ast }$ molecular state. Two kinds of meson loops of $B^{(\ast )}{\bar{B}}^{(\ast )}$ and $B_1^{\prime }{\bar{B}}^{(\ast )}$ 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 ${\rm Y}(5S,6S)\to \gamma X_b$ 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 $X_b$.

Comments: 9 pages, 2 figures, comments are welcome