Production of $B\bar{B}$ bound state via ${\rm Y}(4S)$ radiative decays

Abstract

Motivated by recent theoretical predictions about the existence of a $B\bar{B}$ bound state (also denoted as $X(10550)$), in this work we estimate the production of the $S$-wave $B^{+}{B}^{-}$ molecule via ${\rm Y}(4S)$ radiative decays. In particular, we make use of effective Lagrangian approach and the compositeness condition to calculate the $X(10550)$ production rate via ${\rm Y}(4S)\to \gamma X(10550)$ decays employing triangle diagrams. Our results show that the partial decay width of this reaction is of the order of $0.5-192\text{keV}$ for a respective binding energy of $1-100$ MeV, corresponding to a branching fraction of $10^{-5}-10^{-3}$. These findings suggest that the existence of the $X(10550)$ might be checked via the analysis of the mentioned decay in present and future experiments.

Comments: 13 pages, 4 figures