Productions of $X(3872)$, $Z_c(3900)$, $X_2(4013)$, and $Z_c(4020)$ in $B_{(s)}$ decays offer strong clues on their molecular nature

Qi Wu, Ming-Zhu Liu, Li-Sheng Geng

The exotic states $X(3872)$ and $Z_c(3900)$ have long been conjectured as isoscalar and isovector ${\bar{D}}^{\ast }D$ molecules. In this work, we first propose the triangle diagram mechan…