Hidden charmonium decays of spin-2 partner of $X(3872)$

Yuanxin Zheng, Zuxin Cai, Gang Li +3

The Belle collaboration recently reported a promising candidate for the spin-2 $D^{\ast }{\bar{D}}^{\ast }$ partner of the $X(3872)$, called the $X_2$ for short, having a mass of $(4014.3 \pm 4.…