Investigating the internal structure of $X(6900)$ in the $2J/\psi$ decay channel

Duo-Duo Lu, Shao-Zhou Jiang

Assuming $X(6900)$ is a tetraquark state, the decay width of $X(6900)\to 2J/\psi$ is calculated in a covariant quark model, with the diquark-antidiquark $[cc][\bar{c}\bar{c}]$ picture…