Tetraquark state $X(6900)$ and the interaction between diquark and antidiquark

Hong-Wei Ke, Xin Han, Xiao-Hai Liu +1

Recently LHCb declared a new structure $X(6900)$ in the final state di-$J/\psi$ which is popularly regarded as a $cc$-$\bar{c}\bar{c}$ tetraquark state. %popularly. Within the Bethe-Sal…