Study of $X(6900)$ with unitarized coupled channel scattering amplitudes

Shi-Qing Kuang, Qi Zhou, Di Guo +2

In this paper, we study the resonant state $X(6900)$. The scattering amplitudes of coupled channels, $J/\psi J/\psi$-$J/\psi \psi (2S)$-$J/\psi \psi (3770)$, are constructed with the interaction of four…