Study of X(6900) with unitarized coupled channel scattering amplitudes Shi-Qing Kuang, Qi Zhou, Di Guo, Qin-He Yang and Ling-Yun Dai Eur. Phys. J. C, 83 5 (2023) 383 Published online: 09 May 2023 DOI: 10.1140/epjc/s10052-023-11473-3