Effects of heavy meson loops on higher charmonia radiative transitions Wen-Hua Qin, Chun-Sheng An, Gang Li, Chao Wang and Yan Wang Eur. Phys. J. C, 79 9 (2019) 757 Published online: 11 September 2019 DOI: 10.1140/epjc/s10052-019-7274-6