Diphoton excess at 750 GeV: gluon–gluon fusion or quark–antiquark annihilation? Jun Gao, Hao Zhang and Hua Xing Zhu Eur. Phys. J. C, 76 6 (2016) 348 Published online: 23 June 2016 DOI: 10.1140/epjc/s10052-016-4200-z