Revealing the inner structure of the newly observed ${\eta }_1(1855)$ via photoproduction

Yin Huang, Hong Qiang Zhu

Very recently, a new hadronic exotic state ${\eta }_1(1855)$ at the invariant mass spectrum of $\eta {\eta }^{{}^{\prime }}$ was observed by the BESIII Collaboration. According to its properties, such as the…