Analysis of the $$e^+e^- \rightarrow \eta J/\psi $$ cross section within a unitarized coupled-channel approach

Abstract We investigate the $$e^+ e^- \rightarrow \eta J/\psi $$ e + e - → η J / ψ cross section by employing a model that combines relativistic Breit–Wigner amplitudes with a unitarized coupled-channel approach to account for resonant and non-resonant contributions, respectively. By performing a global fit to the BESIII experimental data, we determine the essential free parameters of the transition amplitudes. Furthermore, we analyze the role of a dynamically generated $$D\bar{D}^*$$ D D ¯ ∗ pole near 3.88 GeV and demonstrate its critical contribution to shaping the observed cross-section line shape.