Photoproduction of γ p → f 0 ( 980 ) p in an effective Lagrangian approach

The most recent data on differential cross sections and photon beam asymmetries Σ from the LEPS2/BGOegg Collaboration for the γ p → f 0 ( 980 ) p reaction are analyzed within a tree-level effective Lagrangian approach. The t -channel ρ and ω exchanges, the u - and s -channel N exchanges, the interaction current, and the possible s -channel N * exchanges are taken into account in constructing the reaction amplitudes to reproduce the data. The results show that the contributions from either the N ( 2040 ) 3 / 2 + or the N ( 2100 ) 1 / 2 + resonance exchange in the s channel are necessarily required to describe the LEPS2/BGOegg data and they dominate the differential cross sections of γ p → f 0 ( 980 ) p . Further analysis shows that the contributions from the t -channel ρ and ω exchanges and the interaction current are rather small to both differential cross sections and photo beam asymmetries, and the contributions from u -channel N exchange are considerable in the case of including N ( 2040 ) 3 / 2 + in the model while negligible in the case of including N ( 2100 ) 1 / 2 + in the model. Predictions of target asymmetries T for γ p → f 0 ( 980 ) p are given, which can be examined by future experiments.