Photoproduction in an effective Lagrangian approach * *Partially supported by the National Natural Science Foundation of China (12175240, 11475181, 11635009), the Fundamental Research Funds for the Central Universities, the China Postdoctoral Science Foundation (2021M693141, 2021M693142), and the Key Research Program of Frontier Sciences of Chinese Academy of Sciences (Y7292610K1)

Abstract

A gauge-invariant model is constructed for the reaction within a tree-level effective Lagrangian approach to understand the underlying production mechanisms and study the resonance contributions in this reaction. In addition to the t-channel K and exchanges, s-channel nucleon exchange, and interaction current, the s-channel nucleon resonance exchanges are included in constructing the reaction amplitudes to describe the data. It is found that the contributions from the s-channel exchange are required to describe the most recently measured total cross-section data for from the CLAS Collaboration. Further analysis indicates that the interaction current dominates the reaction near the threshold as a result of gauge invariance. The t-channel K exchange contributes significantly, while the contributions from the t-channel exchange and s-channel nucleon exchange are ultimately negligible. The contributions from the s-channel exchange are found to be responsible for the bump structure shown in the CLAS total cross-section data above the center-of-mass energy GeV. The predictions of the differential cross sections for are presented and discussed, which can provide theoretical guidance for future experiments.