Phenomenological Analysis of the Experimental Data on the Photoproduction of η Mesons off Nucleons

摘要

The initial stage of a phenomenological analysis of experimental data on the η meson photoproduction off nucleons in the energy range from the threshold to 1.1 GeV is carried out based on a linear nonparametric model. The goal of this stage of the analysis is to obtain statistically reliable information about the partial waves that form the main characteristics of the process. The analysis uses the data of three laboratories about the angular distributions of η-mesons and their Σ and T asymmetries. The results of the analysis of the angular distributions demonstrate the presence of contradictions in the data obtained by different laboratories. The results of the analysis of the energy dependences of the polarization observables Σ and T show that the process regime probably changes in the vicinity of 0.9 GeV, which may be caused by the transition from the region of the S_(11)(1535) and D_(13)(1520) resonances to the region of the D_(15)(1675) and F_(15)(1630) resonances.