eta photoproduction and N* resonances

TL;DR

This paper analyzes eta photoproduction using an effective Lagrangian approach, focusing on the N*(1675) resonance, and explores its possible quantum states and implications for baryon structure.

Contribution

It introduces a theoretical investigation of the N*(1675) resonance's spin and parity, including multiple resonances and background effects, and predicts isospin asymmetries in transition amplitudes.

Findings

Noticeable isospin asymmetry in transition amplitudes

Possible identification of N*(1675) as a non-strangeness baryon antidecuplet member

Calculated cross sections and beam asymmetries for neutron and proton targets

Abstract

We investigate the eta photoproduction using the effective Lagrangian approach at the tree level. We focus on the new nucleon resonance N*(1675), which was reported by the GRAAL, CB-ELSA and Tohoku LNS, testing its possible spin and parity states theoretically (J^P=1/2^+-,3/2^+-). In addition, we include six nucleon resonances, D_13(1520), S_11(1535), S_11(1650), D_15(1675), P_11(1710), P_13(1720) as well as the possible background contributions. We calculate various cross sections including beam asymmetries for the neutron and proton targets. We find noticeable isospin asymmetry in transition amplitudes for photon and neutron targets. This observation may indicate that the new resonance can be identified as a non-strangeness member of the baryon antidecuplet.