Spin asymmetry for the 16O(gamma,pi- p) reaction in the Delta(1232) region within an effective Lagrangian approach

The spin asymmetry of the photon in the exclusive A(gamma,pi N)A-1 reaction is computed employing a recently developed fully relativistic model based on elementary pion production amplitudes that include a consistent treatment of the spin-3/2 nucleon resonances. We compare the results of this model to the only available data on Oxygen [Phys. Rev. C 61 (2000) 054609] and find that, contrary to other models, the predicted spin asymmetry compares well to the available experimental data in the Delta(1232) region. Our results indicate that no major medium modifications in the Delta(1232) properties are needed in order to describe the measured spin asymmetries.