Eur. Phys. J. A (2004) 21: 323-333
https://doi.org/10.1140/epja/i2003-10216-x

Helicity dependence of the channels and multipole analysis in the region

Abstract

A high-quality double-polarization data set for the helicity dependence of the total and differential cross-sections for both channels in the region has been obtained in the framework of the GDH experiment. The experiment, performed at the Mainz microtron MAMI, used a 4 detection system, a circularly polarized photon beam, and a longitudinally polarized frozen-spin target. These data are included in the database to perform a multipole analysis to determine the properties of the -resonance. For the resonant (1232) multipoles we find a very good agreement with previous analyses, while the nonresonant ones show significant deviations.