Helicity dependence of the \(\gamma p\rightarrow N \pi\) channels and multipole analysis in the \(\Delta\) region

  • The GDH and A2 Collaborations
Article

Abstract.

A high-quality double-polarization data set for the helicity dependence of the total and differential cross-sections for both \(\gamma p\rightarrow N \pi\) channels in the \(\Delta\) region has been obtained in the framework of the GDH experiment. The experiment, performed at the Mainz microtron MAMI, used a 4\(\pi\) 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 \(\Delta(1232)\)-resonance. For the resonant \(\Delta\)(1232) multipoles we find a very good agreement with previous analyses, while the nonresonant ones show significant deviations.

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© Springer-Verlag Berlin/Heidelberg 2004

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  • The GDH and A2 Collaborations

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