R. Davidson, Niami C. Mukhopadhyay, R. Wittman

Feb 24, 1986

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0

Influential Citations

51

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Journal

Physical review letters

Abstract

We have analyzed available data on magnetic dipole and electric quadrupole amplitudes for the photoproduction of pions around the delta region, in the framework of a phenomenological ..gamma..N..delta.. interaction and background. The unitarity constraint via Watson's theorem limits severely the range of allowed gauge couplings in the ..gamma..N..delta.. vertex. We obtain (-1.5 +- 0.2)% as the ratio of the electric quadrupole to magnetic dipole resonant amplitudes, a value of the same order of magnitude as predicted in the skyrmion model of baryons. This ratio suggests a deformed structure of the nucleon and the delta isobar.

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