Ratio of electric quadrupole to magnetic dipole amplitudes in the nucleon-delta transition
- 24 February 1986
- journal article
- Published by American Physical Society (APS) in Physical Review Letters
- Vol. 56 (8), 804-807
- https://doi.org/10.1103/physrevlett.56.804
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 γNΔ interaction and background. The unitarity constraint via Watson’s theorem limits severely the range of allowed gauge couplings in the γNΔ 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.Keywords
This publication has 26 references indexed in Scilit:
- Deformation of the nucleon and delta in excited statesPhysical Review Letters, 1985
- Effect of quark-quark tensor and spin-spin force on the radiative decay of Δ-isobarPhysics Letters B, 1984
- Pion photoproduction in theregion and chiral bag modelsPhysical Review D, 1983
- A shell model study of six quark systemPhysics Letters B, 1982
- Color-electric instabilities in baryons and dibaryons?Physics Letters B, 1982
- waves in the nucleon: A test of color magnetismPhysical Review D, 1982
- Deformed bags and the πNΔ coupling constantPhysics Letters B, 1981
- Chiral pion dynamics for spherical nucleon bagsNuclear Physics A, 1980
- The unmellisonant quarkPhysica A: Statistical Mechanics and its Applications, 1979
- -wave baryons in the quark modelPhysical Review D, 1978