Electromagnetic Nucleon-to-Delta Transition in Chiral Effective-Field Theory

28 November 2005

journal article
Published by American Physical Society (APS) in Physical Review Letters

Vol. 95 (23) , 232001
https://doi.org/10.1103/physrevlett.95.232001

Abstract

We perform a relativistic chiral effective-field theory calculation of pion electroproduction off the nucleon (e- N --> e- N(pi)) in the delta(1232)-resonance region. After fixing the three low-energy constants, corresponding to the magnetic (M1), electric (E2), and Coulomb (C2) gammaNdelta couplings, our calculation provides a prediction for the momentum transfer and pion-mass dependence of the gammaNdelta form factors. The prediction for the pion-mass dependence resolves the discrepancy between the recent lattice QCD results and the experimental value for the "C2/M1 ratio" at low Q2.

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