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Title: Chiral effective-field theory in the {delta}(1232) region: Pion electroproduction on the nucleon

Abstract

We develop an extension of chiral perturbation theory to the {delta}(1232)-resonance energy region and apply it to investigate the pion electroproduction off the nucleon (e{sup -}N{yields}e{sup -}N{pi}). We present a complete calculation of this process, in the {delta}-resonance region, up to next-to-leading order in the {delta} expansion. At this order, the only free parameters are the three low-energy constants corresponding to the magnetic (M1), electric (E2), and Coulomb (C2) {gamma}N{yields}{delta} transition strength. After fitting these parameters to a few well-known data, our calculation provides a prediction for observables and multipole amplitudes of pion electroproduction. These results compare favorably with the phenomenological multipole solutions and recent experimental results from MIT-Bates and MAMI. Our prediction for the pion-mass dependence of the {gamma}N{delta} form factors offers an explanation for the discrepancy between the recent lattice-QCD results and the experimental value for the 'C2/M1 ratio' at low Q{sup 2}.

Authors:
;  [1]
  1. Physics Department, College of William and Mary, Williamsburg, Virginia 23187 (United States) and Theory Group, Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606 (United States)
Publication Date:
OSTI Identifier:
20776645
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevD.73.034003; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; CHIRAL SYMMETRY; CHIRALITY; COMPARATIVE EVALUATIONS; DELTA-1232 BARYONS; E2-TRANSITIONS; ELECTRON REACTIONS; ELECTROPRODUCTION; FORM FACTORS; M1-TRANSITIONS; NUCLEONS; PERTURBATION THEORY; PIONS; QUANTUM CHROMODYNAMICS; REST MASS

Citation Formats

Pascalutsa, Vladimir, and Vanderhaeghen, Marc. Chiral effective-field theory in the {delta}(1232) region: Pion electroproduction on the nucleon. United States: N. p., 2006. Web. doi:10.1103/PhysRevD.73.034003.
Pascalutsa, Vladimir, & Vanderhaeghen, Marc. Chiral effective-field theory in the {delta}(1232) region: Pion electroproduction on the nucleon. United States. https://doi.org/10.1103/PhysRevD.73.034003
Pascalutsa, Vladimir, and Vanderhaeghen, Marc. Wed . "Chiral effective-field theory in the {delta}(1232) region: Pion electroproduction on the nucleon". United States. https://doi.org/10.1103/PhysRevD.73.034003.
@article{osti_20776645,
title = {Chiral effective-field theory in the {delta}(1232) region: Pion electroproduction on the nucleon},
author = {Pascalutsa, Vladimir and Vanderhaeghen, Marc},
abstractNote = {We develop an extension of chiral perturbation theory to the {delta}(1232)-resonance energy region and apply it to investigate the pion electroproduction off the nucleon (e{sup -}N{yields}e{sup -}N{pi}). We present a complete calculation of this process, in the {delta}-resonance region, up to next-to-leading order in the {delta} expansion. At this order, the only free parameters are the three low-energy constants corresponding to the magnetic (M1), electric (E2), and Coulomb (C2) {gamma}N{yields}{delta} transition strength. After fitting these parameters to a few well-known data, our calculation provides a prediction for observables and multipole amplitudes of pion electroproduction. These results compare favorably with the phenomenological multipole solutions and recent experimental results from MIT-Bates and MAMI. Our prediction for the pion-mass dependence of the {gamma}N{delta} form factors offers an explanation for the discrepancy between the recent lattice-QCD results and the experimental value for the 'C2/M1 ratio' at low Q{sup 2}.},
doi = {10.1103/PhysRevD.73.034003},
url = {https://www.osti.gov/biblio/20776645}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 3,
volume = 73,
place = {United States},
year = {2006},
month = {2}
}