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Title: Scalar resonances: Chiral Breit-Wigner expressions

Abstract

Generalized Breit-Wigner expressions describing both single and coupled scalar resonances are derived by combining chiral symmetry and unitarization. Bare scalar propagators are dressed by two-pion loops, results are analytical, and there is little model dependence, since no form factors are used. In the single resonance case, two free coupling parameters are present, which allow flexible descriptions of masses, widths, and pole positions. The usual K-matrix unitarization procedure is recovered as an approximation. When two resonances are present, intermediate pion loops give rise to a coupled channel problem and there is no simple relationship between the unitarized amplitude and Breit-Wigner expressions for individual resonances. Eventually, we approximate and generalize our results and give friendly expressions that can be used in the parametrization of scalar resonances in data analyses.

Authors:
;  [1]
  1. Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970, Sao Paulo, SP (Brazil)
Publication Date:
OSTI Identifier:
20776670
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevD.73.034028; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; APPROXIMATIONS; BREIT-WIGNER FORMULA; CHIRAL SYMMETRY; CHIRALITY; COUPLED CHANNEL THEORY; COUPLING; DATA ANALYSIS; FORM FACTORS; K MATRIX; PARTICLE WIDTHS; PIONS; PROPAGATOR; QUANTUM CHROMODYNAMICS; RESONANCE PARTICLES; REST MASS; SCALARS

Citation Formats

Arantes, L.O., and Robilotta, M.R.. Scalar resonances: Chiral Breit-Wigner expressions. United States: N. p., 2006. Web. doi:10.1103/PhysRevD.73.034028.
Arantes, L.O., & Robilotta, M.R.. Scalar resonances: Chiral Breit-Wigner expressions. United States. doi:10.1103/PhysRevD.73.034028.
Arantes, L.O., and Robilotta, M.R.. Wed . "Scalar resonances: Chiral Breit-Wigner expressions". United States. doi:10.1103/PhysRevD.73.034028.
@article{osti_20776670,
title = {Scalar resonances: Chiral Breit-Wigner expressions},
author = {Arantes, L.O. and Robilotta, M.R.},
abstractNote = {Generalized Breit-Wigner expressions describing both single and coupled scalar resonances are derived by combining chiral symmetry and unitarization. Bare scalar propagators are dressed by two-pion loops, results are analytical, and there is little model dependence, since no form factors are used. In the single resonance case, two free coupling parameters are present, which allow flexible descriptions of masses, widths, and pole positions. The usual K-matrix unitarization procedure is recovered as an approximation. When two resonances are present, intermediate pion loops give rise to a coupled channel problem and there is no simple relationship between the unitarized amplitude and Breit-Wigner expressions for individual resonances. Eventually, we approximate and generalize our results and give friendly expressions that can be used in the parametrization of scalar resonances in data analyses.},
doi = {10.1103/PhysRevD.73.034028},
journal = {Physical Review. D, Particles Fields},
number = 3,
volume = 73,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2006},
month = {Wed Feb 01 00:00:00 EST 2006}
}
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