Scalar resonances: Chiral Breit-Wigner expressions

Journal Article · Wed Feb 01 04:00:00 EST 2006 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.73.034028· OSTI ID:20776670

Arantes, L O; Robilotta, M R ^[1]

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1. Instituto de Fisica, Universidade de Sao Paulo, C.P. 66318, 05315-970, Sao Paulo, SP (Brazil)

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.

• OSTI ID: 20776670
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 3 Vol. 73; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

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