Chiral sum rules for {ital scrL}{sub (6)}{sup WZ} parameters and its application to {pi}{sup 0},{eta},{eta}{prime} decays

Journal Article · Mon May 01 04:00:00 EDT 1995 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.51.4939· OSTI ID:44760

Moussallam, B ^[1]

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1. Division de Physique Theorique, Institut de Physique Nucleaire, Universite Paris-Sud, 91406 Orsay (France)

The chiral expansion of the low-energy processes {pi}{sup 0}{r_arrow}{gamma}{gamma} and {eta}{r_arrow}{gamma}{gamma} is reconsidered with particular emphasis on the question of the evaluation of the two low-energy parameters from {ital scrL}{sub (6)}{sup WZ} which are involved at chiral order six. It is shown how extensive use of sum rules and saturation with resonances as well as constraints from asymptotic QCD effectively determine their values. Predictions for the widths are presented for both standard and nonstandard values of the quark mass ratio {ital m}{sub {ital s}}/{ital {cflx m}}. A precise relation is established between the usual phenomenological {eta}-{eta}{prime} mixing parameters and those of the chiral expansion. The large size of the chiral correction to the {eta} decay can be understood on the basis of a simple counting rule: {ital O}(1/{ital N}{sub {ital c}}){similar_to}{ital O}({ital m}{sub {ital q}}). It is shown how this counting rule eventually allows one to include the {eta}{prime} into the effective Lagrangian in a consistent and systematic way.

• OSTI ID: 44760
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 9 Vol. 51; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CHIRAL SYMMETRY
CORRECTIONS
ETA MESONS
LAGRANGIAN FUNCTION
PIONS NEUTRAL
QUANTUM CHROMODYNAMICS
RADIATIVE DECAY
SUM RULES
WIDTH