Two chiral nonet model with massless quarks

Journal Article · Fri Feb 01 04:00:00 EST 2008 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.77.034006· OSTI ID:21039021

Fariborz, Amir H ^[1]; Jora, Renata; Schechter, Joseph ^[2]

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1. Department of Mathematics/Physics, State University of New York Institute of Technology, Utica, New York 13504-3050 (United States)
2. Department of Physics, Syracuse University, Syracuse, New York 13244-1130 (United States)

We present a detailed study of a linear sigma model containing one chiral nonet transforming under U(1){sub A} as a quark-antiquark composite and another chiral nonet transforming as a diquark-antidiquark composite (or, equivalently from a symmetry point of view, as a two meson molecule). The model provides an intuitive explanation of a current puzzle in low energy QCD: Recent work has suggested the existence of a lighter than 1 GeV nonet of scalar mesons which behave like four quark composites. On the other hand, the validity of a spontaneously broken chiral symmetric description would suggest that these states be chiral partners of the light pseudoscalar mesons, which are two quark composites. The model solves the problem by starting with the two chiral nonets mentioned and allowing them to mix with each other. The input of physical masses in the SU(3) invariant limit for two scalar octets and an excited pion octet results in a mixing pattern wherein the light scalars have a large four quark content while the light pseudoscalars have a large two quark content. One light isosinglet scalar is exceptionally light. In addition, the pion pion scattering is also studied and the current algebra theorem is verified for massless pions which contain some four quark admixture.

• OSTI ID: 21039021
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 3 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
CHIRALITY
CURRENT ALGEBRA
GEV RANGE
PION-PION INTERACTIONS
PIONS
PSEUDOSCALAR MESONS
QUANTUM CHROMODYNAMICS
SCALAR MESONS
SIGMA MODEL
SU-3 GROUPS
SYMMETRY
U-1 GROUPS