Broken chiral symmetry and the structure of hadrons

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1982

OSTI ID:6825152

Spence, W L

The spontaneous breaking of chiral symmetry plays a decisive role in the structure of hadrons composed of light quarks. The formalism by which the dynamics of chiral symmetry breaking and its implications for hadronic structure can be explored in a simplified world in which fully relativistic zero-bare-mass quarks interact through a chirally symmetric instantaneous confining potential is presented. By thus modeling the essentials of the chiral limit-N/sub c/ infinity limit of QCD contact is made with the successes of existent semiphenomenological models of hadrons but post assumptions which explicitly violate chiral symetry are avoided. This revised approach then makes possible a unification of the dynamics of hadron structure with the mechanism of spontaneous chiral breaking and guarantees the appearance of the correct Goldstone excitations. The chiral breaking order parameter (absolute value anti psi psi), effective quark mass, and Goldstone boson wave function are obtainable by solving a single non-linear integral equation once a potential has been prescribed. The stability of the chiral asymmetric vacuum must then be established by studying the linear eigenvalue problem which determines the spectrum of states with vacuum quantum numbers. The nature of the instability of the chiral symmetric vacuum that leads to spontaneous symmetry breaking is explained and its apparent contingency on details of the dynamics is emphasized. It is argued that a single massless fermion in a chirally symmetric potential does form bound states for which a semi-classical description is given. Coupling to vacuum pairs of such bound states occasions the possibility of chiral symmetry breakdown.

• Research Organization: California Univ., Santa Cruz (USA)
• OSTI ID: 6825152
• Country of Publication: United States
• Language: English

Related Subjects

645400* -- High Energy Physics-- Field Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ALGEBRAIC CURRENTS
AXIAL-VECTOR CURRENTS
BAG MODEL
BOSONS
BOUND STATE
CHIRAL SYMMETRY
COMPOSITE MODELS
CURRENTS
ELEMENTARY PARTICLES
EXTENDED PARTICLE MODEL
FERMIONS
GOLDSTONE BOSONS
HADRONS
INTERACTIONS
MASS
MASSLESS PARTICLES
MATHEMATICAL MODELS
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE STRUCTURE
POSTULATED PARTICLES
POTENTIALS
QUARK MODEL
QUARK-QUARK INTERACTIONS
SINGULARITY
SYMMETRY
SYMMETRY BREAKING