Diquark model of the baryon spectrum

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:6445439

Haire, M L

The presence of a coherent diquark structure within baryons has been suggested, both as a computational tool for simplifying some types of baryon calculations, and as an explanation for scaling violations in deep inelastic scattering. In this paper, the implications of the diquark hypothesis for baryons spectroscopy are considered. Treating the diquark as an s-wave bound state of two quarks reduces the problem of three-body quark excitations within baryons to that of a two-body quark-diquark interaction. The spin-dependent excitation levels of the quark-diquark system can then be calculated in perturbative QCD, using a non-relativistic one-gluon-exchange approximation. The spectrum generated by this model differs from the conventional symmetric quark model spectrum in several crucial respects. Firstly, spin-orbit mass splitting between baryons is easily accommodated in the diquark picture, unlike the conventional model, where it must be cancelled ad hoc in order to obtain a reasonable fit to the mass spectrum. Secondly, the QCD parameters needed to fit the baryon spectrum in the diquark model are essentially the same as those used in the meson spectrum. This allows a unified description of spin-dependent forces in mesons and baryons, which has not been possible in the symmetric quark model. A qualitative discussion of spin-independent (multiple gluon exchange) forces in the diquark model, using effective confining potentials concludes the paper.

• Research Organization: Tufts Univ., Medford, MA (USA)
• OSTI ID: 6445439
• Country of Publication: United States
• Language: English

Related Subjects

645201* -- High Energy Physics-- Particle Interactions & Properties-Theoretical-- General & Scattering Theory
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANGULAR MOMENTUM
BARYONS
COMPOSITE MODELS
COUPLING
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
HADRONS
INTERMEDIATE COUPLING
L-S COUPLING
MANY-BODY PROBLEM
MASS SPECTRA
MATHEMATICAL MODELS
PARTIAL WAVES
PARTICLE MODELS
PARTICLE PROPERTIES
PERTURBATION THEORY
POSTULATED PARTICLES
POTENTIALS
QUANTUM CHROMODYNAMICS
QUANTUM FIELD THEORY
QUARK MODEL
QUARKS
S WAVES
SPECTRA
SPIN
TWO-BODY PROBLEM