Study of Nucleon-Nucleon and Hyperon-Nucleon Interaction

Abstract

In this paper we review recent investigations of nucleon-nucleon andhyperon-nucleon interactions employing a non-relativistic quark cluster model. We concentrate mainly on the short andmed ium-range behavior of the baryon-baryon interaction basedon the onegluon andmeson exchange potentials. The chiral quark mod el basedon pion andsigma exchange between quarks is also discussed. We also review a study of the deuteron and its electromagnetic properties in a quark model with exchange currents. There have been a lot of investigations of single baryon properties using the constituent quark model. The study of Isgur and Karl 1) has shown that the baryon spectra are nicely reproduced using the non-relativistic constituent quark model. The confined quarks interact with each other through residual interactions. Isgur and Karl employed the one-gluon exchange potential (OGEP) 2) as residual interaction. The spin-dependent part of the OGEP, called the color magnetic interaction, can explain the mass difference between octet and decuplet baryons, such as the nucleon and the ∆ resonance. Introducing a flavor SU(3) breaking term due to the strange quark mass, the model can also explain the mass difference between Σ and Λ particles as well as the mass difference between strange baryons and nucleons. A chiral quark model, where the residual interactions among quarks are dominated by Goldstone boson exchange due to the spontaneous chiral symmetry breaking, has been employed to study the baryon spectra. 3) This model has been shown to produce the nucleon and ∆ mass difference due to the pseudoscalar meson exchange interaction in a right direction. The absolute value, however, strongly depends on the model of the baryon. In a model where the baryon size is around 0.6 fm, the contribution from the pseudoscalar (ps) meson exchange is roughly one third of the observed mass difference between the nucleon and ∆. Therefore, the rest of the mass difference must be supplied by another mechanism such as the OGEP. It has been shown that the whole mass difference is given by the ps meson exchange if the nucleon size is about 0.3 fm. 4)