Quark Spin Couplings for Baryons - Revisited

Abstract

A direct connection can be made between mixing angles in negative parity baryons and the spin coupling of constituent quarks. The mixing angles do not depend on spectral data. These angles are recalculated for gluon exchange and pion exchange between quarks. For pion exchange the results of Glozman and Riska are corrected. The experimental data on mixing are very similar to those derived from gluon exchange but substantially different from the values obtained for pion exchange.

Exploration of hyperfine interaction between constituent quarks via η productions

“…Combined with the agreement with the experiments of the theoretical results for η productions, it suggests the data for the η productions support these values strongly. Here the OPE models give 24 • and −47 • , which is close to the ones in Ref [23,25], 25.5 • and −52.5 • , obtained from the mass spectrum directly. As shown in the above subsections, these values will lead to wrong differential cross sections.…”

“…The OGE hyperfine interactions can be derived from the one gluon exchange between two constituent quarks by non-relativization directly as given by Isgur [5,6,23],…”

“…The theoretical results are fitting to the experimental data by the MINUIT program. To do so, we have a total of 25 (23) free parameters for GBE (OPE) model and 19 free parameters for OGE, which will be presented explicitly in the following subsections.…”

“…As suggested and applied by many authors [23,22,58], the mixing angle of two pairs of the negative parity states, θ S for S 11 (1535) and S 11 (1650) and θ D for D 13 (1520) and D 13 (1700), is very important to understand the structure of resonances and underlying dynamics of the interquark interaction. In mid-seventies of the past century, Hey et al [23], which can not reproduce the helicity amplitudes [24]. Glozman [60] pointed out that in the ρ-exchange tensor interaction dominate over the π-exchange tensor interaction in the Pwave baryons.…”

“…As Isgur suggested the successful description of the spectrum is only necessary but not sufficient to determine whether a model is successful [22]. It is first applied by Chizma and Karl [23] though a simple calculation of mixing angles of the low lying negative parity nucleon resonances S 11 (1535) and D 13 (1650) and large deviation are found. With those mixing angles the OPE can be excluded though the calculation of the helicity amplitudes for the nucleon resonances [24].…”