Exploration of hyperfine interaction between constituent quarks via eta productions

TL;DR

This study investigates the hyperfine interactions between constituent quarks using eta production processes, comparing different exchange mechanisms and their ability to fit experimental data and spectra.

Contribution

It provides a combined analysis of eta production processes to evaluate the effectiveness of Goldstone-boson, one-gluon, and one-pion exchanges in constituent quark models.

Findings

Goldstone-boson and one-gluon exchanges fit data well

One-pion exchange fails to describe data and spectra

Experimental data supports specific mixing angles for S11 and D13 states

Abstract

In this work, the different exchange freedom, one gluon, one pion or Goldstone boson, in constituent quark model is investigated, which is responsible to the hyperfine interaction between constituent quarks, via the combined analysis of the eta production processes, $\pi^{-}p\rightarrow\eta n$ and $\gamma p\rightarrow\eta p$. With the Goldstone-boson exchange, as well as the one-gluon or one-pion exchange, both the spectrum and observables, such as, the differential cross section and polarized beam asymmetry, are fitted to the suggested values of Particle Data Group and the experimental data. The first two types of exchange freedoms give acceptable description of the spectrum and observables while the one pion exchange can not describe the observables and spectrum simultaneously, so can be excluded. The experimental data for the two processes considered here strongly support the mixing angles for two lowest S11 sates and D13 states as about -30 and 6 degree respectively.