Hyperon semileptonic decays and quark spin content of the proton

TL;DR

This paper explores hyperon semileptonic decays and the proton's quark spin content, incorporating SU(3) symmetry breaking via the chiral quark-soliton model, and highlights the need for more precise experimental data.

Contribution

It introduces a method to analyze hyperon decays considering symmetry breaking and predicts unmeasured decay constants using experimental data.

Findings

Predicted decay constants for unmeasured hyperon decays.

SU(3) symmetry breaking significantly affects the proton's spin content.

Large experimental errors hinder precise determination of $   $ and $ s$.

Abstract

We investigate the hyperon semileptonic decays and the quark spin content of the proton $\Delta \Sigma$ taking into account flavor SU(3) symmetry breaking. Symmetry breaking is implemented with the help of the chiral quark-soliton model in an approach, in which the dynamical parameters are fixed by the experimental data for six hyperon semileptonic decay constants. As a result we predict the unmeasured decay constants, particularly for $\Xi^0 \to \Sigma^+$, which will be soon measured and examine the effect of the SU(3) symmetry breaking on the spin content $\Delta \Sigma $ of the proton. Unfortunately large experimental errors of $\Xi^-$ decays propagate in our analysis making $\Delta \Sigma$ and $\Delta s$ practically undetermined. We conclude that statements concerning the values of these two quantities, which are based on the exact SU(3) symmetry, are premature. We stress that the meaningful results can be obtained only if the experimental errors for the $\Xi$ decays are reduced.