F and D Values with Explicit Flavor Symmetry Breaking and \Delta s Contents of Nucleons

TL;DR

This paper introduces a new model for baryon semi-leptonic decays that accounts for explicit SU(3) and SU(2) flavor symmetry breaking, providing refined estimates of F, D, and strange quark spin contributions.

Contribution

The paper presents a novel approach incorporating all possible flavor symmetry breaking effects into baryon decay models, improving parameter estimates and predictions for hyperon decays.

Findings

Estimated F=0.477 and D=0.835 with high precision.

Re-evaluated nucleon spin contribution from strange quarks.

Predicted unmeasured hyperon decay parameters.

Abstract

We propose a new model for describing baryon semi-leptonic decays for estimating $F$ and $D$ values with explicit breaking effects of both SU(3) and SU(2) flavor symmetry, where all possible SU(3) and SU(2) breaking effects are induced from an effective interaction. An overall fit including the weak magnetism form factor yields $F=0.477\pm 0.001$ and $D=0.835\pm 0.001$ with $\chi^2=4.43/5$ d.o.f. with $V_{ud}=0.975\pm 0.002$ and $V_{us}=0.221\pm 0.002$. The spin content of strange quarks $\Delta s$ is estimated from the obtained values $F$ and $D$, and the nucleon spin problem is re-examined. Furthermore, the unmeasured values of $(g_1/f_1)$ and $(g_1)$ for other hyperon semi-leptonic decays are predicted from this new formula.