Hyperon-nucleon coupling from QCD sum rules

TL;DR

This paper calculates hyperon-nucleon coupling constants using QCD sum rules, comparing different Dirac structures, and finds significant SU(3) symmetry violation in one of the structures.

Contribution

It extends previous QCD sum rule analyses of hyperon-nucleon couplings by exploring different Dirac structures and highlighting symmetry violations.

Findings

Significant SU(3) symmetry violation in the $\gamma_5 \sigma_{\mu u}$ structure.

Comparison of coupling constants obtained from different Dirac structures.

Extension of previous sum rule calculations for hyperon-nucleon interactions.

Abstract

The NKY coupling constant for $Y = \Lambda$ and $\Sigma$ is evaluated in a QCD sum rule calculation. We discuss and extend the result of a previous analysis in the $\rlap{/}{q}i\gamma_5$ structure and compare it with the result obtained with the use of the $\gamma_5 \sigma_{\mu \nu}$ structure. We find a huge violation of the SU(3) symmetry in the $\gamma_5 \sigma_{\mu \nu}$ structure.