Pseudoscalar-meson--octet-baryon coupling constants in two-flavor lattice QCD

TL;DR

This study uses two-flavor lattice QCD to compute pseudoscalar-meson--octet-baryon coupling constants and monopole masses, revealing weak SU(3)-flavor symmetry breaking across different quark masses.

Contribution

It provides the first lattice QCD calculations of these coupling constants at the physical s-quark mass with analysis of quark-mass dependence and SU(3) symmetry breaking.

Findings

Weak quark-mass dependence of SU(3)-flavor parameters

SU(3)-flavor symmetry broken by only a few percent

Calculated  at physical quark masses

Abstract

We evaluate the $\pi N!N$, $\pi\Sigma\Sigma$, $\pi\Lambda\Sigma$, $K\Lambda N$ and $K \Sigma N $ coupling constants and the corresponding monopole masses in lattice QCD with two flavors of dynamical quarks. The parameters representing the SU(3)-flavor symmetry are computed at the point where the three quark flavors are degenerate at the physical $s$-quark mass. In particular, we obtain $\alpha\equiv F/(F+D)=0.395(6)$. The quark-mass dependences of the coupling constants are obtained by changing the $u$- and the $d$-quark masses. We find that the SU(3)-flavor parameters have weak quark-mass dependence and thus the SU(3)-flavor symmetry is broken by only a few percent at each quark-mass point we consider.