Pseudoscalar-Meson Octet-Baryon Coupling Constants from two-flavor Lattice QCD

TL;DR

This study uses lattice QCD with two dynamical quark flavors to calculate pseudoscalar-meson octet-baryon coupling constants and axial charges across multiple channels, revealing minimal SU(3) flavor symmetry breaking.

Contribution

It provides the first lattice QCD determination of these coupling constants and the SU(3) parameter alpha at various quark masses, including the symmetric point.

Findings

Alpha at SU(3) symmetric point is 0.395(6).

SU(3) flavor symmetry breaking is only a few percent.

Quark-mass dependence of coupling constants is characterized.

Abstract

We evaluate the pseudoscalar-meson octet-baryon coupling constants and the corresponding axial charges in eight channels ($\pi N\N$, $\pi\Sigma\Sigma$, $\pi\Lambda\Sigma$, $K\Lambda N$, $K \Sigma N $, $\pi\Xi\Xi$, $K\Lambda\Xi$ and $K\Sigma\Xi$) in lattice QCD with two flavors of dynamical quarks. The parameter $\alpha\equiv F/(F+D)$ representing the SU(3)-flavor symmetry is computed at each u,d-quark hopping parameter and at the flavor-SU(3) symmetric point where the three quark flavors are degenerate at the physical $s$-quark mass. In particular, we obtain $\alpha=0.395(6)$ at the SU(3) symmetric limit. The quark-mass dependences of the coupling constants are obtained by changing the $u$- and the $d$-quark masses and we find that the SU(3)-flavor symmetry is broken by only a few percent at each quark-mass we employ.