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

Abstract

We evaluate the pseudoscalar-meson octet-baryon coupling constants and the corresponding axial charges in eight channels ($\pi N\mathbb{N}$, $\pi \Sigma \Sigma$, $\pi \Lambda \Sigma$, $K\Lambda N$, $K\Sigma N$, $\pi \Xi \Xi$, $K\Lambda \Xi$ 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.

Comments: 4 pages, Talk given at HYP-X, September 14-18, 2009, Tokai, Japan