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

We evaluate the pseudoscalar-meson octet-baryon coupling constants and the corresponding axial charges in eight channels (πNN, πΣΣ, πΛΣ, KΛN, KΣN, πΞΞ, KΛΞ and KΣΞ) in lattice QCD with two flavors of dynamical quarks. The parameter α≡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 α=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.