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 ( πNN, πΣΣ, πΛΣ, KΛ N, KΣ N, 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.