Baryon-Baryon Interaction in Lattice QCD

Recent studies of baryon-baryon interaction based on lattice QCD are presented. The equal-time Bethe-Salpeter (BS) amplitude of the lowest energy scattering state of baryon number B=2 system (proton-neutron, proton-Λ and proton-Ξ0) is calculated from lattice QCD. The spin singlet central potential is calculated from the BS wave function for the spin J=0 state, whereas the spin triplet central potential as well as the tensor potential are deduced simultaneously from the BS wave function for the spin J=1 state by dividing it into the S-wave and the D-wave components. The energy dependence of the quenched NN potential is studied. The scattering lengths are obtained from the asymptotic behavior of the BS wave function by using the Lüscher's formula. The studies based on the 2 + 1 flavor QCD calculation are also presented.