Lattice Calculation of Baryon-Baryon Interaction and Few-Body Systems

摘要

We perform lattice QCD calculation to study baryon-baryon interaction of the strangeness S = - 1 system. The lattice QCD calculation is carried out by using the N_f = 2 + 1 gauge configurations generated by PACS-CS collaboration. The ΛN and ΣT with the isospin I = 3/2 potentials are presented, which are obtained by measuring Nambu-Bethe-Salpeter wave functions on the Lattice QCD together with employing an improved method recently proposed by HAL QCD Collaboration. For the ~1S_o channel, the central ΣN(I = 3/2) potential and the central ΛN(~1S_o) potential are found to be very similar. For the spin triplet (~3S_1 -~3 D_1) channels, the central AN(~3S_1 -~3D_1) potential is attractive while the central ΣN(I = 3/2,~3S_1-~3D_1) potentials is repulsive. Tensor potentials, on the other hand, are rather weak in both AN and ΣN(I = 3/2) systems. We also conduct a stochastic variational calculation for four-nucleon bound state problem by using a lattice nucleon-nucleon interaction comprising the central and the tensor potentials. A weakly bound state of four-nucleon system is obtained by using the lattice NN potential at slightly heavier quark mass corresponding to the pseudoscalar meson mass m_(ps) = 469 MeV.