KN Potential and Θ+ in Lattice QCD

We study the s-wave KN interactions in the isospin I = 0, 1 channels and associated exotic state Theta(+) from 2+1 flavor full lattice QCD simulation for relatively heavy quark mass corresponding to m(pi) = 871 MeV. The s-wave KN potentials are obtained from the Bethe-Salpeter amplitudes. Potentials in both channels reveal short range repulsions: Strength of the repulsion is stronger in the I = 1 potential. The I = 0 potential is found to have attractive well at mid range. The KN scattering phase shifts are calculated and compared with the experimental data.