Kaon-nucleon potential from lattice QCD

We study the K N interactions in the I(J^π) = 0(1/2^-) and 1(1/2^-) channels and associated exotic state Θ⁺ from 2+1 flavor full lattice QCD simulation for relatively heavy quark mass corresponding to m_π = 871 MeV. The s-wave K N potentials are obtained from the Bethe-Salpeter wave function by using the method recently developed by HAL QCD (Hadrons to Atomic nuclei from Lattice QCD) Collaboration. Potentials in both channels reveal short range repulsions: Strength of the repulsion is stronger in the I = 1 potential, which is consistent with the prediction of the Tomozawa-Weinberg term. The I = 0 potential is found to have attractive well at mid range. From these potentials, the K N scattering phase shifts are calculated and compared with the experimental data.