Nuclear force from lattice QCD

The nucleon-nucleon (NN) potential is studied by lattice QCD simulations in the quenched approximation, using the plaquette gauge action and the Wilson quark action on a 32(4) [similar or equal to(4.4 fm)(4)] lattice. A NN potential V-NN(r) is defined from the equal-time Bethe-Salpeter amplitude with a local interpolating operator for the nucleon. By studying the NN interaction in the S-1(0) and S-3(1) channels, we show that the central part of V-NN(r) has a strong repulsive core of a few hundred MeV at short distances (r less than or similar to 0.5 fm) surrounded by an attractive well at medium and long distances. These features are consistent with the known phenomenological features of the nuclear force.