Lattice QCD Study of the Nucleon-Charmonium Interaction

The J/ψ-nucleon interaction is studied by lattice QCD calculations. At the leading order of the derivative expansion, the interaction consists of four terms: the central, the spin-spin, and two types of tensor forces. We determine these spin-dependent forces quantitatively by using the time-dependent HAL QCD method. We find that the spin-spin force is the main cause of the hyperfine splitting between the J = 1/2 and 3/2 states, while the two tensor forces have much smaller effects on the S-wave scattering processes.