Charmonium-nucleon potential from lattice QCD

We present results for the charmonium-nucleon potential V _cc̄-N(r) from quenched lattice QCD, which is calculated from the equal-time Bethe-Salpeter amplitude through the effective Schrödinger equation. Detailed information of the low-energy interaction between the nucleon and charmonia (η_c and J/ψ) is indispensable for exploring the formation of charmonium bound to nuclei. Our simulations are performed at a lattice cutoff of 1/a 2.1GeV in a spatial volume of (3fm)3 with the nonperturbatively O(a) improved Wilson action for the light quarks and a relativistic heavy quark action for the charm quark. We have found that the potential V_cc̄-N(r) for either the η_c or J/ψ states is weakly attractive at short distances and exponentially screened at large distances. The spin averaged J/ψ-N potential is slightly more attractive than that of the η_c-N case.