Experimental Studies of the phi-nucleon interaction at SPring-8 and J-PARC

To clarify gluon dynamics in hadron-hadron interactions, we investigate low-energy scattering between a nucleon composed of u and d quarks and a ϕ meson consisting solely of an s s ¯ quark pair. Since they share no common quark flavors, quark exchange does not occur, and gluon exchange is expected to dominate at leading order. The nature of the low-energy ϕN interaction remains unsettled. Phenomenological analyses of ϕ photoproduction based on the vector-meson dominance (VMD) model suggest weak attraction, whereas strong attraction has been indicated by momentum correlation measurements in high-energy proton-proton collisions and by lattice QCD calculations. We try to determine the low-energy ϕN scattering parameters by analyzing γd → ϕπ 0 pn data obtained in the LEPS experiment at SPring-8 together with new π − p → ϕ n data from the planned E45 experiment at J-PARC, each of which provides access to the ϕN interaction without relying on the VMD framework.