Recent results on deuteron-proton scattering from RIKEN

Nucleon-deuteron (Nd) scattering, for which a rigorous formulation in terms of Faddeev equations exists and exact solutions of these equations for any dynamical input can be obtained, offers a good opportunity to study the dynamical aspects of 3NFs, such as momentum and spin dependences. Since the first indication of 3NF effects in Nd elastic scattering around 100 MeV/nucleon, precise measurements of proton deuteron / neutron deuteron scattering have been extensively performed at 60-300 MeV/nucleon. Direct comparison between the data and the Faddeev calculations based on realistic nucleon nucleon forces plus 27r exchange three nucleon forces draws the following conclusions. (1) The 3NF is definitely needed in Nd elastic scattering. (2) The spin dependent parts of the 3NFs may be deficient. (3) The shorter-range components of the 3NFs are probably required for the cross section as well as the spin observables at backward angles with increasing an incident energy.