Nd scattering at intermediate energies:: An epoch-making experimental study of the three nucleon force

Recent progress in our three nucleon force study with three nucleon scattering at intermediate energies (E/A approximate to 100 MeV) is presented, especially focusing on experimental deuteron-proton elastic scattering and breakup reactions at RIKEN. One signature of three nucleon forces is identified in the cross section minimum for deuteron-proton elastic scattering by direct comparison between precision data and state-of-the-art Faddeev calculations based on realistic nucleon-nucleon forces plus 2 pi-exchange three nucleon forces. However, the polarization observables are not always well described by adding the model three nucleon forces, indicating that components other than a 2 pi-exchange three nucleon force are required to describe the data.