Polarization transfer measurement for 1H(d-vector),p-vector)2H elastic scattering at 135 MeV/nucleon and three-nucleon force effects

The deuteron-to-proton polarization-transfer coefficients for d-p elastic scattering were precisely measured with an incoming deuteron energy of 135 MeV/nucleon at the RIKEN Accelerator Research Facility. The data are compared to theoretical predictions based on exact solutions of the three-nucleon Faddeev equations with high-precision nucleon-nucleon forces combined with the current, most popular three-nucleon force (3NF) models: the 2π-exchange Tucson-Melbourne model, a modification thereof based on chiral symmetry, TM'(99), and the Urbana IX 3NF. Theory predicts large 3NF effects, especially in the angular range around the cross section minimum, predominantly for Kxxy'-Kyyy' (Kxxy',Kyyy'), but the present data only partially concurs with the calculations. For the induced polarization, Py', the TM'(99) and Urbana IX 3NFs reproduce the data, but the Tucson-Melbourne 3NF fails to describe the data. For the polarization-transfer coefficients, Kyy' and Kxzy', the predicted 3NF effects are in drastic disagreement with the data. These facts clearly reveal the defects of the 3NF models currently used