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 K xxy′-Kyyy′ (K xxy′,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.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics