np final-state interaction in the reaction ²H(p⃗,pp)n at E_p⃗=19 MeV

We investigated the ²H(p⃗,pp)n breakup reaction by measuring an angular distribution of the cross section and analyzing power in the np final-state interaction (FSI) at E_p⃗=19MeV as a function of the np production angle. Kinematically complete measurements at 12 angular settings of detectors have been done. The observables around the exact FSI point were compared with predictions of four modern NN potentials, calculated for ²H(n,np)n, i.e., without inclusion of the Coulomb interaction. The resulting good overall agreement between the data and theory indicates the smallness of three-nucleon force (3NF) effects as well as the insignificance of the Coulomb force for this particular configuration and energy. This conclusion is supported by results of three-nucleon (3N) Faddeev calculations performed with 2π-exchange Tucson-Melbourne 3NF with cutoff parameter adjusted individually for each NN interaction to fit the experimental triton binding.