Analyzing powers at low nucleon-nucleon relative energies in proton-deuteron breakup reaction

Vector analyzing powers for the d((p)over-right-arrow, pp)n reaction have been measured at KVI for different kinematical configurations using a polarized proton beam with an energy of 190 MeV. We compared our data with different theoretical calculations at extremely low relative energies of the proton-proton and proton-neutron systems in the final state. For the proton-neutron case, we used the information of the two detected protons in the final state in which one of them scattered to an angle smaller than 40 degrees and the other one to an angle larger than 100 degrees in the laboratory frame. We extrapolated our measurements towards a kinematical configuration to a vanishing relative energy. Our results show that none of the theoretical models presented here is able to reproduce experimental data for the proton-proton case at very low relative energies. For the proton-neutron case, we were not able to provide a reliable extrapolation to small relative energies of less than 1 MeV. Present results are the basis for future investigations of spin-isospin dependencies in the nuclear many-body force.