Analyzing powers of the proton-deuteron break-up reaction at large proton scattering angles measured with BINA at 135 MeV

Polarization observables in the proton-deuteron break-up reaction are sensitive probes to investigate the spin structure of the nucleon-nucleon and three-nucleon forces. A measurement of the analyzing powers for the 2H(p,pp)n break-up reaction was carried out at KVI exploiting a polarized-proton beam produced in an atomic-beam type polarized ion source at a proton-beam energy of 135 MeV. The scattering angles and energies of the final-state protons were measured using the Big Instrument for Nuclear-polarization Analysis (BINA) with a nearly 4π geometrical acceptance. In this work, we extended the earlier measurements that were done for kinematical configurations at small proton scattering angles by analyzing configurations at which one of the final-state protons scatters towards the backward part of BINA. The results are compared with theoretical calculations based on NN potential alone or combined with the 3N potential, with or without the inclusion of the Coulomb effect. The effects of Coulomb and the ∆ resonance in many kinematical configurations of proton-deuteron break-up are small. Coulomb effects are even negligible for the configurations. The addition of the ∆ resonance in the calculations makes the agreement with the experiments even worse in some cases. The behavior of the discrepancies observed between data and theory predictions depends on the azimuthal opening angle and the relative energy of the outgoing protons