Backward elastic pd scattering at intermediate energies

Abstract

The theoretical approaches to the description of backward elastic pd scattering at energies 0.5–2 GeV are reviewed. In addition to the mechanisms of neutron exchange and single pN scattering, the role of N * -isobar exchange is studied using the six-quark model for the dNN * vertex. Relativistic effects are taken into account within the Hamiltonian dynamics of systems with a fixed number of particles. The important role of Glauber rescatterings in the initial and final states in the neutron-transfer mechanism is displayed. Special attention is paid to the mechanism of Δ-isobar excitation, which, despite the large momentum transfer, is rather weakly sensitive to the high-momentum components of the deuteron wave function and dominates at incident protonenergies T p =0.5–1 GeV . The reaction pp→pnπ + is studied in the Δ-resonance region in order to determine the parameters of the amplitudes for NN↔NΔ transitions needed to calculate the Δ-isobar contribution to the process pd→dp. It is shown that the amplitude of the Δ-resonance mechanism for the process pd→dp is very sensitive to the parameters of the πNN, πNΔ, ρNN, and ρNΔ vertex form factors. The role of more exotic mechanisms is briefly discussed.