Approximations dans le calcul de la diffusion élastique proton-deutéron à moyenne énergie

Abstract

Usual calculations of the proton-deuteron elastic scattering cross section are analysed for energies of about 100 MeV. Several approximations usually performed in the impulse term, such as the factorization method and the introduction of the free nucleon-nucleon scattering operator (on the energy shell) are studied. The use of a simple separable S-interaction allows the derivation of a ratio between the exact and approximate values of the impulse approximation term. The variations with the incident energy or the centre-of-mass angle are small, and the corrections are not greater than 10%. This result is due to the properties of the deuteron wave function. We conclude that these approximations are not responsible for the observed disagreement with respect to experiments and that consequently a multiple scattering mechanism must be involved.