Energy spectra of protons in diffraction break-up of deuterons on 12C and 40Ca at intermediate energies

Abstract

In the diffraction approximation generalized to the case of inelastic processes with longitudinal momentum transfer, the reaction of the deuteron break-up on nuclei at medium energies is studied, taking into account the Coulomb and nuclear interactions. The formulas for the calculation of the energy spectra of the emerging protons are obtained up to the second order with respect to the ratio of the deuteron radius to the nucleus radius. Three types of model wave functions of the deuteron were used in the calculations: Yukawa, exponential and Gaussian. The wave function of np-pair in continuum is built orthogonal to the wave function of deuteron. This allows one to take into account qualitatively the interaction in the final state and avoid false contributions to the cross section at near zero momentum transfer. A comparison with experimental data on the break-up of deuterons with energy of 56 MeV on carbon and calcium with the registration of the emitted neutrons and protons at zero angles is carried out. It is shown that the contribution of the Coulomb mechanism dominates in the cross section. The best description of the spectra of protons is achieved by using the Yukawa form of the wave function of the deuteron. It is also shown that taking into account the transfer of longitudinal momentum to the deuteron nucleons improves the experimental data description. In the case of non-zero nucleon escape angles, the effect of taking into account longitudinal momentum can reach several hundred percent.

Keywords

• diffraction approximation
• deuteron break-up reaction
• mechanisms of reaction