A RELATIVISTIC MODEL FOR ALPHA-NUCLEUS ELASTIC-SCATTERING

It is the purpose of this paper to present the first relativistic description of alpha-nucleus elastic scattering using an optical model with the Duffin-Kemmer-Petiau (DKP) equation as the applicable wave equation. The DKP optical model potentials that are used are obtained by a folding procedure involving phenomenological Lorentz scalar and vector Dirac nucleon-nucleus potentials, In order to probe the DKP description of the alpha-nucleus interaction, we consider the elastic alpha-scattering on a range of nuclei over the 100 < E < 200 MeV energy range. The effective potential has, in its Schrodinger equivalent form, a linear energy dependence and differs from the form factors commonly used. We find that this model gives a good description of the elastic scattering data and reproduces the diffraction pattern and the exponential fall-off of the cross section beyond the rainbow region. The predictive power of the model is emphasized noting that all the energy dependence is inherently built into the model and no fits were thus necessary when going from one energy to the next. A comparison of the DKP model with non-relativistic models is also carried out highlighting the advantages of the relativistic approach over the non-relativistic one.