A RELATIVISTIC MODEL FOR ALPHA-NUCLEUS ELASTIC-SCATTERING

It is the purpose of this paper to present the first relativistic desc ription of alpha-nucleus elastic scattering using an optical model wit h the Duffin-Kemmer-Petiau (DKP) equation as the applicable wave equat ion. 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 descripti on of the alpha-nucleus interaction, we consider the elastic alpha-sca ttering on a range of nuclei over the 100 < E < 200 MeV energy range. The effective potential has, in its Schrodinger equivalent form, a lin ear energy dependence and differs from the form factors commonly used. We find that this model gives a good description of the elastic scatt ering data and reproduces the diffraction pattern and the exponential fall-off of the cross section beyond the rainbow region. The predictiv e power of the model is emphasized noting that all the energy dependen ce 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 adva ntages of the relativistic approach over the non-relativistic one.