Optical-model analysis of vector polarized6Li elastic scattering on12C,16O,28Si and58Ni nuclei

Abstract

WEISS et al. (t) have investigated the elastic scattering of vector polarized eLi on ~2C, ~eO, 2sSi and 5SNi nuclei using the Heidelberg ENtandem seource (2). These authors give an interpretat ion of the cross-sections and vector analysing powers in terms of an optical model with a folded spin-orbit potential , derived from known deuteron target I. s potentials and a eLi S-wave function (3). Their results are quite good and the main advantage of this analysis is to have a fixed spin-orbit potential , since such a part is not yet well understood. However, the use of a folded spin-orbit potential in a D W B A analysis of (SLi, d) and (eLi, ~) transfer reactions (4.5) is very t ime consuming. For example, on our CDC 6600 computer, the calculation of the e l i distorted wave with folded l . s potential is about 10 times longer than with a conventional optical potential . In order to define some complete sets of optical parameters for these elastic-scattering cross-sections and vector analysing powers, we have reanalysed these data in terms of full optical model. We use Raynal ' s MAGALI Code (e) which performs an automat ic research of central and spin-orbit optical-potential parameters. The exact forms of the central and spin-orbit potentials (Saxon-Wood an Thomas forms, respectively) have bcen given by RAYNAL et al. (7). The ( iTi~) analysing power data take into account the value P = 0.63 • 0.03 for the beam polarization (we use in fact P = ]) (s). We use also corrected cross-section data for the 2sSi nucleus (8).