Nucleon polarization in three-body models of polarized \bbox{^6}Li

Abstract

Just as $^3\roarrow{\rm He}$ can be approximately characterized as a polarized neutron target, polarized \Li6D has been advocated as a good {\em isoscalar} nuclear target for the extraction of the polarized gluon content of the nucleon. The original argument rests upon a presumed ``alpha + deuteron'' picture of \Li6, with the polarization of the nucleus carried by the polarization of the deuteron. We have calculated the polarization of the constituents of \Li6 as a three-body bound state of $α+ n + p$ interacting with local potentials fitted to the scattering data. It is necessary to include partial waves up to $j=17/2$ (75 channels, or, when including the $T=1$ state, 150 channels) in the Faddeev equations before the energy eigenvalue converges. The longitudinal formfactors are then described well by the wave function. Various combinations of $α$N and NN strong and Coulomb potentials yield a straight line in the charge radius {\em vs.} energy plane which, unlike those of previous calculations, passes through the experimental datum. We find for all cases a polarization of the valence neutron in excess of 90\%. This may make polarized \Li6D an attractive target for many nuclear physics purposes, since its neutrons are effectively 45\% polarized.