DENSITY-DEPENDENCE OF THE SIGMA-NUCLEUS OPTICAL-POTENTIAL DERIVED FROM SIGMA-ATOM DATA

We study phenomenologically the density dependence of the SIGMA nucleus optical potential V(opt)(r) at zero kinetic energy by fitting it to a comprehensive set of atomic data across the periodic table. The best fit solutions for V(opt) depart considerably from a standard t(eff)rho(r) form in that Re V(opt) tends to flip sign from attraction outside the nucleus to repulsion in the surface region. However, the quality of the atomic data is too poor to determine unambiguously V(opt) inside the nucleus. For such density dependent potentials, well defined single-particle hypernuclear states are unlikely to exist.