Precise determination of the effective-range parameters up to an arbitrary order

Abstract

We propose a method to compute, for a given potential model, an arbitrary coefficient of the effective-range function expanded as a power series in energy. The method is based on a set of recurrence relations at low energy, that allows a compact and general description to any order in energy for neutral and charged cases. By using the Lagrange mesh technique to compute the R-matrix at zero energy, this proposal permits to compute, with a very good precision, the effective-range parameters. We use a potential model for some nuclear systems to illustrate the effectiveness of this method and to discuss its numerical limitations.

Comments: Keywords: scattering length, effective range, shape parameter, effective-range parameters and phase-shifts. 13 pages, 6 figures