A Small Parameter Method for Few-Body Problems

Abstract

A procedure to solve few-body problems which is based on an expansion over a small parameter is developed. The parameter is the ratio of potential energy to kinetic energy in the subspace of states having not small hyperspherical quantum numbers, K>K_0. Dynamic equations are reduced perturbatively to those in the finite subspace with K \le K_0. The contribution from the subspace with K>K_0 is taken into account in a closed form, i.e. without an expansion over basis functions.

Comments: 19 pages, 1 figure. A misprint in Eqs. (31)-(33) of the primary version is corrected