ACCURATE 3-NUCLEON BOUND-STATE CALCULATION WITH AN EXTENDED SEPARABLEEXPANSION OF THE 2-BODY T-MATRIX

An accurate solution for the three-nucleon bound state is obtained wit hin 1 keV in the binding energy and, on the whole, better than 1% in t he wave function, using a new systematic and efficient method. The met hod is based on a recently developed separable expansion for any finit e-range interaction, in which a rigorous separable series for the two- body t-matrix is obtained by expanding the wave function in terms of a complete set of basis functions inside the range of the potential. In order to treat a potential with a strong repulsive core, as in the ca se of the Argonne potential, we develop a two-potential formalism. The expansion starts with a few EST (Ernst, Shakin, and Thaler) terms in order to accelerate the convergence and continues with an orthogonal s et of polynomials, avoiding the known difficulties of a pure EST expan sion. Thus, several techniques are combined in the present extended se parable expansion (ESE). In this way, the method opens a new systemati c treatment for accurate few-body calculations resulting in a dramatic reduction in the CPU time required to solve few-body equations.