Application of correlated basis to a description of continuum states

¹ Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
² Department of Physics, Faculty of Science and Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan

^a e-mail: horiuchi@nt.sc.niigata-u.ac.jp
^b e-mail: suzuki@nt.sc.niigata-u.ac.jp

Abstract

In this contribution, we present a simple approach to the scattering problem using the technique for discrete states, particularly developed for a basis expansion method. An idea is very simple and the following: First, we calculate a spectroscopic amplitude (SA) between two subsystems from the “discretized” wave function obtained in the bound-state calculation. When one uses square-integrable basis, the asymptotics of the SA shows ill behavior. The behavior is easily corrected by use of the Green’s function, and then phase shift is accurately determined from the SA with “correct” asymptotics. Test examples confirm the accuracy of the method. The α + n scattering is described using realistic nucleon-nucleon potentials. The 1/2⁺ phase shifts are in reasonable agreement with experiment, and gain contributions both from the tensor and central components of the nucleon-nucleon potential. The 3/2⁻ and 1/2⁻ phase shifts obtained in a single-channel calculation are too small in comparison with experiment and point out the importance of including distorted configurations of the α particle.