Physical consequences of anomalies in nonlocal potential problems

An $s$-wave two-body separable potential may give rise to several phenomena which are absent for nonsingular local potentials. We examine the physical implications of a well known example of such phenomena, the continuum bound state, as well as of two lesser known anomalies, the so-called positive energy spurious state and negative energy bound states with improper long-range behavior. By examining these anomalies in light of Levinson's theorem, Wigner's phase shift inequality, and the effect of a perturbation on the anomalous states by their insertion in a three-body scattering situation, we find in agreement with previous studies that the continuum bound state acts as a resonance of negligible width. However, we find it difficult to see how the presence of a spurious state can be detected experimentally.

NUCLEAR REACTIONS Scattering by a nonlocal potential, continuum bound states, spurious states, wave functions with improper long-range behavior. Levinson's theorem. Three-particle scattering.