Resonance widths and positions of nondilation-analytical potential by the complex-coordinate method

Abstract
For nondilation analytic potentials the applicability of the complex coordinate method (CCM) depends on the representation. In particular, it was shown by Colbert, Mashorfer, and Certain that the CCM fails for the Natanzon potential. Analytic expressions for the resonances for this problem were given by Ginocchio and by Alhassid, Iachello, and Levine. It is shown here that the resonances can be obtained by an analytic transformation rather than analytic dilation of the potential.