The contour deformation method in momentum space, applied to subatomic physics

A generalized contour deformation method (CDM), which combines complex rotation and translation in momentum space, is discussed. CDM gives accurate calculation of two-body spectral structures: bound, antibound, resonant and continuum states forming a Berggren basis. It provides a basis for full off-shell t-matrix calculations both for real and complex input energies. Results for both spectral structures and scattering amplitudes compare perfectly well with exact values for the analytically solvable separable non-local Yamaguchi potential as a testcase. Accurate calculation of antibound states in the Malfliet–Tjon and the realistic CD–Bonn nucleon–nucleon potential are presented. Calculation of antibound states in the CD–Bonn potential are not known to have been given elsewhere.