The resonance levels of the Yukawa potential

The eigenenergy spectrum resulting from the Yukawa spherically symmetric potential is extensively investigated, including for the first time the resonance states. The energy levels for different orbital angular momentum values, l = 1, … , 10, are studied as functions of the screening parameter, λ. With λ increasing they reach the continuum threshold, then become resonances and finally disappear completely diluted in the continuum. In the continuum-threshold region, for sufficiently large λ, numerous level crossings appear - a consequence of breaking the O(4) symmetry. It has been observed that in the investigated range of l, only one resonance state appears for a given (l, λ) pair.