  The concept of phase and dwell times used in tunneling is extended to quantum
collisions to derive a relation between the phase and dwell time delays in
scattering. This relation can be used to remove the near threshold s-wave
singularities in the Wigner-Eisenbud delay times and amounts to an extension of
the concept of quantum reflection to strong interactions. Dwell time delay
emerges as the quantity which gives the correct behaviour of the density of
states of a metastable state at all energies. This fact is demonstrated by
investigating some recently found metastable states of mesic-nuclei.
