  Pion dissociation by the Mott effect in quark plasma is described within the
generalized Beth-Uhlenbeck approach on the basis of the PNJL model which allows
for a unified description of bound, resonant and scattering states. As a first
approximation, we utilize the Breit-Wigner ansatz for the spectral function and
clarify its relation to the complex mass pole solution of the pion
Bethe-Salpeter equation. Application of the Levinson theorem proves that
describing the pion Mott dissociation solely by means of spectral broadening of
the pion bound state beyond T_Mott leaves out a significant aspect. Thus we
acknowledge the importance of the continuum of scattering states and show its
role for the thermodynamics of pion dissociation.
