mgr Agnieszka Wergieluk

Role of the Levinson theorem for modeling pion dissociation in hot PNJL quark matter

Pion dissocation by the Mott effect in quark plasma is described within the generalized Beth-Uhlenbeck approach on the basis of a PNJL model which allows for a unified description of the 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. Describing the pion Mott dissociation as a spectral broadening of the pion bound state beyond T_Mott leaves out significant aspect: the continuum of scattering states. We utilize the Levinson theorem in order to specify a generic ansatz for the contribution from the scattering continuum and demonstrate its role for the thermodynamics of pion dissociation.