Chiral Condensate and Mott–Anderson Freeze-Out

Abstract

We present the idea of a Mott-Anderson freeze-out that suggests a key role of the localization of the hadron wave functions when traversing the hadronization transition. The extension of hadron wave functions in dense matter is governed by the behavior of the chiral quark condensate such that its melting at finite temperatures and chemical potentials entails an increase of the size of hadrons and thus their geometrical strong interaction cross sections. It is demonstrated within a schematic resonance gas model, that a kinetic freeze-out condition reveals a correlation with the reduction of the chiral condensate in the phase diagram up to 50% of its vacuum value. Generalizing the description of the chiral condensate by taking into account a full hadron resonance gas such correlation gets distorted. We discuss, that this may be due to our approximations in calculating the chiral condensate which disregard both, in-medium effects on hadron masses and hadron-hadron interactions. The latter, in particular due to quark exchange reactions, could lead to a delocalization of the hadron wave functions in accordance with the picture of a Mott-Anderson transition.

Chiral condensate in hadronic matter

“…[14] for the light quark condensate (following earlier work by Leupold [13]). This model is also compared with a another approach, which gives a parametric dependence of hadron masses on the pion mass [27,28] and was previously used for the calculation of both light and strange quark condensates [47].…”

“…The importance of the hadronic contribution to the melting of the chiral condensate was appreciated in a model for the freeze-out stage of heavy ion collisions, where it was related to the Mott-Anderson delocalization of hadrons [14]. The model is based on assumptions for hadron-hadron interactions and on the evolution of the matter formed in heavy ion collisions.…”

“…However, in Ref. [14] only the light quark condensate was considered, so one of the possible improvements of the model is to include also the strange sector. This is one of the motivations for the present studies.…”

Medium induced Lorentz symmetry breaking effects in nonlocal Polyakov–Nambu–Jona-Lasinio models

“…Masses and widths can be extracted which encode information on the medium modification of mesons by the underlying quark-antiquark substructure. Therefore, the nl-PNJL, and quark (and gluon) models in general, are in an interesting position to properly account for the degrees of freedom in both, the hadron and the QGP phases, with the underlying physical mechanism for the vanishing of hadronic states from the spectrum in the QGP phase being their dissolution in the continuum of scattering states (the Mott effect) [55][56][57][58][59][60][61][62].…”

Quantum mechanical model for J/ψ suppression in the LHC era

“…Evidence for the existence of such resonances in the sQGP comes from lattice QCD (LQCD) analyses of correlation functions (for recent references see, e.g., [44,45]) and is expected in accordance with the Mott mechanism [16,17,20,21]. The strong increase of rate coefficients for flavor kinetic processes between hadronic resonances in the vicinity of the hadronization transition [46] has been a main ingredient to a recent model for chemical freezeout in heavy-ion collisions [47,48].…”