Bonn 2020 – wissenschaftliches Programm
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HK 16.4: Vortrag
Dienstag, 31. März 2020, 18:00–18:15, J-HS G
Self-consistent meson spectral functions from analytically continued FRG flow equations — •Jan-Hendrik Otto, Lorenz von Smekal, and Christopher Jung — Justus Liebig Universität Giessen
The Functional Renormalization Group (FRG) can be used to calculate spectral functions from analytically continued (aFRG) flow equations for two-point correlation functions. Of particular relevance for the electromagnetic spectral function and thus for thermal dilepton rates in the resonance region, are the vector and axial-vector meson spectral functions in the hot and dense medium. Because chiral symmetry restoration at finite temperature and/or density is reflected in these spectral functions, this can be exploited to search for experimental signatures, from heavy-ion collisions at HADES energies and later with CBM at FAIR, of a chiral first-order phase transition and the associated critical endpoint (CEP) in the phase diagram of QCD. While present calculations are thermodynamically consistent and symmetry preserving, fully self-consistent solutions are still a challenge. On the other hand, self-consistent calculations are particularly important for possible signatures of a CEP. In this contribution we therefore present a simplified scheme to calculate self-consistent spectral functions from aFRG flow equations, based on self-energy parametrisations inspired by one-loop structures, for π and σ mesons in the O(4)-model.