Abstract
We investigate the restoration of chiral symmetry at finite temperature in the SU(2) quark meson model where the mean field approximation is compared to the renormalized version for quarks and mesons. In a combined approach at finite temperature all the renormalized versions show a crossover transition. The inclusion of different renormalization scales leave the order parameter and the mass spectra nearly untouched, but strongly influence the thermodynamics at low temperatures and around the phase transition. We find unphysical results for the renormalized version of mesons and the combined one.
Highlights
Since QCD is non-perturbative in the low energy regime, effective theories and models based on the QCD Lagrangian and its properties have to be utilized [1,2,3,4]
The QCD Lagrangian possesses an exact color and flavor symmetry for Nf massless quark flavours [5,6,7,8,9,10,11], and chiral symmetry controls the hadronic interactions in the low energy regime [12,13]
Perturbative expansion in powers of the coupling constant breaks down due to infrared divergencies, and an approach for the mesonic fields via the path integral formalism leads to difficulties, because at low momentum, spontaneous symmetry breaking, for instance, leads to quasiparticle exitations with imaginary energies [26,27,29]
Summary
Since QCD is non-perturbative in the low energy regime, effective theories and models based on the QCD Lagrangian and its properties have to be utilized [1,2,3,4]. We study quarks, by using a chiral SU(2) quark-meson model within the path integral formalism, and mesons, which are examined within the 2PI formalism, within a combined approach. We investigate this approach in the mean field approximation and consider the vacuum term contribution, which depends on a. The masses of the pion and the sigma meson start to be degenerate around the phase transition, which is defined by the order parameter. We find that the renormalization scale cancels when considering the SU(2) quark-meson model for the quark fields, and the inclusion of the vacuum term shifts the phase transition to larger temperatures. A combined model for quarks and mesons is only acceptable in the mean field approximation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
