O(N) linear sigma model beyond the Hartree approximation at finite temperature
High Energy Physics - Phenomenology
2007-05-23 v1 High Energy Physics - Theory
Abstract
We study the O(N) linear sigma model with spontaneous symmetry breaking at finite temperature in the framework of the two-particle point-irreducible (2PPI) effective action. We go beyond the Hartree approximation by including the two-loop contribution, i.e., the sunset diagram. A phase transition of second order is found, whereas it is of first order in the one-loop Hartree approximation. Furthermore, we show the temperature-dependence of the variational mass parameters and comment on their relation to the physical sigma and pion masses.
Keywords
Cite
@article{arxiv.hep-ph/0312031,
title = {O(N) linear sigma model beyond the Hartree approximation at finite temperature},
author = {J. Baacke and Stefan Michalski},
journal= {arXiv preprint arXiv:hep-ph/0312031},
year = {2007}
}
Comments
6 pages. To appear in the proceedings of International Workshop on Quantum Field Theory Under the Influence of External Conditions (QFEXT '03). Norman OK (USA), September 2003