Degeneracy patterns of chiral companions at finite temperature

  • Chiral symmetry represents a fundamental concept lying at the core of particle and nuclear physics. Its spontaneous breaking in vacuum can be exploited to distinguish chiral hadronic partners, whose masses differ. In fact, the features of this breaking serve as guiding principles for the construction of effective approaches of QCD at low energies, e.g., the chiral perturbation theory, the linear sigma model, the (Polyakov)–Nambu–Jona-Lasinio model, etc. At high temperatures/densities chiral symmetry can be restored bringing the chiral partners to be nearly degenerated in mass. At vanishing baryochemical potential, such restoration follows a smooth transition, and the chiral companions reach this degeneration above the transition temperature. In this work I review how different realizations of chiral partner degeneracy arise in different effective theories/models of QCD. I distinguish the cases where the chiral states are either fundamental degrees of freedom or (dynamically-generated) composed states. In particular, I discuss the intriguing case in which chiral symmetry restoration involves more than two chiral partners, recently addressed in the literature.

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Author:Juan M. Torres-RinconORCiDGND
Parent Title (English):Symmetry
Place of publication:Basel
Document Type:Article
Date of Publication (online):2021/08/01
Date of first Publication:2021/08/01
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/09/28
Tag:Nambu–Jona-Lasinio model; chiral perturbation theory; chiral symmetry restoration; effective field theories; finite-temperature quantum-field theory; heavy-quark effective theory; linear sigma mode; mass degeneracy
Issue:8, art. 1400
Page Number:31
First Page:1
Last Page:31
This research was funded by the Deutsche Forschungsgemeinschaft (German Research Foundation) grant numbers 411563442 (Hot Heavy Mesons) and 315477589—TRR 211 (Strong-interaction matter under extreme conditions).
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoCreative Commons - Namensnennung 4.0