Journal article

Publication year: 2023

Journal: Physical Review D

Volume number: 108

Issue number: 11

ISSN: 2470-0010

eISSN: 2470-0029

Open access status: Hybrid

DOI Link: https://doi.org/10.1103/PhysRevD.108.114018

Publisher: American Physical Society

Abstract: 
We investigate the order of the QCD chiral transition in the limit of vanishing bare up/down quark masses and variations of the bare strange-quark mass 0 <= ms <= infinity. In this limit and due to universality long range correlations with the quantum numbers of pseudoscalar and scalar mesons may dominate the physics. In order to study the interplay between the microscopic quark and gluon degrees of freedom and the long range correlations we extend a combination of lattice Yang-Mills theory and a (truncated) version of DysonSchwinger equations by also taking backreactions of mesonic degrees of freedom into account. Both this system and the meson backcoupling approach have been studied extensively in the past but this is the first work in a full (2 + 1)-flavor setup. Starting from the physical point, we determine the chiral susceptibilities for decreasing up/down quark masses and find good agreement with both lattice and functional renormalization group results. We then proceed to determine the order of the chiral transition along the left-hand side of the Columbia plot, for chemical potentials in the range -(30 MeV)2 <= mu 2q <= (30 MeV)2. We find a second-order phase transition throughout and no trace of a first-order region in the Nf = 3 corner of the Columbia plot. This result remains unchanged when an additional Goldstone boson due to a restored axial UA(1) is taken into account.

Harvard Citation style: Bernhardt, J. and Fischer, C. (2023) QCD phase transitions in the light quark chiral limit, Physical Review D, 108(11), Article 114018. https://doi.org/10.1103/PhysRevD.108.114018

APA Citation style: Bernhardt, J., & Fischer, C. (2023). QCD phase transitions in the light quark chiral limit. Physical Review D. 108(11), Article 114018. https://doi.org/10.1103/PhysRevD.108.114018