Sound velocity peak induced by the chiral partner in dense two-color QCD

Abstract

Recently, the peak structure of the sound velocity was observed in the lattice simulation of two-color and two-flavor QCD at the finite quark chemical potential. The comparison with the chiral perturbation theory (ChPT) result was undertaken, however, the ChPT failed in reproducing the peak structure. In this study, to extend the ChPT framework, we incorporate contributions of the $\sigma$ meson, that is identified as the chiral partner of pions, on top of the low-energy pion dynamics by using the linear sigma model (LSM). Based on the LSM we derive analytic expressions of the thermodynamic quantities as well as the sound velocity within a mean-field approximation. As a result, we find that those quantities are provided by sums of the ChPT results and corrections, where the latter is characterized by a mass difference between the chiral partners, the $\sigma$ meson and pion. The chiral partner contributions are found to yield a peak in the sound velocity successfully. We furthermore show that the sound velocity peak emerges only when $m_{\sigma }>\sqrt{3}{m}_{\pi }$ and ${\mu }_q>m_{\pi }$, with $m_{\sigma (\pi )}$ and ${\mu }_q$ being the $\sigma$ meson (pion) mass and the quark chemical potential, respectively. The correlation between the sound velocity peak and the sign of the trace anomaly is also addressed.

14 pages, 4 figures; some references added; version accepted in PRD

References in corpus (25)

• Finite-density lattice QCD and sign problem: current status and open problems
• Deconfinement in dense 2-color QCD
• Towards the phase diagram of dense two-color matter
• Merger and post-merger of binary neutron stars with a quark-hadron crossover equation of state
• Implications of NICER for neutron star matter: the QHC21 equation of state
• Equation of state and speed of sound of isospin-asymmetric QCD on the lattice
• Quark-hadron crossover equations of state for neutron stars: constraining the chiral invariant mass in a parity doublet model
• Stiffening of matter in quark-hadron continuity
• Chiral Lagrangian and spectral sum rules for dense two-color QCD
• Dense 2-color QCD towards continuum and chiral limits
• Hadron Spectrum in a Two-Colour Baryon-Rich Medium
• Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations
• Two-colour QCD phases and the topology at low temperature and high density
• Behaviour of the topological susceptibility in two colour QCD across the finite density transition
• Phase-diagram of two-color lattice QCD in the chiral limit
• Lattice study of thermodynamic properties of dense QC${}_2$D
• Equation of state of cold and dense QCD matter in resummed perturbation theory
• Sound velocity peak and conformality in isospin QCD
• Continuum Goldstone spectrum of two-color QCD at finite density with staggered quarks
• Effects of Dense Quark Matter on Gluon Propagators in Lattice QC${}_2$D
• Thermal quarks and gluon propagators in two-color dense QCD
• Color screening in cold quark matter
• Speed of sound in dense strong-interaction matter
• Probing the hadron mass spectrum in dense two-color QCD with the linear sigma model
• Fate of the topological susceptibility in two-color dense QCD

Cited by in corpus (8)

• Thermal effects on sound velocity peak and conformality in isospin QCD
• Chiral effective model of cold and dense two-color QCD: The linear sigma model approach
• Investigating the Impact of Higher-Order Phase Transitions in Binary Neutron-Star Mergers
• Speed of sound peak in two-color dense QCD: confronting effective models with lattice data
• Enhancement of axial anomaly effects in hot two-color QCD: FRG approach in the linear sigma model
• Roles of $U(1)$ axial anomaly effects in cold and dense two-color QCD with $2+2$ flavors
• Recurring region for neutron-star observables
• Thermal quarks and Polyakov loops in two-color dense QCD