Fate of the topological susceptibility in two-color dense QCD

Abstract

We explore the topological susceptibility at finite quark chemical potential and zero temperature in two-color QCD (QC${}_2$D) with two flavors. Through the Ward-Takahashi identities of QC${}_2$D, we find that the topological susceptibility in the vacuum solely depends on three observables: the pion decay constant, the pion mass, and the $\eta$ mass in the low-energy regime of QC${}_2$D. Based on the identities, we numerically evaluate the topological susceptibility at finite quark chemical potential using the linear sigma model with the approximate Pauli-Gursey $SU(4)$ symmetry. Our findings indicate that, in the absence of $U(1{)}_A$ anomaly effects represented by the Kobayashi-Maskawa-'t Hooft-type determinant interaction, the topological susceptibility vanishes in both the hadronic and baryon superfluid phases. On the other hand, when the $U(1{)}_A$ anomaly effects are present, the constant and nonzero topological susceptibility is induced in the hadronic phase, reflecting the mass difference between the pion and $\eta$ meson. Meanwhile, in the superfluid phase it begins to decrease smoothly. The asymptotic behavior of the decrement is fitted by the continuous reduction of the chiral condensate in dense QC${}_2$D, which is similar to the behavior observed in hot three-color QCD matter. In addition, effects from the finite diquark source on the topological susceptibility are discussed. We expect that the present study provides a clue to shed light on the role of the $U(1{)}_A$ anomaly in cold and dense QCD matter.

37 pages, 8 figures, some references added, version accepted in JHEP

References in corpus (23)

• Color superconductivity in dense quark matter
• BEC-BCS Crossover in the Nambu--Jona-Lasinio Model of QCD
• Deconfinement in dense 2-color QCD
• Towards the phase diagram of dense two-color matter
• Chiral Lagrangian and spectral sum rules for dense two-color QCD
• Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations
• Hadron Spectrum in a Two-Colour Baryon-Rich Medium
• 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
• Electric conductivity in finite-density SU(2) lattice gauge theory with dynamical fermions
• Continuum Goldstone spectrum of two-color QCD at finite density with staggered quarks
• The dual properties of chiral and isospin asymmetric dense quark matter formed of two-color quarks
• Effects of Dense Quark Matter on Gluon Propagators in Lattice QC${}_2$D
• Thermal quarks and gluon propagators in two-color dense QCD
• Static magnetic susceptibility in finite-density SU(2) lattice gauge theory
• Numerical Study of the Chiral Separation Effect in Two-Color QCD at Finite Density
• Probing the hadron mass spectrum in dense two-color QCD with the linear sigma model
• Analysis on nonperturbative flavor violation at chiral crossover criticality in QCD
• New interpretation of chiral phase transition: Violation of trilemma in QCD
• Delineating chiral separation effect in two-color dense QCD
• Nonperturbative Flavor Breaking in Topological Susceptibility at Chiral Crossover

Cited by in corpus (9)

• Sound velocity peak induced by the chiral partner in dense two-color QCD
• QCD topology and axion properties in an isotropic hot and dense medium
• Thermal behavior of effective U_A(1) anomaly couplings in reflection of higher topological sectors
• Chiral effective model of cold and dense two-color QCD: The linear sigma model approach
• Enhancement of axial anomaly effects in hot two-color QCD: FRG approach in the linear sigma model
• Speed of sound peak in two-color dense QCD: confronting effective models with lattice data
• Roles of $U(1)$ axial anomaly effects in cold and dense two-color QCD with $2+2$ flavors
• Susceptibilities of rotating quark matter in Fourier-Bessel basis
• Probing the chiral and $U(1)$ axial symmetry restoration via meson susceptibilities in holographic QCD