The chiral phase transition and the axial anomaly

Abstract

To date numerical simulations of lattice QCD have not found a chiral phase transition of first order which is expected to occur for sufficiently light pions. We show how the restoration of an exact global chiral symmetry can strongly decrease the breaking of the approximate, anomalous $U_A(1)$ symmetry. This is testable on the lattice through simulations for one through four flavors. In QCD a small breaking of the $U_A(1)$ symmetry in the chirally symmetric phase generates novel experimental signals.

arXiv commentUpdated discussion of literature

References in corpus (69)

• The order of the quantum chromodynamics transition predicted by the standard model of particle physics
• Signatures of the Tricritical Point in QCD
• Event-by-Event Fluctuations in Heavy Ion Collisions and the QCD Critical Point
• Chiral Magnetic and Vortical Effects in High-Energy Nuclear Collisions --- A Status Report
• Chiral crossover in QCD at zero and non-zero chemical potentials
• Mapping the Phases of Quantum Chromodynamics with Beam Energy Scan
• The QCD phase transition with physical-mass, chiral quarks
• The QCD crossover at finite chemical potential from lattice simulations
• Meson vacuum phenomenology in a three-flavor linear sigma model with (axial-)vector mesons
• Baryogenesis from the weak scale to the grand unification scale
• The three-flavor chiral phase structure in hot and dense QCD matter
• Relevance of the axial anomaly at the finite-temperature chiral transition in QCD
• The QCD chiral transition, $\ua$ symmetry and the Dirac spectrum using domain wall fermions
• The chiral transition and U(1)_A symmetry restoration from lattice QCD using Domain Wall Fermions
• Conformal Bootstrap Dashing Hopes of Emergent Symmetry
• Bootstrapping phase transitions in QCD and frustrated spin systems
• Higher order quark-mesonic scattering processes and the phase structure of QCD
• Microscopic Origin of \boldmath{$U_A(1)$} Symmetry Violation in the High Temperature Phase of QCD
• Evidence of effective axial U(1) symmetry restoration at high temperature QCD
• On the nature of the finite-temperature transition in QCD
• Phase Transitions in Particle Physics -- Results and Perspectives from Lattice Quantum Chromo-Dynamics
• The High Temperature Phase of QCD and {\boldmath $U(1{)}_A$} Symmetry
• Correlated Dirac Eigenvalues and Axial Anomaly in Chiral Symmetric QCD
• Fluctuation-induced modifications of the phase structure in (2+1)-flavor QCD
• Fluctuations and the axial anomaly with three quark flavors
• $U_A(1)$ symmetry restoration in QCD with $N_f$ flavors
• Chiral phase structure of three flavor QCD at vanishing baryon number density
• Etaprime and Eta Mesons with Connection to Anomalous Glue
• Indirect observation of an in-medium eta' mass reduction in sqrt(s_{NN})=200 GeV Au+Au collisions
• On the strength of the $U_A(1)$ anomaly at the chiral phase transition in $N_f=2$ QCD
• The Chiral Phase Transition in three-flavor QCD from Lattice QCD
• Functional renormalization group study of the two-flavor linear sigma model in the presence of the axial anomaly
• Lévy-stable two-pion Bose-Einstein correlations in $\sqrt{s_{{}_{NN}}}=200$ GeV Au$+$Au collisions
• Study of the axial U(1) anomaly at high temperature with lattice chiral fermions
• Mass sensitivity of the three-flavor chiral phase transition
• Nature of the phase transition for finite temperature $N_{\mathrm{f}}=3$ QCD with nonperturbatively O($a$) improved Wilson fermions at $N_{\mathrm{t}}=12$
• Topological Charge and $U(1{)}_A$ Symmetry in the High Temperature Phase of QCD
• How the axial anomaly controls flavor mixing among mesons
• Eigenvalue spectra of QCD and the fate of $U_A(1)$ breaking towards the chiral limit
• The role of the chiral anomaly in polarized deeply inelastic scattering I: Finding the triangle graph inside the box diagram in Bjorken and Regge asymptotics
• Observation of Partial U_A(1) Restoration from Two-Pion Bose-Einstein Correlations
• Analytic and Numerical Bootstrap of CFTs with $O(m)\times O(n)$ Global Symmetry in 3D
• Five-loop epsilon expansion for U(n)xU(m) models: finite-temperature phase transition in light QCD
• Significant in-medium eta' mass reduction in sqrt(s(NN))=200 GeV Au+Au collisions at the BNL Relativistic Heavy Ion Collider
• A Three-Flavor Chiral Effective Model with Four Baryonic Multiplets within the Mirror Assignment
• QCD phase transitions in the light quark chiral limit
• One flavor QCD
• Chiral Anomaly in Interacting Condensed Matter Systems
• Excited Scalar and Pseudoscalar Mesons in the Extended Linear Sigma Model
• Topological susceptibility of pure gauge theory using Density of States
• Functional dependence of axial anomaly via mesonic fluctuations in the three flavor linear sigma model
• The Myriad Uses of Instantons
• U(2)xU(2)-symmetric fixed point from the Functional Renormalization Group
• Second order chiral phase transition in three flavor quantum chromodynamics?
• Fate of the ${\eta }^{\prime }$ in the Quark Gluon Plasma
• Effective linear meson model
• The semi-classical approximation at high temperature revisited
• ${\eta }^{\prime }$ and $\eta$ mesons at high T when the U_A(1) and chiral symmetry breaking are tied
• CFTs with $U(m)\times U(n)$ Global Symmetry in 3D and the Chiral Phase Transition of QCD
• Eigenvalues of the QCD Dirac matrix with improved staggered quarks in the continuum limit
• Anomalies and chiral symmetry in QCD
• Effects of chiral symmetry restoration on meson and dilepton production in relativistic heavy-ion collisions
• Anomalous interactions between mesons with nonzero spin and glueballs
• Topological susceptibility in finite temperature QCD with physical $(u/d,s,c)$ domain-wall quarks
• Fractional topological charge in $SU(N)$ gauge theories without dynamical quarks
• Higher topological charge in the QCD vacuum and axion cosmology
• Effects of chain decays, radial flow and $U_A(1)$ restoration on the low-mass dilepton enhancement in $\sqrt{s_{NN}}=200$ GeV Au+Au reactions
• Berry's phase and chiral anomalies
• Multicanonical reweighting for the QCD topological susceptibility

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• Range of topological fluctuations in the three-flavor linear sigma model
• Parity-doubled nucleons can rapidly cool neutron stars
• On the nature of the QCD chiral phase transition with imaginary chemical potential
• Different scenarios of dynamical chiral symmetry breaking in the interacting instanton liquid model via flavor symmetry breaking
• Studying the QCD phase diagram using pressure derivatives from lattice QCD