Cumulants of the chiral order parameter at lower RHIC energies

Abstract

We study cumulants of the chiral order parameter as function of beam energy as a possible signal for the presence of a critical end point and first-order phase transition in the QCD phase diagram. We model the expansion of a heavy-ion collision by a fluid dynamic expansion coupled to the explicit propagation of the chiral order parameter sigma via a Langevin equation. We evolve the medium until a parametrized freeze-out condition is met where we calculate event-by-event fluctuations and cumulants of sigma which are expected to follow the trend of net-proton number cumulants. We emphasize the role of a nonequilibrium first-order phase transition: The presence of an unstable phase causes the well-known bending of the trajectories in the space of temperature and baryochemical potential. For these cases at lower beam energies, the system crosses the freeze-out line more than once, allowing us to calculate a range of cumulants for each initial condition which are overall enhanced for the second hit of the freeze-out line. We thus find not only the critical end point but also the phase transition of the underlying model clearly reflected in the cumulants. The impact of volume fluctuations is demonstrated to play a measurable role for fluid dynamical evolutions that last significantly long.

arXiv comment14 pages, 4 figures, ICNFP 2021. arXiv admin note: text overlap with arXiv:2204.00286

References in corpus (52)

• Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions
• The order of the quantum chromodynamics transition predicted by the standard model of particle physics
• The equation of state in (2+1)-flavor QCD
• Is there still any Tc mystery in lattice QCD? Results with physical masses in the continuum limit III
• Non-Gaussian fluctuations near the QCD critical point
• Comparison of Chemical Freeze-Out Criteria in Heavy-Ion Collisions
• Phase diagrams in the three-flavor Nambu--Jona-Lasinio model with the Polyakov loop
• On the sign of kurtosis near the QCD critical point
• Search for the QCD Critical Point with Fluctuations of Conserved Quantities in Relativistic Heavy-Ion Collisions at RHIC : An Overview
• Slowing Out of Equilibrium Near the QCD Critical Point
• Chiral Phase Transition within Effective Models with Constituent Quarks
• The Phase Diagram of the Quark-Meson Model
• Phase structure of three and four flavor QCD
• Hydro+: hydrodynamics with parametric slowing down and fluctuations near the critical point
• Skewness, kurtosis and the 5th and 6th order cumulants of net baryon-number distributions from lattice QCD confront high-statistics STAR data
• Using Higher Moments of Fluctuations and their Ratios in the Search for the QCD Critical Point
• The renormalization group and quark number fluctuations in the Polyakov loop extended quark-meson model at finite baryon density
• Cumulants and Correlation Functions of Net-proton, Proton and Antiproton Multiplicity Distributions in Au+Au Collisions at energies available at the BNL Relativistic Heavy Ion Collider
• Real time evolution of non-Gaussian cumulants in the QCD critical regime
• Volume fluctuations and higher order cumulants of the net baryon number
• Chiral phase structure and critical end point in QCD
• Nonequilibrium chiral fluid dynamics including dissipation and noise
• Spinodal amplification of density fluctuations in fluid-dynamical simulations of relativistic nuclear collisions
• Diffusive dynamics of critical fluctuations near the QCD critical point
• Prelude to Compressed Baryonic Matter
• Phase transition dynamics for baryon-dense matter
• Baryon number fluctuations in the QCD phase diagram from Dyson-Schwinger equations
• Proton number fluctuations in $\sqrt{s_{NN}}$ = 2.4 GeV Au+Au collisions studied with HADES
• Non-Equilibrium Phase Transition in Rapidly Expanding Matter
• (3+1)-Dimensional Hydrodynamic Expansion with a Critical Point from Realistic Initial Conditions
• Dynamical net-proton fluctuations near a QCD critical point
• Chiral phase transition in the presence of spinodal decomposition
• Chiral fluid dynamics with explicit propagation of the Polyakov loop
• Dissipation and Fluctuation at the Chiral Phase Transition
• Spinodal phase separation in relativistic nuclear collisions
• Role of Fluctuations in the Linear Sigma Model with Quarks
• Baryon number fluctuations in chiral effective models and their phenomenological implications
• Equilibration and relaxation times at the chiral phase transition including reheating
• Correlated fluctuations near the QCD critical point
• Formation of droplets with high baryon density at the QCD phase transition in expanding matter
• Modeling the diffusive dynamics of critical fluctuations near the QCD critical point
• Net-baryon number variance and kurtosis within nonequilibrium chiral fluid dynamics
• Search for the critical point of strongly interacting matter in NA49
• Baryon number fluctuations in the 2+1 flavor low energy effective model
• Langevin Simulation of Scalar Fields: Additive and Multiplicative Noises and Lattice Renormalization
• Entropy production and reheating at the chiral phase transition
• Multiplicity fluctuations of net protons on the hydrodynamic freeze-out surface
• Broadening of the chiral critical region in a hydrodynamically expanding medium
• Lattice QCD results on cumulant ratios at freeze-out
• Search for the critical point by the NA61/SHINE experiment
• Dynamical Evolution of the Scalar Condensate in Heavy Ion Collisions
• Enhancements of high order cumulants across the 1st order phase transition boundary

Cited by in corpus (1)

• Net-proton number cumulant ratios as function of beam energy from an expanding nonequilibrium chiral fluid