Probing the Nuclear Symmetry Energy with Heavy Ion Collisions

Abstract

Heavy Ion Collisions (HIC) represent a unique tool to probe the in-medium nuclear interaction in regions away from saturation. In this report we present a selection of new reaction observables in dissipative collisions particularly sensitive to the symmetry term of the nuclear Equation of State ($Iso-EoS$). We will first discuss the Isospin Equilibration Dynamics. At low energies this manifests via the recently observed Dynamical Dipole Radiation, due to a collective neutron-proton oscillation with the symmetry term acting as a restoring force. At higher beam energies Iso-EoS effects will be seen in an Isospin Diffusion mechanism, via Imbalance Ratio Measurements, in particular from correlations to the total kinetic energy loss. For fragmentation reactions in central events we suggest to look at the coupling between isospin distillation and radial flow. In Neck Fragmentation reactions important Iso-EoS information can be obtained from fragment isospin content, velocity and alignement correlations. The high density symmetry term can be probed from isospin effects on heavy ion reactions at relativistic energies (few AGeV range), in particular for high transverse momentum selections of the reaction products. Rather isospin sensitive observables are proposed from nucleon/cluster emissions, collective flows and meson production. The possibility to shed light on the controversial neutron/proton effective mass splitting in asymmetric matter is also suggested. A large symmetry repulsion at high baryon density will also lead to an "earlier" hadron-deconfinement transition in n-rich matter. The binodal transition line of the (T,ρ_B) diagram is lowered to a region accessible through heavy ion collisions in the energy range of the new planned facilities, e.g. the FAIR/NICA projects. Some observable effects of the formation of a Mixed Phase are suggested, in particular a Neutron Trapping mechanism. The dependence of the results on a suitable treatment of the isovector part of the interaction in effective QCD Lagrangian approaches is critically discussed. We stress the interest of this study in nuclear astrophysics, in particular for supernovae explosions and neutron star structure, where the knowledge of the Iso-EoS is important at low as well as at high baryon density.

52 pages, 28 figures, topical review submitted to J. Phys. G: Nucl. Phys (IOP Latex)

References in corpus (42)

• Neutron Star Observations: Prognosis for Equation of State Constraints
• Astrophysical Measurement of the Equation of State of Neutron Star Matter
• Constraints on the symmetry energy and on neutron skins from the pygmy resonances in 68Ni and 132Sn
• The Giant Dipole Resonance as a quantitative constraint on the symmetry energy
• Isotopic dependence of the giant monopole resonance in the even-A ^{112-124}Sn isotopes and the asymmetry term in nuclear incompressibility
• Coalescence Models For Hadron Formation From Quark Gluon Plasma
• Neutron and Proton Transverse Emission Ratio Measurements and the Density Dependence of the Asymmetry Term of the Nuclear Equation of State
• Dense Matter in Compact Stars: Theoretical Developments and Observational Constraints
• Systematics of pion emission in heavy ion collisions in the 1A GeV regime
• Relativistic model for nuclear matter and atomic nuclei with momentum-dependent self-energies
• Quantum Monte Carlo calculation of the equation of state of neutron matter
• Pygmy dipole resonance as a constraint on the neutron skin of heavy nuclei
• Symmetry energy of dilute warm nuclear matter
• Isospin effects on sub-threshold kaon production at intermediate energies
• Spinodal decomposition of low-density asymmetric nuclear matter
• Testing Deconfinement at High Isospin Density
• Hybrid protoneutron stars with the MIT bag model
• Isospin emission and flows at high baryon density: a test of the symmetry potential
• Isospin Dependence of Incomplete Fusion Reactions at 25 Mev/a
• Fusion process studied with preequilibrium giant dipole resonance in time dependent Hartree-Fock theory
• Isospin Dynamics in Peripheral Heavy Ion Collisions at Fermi Energies
• Quark matter in neutron stars within the Nambu - Jona-Lasinio model and confinement
• Nuclear matter in the crust of neutron stars derived from realistic NN interactions
• The Dynamical Dipole Mode in Fusion Reactions with Exotic Nuclear Beams
• Phase transition from nuclear matter to color superconducting quark matter: the effect of the isospin
• Chiral condensate in neutron matter
• Relativistic Effects in Nuclear Matter and Nuclei
• Isospin Distillation with Radial Flow: a Test of the Nuclear Symmetry Energy
• Isospin diffusion in semi-peripheral ${}^{58}Ni$ + ${}^{197}Au$ collisions at intermediate energies (II): Dynamical simulations
• Neutron to proton ratios of quasiprojectile and midrapidity emission in the ${}^{64}$Zn + ${}^{64}$Zn reaction at 45 MeV/nucleon
• Probing the symmetry energy and the degree of isospin equilibrium
• Prompt dipole radiation in fusion reactions
• In-medium effects on particle production in heavy ion collisions
• Nuclear symmetry energy: An experimental overview
• Phase Transition of Finite Size Quark Droplets with Isospin Chemical Potential in the Nanbu--Jona-Lasinio Model
• Distinctive features of Coulomb-related emissions in peripheral heavy ion collisions at Fermi energies
• Testing hadronic interaction packages at cosmic ray energies
• Yukawa's Pion, Low-Energy QCD and Nuclear Chiral Dynamics
• Monte Carlo approach to nuclei and nuclear matter
• The Dynamical Dipole Radiation in Dissipative Collisions with Exotic Beams
• Quark matter and the astrophysics of neutron stars
• The Pervasive Role of the Nuclear Symmetry Energy in the Structure and Evolution of Neutron Stars

Cited by in corpus (59)

• Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density
• Bayesian Inference of High-density Nuclear Symmetry Energy from Radii of Canonical Neutron Stars
• GW190814's secondary component with mass $(2.50-2.67)$ M${}_{\odot }$ as a super-fast pulsar
• Towards a model-independent constraint of the high-density dependence of the symmetry energy
• Quark matter symmetry energy and quark stars
• Bayesian Inference of the Symmetry Energy of Super-Dense Neutron-Rich Matter from Future Radius Measurements of Massive Neutron Stars
• Correlations between emission timescale of fragments and isospin dynamics in ${}^{124}$Sn+${}^{64}$Ni and ${}^{112}$Sn+${}^{58}$Ni reactions at 35 AMeV
• Constraining the symmetry energy with heavy-ion collisions and Bayesian analyses
• Nuclear dynamics and particle production near threshold energies in heavy-ion collisions
• Nuclear in-medium effects and collective flows in heavy-ion collisions at intermediate energies
• Holographic QCD: Past, Present, and Future
• Elliptic flow and the symmetry energy at supra-saturation density
• The Nuclear Matter Symmetry Energy at $0.03\le \rho /{\rho }_0\le 0.2$
• Constraining the high-density nuclear symmetry energy with the transverse-momentum dependent elliptic flow
• Analytical relations between nuclear symmetry energy and single-nucleon potentials in isospin asymmetric nuclear matter
• Transport properties of isospin asymmetric nuclear matter using TDHF
• Isospin transport in 84Kr + 112,124Sn collisions at Fermi energies
• Quark stars under strong magnetic fields
• Impact of NICER's Radius Measurement of PSR J0740+6620 on Nuclear Symmetry Energy at Suprasaturation Densities
• Connecting the Pygmy Dipole Resonance to the neutron skin
• KRATTA, a versatile triple telescope array for charged reaction products
• Neutron-proton effective mass splitting and thermal evolution in neutron rich matter
• Symmetry energy systematics and its high density behavior
• In-medium and isospin effects on particle production near threshold energies in heavy-ion collisions
• Flow probe of symmetry energy in relativistic heavy-ion reactions
• On the elliptical flow and asymmetry of the colliding nuclei
• Isovector properties of quark matter and quark stars in an isospin-dependent confining model
• Effects of in-medium nucleon-nucleon cross section on collective flow and nuclear stopping in heavy-ion collisions in the Fermi-energy domain
• First results from the INDRA-FAZIA apparatus on isospin diffusion in ${}^{58,64}$Ni+${}^{58,64}$Ni systems at Fermi energies
• Comparison of AMD calculations with experimental data for peripheral collisions of 93Nb+93Nb,116Sn at 38 MeV/nucleon
• Second and fourth moments of the charge density and neutron-skin thickness of atomic nuclei
• Effect of the momentum dependence of nuclear symmetry potential on pion-/pion+ ratio in heavy-ion collisions
• Model dependence of isospin sensitive observables at high densities
• Formation and dynamics of exotic hypernuclei in heavy-ion collisions
• Nuclear fragmentation and charge-exchange reactions induced by pions in the $\Delta$-resonance region
• Collective flows of pions in Au+Au collisions at energies 1.0 and 1.5 GeV/nucleon
• Influence of differential elastic nucleon-nucleon cross section on stopping and collective flows in heavy-ion collisions at intermediate energies
• Warm asymmetric quark matter and proto-quark stars within the confined-isospin-density-dependent mass model
• Reconstructed primary fragments and symmetry energy, temperature and density of the fragmenting source in ${}^{64}$Zn + ${}^{112}$Sn at 40 MeV/nucleon
• The effect of internal magnetic field on collective flow in heavy ion collisions at intermediate energies
• Exploiting neutron-rich radioactive ion beams to constrain the symmetry energy
• Relationship between the symmetry energy and the single-nucleon potential in isospin-asymmetric nucleonic matter
• Symmetry energy of dense matter in holographic QCD
• Effects of retarded electrical fields on observables sensitive to the high-density behavior of nuclear symmetry energy in heavy-ion collisions at intermediate energies
• Auxiliary Function Approach for Determining Symmetry Energy at Supra-saturation Densities
• Preequilibrium particle emissions and in-medium effects on the pion production in heavy-ion collisions
• Nuclear symmetry energy and proton-rich reactions at intermediate energies
• Probing nuclear symmetry energy with the sub-threshold pion production
• Initialization effect in heavy-ion collisions at intermediate energies
• Isospin diffusion from ${}^{40,48}$Ca${+}^{40,48}$Ca experimental data at Fermi energies: Direct comparisons with transport model calculations
• Symmetry Energy from Holographic QCD
• Correlation between the charge radii difference in mirror partner nuclei and the symmetry energy slope
• Dynamics of light hypernuclei in collisions of ${}^{197}$Au+${}^{197}$Au at GeV energies
• neuSIM4: A comprehensive GEANT4 based neutron simulation code
• Study of quasi-projectile properties at Fermi energies in 48Ca projectile systems
• Symmetry Energy and Universality classes of holographic QCD
• Correlations between isospin dynamics and Intermediate Mass Fragments emission time scales: a probe for the symmetry energy in asymmetric nuclear matter
• Antiproton production in heavy-ion collisions at subthreshold energies
• Isospin transport in 84Kr+112,124Sn reactions at Fermi energies