Insights on pion production mechanism and symmetry energy at high density

Abstract

The $N\Delta \to NN$ cross sections, which take into account the $\Delta$-mass dependence of M-matrix and momentum $p_{N\Delta }$, are applied on the calculation of pion production within the framework of the UrQMD model. Our study shows that UrQMD calculations with the $\Delta$-mass dependent $N\Delta \to NN$ cross sections enhance the pion multiplicities and decrease the ${\pi }^{-}/{\pi }^{+}$ ratios. By analyzing the time evolution of the pion production rate and the density in the overlapped region for Au+Au at the beam energy of 0.4A GeV, we find that the pion multiplicity probes the symmetry energy in the region of 1-2 times normal density. The process of pion production in the reaction is tracked including the loops of $NN\leftrightarrow N\Delta$ and $\Delta \leftrightarrow N\pi$, our calculations show that the sensitivity of ${\pi }^{-}/{\pi }^{+}$ to symmetry energy is weakened after 4-5 N-$\Delta$-$\pi$ loops in the pion production path, while the ${\pi }^{-}/{\pi }^{+}$ ratio in reactions at near threshold energies remains its sensitivity to the symmetry energy. By comparing the calculations to the FOPI data, we obtain a model dependent conclusion on the symmetry energy and the symmetry energy at two times normal density is $S(2{\rho }_0)$=38-73 MeV within $1\sigma$ uncertainties. Under the constraints of tidal deformability and maximum mass of neutron star, the symmetry energy at two times normal density is reduced to $48-58$ MeV and slope of symmetry energy $L=54-81$ MeV, and it is consistent with the constraints from ASY-EOS flow data.

arXiv comment11 pages, 9 fiigures

References in corpus (60)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• GW170817: Measurements of Neutron Star Radii and Equation of State
• Microscopic Models for Ultrarelativistic Heavy Ion Collisions
• Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar
• Properties of the binary neutron star merger GW170817
• Tidal deformability of neutron stars with realistic equations of state and their gravitational wave signatures in binary inspiral
• Gravitational-wave constraints on the neutron-star-matter Equation of State
• Relativistic tidal properties of neutron stars
• Constraints on the symmetry energy and neutron skins from experiments and theory
• Constraints on the density dependence of the symmetry energy
• The Equation of State of Hot, Dense Matter and Neutron Stars
• Neutron skins and neutron stars in the multi-messenger era
• Tidal Love Numbers of Neutron and Self-Bound Quark Stars
• Study of relativistic nuclear collisions at AGS energies from p+Be to Au+Au with hadronic cascade model
• Particle production and equilibrium properties within a new hadron transport approach for heavy-ion collisions
• Constraining the neutron-proton effective mass splitting using empirical constraints on the density dependence of nuclear symmetry energy around normal density
• Circumstantial evidence for a soft nuclear symmetry energy at supra-saturation densities
• Kaon production in heavy ion reactions at intermediate energies
• Probing the High Density Behaviour of Nuclear Symmetry Energy with High Energy Heavy-Ion Collisions
• Results of the ASY-EOS experiment at GSI: The symmetry energy at suprasaturation density
• Constraints on the Symmetry Energy Using the Mass-Radius Relation of Neutron Stars
• Systematics of pion emission in heavy ion collisions in the 1A GeV regime
• Probing high-density behavior of symmetry energy from pion emission in heavy-ion collisions
• Constraining the nuclear matter equation of state around twice saturation density
• Constraining the High-Density Behavior of Nuclear Symmetry Energy with the Tidal Polarizability of Neutron Stars
• Understanding transport simulations of heavy-ion collisions at 100 and 400 AMeV: Comparison of heavy ion transport codes under controlled conditions
• Comparison of heavy-ion transport simulations: Collision integral in a box
• High Density Behaviour of Nuclear Symmetry Energy and High Energy Heavy-Ion Collisions
• Azimuthal correlations of pions in relativistic heavy ion collisions at 1 GeV/nucl.
• Extracting Nuclear Symmetry Energies at High Densities from Observations of Neutron Stars and Gravitational Waves
• Bayesian Inference of High-density Nuclear Symmetry Energy from Radii of Canonical Neutron Stars
• Comparison of heavy-ion transport simulations: Collision integral with pions and $\Delta$ resonances in a box
• Subthreshold pion production within a transport description of central Au+Au collisions
• Aspects of particle production in isospin asymmetric matter
• Probing the equation of state with pions
• Probing the density dependence of the symmetry potential at low and high densities
• Constraints on the symmetry energy and its associated parameters from nuclei to neutron stars
• The impact of energy conservation in transport models on the ${\pi }^{-}/{\pi }^{+}$ multiplicity ratio in heavy-ion collisions and the symmetry energy
• Transport Theories for Heavy Ion Collisions in the 1 AGeV Regime
• Symmetry energy investigation with pion production from Sn+Sn systems
• Probing the density dependence of the symmetry potential in intermediate energy heavy ion collisions
• Probing neutron-proton dynamics by pions
• Insights on Skyrme parameters from GW170817
• Medium effects on pion production in heavy ion collisions
• ${\Sigma }^{-}/{\Sigma }^{+}$ ratio as a candidate for probing the density dependence of the symmetry potential at high nuclear densities
• Progress of Quantum Molecular Dynamics model and its applications in Heavy Ion Collisions
• Determination of the nuclear incompressibility from the rapidity-dependent elliptic flow in heavy-ion collisions at beam energies 0.4\emph{A} - 1.0\emph{A} GeV
• Symmetry energy at supra-saturation densities via the Gravitational Waves from GW170817
• Symmetry energy constraints from GW170817 and laboratory experiments
• Energy dependence of pion in-medium effects on π^-/π^+ ratio in heavy-ion collisions
• Constraining the density dependence of the symmetry energy using the multiplicity and average $p_T$ ratios of charged pions
• Tides in merging neutron stars: Consistency of the GW170817 event with experimental data on finite nuclei
• Symmetry potential of $\Delta (1232)$ resonance and its effects on the ${\pi }^{-}/{\pi }^{+}$ ratio in heavy-ion collisions near the pion production threshold
• Effects of pion potential and nuclear symmetry energy on the ${\pi }^{-}/{\pi }^{+}$ ratio in heavy-ion collisions at beam energies around the pion production threshold
• Effects of energy conservation on equilibrium properties of hot asymmetric nuclear matter
• Decomposition of sensitivity of the symmetry energy observables
• Collective flows of pions in Au+Au collisions at energies 1.0 and 1.5 GeV/nucleon
• Effects of Pauli blocking on pion production in central collisions of neutron-rich nuclei
• The cumulants of the baryon number from central Au+Au collision at $E_{lab}$= 1.23 GeV$/$nucleon reveal the nuclear mean-field potentials
• Blind spots of probing the high-density symmetry energy in heavy-ion collisions

Cited by in corpus (14)

• Dense Nuclear Matter Equation of State from Heavy-Ion Collisions
• Decoding the Density Dependence of the Nuclear Symmetry Energy
• Horizons: Nuclear Astrophysics in the 2020s and Beyond
• Constraining nuclear symmetry energy with the charge radii of mirror-pair nuclei
• Testing the phase transition parameters inside neutron stars with the production of protons and lambdas in relativistic heavy-ion collisions
• Influence of the treatment of initialization and mean-field potential on the neutron to proton yield ratios
• Studies of the equation-of-state of nuclear matter by heavy-ion collisions at intermediate energy in the multi-messenger era
• Equation of state of nuclear matter and neutron stars: Quark mean-field model versus relativistic mean-field model
• Elliptic flow in heavy-ion collisions at intermediate energy: the role of impact parameter, mean field potential, and collision term
• Auxiliary Function Approach for Determining Symmetry Energy at Supra-saturation Densities
• Correlation between nuclear temperatures and symmetry energy in sub-saturation
• Properties and microscopic structures of dense stellar matter in RMF models
• Constraining the Phase-Transition EoS using the Energy Dependence of Directed Flow
• Isospin blocking and its effects in heavy-ion collisions