Probing neutron-proton dynamics by pions

Abstract

In order to investigate the nuclear symmetry energy at high density, we study the pion production in central collisions of neutron-rich nuclei ${}^{132}\mathrm{Sn}+{}^{124}\mathrm{Sn}$ at 300 MeV/nucleon using a new approach by combining the antisymmetrized molecular dynamics (AMD) and a hadronic cascade model (JAM). The dynamics of neutrons and protons is solved by AMD, and then pions and $\Delta$ resonances in the reaction process are handled by JAM. We see the mechanism how the $\Delta$ resonance and pions are produced reflecting the dynamics of neutrons and protons. We also investigate the impacts of cluster correlations as well as of the high-density symmetry energy on the nucleon dynamics and consequently on the pion ratio. We find that the ${\Delta }^{-}/{\Delta }^{++}$ production ratio agrees very well with the neutron-proton squared ratio $(N/Z{)}^2$ in the high-density and high-momentum region. We show quantitatively that $\Delta$ production ratio, and therefore $(N/Z{)}^2$, are directly reflected in the ${\pi }^{-}/{\pi }^{+}$ ratio, with modification in the final stage of the reaction.

14 pages, 10 figures; Figures 3-8 are updated with corrected numerical results. No change in the main conclusions

References in corpus (6)

• Systematics of pion emission in heavy ion collisions in the 1A GeV regime
• Systematics of central heavy ion collisions in the 1A GeV regime
• Isospin effects on sub-threshold kaon production at intermediate energies
• Dilepton production in proton-induced reactions at SIS energies with the GiBUU transport model
• 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 nuclear symmetry energy and in-medium NN cross section in heavy-ion collisions at beam energies below the pion production threshold

Cited by in corpus (35)

• Dense Nuclear Matter Equation of State from Heavy-Ion Collisions
• Probing the Symmetry Energy with the Spectral Pion Ratio
• Comparison of heavy-ion transport simulations: Collision integral in a box
• Comparison of heavy-ion transport simulations: Collision integral with pions and $\Delta$ resonances in a box
• Dynamics of clusters and fragments in heavy-ion collisions
• Transport approaches for the Description of Intermediate-Energy Heavy-Ion Collisions
• Symmetry energy investigation with pion production from Sn+Sn systems
• Feasability of constraining the curvature parameter of the symmetry energy using elliptic flow data
• Liquid-Gas phase transition in nuclei
• Collision dynamics at medium and relativistic energies
• Sensitivity of Au+Au collisions to the symmetric nuclear matter equation of state at 2 -- 5 nuclear saturation densities
• Pion Production in Rare Isotope Collisions
• Insights on pion production mechanism and symmetry energy at high density
• Modeling pion production in heavy-ion collisions at intermediate energies
• Isospin diffusion measurement from the direct detection of a Quasi-Projectile remnant
• Dynamical fission of the quasiprojectile and isospin equilibration for the system 80Kr+ 48 Ca at 35 MeV/nucleon
• Examination of cluster production in excited light systems at Fermi energies from new experimental data and comparison with transport model calculations
• Comparison of AMD calculations with experimental data for peripheral collisions of 93Nb+93Nb,116Sn at 38 MeV/nucleon
• Symmetry energy extracted from the S$\pi$RIT pion data in Sn+Sn systems
• Influence of fast emissions and statistical de-excitation on the isospin transport ratio
• Studies of the equation-of-state of nuclear matter by heavy-ion collisions at intermediate energy in the multi-messenger era
• Effects of Pauli blocking on pion production in central collisions of neutron-rich nuclei
• Isoscaling in central Sn+Sn collisions at 270 MeV/u
• Effects of symmetry energy in ${}^{132}\mathrm{Sn}{+}^{124}\mathrm{Sn}$ reaction at 300 MeV/nucleon
• Effect of energy conservation on in-medium $\mbox{NN}\to \mbox{N}Δ$ cross section in isospin-asymmetric nuclear matter
• Collision integral with momentum-dependent potentials and its impact on pion production in heavy-ion collisions
• Effects of retarded electrical fields on observables sensitive to the high-density behavior of nuclear symmetry energy in heavy-ion collisions at intermediate energies
• Charged pion production from Au + Au collisions at $\sqrt{s_{NN}}=2.4$ GeV in the Relativistic Vlasov-Uehling-Uhlenbeck model
• Beam energy dependence of the relativistic retardation effects of electrical fields on the ${\pi }^{-}/{\pi }^{+}$ ratio in heavy-ion collisions
• Applying machine learning to determine impact parameter in nuclear physics experiments
• In-medium $\Delta (1232)$ potential, pion production in heavy-ion collisions and the symmetry energy
• Activation of momentum fluctuations in wave packet molecular dynamics: Impacts on momentum distributions of projectilelike fragments
• Isospin blocking and its effects in heavy-ion collisions
• Angular momentum conservation and pion production in intermediate-energy heavy-ion collisions
• Transport Model Comparison Studies of Intermediate-Energy Heavy-Ion Collisions