The Influence of in-medium NN cross-sections, symmetry potential and impact parameter on the isospin observables

Abstract

We explore the influence of in-medium nucleon-nucleon cross section, symmetry potential and impact parameter on isospin sensitive observables in intermediate-energy heavy-ion collisions with the ImQMD05 code, a modified version of Quantum Molecular Dynamics model. At incident velocities above the Fermi velocity, we find that the density dependence of symmetry potential plays a more important role on the double neutron to proton ratio $DR(n/p)$ and the isospin transport ratio $R_i$ than the in-medium nucleon-nucleon cross sections, provided that the latter are constrained to a fixed total NN collision rate. We also explore both $DR(n/p)$ and $R_i$ as a function of the impact parameter. Since the copious production of intermediate mass fragments is a distinguishing feature of intermediate-energy heavy-ion collisions, we examine the isospin transport ratios constructed from different groups of fragments. We find that the values of the isospin transport ratios for projectile rapidity fragments with $Z\ge 20$ are greater than those constructed from the entire projectile rapidity source. We believe experimental investigations of this phenomenon can be performed. These may provide significant tests of fragmentation time scales predicted by ImQMD calculations.

24 pages, 9 figures, to be published in Phys. Rev. C

References in corpus (14)

• Recent Progress and New Challenges in Isospin Physics with Heavy-Ion Reactions
• Constraints on the density dependence of the symmetry energy
• Neutron and Proton Transverse Emission Ratio Measurements and the Density Dependence of the Asymmetry Term of the Nuclear Equation of State
• Detection with RHESSI of high frequency X-ray oscillations in the tail of the 2004 hyperflare from SGR 1806-20
• Elliptic flow and system size dependence of transition energies at intermediate energies
• The influence of cluster emission and the symmetry energy on neutron-proton spectral double ratios
• Isospin emission and flows at high baryon density: a test of the symmetry potential
• Isospin Diffusion and Equilibration for Sn+Sn collisions at E/A=35 MeV
• In-medium NN cross sections determined from stopping and collective flow in intermediate-energy heavy-ion collisions
• Isospin Diffusion Observables in heavy ion reactions
• Isospin Dynamics in Peripheral Heavy Ion Collisions at Fermi Energies
• Single and double pi^{-}/pi^{+} ratios in heavy-ion reactions as probes of the high-density behavior of the nuclear symmetry energy
• Probing the symmetry energy and the degree of isospin equilibrium
• Probing the nuclear equation of state in heavy-ion collisions at Fermi energy in isospin-sensitive exclusive experiments

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• Progress of Quantum Molecular Dynamics model and its applications in Heavy Ion Collisions
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• Sensitivity of Au+Au collisions to the symmetric nuclear matter equation of state at 2 -- 5 nuclear saturation densities
• Transport properties of isospin asymmetric nuclear matter using TDHF
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• Impact parameter smearing effects on isospin sensitive observables in heavy ion collisions
• Effect of energy conservation on in-medium $\mbox{NN}\to \mbox{N}Δ$ cross section in isospin-asymmetric nuclear matter
• Reconstructed primary fragments and symmetry energy, temperature and density of the fragmenting source in ${}^{64}$Zn + ${}^{112}$Sn at 40 MeV/nucleon
• Competition between Coulomb and Symmetry Potential in Semi-peripheral Heavy-ion Collisions
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• A new probe to study symmetry energy at low density by deuteron breakup reaction
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• Probing in-medium nucleon-nucleon inelastic scattering cross section by using energetic n/p ratio
• Isospin effect in peripheral heavy-ion collisions at Fermi energies
• In-medium nucleon-nucleon cross sections from relativistic ab initio calculations
• Probing the symmetry energy with isospin ratio from nucleons to fragments