Preequilibrium particle emissions and in-medium effects on the pion production in heavy-ion collisions

Abstract

Within the framework of the Lanzhou quantum molecular dynamics (LQMD) transport model, pion dynamics in heavy-ion collisions near threshold energies and the emission of preequilibrium particles (nucleons and light complex fragments) have been investigated. A density, momentum and isospin dependent pion-nucleon potential based on the $\Delta$-hole model is implemented in the transport approach, which slightly leads to the increase of the ${\pi }^{-}/{\pi }^{+}$ ratio, but reduces the total pion yields. It is found that a bump structure of the ${\pi }^{-}/{\pi }^{+}$ ratio in the kinetic energy spectra appears at the pion energy close to the $\Delta$(1232) resonance region. The yield ratios of neutrons to protons from the squeeze-out particles perpendicular to the reaction plane are sensitive to the stiffness of nuclear symmetry energy, in particular at the high-momentum (kinetic energy) tails.

8 pages, 9 figures, submitted EPJA. arXiv admin note: text overlap with arXiv:1509.04792

References in corpus (6)

• Big-Bang Nucleosynthesis
• In-medium nuclear interactions of low-energy hadrons
• Neutron-proton bremsstrahlung from intermediate energy heavy-ion reactions as a probe of the nuclear symmetry energy?
• Pion Production in Heavy-ion Collisions in the 1 A GeV region
• Nuclear fragmentation and charge-exchange reactions induced by pions in the $\Delta$-resonance region
• Nuclear in-medium effects on $\eta$ dynamics in proton-nucleus collisions

Cited by in corpus (6)

• Comparison of heavy-ion transport simulations: Collision integral with pions and $\Delta$ resonances in a box
• Nuclear dynamics and particle production near threshold energies in heavy-ion collisions
• Collision dynamics at medium and relativistic energies
• Collective flows of pions in Au+Au collisions at energies 1.0 and 1.5 GeV/nucleon
• Effects of retarded electrical fields on observables sensitive to the high-density behavior of nuclear symmetry energy in heavy-ion collisions at intermediate energies
• Beam energy dependence of the relativistic retardation effects of electrical fields on the ${\pi }^{-}/{\pi }^{+}$ ratio in heavy-ion collisions