2016/06/30 by Zhao-Qing Feng
Physics and Astronomy · #nucl-th
paper · pdf · doi:10.1140/epja/i2017-12217-6
published as Eur. Phys. J. A 53 (2017) 30 · 8 pages, 9 figures, submitted EPJA. arXiv admin note: text overlap with arXiv:1509.04792
arxiv created 2016/12/15 · arxiv updated 2017/02/16
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 Δ-hole model is implemented in the transport approach, which slightly leads to the increase of the π-/π+ ratio, but reduces the total pion yields. It is found that a bump structure of the π-/π+ ratio in the kinetic energy spectra appears at the pion energy close to the Δ(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.