Probing the density dependence of the symmetry potential in intermediate energy heavy ion collisions

Abstract

Based on the ultrarelativistic quantum molecular dynamics (UrQMD) model, the effects of the density-dependent symmetry potential for baryons and of the Coulomb potential for produced mesons are investigated for neutron-rich heavy ion collisions at intermediate energies. The calculated results of the ${\Delta }^{-}/{\Delta }^{++}$ and ${\pi }^{-}/{\pi }^{+}$ production ratios show a clear beam-energy dependence on the density-dependent symmetry potential, which is stronger for the ${\pi }^{-}/{\pi }^{+}$ ratio close to the pion production threshold. The Coulomb potential of the mesons changes the transverse momentum distribution of the ${\pi }^{-}/{\pi }^{+}$ ratio significantly, though it alters only slightly the ${\pi }^{-}$ and ${\pi }^{+}$ total yields. The ${\pi }^{-}$ yields, especially at midrapidity or at low transverse momenta and the ${\pi }^{-}/{\pi }^{+}$ ratios at low transverse momenta, are shown to be sensitive probes of the density-dependent symmetry potential in dense nuclear matter. The effect of the density-dependent symmetry potential on the production of both, K${}^0$ and K${}^{+}$ mesons, is also investigated.

28 pages in RevTex, 11 figures, 1 table, submitted to Journal of Physics G

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Cited by in corpus (36)

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