Isospin-dependent pion in-medium effects on charged pion ratio in heavy ion collisions

Abstract

Using results from the chiral perturbation theory for the s-wave interaction and the delta-resonance model for the p-wave interaction of pions with nucleons, we have evaluated the spectral functions of pions in asymmetric nuclear matter with unequal proton and neutron densities. We find that in hot dense neutron-rich matter the strength of the spectral function of positively charged pion at low energies is somewhat larger than that of negatively charged pion. In a thermal model, this isospin-dependent effect slightly reduces the ratio of negatively charged to positively charged pions that are produced in heavy ion collisions induced by radioactive beams. Relevance of our results to the determination of the nuclear symmetry energy from measured ratio of negatively to positively charged pions produced in heavy ion collisions is discussed.

7 pages, 4 figures, pion-nucleon s-wave interaction included

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Cited by in corpus (24)

• Comparison of heavy-ion transport simulations: Collision integral with pions and $\Delta$ resonances in a box
• The impact of energy conservation in transport models on the ${\pi }^{-}/{\pi }^{+}$ multiplicity ratio in heavy-ion collisions and the symmetry energy
• Nuclear in-medium effects and collective flows in heavy-ion collisions at intermediate energies
• Probing neutron-proton dynamics by pions
• Medium effects on pion production in heavy ion collisions
• Effects of hadronic potentials on elliptic flows in relativistic heavy ion collisions
• Energy dependence of pion in-medium effects on π^-/π^+ ratio in heavy-ion collisions
• Probing nuclear symmetry energy at high densities using pion, kaon, eta and photon productions in heavy-ion collisions
• Symmetry potential of $\Delta (1232)$ resonance and its effects on the ${\pi }^{-}/{\pi }^{+}$ ratio in heavy-ion collisions near the pion production threshold
• Symmetry energy systematics and its high density behavior
• Normal or abnormal isospin-fractionation as a qualitative probe of nuclear symmetry energy at supradensities
• In-medium and isospin effects on particle production near threshold energies in heavy-ion collisions
• Modeling pion production in heavy-ion collisions at intermediate energies
• Effects of energy conservation on equilibrium properties of hot asymmetric nuclear matter
• Isospin splitting of pion elliptic flow in relativistic heavy-ion collisions
• Effect of the momentum dependence of nuclear symmetry potential on pion-/pion+ ratio in heavy-ion collisions
• Effects of Pauli blocking on pion production in central collisions of neutron-rich nuclei
• Effect of energy conservation on in-medium $\mbox{NN}\to \mbox{N}Δ$ cross section in isospin-asymmetric nuclear matter
• 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
• Metastable pions in dense media
• Effects of hadronic mean-field potentials on Hanbury-Brown-Twiss correlations in relativistic heavy-ion collisions
• Microscopic study of baryon stopping in low-energy heavy-ion collisions within UrQMD model
• Angular momentum conservation and pion production in intermediate-energy heavy-ion collisions