Transport theories for heavy-ion collisions in the 1AGeV regime

Abstract

We compare multiplicities as well as rapidity and transverse momentum distributions of protons, pions and kaons calculated within presently available transport approaches for heavy ion collisions around 1 AGeV. For this purpose, three reactions have been selected: Au+Au at 1 and 1.48 AGeV and Ni+Ni at 1.93 AGeV.

Recent progress and new challenges in isospin physics with heavy-ion reactions

“…Since the proposal of Aichelin and Ko that subthreshold kaon yield may be a sensitive probe of the EOS of nuclear matter at high densities [569], a lot of works have been done to investigate the subthreshold kaon (and anti-kaon) production in heavy-ion collisions both theoretically and experimentally [11,264,538,[570][571][572]. The kaon is an iso-doublet meson with the quark content of ds for K 0 and us for K + , so the K 0 /K + ratio provides a potentially good probe of the nuclear symmetry energy, especially its high density behavior since kaons are produced mainly from the high density region during the early stage of the reaction and are essentially free of subsequent reabsorption effects.…”

“…Recent studies by Mishra et al based on the chiral SU(3) model have shown that the isospin dependence of the kaon and antikaon optical potentials in dense hadronic matter is appreciable. Also, results from the transport model depend on the details how kaon production is imple- mented in the model [572,11]. To extract useful information on the high density behavior of the nuclear symmetry energy from subthreshold kaon production in heavy-ion collisions induced by neutron-rich nuclei, further experimental and theoretical studies are thus needed.…”

A way forward in the study of the symmetry energy: experiment, theory, and observation

“…Nevertheless, in an effort to determine the incompressibility of neutron-rich matter, a pioneering experiment was carried out at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan [41,42]. The experiment succeeded in measuring the distribution of isoscalar monopole strength in all stable Tin isotopes having an even number of neutrons, namely, from 112 Sn to 124 Sn. Although the neutron-proton asymmetry along this isotopic chain varies from α = 0.11-0.19, the sensitivity to K τ is poor-even for neutron-rich 124 Sn.…”

“…The experiment succeeded in measuring the distribution of isoscalar monopole strength in all stable Tin isotopes having an even number of neutrons, namely, from 112 Sn to 124 Sn. Although the neutron-proton asymmetry along this isotopic chain varies from α = 0.11-0.19, the sensitivity to K τ is poor-even for neutron-rich 124 Sn. Despite this drawback, the experiment uncovered a puzzle that remains unsolved after more than 5 years: "Why is Tin so soft?"…”

“…An experiment that measures isospin diffusion using radioactive beams of 109 In on a 124 Sn target (∆(δ) = 0.093) has recently been performed at RIKEN. A more desirable reaction is to use a radioactive 132 Sn beam on a 112 Sn target (∆(δ) = 0.135).…”