From Stopping to Viscosity in Nuclear Reactions

Abstract

Data on stopping in intermediate-energy central heavy-ion collisions are analyzed following transport theory based on the Boltzmann equation. In consequence, values of nuclear shear viscosity are inferred. The inferred values are significantly larger than obtained for free nucleon dispersion relations and free nucleon-nucleon cross sections.Comment: 8 pages, 6 figures, Proc. 5th ANL/MSU/JINA/INT FRIB Workshop on Bulk Nuclear Properties, E. Lansing, Nov. 19-22, 200

Temperature dependence of the symmetry energy and neutron skins in Ni, Sn, and Pb isotopic chains

“…As seen from Fig. 7(a), only for the 60 Ni nucleus both proton and neutron rms radii are very similar and behave similarly with temperature. In fact, the dependence of the neutron skin thickness with temperature in 60 Ni is very small and we observe only a tiny effect compatible with an almost null skin thickness [we note the small scale in 60 Ni in Fig.…”

“…7(a), only for the 60 Ni nucleus both proton and neutron rms radii are very similar and behave similarly with temperature. In fact, the dependence of the neutron skin thickness with temperature in 60 Ni is very small and we observe only a tiny effect compatible with an almost null skin thickness [we note the small scale in 60 Ni in Fig. 7 In the latter work properties of hot nuclei have been studied within the relativistic TF approximation and different RMF parametrizations were tested.…”

“…The results for the proton and neutron radii and their difference (neutron-skin thickness) as a function of the temperature T for selected 60 Ni, 78 Ni, and 82 Ni isotopes, are illustrated in Fig. 7 Figs.…”

“…For instance, in the case of Sn isotopes all the N = Z nuclei withĀ (Ā = A) starting at 124 (N = Z = 62) are unbound. So, we consider the cases 64 Ni: N = Z = 32 ( 64 Ge), 68 Ni: N = Z = 34 ( 68 Se), 72 Ni: N = Z = 36 ( 72 Kr), 76 Ni: N = Z = 38 ( 76 Kr), 80 Ni: N = Z = 40 ( 80 Zr). In contrast to the results presented in Fig.…”

“…The latter is commonly defined in terms of the difference between the neutron and proton root-mean-square (rms) radii and is found to be closely related to the density dependence of the NSE, with the EOS of pure neutron matter and properties of neutron stars [39][40][41][42][43][44][45][46]. It is also related to a number of observables in finite nuclei, including the NSE (see, e.g., [4,8,9,[47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65]), although its precise measurement is difficult. As examples, in Ref.…”