The symmetry energy in nuclear reactions
Abstract
New results for the strength of the symmetry energy are presented which illustrate the complementary aspects encountered in reactions probing nuclear densities below and above saturation. A systematic study of isotopic effects in spectator fragmentation was performed at the ALADIN spectrometer with 124Sn primary and 107Sn and 124La secondary beams of 600 MeV/nucleon incident energy. The analysis within the Statistical Fragmentation Model shows that the symmetry-term coefficient entering the liquid-drop description of the emerging fragments decreases significantly as the multiplicity of fragments and light particles from the disintegration of the produced spectator systems increases. Higher densities were probed in the FOPI/LAND study of nucleon and light-particle flows in central and mid-peripheral collisions of 197Au+197Au nuclei at 400 MeV/nucleon incident energy. From the comparison of the measured neutron and hydrogen squeeze-out ratios with predictions of the UrQMD model a moderately soft symmetry term with a density dependence of the potential term proportional to (rho/rho_0)^{gamma} with gamma = 0.9 +- 0.3 is favored.
Keywords
Cite
@article{arxiv.1001.3867,
title = {The symmetry energy in nuclear reactions},
author = {W. Trautmann and S. Bianchin and A. S. Botvina and A. Le Fevre and Y. Leifels and C. Sfienti and N. Buyukcizmeci and R. Ogul and I. N. Mishustin and M. Chartier and P. Z. Wu and R. C. Lemmon and Q. Li and J. Lukasik and P. Pawlowski and A. Pagano and P. Russotto},
journal= {arXiv preprint arXiv:1001.3867},
year = {2011}
}
Comments
11 pages, 7 figures, Proceedings of IWND09, August 22 - 25, 2009, Shanghai (China)