1110.3341 (R. Wada et al.)

The Nuclear Matter Symmetry Energy at $0.03\leq ρ/ρ_0\leq 0.2$    [PDF]

R. Wada, K. Hagel, L. Qin, J. B. Natowitz, G. Röpke, S. Shlomo, A. Bonasera, S. Typel, Z. Chen, M. Huang, J. Wang, H. Zheng, S. Kowalski, C. Bottosso, M. Barbui, M. R. D. Rodrigues, K. Schmidt, D. Fabris, M. Lunardon, S. Moretto, G. Nebbia, S. Pesente, V. Rizzi, G. Viesti, M. Cinausero, G. Prete, T. Keutgen, Y. El Masri, Z. Majka

Measurements of the density dependence of the free symmetry energy in low density clustered matter have been extended using the NIMROD multi-detector at Texas A&M University. Thermal coalescence models were employed to extract densities, $\rho$, and temperatures, $T$, for evolving systems formed in collisions of 47 $A$ MeV $^{40}$Ar + $^{112}$Sn,$^{124}$Sn and $^{64}$Zn + $^{112}$Sn, $^{124}$Sn. Densities of $0.03 \leq \rho/\rho_0 \leq 0.2$ and temperatures in the range 5 to 10 MeV have been sampled. The free symmetry energy coefficients are found to be in good agreement with values calculated using a quantum statistical model. Values of the corresponding symmetry energy coefficient are derived from the data using entropies derived from the model.

View original: http://arxiv.org/abs/1110.3341