Abstract :
The nuclear matter polarizability had been proposed as a suitable framework to investigate the symmetry energy [F.L. Braghin, Nucl. Phys. A 665 (2000) 13; 696 (2001) 413; Err709 (2002) 487; F.L. Braghin, Phys. Rev. C 71 064303 (2005); Phys. Rev. C 79 069902(E) (2009); Proc. of XXX Braz. Meeting on Nucl. Phys. 2007, ed. by A. Suaide, Braz. Phys. Soc. (2008)]. It provides an original and rich conceptual framework yielding the simultaneous dependences of the symmetry energy on diverse variables. We present few different results for the symmetry energy dependence mainly on: temperature and momentum at low nuclear densities (ρ=0.1ρ0). Based on the form of the polarizability we present an argument supporting that, due to the behavior of the density fluctuations, a third order term in the n-p asymmetry can yield a more reasonable result than a linear term.
