Symmetry energy of fragments produced in multifragmentation
  Isospin properties of fragments measured in multifragmentation of 136Xe and 124Xe projectiles in mid-peripheral collisions with a lead target at 1 A GeV were studied within the statistical approach describing the liquid-gas nuclear phase transition. By analyzing the isoscaling phenomenon and the mean N-over-Z ratio of the fragments with Z=10-13 we have concluded that the symmetry energy of hot fragments produced in multifragment environment at subnuclear densities at high temperatures decreases in comparison with cold nuclei. 
D. Henzlova, A.S. Botvina, K.-H. Schmidt, V. Henzl, P. Napolitani,   M.V. Ricciardi