Kinetic energy spectra for fragments and break-up density in   multifragmentation
  We investigate the possibility, in nuclear fragmentation, to extract information on nuclear density at break-up from fragment kinetic energy spectra using a simultaneous scenario for fragment emission. The conclusions we derive are different from the recently published results of Viola et al. [Phys. Rev. Lett. 93, (2004), 132701] assuming a sequential fragment emission and claiming that the experimentally observed decrease of peak centroids for kinetic energy spectra of fragments with increasing bombarding energy is due to a monotonic decrease of the break-up density. 
Ad. R. Raduta, B. Borderie, E. Bonnet, N. Le Neindre, S. Piantelli and   M. F. Rivet