Negative heat capacity in the critical region of nuclear fragmentation: an experimental evidence of the liquid-gas phase transition
/ Authors
M. D'Agostino, F.Gulminelli, P. Chomaz, M. Bruno, F. Cannata, R. Bougault, N. Colonna, F. Gramegna, I.Iori, N. Neindre
and 5 more authors
G. Margagliotti, P. Mastinu, P. Milazzo, A.Moroni, G.Vannini
/ Abstract
Abstract An experimental indication of negative heat capacity in excited nuclear systems is inferred from the event by event study of energy fluctuations in Au quasi-projectile sources formed in Au+Au collisions at 35 A.MeV. Equilibrated events are selected and the excited source configuration is reconstructed through a calorimetric analysis of its de-excitation products. Fragment partitions show signs of a critical behavior at about 4.5 A.MeV excitation energy. Around this value the heat capacity shows a negative branch providing a direct evidence of a first order liquid gas phase transition.
Journal: Physics Letters B