Author/Authors :
M. dAgostino ، نويسنده , , F. Gulminelli، نويسنده , , Ph. Chomaz، نويسنده , , M. Bruno، نويسنده , , Robert F. Cannata، نويسنده , , R. Bougault، نويسنده , , F. Gramegna، نويسنده , , I. Iori، نويسنده , , N. Le Neindre، نويسنده , , G.V. Margagliotti، نويسنده , , A. Moroni، نويسنده , , G. Vannini، نويسنده ,
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.
