Negative heat capacity for hot nuclei using formulation from the microcanonical ensemble INDRA Collaboration

Abstract

By using freeze-out properties of multifragmenting hot nuclei produced in quasifusion central ${}^{129}$Xe+${}^{nat}$Sn collisions at different beam energies (32, 39, 45 and 50 AMeV) which were estimated by means of a simulation based on experimental data collected by the $4\pi$ INDRA multidetector, heat capacity in the thermal excitation energy range 4 - 12.5 AMeV was calculated from total kinetic energies and multiplicities at freeze-out. The microcanonical formulation was employed. Negative heat capacity which signs a first order phase transition for finite systems is observed and confirms previous results using a different method.

Comments: 6 pages,5 figures. arXiv admin note: text overlap with arXiv:1903.02881