Ratio of Shear Viscosity to Entropy Density of Nuclear Participant in the Intermediate Energy Heavy Ion Collisions

Abstract: The ratio of shear viscosity (η) to entropy density (s) of nuclear fireball created in the
central region of intermediate-energy heavy-ion collisions has been investigated within two transport models, namely the Boltzmann-Uehling-Uhlenbeck (BUU) model and the isospin-dependent quantum molecular dynamics (IQMD) model. Different methods are used to calculate η and s. With the collisionenergy increasing, the η/s displays a saturation value or a local minimum value at a certain beam energy.We argue that the saturation or minimum point corresponds to an occurrence of nuclear liquid gas phase
transition.