Consequences of a covariant description of heavy-ion reactions at intermediate energies

Abstract

Heavy-ion collisions at intermediate energies are studied by using a new relativistic quantum molecular dynamics (RQMD) code, which is a covariant generalization of the quantum molecular dymanimcs (QMD) approach. We show that this new implementation is able to produce the same results in the nonrelativistic limit (i.e., 50 MeV/nucleon) as the noncovariant QMD. Such a comparison is not available in the literature. At higher energies (i.e. , 1.5 GeV/nucleon and 2 GeV/nucleon) RQMD and QMD give difFerent results in respect to the time evolution of the phase space, for example for the directed transverse How. These differences show that consequences of a covariant description of heavy-ion reactions within the framework of RQMD exist even at intermediate energies.PACS number(s): 25.70.z, 24.10.3v, 02.70.Ns

Rapidity distribution as a probe for elliptical flow at intermediate energies

“…As noted in Ref. [62,63], the relativistic effects do not play a significant role at these incident energies, and the intensity of sub-threshold particle production is very small. The phase space generated by the IQMD model has been analyzed using the minimum spanning-tree (MST) [24][25][26][27][28][29][30][31][32] method.…”

Heavy-ion collisions and the density dependence of the local mean field

“…Relativistic QMD (RQMD) [11,12,13], up to now only static Skyrme forces combined with the so-called Cugnon parametrization of the nucleon-nucleon cross section were used. These generalized Skyrme forces are treated as scalar potentials in the framework of Constrained Hamilton Dynamics.…”

Covariant equilibrium statistical mechanics

“…Applying the formalism of the constrained Hamiltonian dynamics to the micro-dynamics of the real gas we therefore have to consider a system of N particles in mutual interaction. In this case we prefer to use a set of constraints quite similar to the constraints which have been successfully applied already within non-equilibrium situations when simulating heavy ion reactions (see [11], [12]). The first N constraints are chosen as on-shell constraints…”

“…This formalism is not changing the notion of simultaneity by a change of the frame of reference, means one gets an invariant notion of simultaneity as well as invariant world lines. This method has been successfully applied already in complicated non-equilibrium situations namely, in order to calculate heavy ion reactions at intermediate and high energies ( [11], [12]). …”