Die Poincaré-Kovariante Parton Kaskade (pcpc)

Abstract

Heavy-ion collisions provide an unique experimental access to investigate extremely hot nuclear matter. Although substantial progress have been made in understanding this kind of matter, it is still not clear if the search for the quark gluon plasma has been successful so far. Parton cascades, i.e. microscopic models that describe nuclear reactions in terms of partons (quarks and gluons), make use of the hard parton-parton scattering limit of QCD at high momentum transfers (Q2). These scatterings are the elementary building block of the parton cascade process.With the start of the RHIC program (Relativistic Heavy Ion Collider) in July 2000 nucleus-nucleus interactions reach an energy region for which it seems to be certain that a high percentage of parton interactions occurs at very high Q2, which makes perturbative QCD applicable. This makes it important to have theoretical models suited for these conditions to understand the experimental data.The Poincaré-Covariant Parton Cascade (pcpc) is a new parton cascade model that describes nucleus-nucleus interactions in full phase space. For the description of the relativistic particle dynamics the Poincaré-Covariant Dynamics (PCD) is applied. The parton-parton scattering cross sections used in the model are computed within perturbative QCD in the tree-level approximation. The Q2-dependence of the structure functions is included by an implementation of the DGLAP mechanism suitable for a cascade, so that the number of partons is not static, but varies in space and time as the collision of two nuclei evolves.In this work we present the theoretical basis of, its practical implementation as a cascade program, and some numerical results obtained with this model. The resulting parton distributions are compared with experimental data and comparable models (VNI).