Predictions from Microscopic Models on Particle Correlations at RHIC

This contribution reviews the recent developments on microscopic transport calculations for two-particle correlations at low relative momenta in ultrarelativistic heavy ion collisions at RHIC. We will start with the discussion of a simple hadronic rescattering model, will then continue with the predictions of a hadron+string model (RQMD), and subsequently present the features of a combined hydrodynamical and microscopic hadron+string model (Hydro+UrQMD). We will then address the impact of partonic (elastic) scatterings (MPC) and also discuss the correlation results for a combined parton+hadron model (AMPT). For two-particle correlations of bosons at low relative momenta, BoseEinstein correlations, i.e., the symmetrization of the two-particle wave functions, are usually the desired effect. One is interested in the space-time extent of the particle-emitting source. However, the situation is complicated by the strong time dependence of the dynamical multi-particle system. Thus, two-particle interferometry is not only sensitive to some geometric size parameters but also to the dynamics (for example, collective flow) and many other features of the source as the passing through a phase transition [1, 2, 3]. Indeed, it was predicted that, in case of a first-order phase transition, the correlation radii should be anomalously large due to the large latent heat that needs to be converted into the hadronic phase while the number of degrees of freedom is reduced simultaneously which in turn should lead to large hadronization times. A characteristic measure, being sensitive to the emission duration of the source, was thought to be the ratio of two correlation lengths Rout/Rside. The ratio was originally predicted to grow to large values like 5 or 10, reflecting the rather large emission times, for ultrarelativistic heavy ion collisions (for example Au+Au at RHIC, √ snn = 200GeV), that is, for conditions where a deconfined phase should be produced. However, experimental results from