0 HIJING Model Prediction On Squeeze - Out of Particles in Nucleus - Nucleus Interactions at Super High Energies

Elliptic flow of hard partons (P > 5 GeV), squeeze-out of soft partons (P ≤ 5 GeV) and produced particles are predicted in the framework of the HIJING model. They are caused due to jet quenching and heterogeneity of the interaction region. Collective flows of produced particles and nuclear fragments in nucleus-nucleus interactions have been studied for the last 15 years (see the latest reviews in [1, 2, 3]). Five years ago, the so-called radial flow of nuclear fragments was discovered in central collisions of gold nuclei at intermediate energies (see [4] – [8]). Recently, it was recognized that the elliptic flow of produced particles changes its sign at energies 5 – 10 GeV/nucleon [9]. It is astonished that the collective flows are saved in interactions of lead nuclei at the energy of 158 GeV/nucleon [10]. They may be observed at RHIC and LHC. Now, it is commonly accepted that the hot and compressed nuclear matter is created in a central participant region (a reaction zone) formed by the overlap of projectile and target nuclei during the early stage of the nucleus-nucleus collisions at intermediate energies. This compression leads to the flow in the reaction plane where the majority of spectators are concentrated. The direction perpendicular to the reaction plane is the only direction where the nuclear matter might escape during the whole collision time without being hindered by either the target or projectile nucleus [11]. As a consequence, this leads to a jet-like emission pattern, also referred to as " out-of-plane squeeze-out " [12]. Squeeze-out was first predicted by a hydrodynamic model [12]. In terms of microscopic models, the collective motions are caused by (re)scattering. Providing that the mean free path of the particles is smaller than the dimensions of the spectators, the (re)scattering leads to exactly the same picture. It is hard to expect that this scenario will be realized at RHIC. Nevertheless , the direct HIJING model calculations presented in the Fig. 1 show a clear preferential emission of mid-rapidity particles in the direction perpendicular to the reaction plane (at ϕ ∼ 90 o and ϕ ∼ 270 o). In the 1