Cluster and hypercluster production in relativistic heavy-ion collisions within the parton-hadron-quantum-molecular-dynamics approach

We study cluster and hypernuclei production in heavy-ion collisions at relativistic energies employing the parton-hadron-quantum-molecular-dynamics (PHQMD) approach, a microscopic n-body transport model based on the QMD propagation of the baryonic degrees of freedom with density dependent two-body potential interactions. All other ingredients of PHQMD, including the collision integral and the treatment of the quark-gluon plasma (QGP) phase, are adopted from the parton-hadron-string-dynamics (PHSD) approach. In PHQMD the cluster formation occurs dynamically, caused by the interactions. The clusters are recognized by the Minimum Spanning Tree (MST) algorithm. We present the PHQMD results for cluster and hypernuclei formation in comparison with the available experimental data at energies available at the Alternating Gradient Synchrotron, the Super Proton Synchrotron, and the Beam Energy Scan and fixed-target programs at the BNL Relativistic Heavy Ion Collider. We also provide predictions on cluster production for the upcoming experiments at the GSI Facility for Antiproton and Ion Research (FAIR) and the Nuclotron-based Ion Collider Facility (NICA). PHQMD allows one to study the time evolution of formed clusters and the origin of their production, which helps to understand how such weakly bound objects are formed and survive in the rather dense and hot environment created in heavy-ion collisions. It offers therefore an explanation of the “ice in the fire” puzzle.