UrQMD simulations of higher-order cumulants in Au+Au collisions at high baryon density

Abstract High moments of conserved quantities, such as net-baryon, net-electric charge, and net-strangeness, in heavy-ion collisions are sensitive to fluctuations caused by the quantum chromodynamics critical point (CP). The event-by-event analysis of high moments of the conserved charges has been widely used in experiments to search for the CP, particularly in the RHIC-STAR experiment. To establish a dynamical non-critical baseline , particularly in the high baryon density region, we performed a systematic analysis of the proton multiplicity distributions from Au+Au collisions at GeV. The beam energy, centrality, and rapidity width dependence of proton (factorial) cumulants, up to the order, were extracted from the calculations of a hadronic transport model called the ultra-relativistic quantum molecular dynamics (UrQMD) model. In addition, the effects of the initial volume fluctuation are discussed. These results will be important for the physics analysis of the RHIC Beam Energy Scan (BES) data, particularly for the fixed-target data and experimental data from future CBM experiments at FAIR.