Light-Nuclei Production in Heavy-Ion Collisions at [square root of s[sub.NN]] = 6.4 – 19.6 GeV in THESEUS Generator Based on Three-Fluid Dynamics

Light-nuclei production in relativistic heavy-ion collisions is simulated within an updated Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD (Ultra-relativistic Quantum Molecular Dynamics) final State interactions (THESEUS). The simulations are performed in the collision energy range of [square root of s[sub.NN] ]= 6.4–19.6 GeV. The light-nuclei are produced within the thermodynamical approach on an equal basis with hadrons. Since the light nuclei do not participate in the UrQMD evolution, the only additional parameter related to the light nuclei, i.e., the energy density of late freeze-out, is used for the imitation of the afterburner stage of the collision. The updated THESEUS provides a reasonable reproduction of data on bulk observables of the light nuclei, especially their functional dependence on the collision energy and light-nucleus mass. Various ratios, d/p, t/p, t/d, and N(t)×N(p)/N[sup.2] (d), are also considered. Imperfect reproduction of the light-nuclei data leaves room for medium effects in produced light nuclei.