Within a combined approach we investigate the main features of the production of hyper-fragments in relativistic heavy-ion collisions. The formation of hyperons is modeled within the UrQMD and HSD ...transport codes. To describe the hyperon capture by nucleons and nuclear residues a coalescence of baryons (CB) model was developed. We demonstrate that the origin of hypernuclei of various masses can be explained by typical baryon interactions, and that it is similar to processes leading to the production of conventional nuclei. At high beam energies we predict a saturation of the yields of all hyper-fragments, therefore, this kind of reactions can be studied with high yields even at the accelerators of moderate relativistic energies.
We formulate a statistical approach for description of nuclear composition and equation of state of stellar matter at subnuclear densities and temperature up to 20 MeV, which are expected during the ...collapse and explosion of massive stars. The model includes nuclear, electromagnetic and weak reactions between all constituents of matter, under condition of statistical equilibrium. We construct a realistic ensemble of nuclear species, and demonstrate the differences from the models employing a single-nucleus approximation for heavy nuclei. Thermodynamical characteristics, isentropic trajectories, EOS, and nuclear composition of supernova matter are calculated for different values of the lepton fraction. Special attention is paid to a possible in-medium reduction of the nuclear symmetry energy, as suggested by nuclear multifragmentation experiments. We demonstrate that this effect may lead to significant modifications of the nuclear composition and electron capture rates, which are important for stellar dynamics and nucleosynthesis.
Abstract
We study the production of small nuclei, nuclei of intermediate mass, and hypernuclei in relativistic nuclear reactions by using dynamical and statistical models. We propose a novel ...mechanism responsible for the formation of complex nuclei from nucleons and hyperons produced in collisions: In this reaction the excited clusters consisting of baryons can stochastically be formed at a low sub-nuclear density after the dynamical expansion of the nuclear matter. One can describe the nucleation process within such clusters with the statistical models. We suggest the hybrid approach allowing for the consistent description of the experimental data measured in central collisions, which was not possible with other theoretical methods. The important consequence of this novel mechanism is the correlations of the produced nuclear species. The energy limits for describing the fragmentation and nucleation processes in excited finite nuclear systems with statistical models are also obtained.
This is an introduction to the tabulated database of stellar matter properties calculated within the framework of the Statistical Model for Supernova Matter (SMSM). The tables present thermodynamical ...characteristics and nuclear abundances for 31 values of baryon density (10 super(-8) < rho/rho sub(0) < 0.32, rho sub(0) =0.15 fm super(-3) is the normal nuclear matter density), 35 values of temperature (0.2MeV < T < 25 MeV), and 28 values of electron-to-baryon ratio (0.02 < Ye < 0.56). The properties of stellar matter in beta equilibrium are also considered. The main ingredients of the SMSM are briefly outlined, and the data structure and content of the tables are explained.
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