Relativistic energy density functionals (REDF) provide a complete and accurate, global description of nuclear structure phenomena. A modern semi-empirical functional, adjusted to the nuclear matter equation of state and to empirical masses of deformed nuclei, is applied to studies of shapes of superheavy nuclei. The theoretical framework is tested in a comparison of calculated masses, quadrupole deformations, and potential energy barriers to available data on actinide isotopes.Self-consistent mean-field calculations predict a variety of spherical, axial and triaxial shapes of long-lived superheavy nuclei, and their alpha-decay energies and half-lives are compared to data.A microscopic, REDF-based, quadrupole collective Hamiltonian model is used to study the effect of explicit treatment of collective correlations in the calculation of Q α values and half-lives.

The effect of possible in-medium modifications of nucleon-nucleon ($NN$) cross sections on particle production is investigated in heavy ion collisions ($HIC$) at intermediate energies. In particular, using a fully covariant relativistic transport approach, we see that the density dependence of the {\it inelastic} cross sections appreciably affects the pion and kaon yields and their rapidity distributions. However, the $(\pi^{-}/\pi^{+})$- and $(K^{0}/K^{+})$-ratios depend only moderately on the in-medium behavior of the inelastic cross sections. This is particularly true for kaon yield ratios, since kaons are more uniformly produced in high density regions. Kaon potentials are also suitably evaluated in two schemes, a chiral perturbative approach and an effective meson-quark coupling method, with consistent results showing a similar repulsive contribution for $K^{+}$ and $K^{0}$. As a consequence we expect rather reduced effects on the yield ratios. We conclude that particle ratios appear to be robust observables for probing the nuclear equation of state ($EoS$) at high baryon density and, particularly, its isovector sector.Comment: 29 pages, 15 figures, accepted for publication in Nuclear Physics

Structure of transactinide nuclei with relativistic energy density functionals Prassa, Vaia; Nikšic, T.; Vretenar, D.Prassa, V., Nikšic, T., & Vretenar, D. (2013 A microscopic theoretical framework based on relativistic energy density functionals (REDFs) is applied to studies of shape evolution, excitation spectra, and decay properties of transactinide nuclei. Axially symmetric and triaxial relativistic Hartree-Bogoliubov (RHB) calculations, based on the functional DD-PC1 and with a separable pairing interaction, are performed for the even-even isotopic chains between Fm and Fl. The occurrence of a deformed shell gap at neutron number N = 162 and its role on the stability of nuclei in the region around Z = 108 is investigated. A quadrupole collective Hamiltonian, with parameters determined by self-consistent constrained triaxial RHB calculations, is used to examine low-energy spectra of No, Rf, Sg, Hs, and Ds with neutron number in the interval 158 N 170. In particular, we analyze the isotopic dependence of several observables that characterize the transitions between axially symmetric rotors, γ -soft rotors, and spherical vibrators. An interesting example of a possible occurrence of shape-phase transitions and critical-point phenomena in this mass region is explored.