Parametrisations of relativistic energy density functionals with tensor couplings

Abstract

The relativistic density functional with minimal density dependent nucleon-meson couplings for nuclei and nuclear matter is extended to include tensor couplings of the nucleons to the vector mesons. The dependence of the minimal couplings on either vector or scalar densities is explored. New parametrisations are obtained by a fit to nuclear observables with uncertainties that are determined self-consistently. The corresponding nuclear matter parameters at saturation are determined including their uncertainties. An improvement in the description of nuclear observables, in particular for binding energies and diffraction radii, is found when tensor couplings are considered, accompanied by an increase of the Dirac effective mass. The equations of state for symmetric nuclear matter and pure neutron matter are studied for all models. The density dependence of the nuclear symmetry energy, the Dirac effective masses and scalar densities is explored. Problems at high densities for parametrisations using a scalar density dependence of the couplings are identified due to the rearrangement contributions in the scalar self-energies that lead to vanishing Dirac effective masses.

The Trojan Horse Method: A Nuclear Physics Tool for Astrophysics

“…do not confirm the claim of a strong resonance; rather, they indicate a nearby one at 2.095 MeV that is about one order of magnitude less intense in the 20 Ne+α 1 channel and of similar intensity in the 23 Na+p 1 channel. The present result is in agreement with spectroscopy studies (124,125) with a deep at 2.14 MeV and no particularly strong α state around 2.1 MeV.…”

“…There is a standard way to derive expressions for the cross sections of reactions with two and three particles in the final state (see, e.g., 22,23). These expressions depend on the choice of a reference frame and the selection of the measured quantities in the final state.…”

“…The compound nucleus 24 Mg is formed at an excitation energy above the 12 C+ 12 C decay threshold. Alpha particles, protons, and neutrons are the dominant evaporation channels and lead, respectively, to 20 Ne, 23 Na, and 23 Mg, which can also be produced in excited bound states. Below 2.5 MeV, there is not enough energy to feed 23 Mg even in its ground state, and the α and p channels are the only relevant ones.…”

“…The Trojan Horse Method 14 N+ 12 C experiment. The 12 C+ 12 C fusion cross section at astrophysical energies was determined from the measurement of the 12 C( 12 C,α) 20 Ne and 12 C( 12 C,p) 23 Na reactions via the THM applied to the 12 C( 14 N,α 20 Ne) 2 H and 12 C( 14 N,p 23 Na) 2 H three-body processes in QF kinematics with 2 H from the 14 N spectator to the 12 C+ 12 C reactions (14). The experiment was performed at the INFN-Laboratori Nazionali del Sud in Catania, Italy.…”

“…After completion of data analysis ( 14), the two-body cross section of astrophysical relevance was extracted for four channels: 20 Ne+α 0 , 20 Ne+α 1 , 23 Na+p 0 , and 23 Na+p 1 . A modified onelevel many-channel R-matrix analysis was carried out including the 24 Mg states reported in Reference 14.…”