Paolo Finelli

Relativistic Hartree-Bogoliubov model with density-dependent meson-nucleon couplings

The relativistic Hartree-Bogoliubov (RHB) model is extended to include density-dependent meson-nucleon couplings. The effective Lagrangian is characterized by a phenomenological density dependence of the

Relativistic nuclear model with point-couplings constrained by QCD and chiral symmetry ✩

\ensuremath{\sigma},

Hypernuclear single particle spectra based on in-medium chiral SU(3) dynamics

\ensuremath{\omega},

Nuclear pairing from microscopic forces: singlet channels and higher-partial waves

and

In-medium chiral SU(3) dynamics and hypernuclear structure

\ensuremath{\rho}

Elastic and quasi-elastic electron scattering off nuclei with neutron excess

meson-nucleon vertex functions, adjusted to properties of nuclear matter and finite nuclei. Pairing correlations are described by the pairing part of the finite range Gogny interaction. The new density-dependent effective interaction DD-ME1 is tested in the analysis of the equations of state for symmetric and asymmetric nuclear matter, and of ground-state properties of the Sn and Pb isotopic chains. Results of self-consistent RHB calculations are compared with experimental data, and with results previously obtained in the RHB model with nonlinear self-interactions, as well as in the density-dependent relativistic hadron field (DDRH) model. Parity-violating elastic electron scattering on Pb and Sn nuclei is calculated using a relativistic optical model with inclusion of Coulomb distortion effects, and the resulting asymmetry parameters are related to the neutron ground-state density distributions.

Hypernuclei and in-medium chiral dynamics

Abstract We derive a microscopic relativistic point-coupling model of nuclear many-body dynamics constrained by in-medium QCD sum rules and chiral symmetry. The effective Lagrangian is characterized by density dependent coupling strengths, determined by chiral one- and two-pion exchange and by QCD sum rule constraints for the large isoscalar nucleon self-energies that arise through changes of the quark condensate and the quark density at finite baryon density. This approach is tested in the analysis of the equations of state for symmetric and asymmetric nuclear matter, and of bulk and single-nucleon properties of finite nuclei. In comparison with purely phenomenological mean-field approaches, the built-in QCD constraints and the explicit treatment of pion exchange restrict the freedom in adjusting parameters and functional forms of density dependent couplings. It is shown that chiral (two-pion exchange) fluctuations play a prominent role for nuclear binding and saturation, whereas strong scalar and vector fields of about equal magnitude and opposite sign, induced by changes of the QCD vacuum in the presence of baryonic matter, generate the large effective spin–orbit potential in finite nuclei.

Chiral pion-nucleon dynamics in finite nuclei: Spin-isospin excitations

Abstract.We present a novel description of nuclear many-body systems, both for nuclear matter and finite nuclei, emphasizing the connection with the condensate structure of the QCD ground state and spontaneous chiral symmetry breaking. Lorentz scalar and vector mean fields are introduced in accordance with QCD sum rules. Nuclear binding arises from pionic fluctuations, using in-medium chiral perturbation theory up to three-loop order. Ground-state properties of 16O and 40Ca are calculated. The built-in QCD constraints reduce the number of input parameters significantly in comparison with purely phenomenological relativistic mean-field approaches.

Optical potentials derived from nucleon-nucleon chiral potentials at N4LO

Abstract A previously derived relativistic energy density functional for nuclei, based on low-energy in-medium chiral dynamics, is generalized to implement constraints from chiral SU ( 3 ) effective field theory and applied to Λ hypernuclei. Density-dependent central and spin–orbit mean fields are calculated for a Λ hyperon using the SU ( 3 ) extension of in-medium chiral perturbation theory to two-loop order. Long range ΛN interactions arise from kaon-exchange and from two-pion-exchange with a Σ hyperon in the intermediate state. Short-distance dynamics is encoded in contact interactions. They include scalar and vector mean fields reflecting in-medium changes of quark condensates, constrained by QCD sum rules. The Λ single particle orbitals are computed for a series of hypernuclei from 13 Λ C to 208 Λ Pb. The role of a surface (derivative) term is studied. Its strength is found to be compatible with a corresponding estimate from in-medium chiral perturbation theory. Very good agreement with hypernuclear spectroscopic data is achieved. The smallness of the Λ -nuclear spin–orbit interaction finds a natural explanation in terms of an almost complete cancellation between short-range scalar/vector contributions and longer range terms generated by two-pion exchange.