G. Gori

Many-body effects in nuclear structure

Abstract.We calculate, for the first time, the state-dependent pairing gap of a finite nucleus (120Sn) diagonalizing the bare nucleon-nucleon potential (Argonne v14) in a Hartree-Fock basis (with effective k-mass

Attractive and repulsive contributions of medium fluctuations to nuclear superfluidity

m_k \approx 0.7 m

Correlation energy contribution to nuclear masses

), within the framework of the generalized Bogoliubov-Valatin approximation including scattering states up to 800 MeV above the Fermi energy to achieve convergence. The resulting gap accounts for about half of the experimental gap. The combined effect of the bare nucleon-nucleon potential and of the induced pairing interaction arising from the exchange of low-lying surface vibrations between nucleons moving in time-reversal states close to the Fermi energy accounts for the experimental gap.

Nuclear field theory description of the three-body system 11Li

Oscillations of mainly surface character (

Effective pairing interaction induced by polarization effects in deformed nuclei

S=0

Quasi-particle properties of trapped Fermi gases

modes) give rise, in atomic nuclei, to an attractive (induced) pairing interaction, while spin (

Role of surface vibrations in the pairing gap of atomic nuclei

S=1

Collective aspects of pairing interaction in nuclei

) modes of mainly volume character generate a repulsive interaction, the net effect being an attraction which accounts for a sizeable fraction of the experimental pairing gap. Suppressing the particle-vibration coupling mediated by the proton degrees of freedom, i.e., mimicking neutron matter, the total surface plus spin-induced pairing interaction becomes repulsive.

Sources of Pairing in Nuclei

The ground-state correlation energies associated with collective surface and pairing vibrations are calculated for Pb and Ca isotopes. It is shown that this contribution, when added to those predicted by one of the most accurate modern nuclear mass formulae (HFBCS MSk7 mass formula), reduces the associated rms error by an important factor, making mean-field theory, once its time dependence is taken into account, a quantitative predictive tool for nuclear masses.

Surface Vibrations and the Pairing Interaction in Nuclei

The three-body description of two-neutron halo systems is extended to allow for core polarization taking into account the associated effects of mass-renormalization (single-particle motion) and induced interaction (density dependent pairing force) in terms of the particle-vibration coupling formalism. This formalism is applied to 10Li and 11Li. Theory reproduces most of the attractive features of Faddeev type calculations providing, in addition, an overall account of the experimental findings.