O. Benhar

Realistic many-body wave functions and nucleon momentum distributions in finite nuclei

Abstract The nucleon momentum distributions n(k) in 12C, 16O and 40Ca have been calculated within a many-body approach and using a realistic nucleon-nucleon interaction. Our results satisfactorily agree with those obtained within the Brueckner-Bethe-Goldstone theory and, at the same time, yield a much larger content of high momentum components with respect to the results obtained within the Hartree-Fock approach or within methods taking into account the effects of correlations phenomenologically.

Lowest-order and hyper-netted-chain calculations of nuclear matter

Abstract Employing two model central interactions the binding energy of nuclear matter is calculated within the framework of the Jastrow variational approach using different types of constrains and including all the contributions from hypernetted-chain diagrams.

Variational calculation of nuclear matter

Abstract The energy of nuclear matter has been calculated variationally with an approach based on FHNC equations which include central spin, isospin and tensor correlations. Various types of two-body interactions, namely the 5200, the model Reid V6, the Hamada-Johnston and the full Reid soft-core interactions have been considered. The results of the calculations have been compared with the results of other types of variational methods as well as with the results of Brueckner-Bethe-Goldstone approaches.

Subsidiary conditions and variational calculations of nuclear and neutron matters

Abstract The energy of nuclear and neutron matter is calculated within the framework of the variational approach including the contribution from three-body clusters. Two types of constrains for the two-body correlation function and realistic S-wave forces are used. It is shown that the energy strongly depends upon the type of constraint and that the variational calculation may lead to much more energy than the lowest order Brueckner theory calculations.

On the existence of a nonuniform spin-isospin ordered phase in high-density neutron matter

Abstract Using a Jastrow-like correlated wavefunction and a realistic two-body interaction, the energy per particle of neutron matter has been evaluated both in the normal uniform phase and in a π0-condensed phase exhibiting one-dimensional density fluctuations and spin-isospin order. The numerical results indicate that the standard configuration is energetically favored, even at very high densities.

Variational calculation of nonuniform spin-ordered neutron matter including Δ isobar mixing

Abstract A modified two-nucleon interaction describing the effect of Δ (1236) isobar mixing into neutron states has been used in a Jastrow-like variational calculation of nonuniform spin-ordered neutron matter. The results indicate that, at a density larger than normal nuclear density by a factor 3–4, a transition to the inhomogeneous phase, associated with a neutral pion condensate, takes place.

Inclusive electron scattering by nuclei and free nucleon form factors

Abstract The effect of using different free nucleon electromagnetic form factors in theoretical calculations of (e, e′) longitudinal and transverse responses has been investigated, both in three-nucleon systems and in a complex nucleus. Large discrepancies have been found between the results corresponding to different models of nucleon form factors, mainly due to the uncertainty of the neutron form factors at high momentum transfer.

On the validity of the Hartree approximation and the effect of short-range correlations in π0-condensation in finite nuclei

Abstract The validity of the Hartree approximation and the effects of short-range correlations have been investigated in the π 0 -condensation in 12 C within the framework of the Jastrow variational approach and using a realistic nucleon-nucleon interaction (Reid V6).