Nir Barnea

State dependent effective interaction for the hyperspherical formalism

The effective interaction method, traditionally used in the framework of a harmonic oscillator basis, is applied to the hyperspherical formalism of few-body nuclei

Realistic calculations of K¯NN, K¯NNN, and K¯K¯NN quasibound states

(A=3\ensuremath{-}6)

Neutron and weak-charge distributions of the 48Ca nucleus

. The separation of the hyperradial part leads to a state dependent effective potential. Undesirable features of the harmonic oscillator approach associated with the introduction of a spurious confining potential are avoided. It is shown that with the present method one obtains an enormous improvement of the convergence of the hyperspherical harmonics series in calculating ground state properties, excitation energies, and transitions to continuum states.

Photoabsorption on ^4He with a Realistic Nuclear Force

Binding energies and widths of three-body KbarNN, and of four-body KbarNNN and KbarKbarNN nuclear quasibound states are calculated in the hyperspherical basis, using realistic NN potentials and subthreshold energy dependent chiral KbarN interactions. Results of previous K^-pp calculations are reproduced and an upper bound is placed on the binding energy of a K^-d quasibound state. A self consistent handling of energy dependence is found to restrain binding, keeping the calculated four-body ground-state binding energies to relatively low values of about 30 MeV. The lightest strangeness -2 particle-stable Kbar nuclear cluster is most probably KbarKbarNN. The calculated Kbar N -> pi Y conversion widths range from approximately 30 MeV for the KbarNNN ground state to approximately 80 MeV for the KbarKbarNN ground state.

Ground state wave functions in the hyperspherical formalism for nuclei with A>4

What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. While the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus

Isoscalar monopole resonance of the alpha particle: a prism to nuclear Hamiltonians.

^{48}

Neutrino Breakup of A=3 Nuclei in Supernovae

Ca. We show that the neutron skin (difference between radii of neutron and proton distributions) is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities are currently targeted by precision measurements. Based on ab initio results for

First principles description of the giant dipole resonance in 16O.

^{48}

Role of the final-state interaction and three-body force on the longitudinal response function of 4He.

Ca, we provide a constraint on the size of a neutron star.

Low-energy inelastic neutrino reactions on 4He.

The 4He total photoabsorption cross section is calculated with the realistic nucleon-nucleon potential Argonne V18 and the three-nucleon force (3NF) Urbana IX. Final state interaction is included rigorously via the Lorentz Integral Transform method. A rather pronounced giant resonance with peak cross sections of 3 (3.2) mb is obtained with (without) 3NF. Above 50 MeV strong 3NF effects, up to 35%, are present. Good agreement with experiment is found close to threshold. A comparison in the giant resonance region is inconclusive, since present data do not show a unique picture.