89 research outputs found
Ab initio optical potentials and nucleon scattering on medium mass nuclei
We show the first results for the elastic scattering of neutrons off oxygen
and calcium isotopes obtained from ab initio optical potentials. The potential
is derived using self consistent Green's function theory (SCGF) with the
saturating chiral interaction NNLO. Our calculations are
compared to available scattering data and show that it is possible to reproduce
low energy scattering observables in medium mass nuclei from first principles.Comment: 6 pages, 4 figures, Zakopane conference on nuclear physic
From bare to renormalized order parameter in gauge space: structure and reactions
The physical reason why one can calculate with similar accuracy, as compared
to the experimental data, the absolute cross section associated with
two-nucleon transfer processes between members of pairing rotational bands,
making use of simple BCS (constant matrix elements) or of many-body
(Nambu-Gorkov (NG), nuclear field theory (NFT)) spectroscopic amplitudes, is
not immediately obvious. Restoration of spontaneous symmetry breaking and
associated emergent generalised rigidity in gauge space provides the answer,
and points to a new emergence: a physical sum rule resulting from the
intertwining of structure and reaction processes and closely connected with the
central role induced pairing interaction plays in structure together with the
fact that successive transfer dominates Cooper pair tunnelling
Testing two-nucleon transfer reaction mechanism with elementary modes of excitation in exotic nuclei
Nuclear Field Theory of structure and reactions is confronted with
observations made on neutron halo dripline nuclei, resulting in the prediction
of a novel (symbiotic) mode of nuclear excitation, and on the observation of
the virtual effect of the halo phenomenon in the apparently non-halo nucleus
Li. This effect is forced to become real by intervening the virtual process
with an external (t,p) field which, combined with accurate predictive abilities
concerning the absolute differential cross section, reveals an increase of a
factor 2 in the cross section due to the presence of halo ground state
correlations, and is essential to reproduce the value of the observed Li(t,p)Li)/d.Comment: Submitted to CERN proceedings for the 14th International Conference
on Nuclear Reaction mechanisms, Varenna, June 15 - 19, 201
Cooper pair transfer in nuclei
The second order DWBA implementation of two-particle transfer direct
reactions which includes simultaneous and successive transfer, properly
corrected by non-orthogonality effects is tested with the help of controlled
nuclear structure and reaction inputs against data spanning the whole mass
table, and showed to constitute a quantitative probe of nuclear pairing
correlations
Mineralogical-geochemical study of the anionic competition effect on the octacalcium phosphate reaction into fluorapatite
The unstable compound octacalcium phosphate (OCP) is one of the crystalline precursors of the apatite mineral series composed by hydroxyapatite, fluorapatite and chlorapatite. The feature of OCP to react into apatite, depending on the media conditions, has been mainly exploited for biomedical applications as bone and tooth substitute material. Recently, some important applications of OCP have been documented: e.g. as electrode material for supercapacitors and as fluoride remover reagent for environmental purposes. With the aim of deepening the property of OCP to be the crystalline precursor of apatite and assessing if and how the anionic competition can influence the formation of the different apatite end-members, the OCP â apatite reaction has been here investigated placing 0.223 mmol of OCP in 50 mL aqueous solution with 0.368 mmol of dissolved fluoride, chloride, hydroxyl and carbonate anions (fluoride alone, fluoride with each of the other anions, and all the anions together) at room temperature. The post-experiment analyses of solid and liquid phases, conducted by using XRD, ESEM and ICP-OES, show that fluoride is always the main anion removed from solution during the OCP transformation reaction. The precise mineralogical characterization of solid phases formed, performed using the Rietveld algorithm, shows that fluorapatite is always the main resulting apatitic phase, followed by hydroxyapatite. Taking into account the different application fields of OCP, these results could be significant in better defining the OCP â apatite reaction in aqueous solutions where different competing anions are involved
Landau parameters for energy density functionals generated by local finite-range pseudopotentials
In Landau theory of Fermi liquids, the particle-hole interaction near the Fermi energy in different spin-isospin channels is probed in terms of an expansion over the Legendre polynomials. This provides a useful and efficient way to constrain properties of nuclear energy density functionals in symmetric nuclear matter and finite nuclei. In this study, we present general expressions for Landau parameters corresponding to a two-body central local regularized pseudopotential. We also show results obtained for two recently adjusted NLO and (NLO)-L-2 parametrizations. Such pseudopotentials will be used to determine mean-field and beyond- meanfield properties of paired nuclei across the entire nuclear chart.Peer reviewe
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