85 research outputs found

    Low-energy nuclear physics and global neutron star properties

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    We address the question of the role of low-energy nuclear physics data in constraining neutron star global properties, e.g., masses, radii, angular momentum, and tidal deformability, in the absence of a phase transition in dense matter. To do so, we assess the capacity of 415 relativistic mean field and non-relativistic Skyrme-type interactions to reproduce the ground state binding energies, the charge radii and the giant monopole resonances of a set of spherical nuclei. The interactions are classified according to their ability to describe these characteristics and we show that a tight correlation between the symmetry energy and its slope is obtained providing N=ZN=Z and N≠ZN\ne Z nuclei are described with the same accuracy (mainly driven by the charge radius data). By additionally imposing the constraints from isobaric analog states and neutron skin radius in 208^{208}Pb, we obtain the following estimates: Esym,2=31.8±0.7E_{sym,2}=31.8\pm 0.7 MeV and Lsym,2=58.1±9.0L_{sym,2}=58.1\pm 9.0 MeV. We then analyze predictions of neutron star properties and we find that the 1.4M⊙M_\odot neutron star (NS) radius lies between 12 and 14 km for the "better" nuclear interactions. We show that i) the better reproduction of low-energy nuclear physics data by the nuclear models only weakly impacts the global properties of canonical mass neutron stars and ii) the experimental constraint on the symmetry energy is the most effective one for reducing the uncertainties in NS matter. However, since the density region where constraints are required are well above densities in finite nuclei, the largest uncertainty originates from the density dependence of the EDF, which remains largely unknown.Comment: 26 pages, 20 figure

    Self-consistent single-particle approximation to nuclear state densities at high excitation energy

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    We compute nuclear state densities for a number of magic and semimagic nuclei in the usual saddle point approximation within the framework of the grand-canonical formalism in an energy range where residual two-body interactions and collective effects can reasonably be neglected. The single-particle states used in the calculations are generated in a relativistic self-consistent mean field at finite temperature based on widely adopted effective interactions. Observed limits and possible improvements of the adopted formalism are discussed

    Dirac-Brueckner Hartree-Fock Approach: from Infinite Matter to Effective Lagrangians for Finite Systems

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    One of the open problems in nuclear structure is how to predict properties of finite nuclei from the knowledge of a bare nucleon-nucleon interaction of the meson-exchange type. We point out that a promising starting point consists in Dirac-Brueckner-Hartree-Fock (DBHF) calculations us- ing realistic nucleon-nucleon interactions like the Bonn potentials, which are able to reproduce satisfactorily the properties of symmetric nuclear matter without the need for 3-body forces, as is necessary in non-relativistic BHF calculations. However, the DBHF formalism is still too com- plicated to be used directly for finite nuclei. We argue that a possible route is to define effective Lagrangians with density-dependent nucleon-meson coupling vertices, which can be used in the Relativistic Hartree (or Relativistic Mean Field (RMF)) or preferrably in the Relativistic Hartree- Fock (RHF) approach. The density-dependence is matched to the nuclear matter DBHF results. We review the present status of nuclear matter DBHF calculations and discuss the various schemes to construct the self-energy, which lead to differences in the predictions. We also discuss how effective Lagrangians have been constructed and are used in actual calculations. We point out that completely consistent calculations in this scheme still have to be performed.Comment: 16 pages, to be published in Journal of Physics G: Nuclear and Particle Physics, special issue

    Elastic, inelastic, and 1 n transfer cross sections for the 10 B + 120 Sn reaction

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    The 10 B + 120 Sn reaction has been investigated at E Lab = 37.5 MeV. The cross sections for different channels, such as the elastic scattering, the excitation of the 2 + and 3 − 120 Sn states, the excitation of the 1 + state of 10 B , and the 1 n pick-up transfer, have been measured. One-step distorted-wave Born approximation and coupled-reaction-channels calculations have been performed in the context of the double-folding SĂŁo Paulo potential. The effect of coupling the inelastic and transfer states on the angular distributions is discussed in the paper. In general, the theoretical calculations within the coupled-reaction-channels formalism yield a satisfactory agreement with the corresponding experimental angular distributions.Instituto Nacional de CiĂȘncia e Tecnologia-FĂ­sica Nuclear e AplicaçÔes de Brasil (INCT-FNA) 464898/2014-

    Determination of the 12C nuclear density through heavy-ion elastic scattering experiments

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    Precise elastic scattering differential cross sections have been measured for the 12C158Ni,208Pb systems at sub-barrier energies. The corresponding bare potentials have been determined at interaction distances larger than the respective barrier radii, and the results have been compared with those from an early extensive systematics for the nuclear potential. The present data have been combined with others for the 12C 112C,208Pb systems at intermediate energies, in order to extract the 12C ground-state nuclear density through an unfolding method

    Experimental determination of the surface density for the 6He exotic nucleus

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    Angular distributions for the elastic scattering of 4,6He on 58Ni have been measured at near-barrier energies. The present data, combined with others for the 4He158Ni system at intermediate energies, allowed the determination of the 4,6He ground-state nuclear densities through an unfolding method. The experimentally extracted nuclear densities are compared with the results of theoretical calculations

    IAEA coordinated research project on nuclear data for charged-particle monitor reactions and medical isotope production

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    An IAEA coordinated research project was launched in December 2012 to establish and improve the nuclear data required to characterise charged-particle monitor reactions and extend data for medical radionuclide production. An international team was assembled to undertake work addressing the requirements for more accurate cross-section data over a wide range of targets and projectiles, undertaken in conjunction with a limited number of measurements and more extensive evaluations of the decay data of specific radionuclides. These studies are nearing completion, and are briefly described below.Work at ANL is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contract No. DE-AC02-06CH11357
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