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Nuclear Theory·nucl-th

Tuesday·July 3, 2018

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 30 Jun 2018]

    Domains and defects in nuclear "pasta"

    Andre da Silva Schneider🇺🇸 · Matt E. Caplan🇨🇦 · Don K. Berry🇺🇸 · Charles J. Horowitz🇺🇸

    Nuclear pasta topology is an essential ingredient to determine transport properties in the inner crust of neutron stars. We perform semi-classical molecular dynamics simulations of nuclear pasta for proton fractions and near one third of nuclear saturation density, , at a temperature . Our simulations are, to our knowledge, the largest nuclear pasta simulations to date and contain up to nucleons in the and nucleons in the case. An algorithm to determine which nucleons are part of a given sub-domain in the system is presented. By comparing runs of different sizes we study finite size effects, equilibration time, the formation of multiple domains and defects in the pasta structures, as well as the structure factor dependence on simulation size. Although we find qualitative agreement between the topological structure and the structure factors of runs with nucleons and those with nucleons or more, we show that simulations with hundreds of thousands of nucleons may be necessary to accurately predict pasta transport properties.

    Comments:
    21 pages and 21 figures. Submitted to Physical Review C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.00102 [pdf]
    PRC(2018)·32 citations
  2. 02

    [Submitted on 30 Jun 2018]

    Jost-matrix analysis of the resonance 5He*(3/2+) near the dt-threshold

    S.A. Rakityansky🇿🇦 · S.N. Ershov🇷🇺

    Experimental data on the n-alpha and dt collisions in the quantum state J^pi=3/2+ near the dt-threshold are fitted using the semi-analytic multi-channel Jost matrix with proper analytic structure and some adjustable parameters. Then the spectral points are sought as zeros of the Jost matrix determinant (which correspond to the S-matrix poles) at complex energies. The correct analytic structure makes it possible to calculate the fitted Jost matrix on any sheet of the Riemann surface whose topology involves not only the square-root but also the logarithmic branching caused by the Coulomb interaction. Within a distance of 100,keV above the dt-threshold, three 3/2+ resonances are found on the non-physical sheet of the Riemann surface. Several S-matrix (shadow) poles on the other sheets of this surface are located as well.

    Comments:
    49 pages, 19 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1807.00209 [pdf]
    IJMPE(2019)·7 citations
  3. 03

    [Submitted on 1 Jul 2018]

    Cluster Radioactivity in Super Heavy Nuclei

    M. Warda🇵🇱 · A. Zdeb🇵🇱 · L.M. Robledo🇪🇸

    Cluster radioactivity is an exotic nuclear decay observed in actinides where a light nucleus is emitted while the remaining heavy mass residue is the doubly magic Pb or a nucleus in its neighborhood. We have investigated this type of decay in heavier nuclei up to Lv within a microscopic theory. It has been found that super asymmetric fission with Pb as heavy fragment may be dominant decay channel in some super heavy nuclei. This reaction is closely related with cluster radioactivity.

    Comments:
    6 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.00342 [pdf]
    PRC(2018)·64 citations
  4. 04

    [Submitted on 2 Jul 2018]

    Microscopic predictions of the nuclear matter liquid-gas phase transition

    Arianna Carbone · Artur Polls · Arnau Rios

    We present first-principle predictions for the liquid-gas phase transition in symmetric nuclear matter employing both two- and three-nucleon chiral interactions. Our discussion focuses on the sources of systematic errors in microscopic quantum many body predictions. On the one hand, we test uncertainties of our results arising from changes in the construction of chiral Hamiltonians. We use five different chiral forces with consistently derived three-nucleon interactions. On the other hand, we compare the ladder resummation in the self-consistent Green's functions approach to finite temperature Brueckner--Hartree--Fock calculations. We find that systematics due to Hamiltonians dominate over many-body uncertainties. Based on this wide pool of calculations, we estimate that the critical temperature is MeV, in reasonable agreement with experimental results. We also find that there is a strong correlation between the critical temperature and the saturation energy in microscopic many-body simulations.

    Comments:
    14 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1807.00596 [pdf]
    PRC(2018)·45 citations
  5. 05

    [Submitted on 28 Jun 2018]

    A systematic study of alpha and cluster decay in Platinum isotopes

    Nithu Ashok🇮🇳 · Antony Joseph🇮🇳

    The feasibility of alpha and cluster decay from Pt isotopes has been investigated within the framework of Skyrme Hartree-Fock-Bogoliubov theory. Calculation has been carried out for various Skyrme forces. Harmonic oscillator and transformed harmonic oscillator basis are used to solve HFB equations. The role played by shell closure is withal analysed. Half-lives are estimated with the help of Universal Decay Law (UDL). Geiger-Nuttel plots are also plotted and successfully preserves its linear nature.

    Comments:
    12 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.00680 [pdf]
    IJMPE(2019)·5 citations
  6. 06

    [Submitted on 2 Jul 2018]

    Irreducible nonlocality of optical model potentials based on realistic NN interactions

    H. F. Arellano🇨🇱 · G. Blanchon🇫🇷

    We investigate the nonlocal structure of optical model potentials for nucleon-nucleus scattering based on microscopic approaches. To this purpose, \emph{in-medium} folding optical potentials are calculated in momentum space and their corresponding coordinate-space counterpart are examined, paying special attention to their nonlocal shape. The nucleon-nucleon effective interaction consists of the actual full off-shell matrix in Brueckner-Hartree-Fock approximation. The nonlocality of effective interactions is preserved throughout all stages in the the calculation. Argonne bare potential and chiral next-to-next-to-next-to-leading order bare interaction are used as starting point. The study is focused on proton elastic scattering off Ca at beam energies between 30 and 800 MeV. We find that the gradual suppression of high-momentum contributions of the optical potential results in quite different-looking coordinate-space counterparts. Despite this non-uniqueness in their nonlocal structure, the implied scattering observables remain unchanged for momentum cutoff above a critical one, which depends on incident energy of the projectile. We find that coordinate-space potentials with momentum cutoffs at the critical value yield the least structured nonlocal behavior. Implications of these findings are discussed.

    Comments:
    14 pages; 16 figures. Submitted to PRC
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1807.00733 [pdf]
    PRC(2018)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE