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Nuclear Theory·nucl-th

Friday·April 24, 2020

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    [Submitted on 22 Apr 2020]

    Fission of Pu with symmetry-restored density functional theory

    Petar Marević · Nicolas Schunck

    Nuclear fission plays an important role in fundamental and applied science, from astrophysics to nuclear engineering, yet it remains a major challenge to nuclear theory. Theoretical methods used so far to compute fission observables rely on symmetry-breaking schemes where basic information on the number of particles, angular momentum, and parity of the fissioning nucleus is lost. In this work, we analyze the impact of restoring broken symmetries in the benchmark case of Pu.

    Comments:
    7 pages, 3 figures, 1 table; Phys. Rev. Lett, in press
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2004.10804 [pdf]
    PRL(2020)·25 citations
  2. 02

    [Submitted on 22 Apr 2020]

    Structure of Krypton Isotopes using the Generalised Bohr Hamiltonian Method

    David Muir · Leszek Próchniak · Alessandro Pastore · Jacek Dobaczewski

    We investigate the properties of the excited spectra of the even-even isotopes of krypton using a Generalised Bohr Hamiltonian with three different Skyrme functionals. In particular, we investigate the evolution of the low-lying and states and their associated electromagnetic transitions. The model reproduces quite nicely the energy trends apart from Kr, where none of the interactions used here are able to grasp a sudden change in the energy spectrum. Additionally, we explore the neutron deficient region Kr which is a proposed region for shape coexistence. We observe that the model can reproduce the structure of the experimental spectrum of Kr exceedingly well.

    Comments:
    Presented at the 27th International Nuclear Physics Conference (INPC) 2019, Glasgow, Scotland, UK, 29th July - 2 August
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2004.10835 [pdf]
    J.Phys.Conf.Ser.(2020)·2 citations
  3. 03

    [Submitted on 23 Apr 2020]

    Entropy Production in Dissipationless Hydrodynamics with an order parameter

    Shu Lin · Gezheng Zhou

    We study hydrodynamics coupled to order parameter based on linear sigma model. We obtain numerical solutions for both boost invariant and non-boost invariant solutions. Both solutions show the order parameter rises with oscillations, which persist at late time. The temperature drops with correlated oscillations, which can be approximated by a power law at mid-rapidity. We also find the entropy is conserved in the boost invariant case, but entropy production is seen in non-boost invariant solution. We interpret the entropy production as due to smoothening of inhomogeneity in the off-equilibrium state.

    Comments:
    13 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2004.10935 [pdf]
    0 citations
  4. 04

    [Submitted on 23 Apr 2020]

    Thresholds of ultraperipheral processes

    I.M. Dremin🇷🇺

    Threshold behavior of the cross sections of ultraperipheral nuclear interactions is studied. Production of and pairs as well as and parapositronium is treated. The values of corresponding energy thresholds are presented and the total cross sections of these processes at the newly constructed NICA and FAIR facilities are estimated.

    Comments:
    8 pg
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2004.11074 [pdf]
    Int.J.Mod.Phys.A(2020)·2 citations
  5. 05

    [Submitted on 23 Apr 2020]

    Designing Optimal Experiments: An Application to Proton Compton Scattering

    J. A. Melendez · R. J. Furnstahl · H. W. Griesshammer · J. A. McGovern · D. R. Phillips · M. T. Pratola

    Interpreting measurements requires a physical theory, but the theory's accuracy may vary across the experimental domain. To optimize experimental design, and so to ensure that the substantial resources necessary for modern experiments are focused on acquiring the most valuable data, both the theory uncertainty and the expected pattern of experimental errors must be considered. We develop a Bayesian approach to this problem, and apply it to the example of proton Compton scattering. Chiral Effective Field Theory (EFT) predicts the functional form of the scattering amplitude for this reaction, so that the electromagnetic polarizabilities of the nucleon can be inferred from data. With increasing photon energy, both experimental rates and sensitivities to polarizabilities increase, but the accuracy of EFT decreases. Our physics-based model of EFT truncation errors is combined with present knowledge of the polarizabilities and reasonable assumptions about experimental capabilities at HIS and MAMI to assess the information gain from measuring specific observables at specific kinematics, \emph{i.e.}, to determine the relative amount by which new data are apt to shrink uncertainties. The strongest gains would likely come from new data on the spin observables and at to MeV and to . These would tightly constrain . New data on the differential cross section between and \,MeV and over a wide angle range will substantially improve constraints on , and . Good signals also exist around MeV for and . Such data will be pivotal in the continuing quest to pin down the scalar polarizabilities and refine understanding of the spin polarizabilities.

    Comments:
    47 pages LaTeX2e (pdflatex) including 33 figures as .jpg files using includegraphics. Improved presentation with corrections do not affect the conclusions by details of the figures. Higher-resolution figures are available at https://home.gwu.edu/~hgrie/Compton/one-N-comprehensive-observables-delta4.v2.0.high-resolution-figures.tgz. Final version with minor corrections published in EPJA57(2021)81
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Data Analysis, Statistics and Probability (physics.data-an)
    arXiv:
    2004.11307 [pdf]
    EPJA(2021)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE