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Nuclear Theory·nucl-th

Friday·September 4, 2020

18 papers—7 primary·11 cross-listed

All18Primary7Cross-lists11
  1. 01

    [Submitted on 2 Sept 2020]

    Alternate Solution of the -Potential Mystery

    Vlad Avrigeanu · Marilena Avrigeanu

    A consistent set of statistical-model input parameters, validated by analysis of various independent data, makes possible the assessment of an -particle optical model potential [Phys. Rev. C {\bf 90}, 044612 (2014)] also for nucleon-induced -emission within 60 mass-number range. The advantage of recent data for low-lying states feeding is taken as well. Consideration of additional reaction channels leading to increase of the -emission beyond the statistical predictions has concerned the pickup direct interaction and Giant Quadrupole Resonance similar features.

    Comments:
    5+28 pages, 5+24 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2009.01361 [pdf]
    0 citations
  2. 02

    [Submitted on 3 Sept 2020]

    Utility of antiproton-nucleus scattering for probing nuclear surface density distributions

    K. Makiguchi · W. Horiuchi · A. Kohama

    Antiproton-nucleon () total cross sections are typically 3-4 times larger than the ones at incident energies from a few hundreds to thousands MeV. We investigate antiproton-nucleus scattering as it could work as a probe of the nuclear structure giving the sensitivity differently from a proton probe. High-energy antiproton-nucleus reactions are reasonably described by the Glauber model with a minimal profile function that reproduces the and -C cross section data. In contrast to the proton-nucleus scattering, we find that the complete absorption occurs even beyond the nuclear radius due to the large elementary cross sections, which shows stronger sensitivity to the nuclear density distribution in the tail region. This sensitivity is quantified in the total reaction cross sections with various density profiles for future measurement including neutron-rich unstable nuclei.

    Comments:
    9 pages, 9 figures, to appear in Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2009.01413 [pdf]
    PRC(2020)·4 citations
  3. 03

    [Submitted on 3 Sept 2020]

    Jet quenching in the hadron gas: An exploratory study

    Hannah Elfner🇳🇴 · Philipp Dorau🇩🇪 · Jean-Bernard Rose🇩🇪 · Daniel Pablos🇳🇴

    In most calculations of hard particle suppression in heavy-ion reactions the hadronic stage has been neglected due to formation time arguments. Most of the hard particle shower exits the hot and dense medium before the system enters the hadronic evolution. In this contribution, a first assessment within the hadronic transport approach SMASH (Simulating Many Accelerated Strongly-interacting Hadrons) of rescattering effects on hard particles is presented. In particular, it is shown that the hadronic energy loss depends on the particle species as well as the energy of the probe. A parametrization for the parameter as a function of temperature and particle energy is given for pions. Overall, major effects of the hadronic stage are expected in the transverse momentum range from 2-10 GeV and therefore jet sub-structure analysis and (hard-soft) correlation observables might be affected.

    Comments:
    5 pages, 4 figures, Proceedings for HardProbes2020, 1-6 June 2020, Austin, Texas (virtual)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2009.01736 [pdf]
    PoS(2021)·2 citations
  4. 04

    [Submitted on 3 Sept 2020]

    Electron capture in stars

    Karlheinz Langanke · Gabriel Martínez-Pinedo · Remco Zegers

    Electron captures on nuclei play an essential role for the dynamics of several astrophysical objects. The capture rate can be derived in perturbation theory where allowed nuclear transitions (Gamow-Teller transitions) dominate, except at the higher temperatures achieved in core-collapse supernovae where also forbidden transitions contribute significantly to the rates. There has been decisive progress in recent years in measuring Gamow-Teller (GT) strength distributions using novel experimental techniques based on charge-exchange reactions. These measurements provide not only data for the GT distributions of ground states for many relevant nuclei, but also serve as valuable constraints for nuclear models which are needed to derive the capture rates for the many nuclei, for which no data exist yet. In particular models are needed to evaluate the stellar capture rates at finite temperatures, where the capture can also occur on excited nuclear states. There has also been significant progress in recent years in the modelling of stellar capture rates. This has been made possible by advances in nuclear many-body models as well as in computer soft- and hardware. Specifically to derive reliable capture rates for core-collapse supernovae a dedicated strategy has been developed based on a hierarchy of nuclear models specifically adapted to the abundant nuclei and astrophysically conditions present at the various collapse conditions. This manuscript reviews the experimental and theoretical progress achieved recently in deriving stellar electron capture rates. It also discusses the impact these improved rates have on the various astrophysical objects. (Abridged)

    Comments:
    64 pages, 24 figures, Review article submitted to Reports on Progress in Physics
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)
    arXiv:
    2009.01750 [pdf]
    Rept.Prog.Phys.(2021)·59 citations
  5. 05

    [Submitted on 3 Sept 2020]

    Coulomb sum rule for He and O from coupled-cluster theory

    J. E. Sobczyk🇩🇪 · B. Acharya🇩🇪 · S. Bacca🇩🇪 · G. Hagen🇺🇸

    We demonstrate the capability of coupled-cluster theory to compute the Coulomb sum rule for the He and O nuclei using interactions from chiral effective field theory. We perform several checks, including a few-body benchmark for He. We provide an analysis of the center-of-mass contaminations, which we are able to safely remove. We then compare with other theoretical results and experimental data available in the literature, obtaining a fair agreement. This is a first and necessary step towards initiating a program for computing neutrino-nucleus interactions from first principles and supporting the experimental long-baseline neutrino program with a state-of-the-art theory that can reach medium-mass nuclei.

    Comments:
    10 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
    arXiv:
    2009.01761 [pdf]
    PRC(2020)·19 citations
  6. 06

    [Submitted on 3 Sept 2020]

    The importance of charged particle reactions in the r-process on supernovae and neutron stars

    Pedro V. Guillaumon · Iuda D. Goldman

    We propose a mechanism with dynamic production as a new set of nuclear reactions that could produce high density neutrons and explain the r- and rp-elements. We calculate the rate of thorium and uranium produced by our proposed mechanism and show that it is compatible with different stellar conditions found in explosive events at an initial temperature of with a "freeze-out" by a neutrino-driven wind. We show that charged particle reactions could explain the discrepancies in the abundances of and nucleochronometers. We extend the endpoint of the rapid proton (rp) process far beyond the previous work by showing that reactions could contribute to the nucleosynthesis of heavy stable neutron deficient nuclides, like , , and Hf. This implies in a broader definition of the rp-process and has important consequences for the nucleosynthesis of heavy elements. We show that we did not need to assume an extreme condition for the drip line of super neutron-rich nuclei.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2009.01814 [pdf]
    1 citation
  7. 07

    [Submitted on 3 Sept 2020]

    Moving away from singly-magic nuclei with Gorkov Green's function theory

    Vittorio Somà🇫🇷 · Carlo Barbieri🇬🇧 · Thomas Duguet🇫🇷 · Petr Navrátil🇨🇦

    Ab initio calculations of bulk nuclear properties (ground-state energies, root mean square charge radii and charge density distributions) are presented for seven complete isotopic chains around calcium, from argon to chromium. Calculations are performed within the Gorkov self-consistent Green's function approach at second order and make use of two state-of-the-art two- plus three-nucleon Hamiltonians, + and NNLO. An overall good agreement with available experimental data is found, in particular for differential energies (charge radii) when the former (latter) interaction is employed. Remarkably, neutron magic numbers emerge and evolve following experimental trends. In contrast, pairing gaps are systematically underestimated. General features of the isotopic dependence of charge radii are also reproduced, as well as charge density distributions. A deterioration of the theoretical description is observed for certain nuclei and ascribed to the inefficient account of (static) quadrupole correlation in the present many-body truncation scheme. In order to resolve these limitations, we advocate the extension of the formalism towards incorporating breaking of rotational symmetry or, alternatively, performing a stochastic sampling of the self-energy.

    Comments:
    17 pages, 14 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2009.01829 [pdf]
    EPJA(2021)·42 citations

Affiliations

first authorsco-authorsvia INSPIRE