PaperPanorama

Nuclear Theory·nucl-th

Thursday·October 11, 2018

5 papers3 primary·2 cross-listed

  1. 04

    [Submitted on 16 Jun 2016] (cross-list from physics.atom-ph)

    Theory of the Lamb shift and Fine Structure in muonic ions and the muonic Isotope Shift

    Marc Diepold (1) · Beatrice Franke (1 and 2) · Julian J. Krauth (1 and 3) · Aldo Antognini (4 and 5) · Franz Kottmann (4) · Randolf Pohl (3 and 1) ((1) Max Planck Institute of Quantum Optics, 85748 Garching, Germany, (2) TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada, (3) Johannes Gutenberg-Universität Mainz, QUANTUM, Institut für Physik & Exzellenzcluster PRISMA, 55099 Mainz, (4) Institute for Particle Physics and Astrophysics, ETH Zurich, 8093 Zurich, Switzerland, (5) Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland)

    We provide an up to date summary of the theory contributions to the 2S-2P Lamb shift and the fine structure of the 2P state in the muonic helium ion . This summary serves as the basis for the extraction of the alpha particle charge radius from the muonic helium Lamb shift measurements at the Paul Scherrer Institute, Switzerland. Individual theory contributions needed for a charge radius extraction are compared and compiled into a consistent summary. The influence of the alpha particle charge distribution on the elastic two-photon exchange is studied to take into account possible model-dependencies of the energy levels on the electric form factor of the nucleus. We also discuss the theory uncertainty which enters the extraction of the isotope shift from the muonic measurements. The theory uncertainty of the extraction is much smaller than a present discrepancy between previous isotope shift measurements. This work completes our series of theory compilations in light muonic atoms which we have performed already for muonic hydrogen, deuterium, and helium-3 ions.

    Comments:
    18 Pages, revised and updated manuscript, numbers are now same as in published version
    Subjects:
    Atomic Physics (physics.atom-ph); Nuclear Theory (nucl-th)
    arXiv:
    1606.05231 [pdf]
    Annals Phys.(2018)·47 citations
  2. 05

    [Submitted on 10 Oct 2018] (cross-list from astro-ph.SR)

    The s-process nucleosynthesis in low mass stars: impact of the uncertainties in the nuclear physics determined by Monte Carlo variations

    G. Cescutti · R. Hirschi · N. Nishimura · T. Rauscher · J. den Hartogh · A. St. J. Murphy · S. Cristallo

    We investigated the impact of uncertainties in neutron-capture and weak reactions (on heavy elements) on the s-process nucleosynthesis in low-mass stars using a Monte-Carlo based approach. We performed extensive nuclear reaction network calculations that include newly evaluated temperature-dependent upper and lower limits for the individual reaction rates. Our sophisticated approach is able to evaluate the reactions that impact more significantly the final abundances. We found that beta-decay rate uncertainties affect typically nuclides near s-process branchings, whereas most of the uncertainty in the final abundances is caused by uncertainties in neutron capture rates, either directly producing or destroying the nuclide of interest. Combined total nuclear uncertainties due to reactions on heavy elements are approximately 50%.

    Comments:
    3 pages, 1 figure; to appear in Springer Proceedings of Physics as proceedings of the XV Int. Conf. "Nuclei in the Cosmos", L'Aquila, Italy, June 2018. This conference contribution presents results published in MNRAS 478 (2018) 4101
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1810.04556 [pdf]
    Springer Proc.Phys.(2019)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE