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Nuclear Theory·nucl-th

Tuesday·February 20, 2018

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 01

    [Submitted on 16 Feb 2018]

    Decay Modes of the Hoyle State in

    H. Zheng · A. Bonasera · M. Huang · S. Zhang

    Recent experimental results give an upper limit less than 0.043\% (95\% C.L.) to the direct decay of the Hoyle state into 3 respect to the sequential decay into {Be}+. We performed one and two-dimensional tunneling calculations to estimate such a ratio and found it to be more than one order of magnitude smaller than experiment depending on the range of the nuclear force. This is within high statistics experimental capabilities. Our results can also be tested by measuring the decay modes of high excitation energy states of C where the ratio of direct to sequential decay might reach 10\% at (C)=10.3 MeV. The link between a Bose Einstein Condensate (BEC) and the direct decay of the Hoyle state is also addressed. We discuss a hypothetical `Efimov state' at (C)=7.458 MeV, which would mainly {\it sequentially} decay with 3 of {\it equal energies}: a counterintuitive result of tunneling. Such a state, if it would exist, is at least 8 orders of magnitude less probable than the Hoyle's, thus below the sensitivity of recent and past experiments.

    Comments:
    6 pages, 2 figures, accepted by Phys. Lett. B
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1802.06078 [pdf]
    PLB(2018)·25 citations
  2. 02

    [Submitted on 18 Feb 2018]

    Octupole deformation in neutron-rich actinides and superheavy nuclei and the role of nodal structure of single-particle wavefunctions in extremely deformed structures of light nuclei

    A. V. Afanasjev · H.Abusara · S.E.Agbemava

    Octupole deformed shapes in neutron-rich actinides and superheavy nuclei as well as extremely deformed shapes of the N~Z light nuclei have been investigated within the framework of covariant density functional theory. We confirmed the presence of new region of octupole deformation in neutron-rich actinides with the center around Z~96, N~196 but our calculations do not predict octupole deformation in the ground states of superheavy Z~108 nuclei. As exemplified by the study of 36Ar, the nodal structure of the wavefunction of occupied single-particle orbitals in extremely deformed structures allows to understand the formation of the alpha-clusters in very light nuclei, the suppression of the alpha-clusterization with the increase of mass number, the formation of ellipsoidal mean-field type structures and nuclear molecules.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1802.06461 [pdf]
    Phys.Scripta(2018)·13 citations
  3. 03

    [Submitted on 19 Feb 2018]

    Exactly Solvable Pairing Models

    J. P. Draayer · V. G. Gueorguiev · K. D. Sviratcheva · C. Bahri · Feng Pan · A. I. Georgieva

    Some results for two distinct but complementary exactly solvable algebraic models for pairing in atomic nuclei are presented: 1) binding energy predictions for isotopic chains of nuclei based on an extended pairing model that includes multi-pair excitations; and 2) fine structure effects among excited states in nuclei that track with the proton-neutron () and like-particle isovector pairing interactions as realized within an algebraic shell model. The results show that these models can be used to reproduce significant ranges of known experimental data, and in so doing, confirm their power to predict pairing-dominated phenomena in domains where data is unavailable.

    Comments:
    12 pages, 3 figures, Proceedings of the 8th International Spring Seminar on Nuclear Physics in Paestum, Italy, 23 - 27 May 2004. Published by World Scientific as Key Topics in Nuclear Structure. March 2005, pp 483-494, Edited by Aldo Covello
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1802.06508 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE