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Nuclear Theory·nucl-th

Thursday·May 13, 2021

6 papers—4 primary·2 cross-listed

All6Primary4Cross-lists2
  1. 01

    [Submitted on 11 May 2021]

    Density matrix renormalization group description of the island of inversion isotopes F

    K. Fossez🇺🇸 · J. Rotureau🇸🇪

    Recent experiments have confirmed that the neutron-rich isotopes F belong to the so-called island of inversion (IOI), a region of the nuclear chart around and where nuclear structure deviates from the standard shell model predictions due to deformation and continuum effects. However, while the general principles leading to the IOI are relatively well understood, the details of the low-lying structure of the exotic fluorine isotopes F are basically unknown. In this work, we perform large-scale shell model calculations including continuum states to investigate the properties of the neutron-rich isotopes F, using a core of O and an effective two-body interaction with only three adjustable parameters. We adjust the core potential and interaction on experimentally confirmed states in O and F and solve the many-body problem using the density matrix renormalization group method for open quantum systems in a - model space. We obtain the first detailed spectroscopy of F in the continuum and show how the interplay between continuum effects and deformation explains the recent data on F, and produces an inversion of the and states in F. Several deformed one- and two-neutron halo states are predicted in F, and we predict the ground state of F to have a structure similar to that of the first state of F. We also suggest several experimental studies to constraint models and test the present predictions. The complex structure of neutron-rich fluorine isotopes offers a trove of information about the formation of the southern shore of the IOI through a subtle interplay of deformation and continuum couplings driven by the occupation of the quasi-degenerate neutron shells and .

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2105.05287 [pdf]
    PRC(2022)·23 citations
  2. 02

    [Submitted on 12 May 2021]

    Ab initio calculation of the contact operator contribution in the standard mechanism for neutrinoless double beta decay

    R. Wirth🇺🇸 · J. M. Yao🇨🇳 · H. Hergert🇺🇸

    Starting from chiral nuclear interactions, we evaluate the contribution of the leading-order contact transition operator to the nuclear matrix element (NME) of neutrinoless double-beta decay, assuming a light Majorana neutrino-exchange mechanism. The corresponding low-energy constant (LEC) is determined by fitting the transition amplitude of the process to a recently proposed synthetic datum. We examine the dependence of the amplitude on similarity renormalization group (SRG) scale and chiral expansion order of the nuclear interaction, finding that both dependences can be compensated to a large extent by readjusting the LEC. We evaluate the contribution of both the leading-order contact operator and standard long-range operator to the neutrinoless double-beta decays in the light nuclei He and the candidate nucleus Ca. Our results provide the first clear demonstration that the contact term enhances the NME by 43(7)% in Ca, where the uncertainty is propagated from the synthetic datum.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2105.05415 [pdf]
    PRL(2021)·85 citations
  3. 03

    [Submitted on 12 May 2021]

    Probing nuclear quadrupole deformation from correlation of elliptic flow and transverse momentum in heavy ion collisions

    Jiangyong Jia🇺🇸 · Shengli Huang🇺🇸 · Chunjian Zhang🇺🇸

    In heavy ion collisions, elliptic flow and radial flow, characterized by event-wise average transverse momentum , are related to the shape and size of the overlap region, which are sensitive to the shape of colliding atomic nuclei. The Pearson correlation coefficient between and , , was found to be particularly sensitive to the quadrupole deformation parameter that is traditionally measured in low energy experiments. Built on earlier insight that the prolate deformation reduces the in ultra-central collisions (UCC), we show that the prolate deformation enhances the value of . As and are the two extremes of triaxiality, the strength and sign of correlation can be used to provide valuable information on the triaxiality of the nucleus. Our study provide further arguments for using the hydrodynamic flow as a precision tool to directly image the deformation of the atomic nuclei at extremely short time scale (s).

    Comments:
    13 pages, 10 figures, update to the Accepted version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Atomic Physics (physics.atom-ph)
    arXiv:
    2105.05713 [pdf]
    PRC(2022)·57 citations
  4. 04

    [Submitted on 12 May 2021]

    Nucleon decay in the deuteron

    F. Oosterhof🇳🇱 · J. de Vries🇳🇱 · R. G. E. Timmermans🇳🇱 · U. van Kolck🇫🇷

    We calculate the lifetime of the deuteron from dimension-six quark operators that violate baryon number by one unit. We construct an effective field theory for interactions that give rise to nucleon and deuteron decay in a systematic expansion. We show that up to and including next-to-leading order the deuteron decay rate is given by the sum of the decay rates of the free proton and neutron. The first nuclear correction is expected to contribute at the few-percent level and comes with an undetermined low-energy constant. We discuss its relation to earlier potential-model calculations.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2105.05715 [pdf]
    PLB(2021)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE