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Nuclear Theory·nucl-th

Monday·May 14, 2018

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    [Submitted on 11 May 2018]

    Resolving the hypernuclear overbinding problem in pionless effective field theory

    Lorenzo Contessi🇮🇱 · Nir Barnea🇮🇱 · Avraham Gal🇮🇱

    We address the -hypernuclear `overbinding problem' in light hypernuclei which stands for a 1--3 MeV excessive separation energy calculated in He. This problem arises in most few-body calculations that reproduce ground-state separation energies in the lighter hypernuclei within various hyperon-nucleon interaction models. Recent pionless effective field theory nuclear few-body calculations are extended in this work to hypernuclei. At leading order, the low-energy constants are associated with scattering lengths and the low-energy constants are fitted to separation energies () for . The resulting pionless-EFT interaction reproduces in few-body stochastic variational method calculations the reported value He)=3.120.02 MeV within a fraction of MeV over a broad range of momentum-space cut-off parameters. Possible consequences and extensions to heavier hypernuclei and to neutron-star matter are discussed.

    Comments:
    matches published PRL 121 (2018) 102502 with one minor correction: the number of nuclear plus hypernuclear LECs at LO is eight, not seven
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1805.04302 [pdf]
    PRL(2018)·43 citations
  2. 02

    [Submitted on 11 May 2018]

    Tetraneutron: Rigorous continuum calculation

    A. Deltuva

    The four-neutron system is studied using exact continuum equations for transition operators and solving them in the momentum-space framework. A resonant behavior is found for strongly enhanced interaction but not a the physical strength, indicating the absence of an observable tetraneutron resonance, in contrast to a number of earlier works. As the transition operators acquire large values at low energies, it is conjectured that this behavior may explain peaks in many-body reactions even without a resonance.

    Comments:
    4+ pages, 3 figures, submitted to Phys.Lett.B
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Nuclear Experiment (nucl-ex)
    arXiv:
    1805.04349 [pdf]
    PLB(2018)·45 citations
  3. 03

    [Submitted on 11 May 2018] (cross-list from hep-ph)

    Baryon clustering at the critical line and near the hypothetical critical point in heavy-ion collisions

    Edward Shuryak🇺🇸 · Juan M. Torres-Rincon🇺🇸

    We study clustering of baryons at the freeze-out point of relativistic heavy-ion collisions. Using a Walecka-Serot model for the nucleon-nucleon (NN) interaction we analyze how the modified/critical mode---responsible for the NN attraction---allows for clustering of nucleons when the system is close to a possible critical point of QCD. We investigate clusters of few nucleons, and also the internal cluster configuration when the system is long lived. For realistic heavy-ion collisions we study to how extend such clusters can be formed in a finite time, and perform the statistical analysis of cumulants and higher-order moments (skewness and kurtosis) for collisions at the Beam Energy Scan of RHIC.

    Comments:
    l additions: (i) about small clusters with 4 nucleons, contributing to He4 production; (ii) inter-baryon potential from functional renormalization group results
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1805.04444 [pdf]
    PRC(2019)·50 citations
  4. 04

    [Submitted on 10 May 2018] (cross-list from hep-ph)

    Neutron disappearance inside the nucleus

    H. Ejiri (RCNP, Osaka University, Osaka, Japan)🇯🇵 · J.D. Vergados (University of Ioannina, Ioannina, Greece)🇬🇷

    We consider the possibility that a neutron may disappear inside the nucleus, which will demonstrate the existence of baryon violating interactions. It has recently been proposed that such a process may have an effect on the free neutron decay life time. We evaluate the widths for and , with being a light dark matter particle emitted by a loosely bound neutron in various light nuclei. We find that, assuming a mass close to 938 MeV, the obtained width for in Be is much larger than the corresponding beta decay width. This suggests a severe limit on the possible decay channel of for free neutron.

    Comments:
    3 figures, 1 table. References added.To appear 2018 J. Phys. G: Nucl. Part. Phys. https://doi.org/10.1088/1361-6471/aaf55b arXiv admin note: text overlap with arXiv:1801.01124, arXiv:1203.3081 by other authors
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1805.04477 [pdf]
    J.Phys.G(2019)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE