PaperPanorama

Nuclear Theory·nucl-th

Monday·May 14, 2018

4 papers2 primary·2 cross-listed

  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

Affiliations

first authorsco-authorsvia INSPIRE