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arXiv · 1706.06455

Onset of $η$-meson binding in the He isotopes

N. Barnea·E. Friedman·A. Gal
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Abstract

The onset of binding $η$(548) mesons in nuclei is studied in the He isotopes by doing precise $ηNNN$ and $ηNNNN$ few-body stochastic variational method calculations for two semi-realistic $NN$ potentials and two energy dependent $ηN$ potentials derived from coupled-channel models of the $N^{\ast}(1535)$ nucleon resonance. The energy dependence of the $ηN$ subthreshold input is treated self consistently. It is found that a minimal value of the real part of the $ηN$ scattering length $a_{ηN}$ close to 1 fm is required to bind $η$ mesons in $^3$He, yielding then a few MeV $η$ binding in $^4$He. The onset of $η$-meson binding in $^4$He requires that Re$\,a_{ηN}$ exceeds 0.7 fm approximately. These results compare well with results of recent $ηNNN$ and $ηNNNN$ pionless effective field theory calculations. Related optical-model calculations are also discussed.

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N. Barnea, E. Friedman, A. Gal. 2017-09-06. Onset of $η$-meson binding in the He isotopes. https://doi.org/10.1016/j.nuclphysa.2017.07.021

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