The nature of the Λnn and H∗Λ3(Jπ=3/2+,I=0) states is investigated within a pionless effective field theory at leading order, constrained by the low-energy ΛN scattering data and hypernuclear three- and four-body data. Bound-state solutions are obtained using the stochastic variational method, and the continuum region is studied by employing two independent methods: the inverse analytic continuation in the coupling constant method and the complex scaling method. Our calculations yield both the Λnn and H∗Λ3 states unbound. We conclude that the excited state H∗Λ3 is a virtual state and the Λnn pole located close to the three-body threshold in a complex energy plane could convert to a true resonance with Re(E)>0 for some considered ΛN interactions. Finally, the stability of resonance solutions is discussed and limits of the accuracy of performed calculations are assessed.
Bibliographical noteFunding Information:
We are grateful to Avraham Gal for valuable discussions and careful reading of the paper. This work was partly supported by the Czech Science Foundation GACR Grant No. 19-19640S. The work of N.B. was supported by the Pazy Foundation and by the Israel Science Foundation Grant No. 1308/16. Furthermore, M.S. and N.B. were partially funded by the European Union's Horizon 2020 research and innovation programme under Grant No. 824093.
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