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arXiv · 1612.01502

Is a Trineutron Resonance Lower in Energy than a Tetraneutron Resonance?

S. Gandolfi·H. -W. Hammer·P. Klos·J. E. Lynn·A. Schwenk
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Abstract

We present quantum Monte Carlo calculations of few-neutron systems confined in external potentials based on local chiral interactions at next-to-next-to-leading order in chiral effective field theory. The energy and radial densities for these systems are calculated in different external Woods-Saxon potentials. We assume that their extrapolation to zero external-potential depth provides a quantitative estimate of three- and four-neutron resonances. The validity of this assumption is demonstrated by benchmarking with an exact diagonalization in the two-body case. We find that the extrapolated trineutron resonance, as well as the energy for shallow well depths, is lower than the tetraneutron resonance energy. This suggests that a three-neutron resonance exists below a four-neutron resonance in nature and is potentially measurable. To confirm that the relative ordering of three- and four-neutron resonances is not an artifact of the external confinement, we test that the odd-even staggering in the helium isotopic chain is reproduced within this approach. Finally, we discuss similarities between our results and ultracold Fermi gases.

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S. Gandolfi, H. -W. Hammer, P. Klos, J. E. Lynn, A. Schwenk. 2016-12-05. Is a Trineutron Resonance Lower in Energy than a Tetraneutron Resonance?. https://doi.org/10.1103/physrevlett.118.232501

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