Five-body cluster structure of double-$\Lambda$ hypernucleus $^{11}_{\Lambda \Lambda}$Be

TL;DR

This paper models the energy levels of the double-$\Lambda$ hypernucleus $^{11}_{\Lambda \Lambda}$Be using a five-body approach, reproducing observed data and interpreting recent experimental events.

Contribution

It introduces a parameter-free five-body model to calculate hypernuclear energy levels, aligning theoretical predictions with recent experimental observations.

Findings

Calculated $B_{\Lambda \\Lambda}$ for $^{11}_{\\Lambda \\Lambda}$Be ground and excited states.

Interpreted the Hida event as the hypernucleus's ground state.

Constructed an effective $\\Lambda \\Lambda$ interaction consistent with experimental data.

Abstract

Energy levels of the double $\Lambda$ hypernucleus, $^{11}_{\Lambda \Lambda}$Be are calculated within the framework of an $\alpha \alpha n \Lambda \Lambda$ five-body model. Interactions between constituent particles are determined so as to reproduce reasonably the observed low-energy properties of the $\alpha \alpha$, $\alpha \alpha n$ nuclei and the existing data for $\Lambda$-binding energies of the $\alpha \Lambda$, $\alpha \alpha \Lambda$, $\alpha n \Lambda$ and $\alpha \alpha n \Lambda$ systems. An effective $\Lambda \Lambda$ interaction is constructed so as to reproduce, within the $\alpha \Lambda \Lambda$ three-body model, the $B_{\Lambda \Lambda}$ of $^6_{\Lambda \Lambda}$He, which was extracted from the emulsion experiment, the NAGARA event. With no adjustable parameters for the $\alpha \alpha n \Lambda \Lambda$ system, $B_{\Lambda \Lambda}$ of the ground and bound excited states of $^{11}_{\Lambda \Lambda}$Be are calculated with the Gaussian Expansion Method. The Hida event, recently observed at KEK-E373 experiment, is interpreted as an observation of the ground state of the $^{11}_{\Lambda \Lambda}$Be.