Is there a bound Lambda-n-n ?

TL;DR

This paper critically examines the existence of a bound Lambda-n-n state by analyzing hypernuclear systems and concludes that such a bound state is unlikely based on derived constraints.

Contribution

It provides a theoretical analysis incorporating Lambda N - Sigma N coupling to challenge previous claims of a Lambda-n-n bound state.

Findings

Constraints from hypernuclear systems suggest no bound Lambda-n-n.

Full consideration of Lambda N - Sigma N coupling is crucial for accurate predictions.

The observed decay modes do not support the existence of a bound Lambda-n-n.

Abstract

The HypHI Collaboration at GSI argued recently for a (Lambda-n-n) bound state from the observation of its two-body (t + pi-) weak-decay mode. We derive constraints from several hypernuclear systems, in particular from the A=4 hypernuclei with full consideration of (Lambda N <--> Sigma N) coupling, to rule out a bound (Lambda-n-n).