Is there 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).

Comments: 12 pages, 4 tables; v2--extended (i) discussion of Table 4 with a new Eq.(7), (ii) discussion of CSB effects; v3 matches published version