Lightest neutral hypernuclei with strangeness -1 and -2

Our current knowledge of the baryon-baryon interaction suggests that the dineutron (n,n) and its strange analog (n,Lambda) are unstable. In contrast, the situation is more favorable for the strange three-body system (n,n,Delta), and even better for the four-body system T equivalent to (n,n,Lambda,Lambda) with strangeness -2, which is likely to be stable under spontaneous dissociation. The recent models of the hyperon-nucleon and hyperon-hyperon interactions suggest that the stability of the (n,n,Lambda) and T is possible within the uncertainties of our knowledge of the baryon-baryon interactions. This new nucleus T could be produced and identified in central deuteron-deuteron collisions viathe reaction d + d --> T + K+ + K+, and the tetrabaryon T could play an important role in catalyzing the formation