3-BODY HALOS IN 2 DIMENSIONS

A method to study weakly bound three-body quantum systems in two dimen sions is formulated in coordinate space for short-range potentials. Oc currences of spatially extended structures (halos) are investigated. B orromean systems are shown to exist in two dimensions for a certain cl ass of potentials. An extensive numerical investigation shows that a w eakly bound two-body state gives rise to two weakly bound three-body s tates, a reminiscence of the Efimov effect in three dimensions. The pr operties of these two states in the weak binding limit turn out to be universal.