Loosely bound states of three particles

Loosely bound states of three particles for particles interacting via short range forces were predicted by Efimov. They are shown to arise naturally in the adiabatic hyperspherical approximation presently used to compute reactions along hyperspherical coordinates. Because of the loosely bound nature of such states, the asymptotic form of the effective hyper-radial potential is critical. A variational wave function is suggested and is shown to reproduce the asymptotic potenial obtained by Efimov. Implications and extensions of the theory are suggested.