Minimal relativistic three particle equations

A relativistic, 3-particle equation with minimal 2-body input has unique solutions for bound states, and exhibits the Efimov effect (that there is an infinite accumulation of 3-particle bound states as the scattering length between the pairs increases without bound). The theory is Lorentz invariant and unitary. The physical input (for the three equal mass case) is in one parameter ..mu.., the mass of the 2-body bound (or virtual) states. The Efimov effect for the nonrelativistic theory occurs for (absolute value a/R) ..-->.. infinity, where a is the scattering length and R an effective range parameter, whereas in this theory the behavior is for ..mu.. ..-->.. 2m, where m is the mass of any one of the three particles