Universality of low-energy scattering in three-dimensional field theory - art. no. 081701

The universal low-energy behavior, 2mc/ln \s-4m(2)\ of the scattering funct ion of particles of positive mass m near the threshold s=4m(2), and pi/ln \ s-4m(2)\ for the corresponding S-wave phase shift, is established for weakl y coupled field theory models with a mass m>0 in space-time dimension 3; c is a numerical constant independent of the model and couplings. This result is a nonperturbative property based on an exact analysis of the scattering function in terms of a two-particle irreducible (or Bethe-Salpeter) struct ure function. It also appears as generic by the same analysis in the framew ork of general relativistic quantum field theory. [S0556-2821(99)50208-7].