Relativistic Bound States in 2+1 and 1+1 Dimensions in the Null-Plane
  The Relativistic formulation of the three-boson model interacting via a zero-range two-body force in the null-plane is given in 2+1 and 1+1 space-time dimension. The bound state energy is calculed as function of the two-body boson binding energy. 
J. P. B. C de Melo (Division de Physique Theorique,Institut de   Physique Nucleaire, Orsay,France and LPTPE Universite P. & ...