Summing Planar Diagrams by an Integrable Bootstrap
  Correlation functions of matrix-valued fields are not generally known for massive renormalized field theories. We find the large-N limit of form factors of the (1+1)-dimensional sigma model with SU(N) X SU(N) symmetry. These form factors give a correction to the free-field approximation for the N=infinity Wightman function. The method is a combination of the 1/N-expansion of the S-matrix and Smirnov's form-factor axioms. We expand the renormalized field in terms of a free massive Bosonic field as N goes to infinity. 
Peter Orland (Baruch + Grad Center, CUNY, NBIA)
hep-th cond-mat.stat-mech hep-lat math-ph math.MP