Anomalous Effective Lagrangian and Theta Dependence in QCD at Finite N_c
  We generalize the large N_c Di Vecchia-Veneziano-Witten (VVW) effective chiral Lagrangian to the case of finite N_c by constructing the anomalous effective Lagrangian for QCD. The latter is similar to its SUSY counterpart, and has a holomorphic structure. The VVW construction is then recovered, along with 1/N_c corrections, after integrating out the heavy "glueball" fields. A new mass formula for eta' meson in terms of QCD condensates is obtained. The picture of theta dependence in QCD for finite N_c is more complicated than the one predicted by the large N_c approach. 
Igor Halperin and Ariel Zhitnitsky (Univ. of British Columbia)