A test of the instanton vacuum with low-energy theorems of the axial   anomaly
  We revisit the QCD+QED axial anomaly low-energy theorems which give an exact relation between the matrix elements of the gluon and photon parts of the axial anomaly operator equation within the framework of the {\em effective action} derived from the instanton vacuum. The matrix elements between the vacuum and two photon states and between the vacuum and two gluon states are investigated for arbitrary $N_f $ in the chiral limit. Having gauged the effective action properly, we show that the model does exactly satisfy the low-energy theorems. 
M.M. Musakhanov (Uzbekistan Nat'l Univ.) and Hyun-Chul Kim (Pusan   Nat'l Univ.)