On the structure of two-point Green-functions at next-to-leading order in 1/NC1/NC

The structure of the two-point QCD Green-functions is studied in this Letter in the limit of large number of colours. Their general form at next-to-leading order in 1/NC1/NC is derived keeping the infinite resonance summation and without relying on a particular realization of the hadronic action. It is found that the contributions from chiral operators without resonance fields of order p4p4 or higher are irrelevant for the computation of the correlators and, hence, they can be dropped at the beginning of the calculation. The possibility of a more general cancelation of these local terms at the level of the generating functional is discussed.