Odd-intrinsic-parity processes within the Resonance Effective Theory of QCD

Abstract

We analyse the most general odd-intrinsic-parity effective Lagrangian of QCD valid for processes involving one pseudoscalar with vector mesons described in terms of antisymmetric tensor fields. Substantial information on the odd-intrinsic-parity couplings is obtained by constructing the vector-vector-pseudoscalar Green's three-point function, at leading order in 1/Nc, and demanding that its short-distance behaviour matches the corresponding OPE result. The QCD constraints thus enforced allow us to predict the decay amplitude omega -> pion gamma, and the O(p^6) corrections to pion -> gamma gamma. Noteworthy consequences concerning the vector meson dominance assumption in the decay omega -> 3 pions are also extracted from the previous analysis.