Partial waves and large $N_C$ resonance sum rules

Abstract

Using $1/N_C$ expansion and dispersion theory techniques, without relying on any explicit resonance lagrangian, we generalize the KSRF relation beyond the leading chiral order. Two sum rules for the low energy constants $L_2$, $L_3$ and a new relation between resonance couplings are derived. A rather detailed examination to the new relation is also given.

Comments: discussions expanded, reference added, version to be published in JHEP