Resonance Form-Factors: L8 Determination at Next-to-Leading Order in 1/NC

This talk presents a systematic procedure for the computation of the SS-PP correlator beyond the large--NC limit. The present calculation is carried on within a perturbative 1/NC framework . By constraining the meson form-factors at leading order in 1/NC, one obtains a one-loop spectral function well behaved at short distances. The Weinberg sum-rules get modified, gaining an extra contribution suppressed by 1/NC. This leads to a prediction for the low energy chiral perturbation theory coupling L8^r(mu) at the one-loop level, i.e., up to next-to-leading order in 1/NC.