Scalar and pseudoscalar correlators in Resonance Chiral Theory

The SU(3) octet SS-PP correlator and the difference of the singlet and octet scalar correlators are computed within Resonance Chiral Theory. The calculation is carried on up to the one-loop level, i.e., up to next-to-leading order in the 1/NC expansion. Using the resonance expressions as interpolators between long and short distances, we demand the correlators to follow the high-energy power behavior prescribed by the operator product expansion and extract predictions for the low-energy constants. By adding more and more complicated operators to the hadronic action, our description is progressively improved, producing for the SS-PP correlator the chiral coupling estimates L8(μ)=(1.0±0.4).10-3 and C38(μ)=(8±5).10-6 for μ=770MeV. Some first results for the S1S1-S8S8 correlator are shown, like, for instance, the positivity of the spectral function for two-meson cuts, the high-energy constraints for each separate scalar form-factor and preliminary expressions for the L6(μ) low-energy constant. © 2010 Elsevier B.V.