Ratio of strange to non-strange quark condensates in QCD

Laplace transform QCD sum rules for two-point functions related to the strangeness-changing scalar and pseudoscalar Greenʹs functions ψ(Q2) and ψ5(Q2), are used to determine the subtraction constants ψ(0) and ψ5(0), which fix the ratio Rsu≡〈s̄s〉/〈ūu〉. Our results are ψ(0)=−(1.06±0.21)×10−3 GeV4, ψ5(0)=(3.35±0.25)×10−3 GeV4, and Rsu≡〈s̄s〉/〈ūu〉=0.5±0.1. This implies corrections to kaon-PCAC at the level of 50%, which although large, are not inconsistent with the size of the corrections to Goldberger–Treiman relations in SU(3)⊗SU(3).