Isospin-breaking vector meson decay constants from continuous families of finite energy sum rules

Abstract

The isospin-breaking vector meson decay constants are determined from a QCD sum rule analysis of the vector current correlator $<O| T(V^3_\mu V^8_\nu)| O>$, using a recently proposed implementation of the finite energy sum rule approach. The analysis employs the three-loop version of the OPE, and two different families of weight functions. It is shown that the requirement of consistency between results obtained using these two different weight families leads to a rather good determination of the parameter describing the deviation of the D=6 condensate term in the OPE from its vacuum saturation value, and that the ability to determine this value has non-trivial numerical consequences to the analysis. The phenomenological relevance of the results to the extraction of the strange quark mass and the determination of the $6^{th}$ order chiral low energy constant, $Q$, is also briefly discussed.