On the QCD sum rule determination of the strange quark mass

In the QCD sum rule determination of m(s) using the two-point correlator of divergences of Delta S = 1 vector currents, the final uncertainty on m(s) is mainly due to the hadronic spectral function. Using a specific parameterization which fully takes into account the available experimental data on the K pi (I = 1/2, J(P) = 0(+)) system, characterized by the presence of a relevant nonresonant component in addition to the resonant one, we find (m) over bar(s)(1 GeV) greater than or equal to 120 MeV. In particular, varying only the parameters describing the nonresonant K pi component and Lambda nf=3/MS we obtain (m) over bar(s)(1 GeV) = 125-160 MeV. This result is smaller than analogous ones obtained by using a parameterization in terms of only resonant states. We discuss how to systematically improve the determination of m(s) by this method. (C) 1997 Elsevier Science B.V.