On the QCD Sum Rule Determination of the Strange Quark Mass

Abstract

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 ${\bar{m}}_s(1GeV)\ge 120MeV$. In particular, varying only the parameters describing the nonresonant $K\pi$ component and ${\Lambda }_{\overline{MS}}^{n_f=3}$ we obtain ${\bar{m}}_s(1GeV)=125-160MeV$. 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.

Comments: Latex, 13 pages, 3 figures