The strange-quark mass from QCD sum rules: An Update

Abstract

Three different ways of determining the strange quark mass using QCD sum rules are reviewed. First, from a QCD sum rule determination of the up and down quark masses, together with the current algebra ratio $ m_{s}/(m_{u}+m_{d})$. Second and third, from QCD sum rules involving the strangeness changing vector and axial-vector current divergences, respectively. Present results are encompassed in the value: $m_{s} {(1 GeV)} = 150 \pm {70 MeV}$. It is argued that until direct, and precision measurements of the relevant spectral functions become available, the above error is not likely to be reduced.