Eur. Phys. J. C (2006) 46: 721-728
https://doi.org/10.1140/epjc/s2006-02508-8

Theoretical Physics

Strange quark mass from pseudoscalar sum rule with accuracy

¹ Institut für Theoretische Teilchenphysik, Universität Karlsruhe, 76128, Karlsruhe, Germany
² Theoretische Physik 1, Fachbereich Physik, Universität Siegen, 57068, Siegen, Germany

^* e-mail: khodjam@hep.physik.uni-siegen.de

Received: 11 January 2006
Published online: 30 March 2006

Abstract

We include the new, five-loop, O(α_s ⁴) correction into the QCD sum rule used for the s-quark mass determination. The pseudoscalar Borel sum rule is taken as a study case. The OPE for the correlation function with N⁴LO, O(α_s ⁴) accuracy in the perturbative part, and with dimension d≤6 operators reveals a good convergence. We observe a significant improvement of stability of the sum rule with respect to the variation of the renormalization scale after including the O(α_s ⁴) correction. We obtain the interval m̄_s(2 GeV)=105±6±7 MeV, which exhibits about 2 MeV increase of the central value, if the O(α_s ⁴) terms are removed.