Strange quark mass from pseudoscalar sum rule with \(O(\alpha_s^4)\) accuracy

We include the new, five-loop, O(αs4) 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(αs4) 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(αs4) correction. We obtain the interval m̄s(2 GeV)=105±6±7 MeV, which exhibits about 2 MeV increase of the central value, if the O(αs4) terms are removed.