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Strange Quark Mass from Tau Lepton Decays with O(alpha_s^3) Accuracy

P. A. Baikov·K. G. Chetyrkin·J. H. Kühn
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Abstract

The first complete calculation of the quadratic quark mass correction to the correlator of the two currents relevant for the strangeness-changing semihadronic tau-decay rate is presented including its real part at the four-loop level. This allows to perform the extraction of the strange quark mass m_s from the decay width of the tau-lepton with full O(alpha_s^3) accuracy. In agreement with previous estimates the newly computed alpha_s^3 term proves to be rather large. This justifies inclusion of the similarly estimated alpha_s^4 term in phenomenological analysis. Combined with an updated value of V_{us} and an ``'improved'' version of the renormalization group improvement of the perturbative series this leads to an increase of the central value of m_s by about 20 % and a partial reduction of the theoretical uncertainty by about 50 %.

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P. A. Baikov, K. G. Chetyrkin, J. H. Kühn. 2005-05-18. Strange Quark Mass from Tau Lepton Decays with O(alpha_s^3) Accuracy. https://doi.org/10.1103/physrevlett.95.012003

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