Speaker
Martin Beneke
(Technische Universität München)
Description
We subtract the gluon-condensate renormalon singularity in the Adler function, which causes the discrepancy between fixed-order (FOPT) and contour-improved perturbation theory (CIPT), employing the gradient flow action density. The scheme leads to automatic subtraction, does not require knowledge of the Stokes constant (renormalon residue), and relates to a non-perturbatively defined cut-off gluon condensate. Unlike unsubtracted perturbation theory, FOPT and CIPT give consistent results for the inclusive hadronic tau decay width, removing a major uncertainty in the determination of the strong coupling from tau decay.
