Contributor info: Prof. Andre Hoang

Miguel A. Benitez-Rathgeb, Diogo Boito, Andre H. Hoang, Matthias Jamin

SciPost Phys. Proc. 16, 007 (2025) · published 14 July 2025 | Toggle abstract · pdf

In a recent work it was suggested that the discrepancy observed in the perturbation series behavior of the $\tau$ hadronic decay rate determined in the FOPT and CIPT approaches can be explained from a different infrared sensitivity inherent to both methods, assuming that the major source of the discrepancy is the asymptotic behavior of the series related to the gluon condensate renormalon. This implies that the predictions of both methods may be reconciled in infrared subtracted perturbation theory. In this talk we explore this implication concretely in the large-$\beta_0$ approximation, where the perturbation series is known to all orders, using a renormalon-free scheme for the gluon condensate.

Andre H. Hoang, Christoph Regner

SciPost Phys. Proc. 7, 005 (2022) · published 20 June 2022 | Toggle abstract · pdf

The discrepancy between the FOPT and CIPT approaches for hadronic tau spectral function moments constitutes the major theoretical uncertainty for strong coupling determinations from tau decay data. We show that the discrepancy can be analytically understood since the Borel representations -- which have been assumed to be identical for both approaches previously -- differ in the presence of IR renormalons. This implies that the OPE condensate corrections are different for both approaches and that the discrepancy may eventually be reconciled. In the talk we explain the difference and some mathematical aspects of the FOPT and CIPT Borel representations and show numerical results.