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On the use of the Operator Product Expansion in finiteenergy sum rules for lightquark correlators
by Diogo Boito, Maarten Golterman, Kim Maltman, Santiago Peris
Submission summary
Authors (as registered SciPost users):  Maarten Golterman 
Submission information  

Preprint Link:  scipost_202112_00035v1 (pdf) 
Date submitted:  20211214 21:33 
Submitted by:  Golterman, Maarten 
Submitted to:  SciPost Physics Proceedings 
Proceedings issue:  16th International Workshop on Tau Lepton Physics (TAU2021) 
Ontological classification  

Academic field:  Physics 
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Approach:  Theoretical 
Abstract
Taubased finiteenergy sumrule (FESR) analyses often assume that scales $s_0\sim m_\tau^2$ are large enough that (i) integrated duality violations (DVs) can be neglected, and (ii) contributions from nonperturbative OPE condensates of dimension $D$ scale as $(\Lambda_{\rm QCD}/m_\tau )^D$, allowing the OPE series to be truncated at low dimension. The latter assumption is not necessarily valid since the OPE series is not convergent, while the former is open to question given experimental results for the electromagnetic, $I=1$ vector ($V$), $I=1$ axial vector ($A$) and $I=1$ $V+A$ current spectral functions, which show DV oscillations with amplitudes comparable in size to the corresponding $\alpha_s$dependent perturbative contributions at $s\sim23$~GeV$^2$. Here, we discuss recently introduced new tools for assessing the numerical relevance of omitted higher$D$ OPE contributions. Applying these to the ``truncated OPE'' strategy used in Refs.~{\cite{Davier:2013sfa,Pich:2016bdg}} and earlier work by the same authors, we find that this strategy fails to yield reliable results for the strong coupling from hadronic $\tau$ decays.