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Determining $\alpha_s$ from hadronic $\tau$ decay:\\ the pitfalls of truncating the OPE
by D. Boito, M. Golterman, K. Maltman and S. Peris
This Submission thread is now published as
Submission summary
| Submission information |
| Preprint Link: |
scipost_201901_00045v2
(pdf)
|
| Date accepted: |
2019-02-14 |
| Date submitted: |
2019-02-11 01:00 |
| Submitted by: |
Peris, Santiago |
| Submitted to: |
SciPost Physics Proceedings |
| Proceedings issue: |
The 15th International Workshop on Tau Lepton Physics (TAU2018) |
| Ontological classification |
| Academic field: |
Physics |
| Specialties: |
- High-Energy Physics - Theory
|
| Approach: |
Theoretical |
Abstract
We discuss sum-rule determinations of $\alpha_s$ from non-strange hadronic $\tau$-decay data. We investigate, in particular, the reliability of the assumptions underlying the ``truncated OPE strategy,'' which specifies a certain treatment of non-perturbative contributions, and which was employed in Refs.~\cite{Pich,Aleph, Opal}. Here, we test this strategy by applying the strategy to the $R$-ratio obtained from $e^+e^-$ data, which extend beyond the $\tau$ mass, and demonstrate that the assumptions underlying this strategy are not, in general, valid. We then present a brief overview of new results on the form of duality-violating non-perturbative contributions, which are conspicuously present in the experimentally determined spectral functions. As we show, with the current precision claimed for the extraction of $\alpha_s$, including a representation of duality violations is unavoidable if one wishes to avoid uncontrolled theoretical errors.
