Determining $$\alpha_s$$ from hadronic $$\tau$$ decay: the pitfalls of truncating the OPE

Journal Article · 21 February 2019 · SciPost Physics Proceedings

DOI: https://doi.org/10.21468/SciPostPhysProc.1.053 · OSTI ID:1495814

Boito, Diogo ^[1]; Golterman, Maarten  ^[2]; Maltman, Kim ^[3]; Peris, Santiago  ^[4]

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1. University of Sao Paulo
2. San Francisco State University
3. University of Adelaide, York University
4. Autonomous University of Barcelona

We discuss sum-rule determinations of \alpha_s ${\alpha }_s$ from non-strange hadronic \tau $\tau$ -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. . Here, we test this strategy by applying the strategy to the R $R$ -ratio obtained from e^+e^- $e^{+}{e}^{-}$ data, which extend beyond the \tau $\tau$ 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 ${\alpha }_s$ , including a representation of duality violations is unavoidable if one wishes to avoid uncontrolled theoretical errors.

• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0013682
• OSTI ID: 1495814
• Journal Information: SciPost Physics Proceedings, Journal Name: SciPost Physics Proceedings Journal Issue: 1
• Publisher: Stichting SciPostCopyright Statement
• Country of Publication: Country unknown/Code not available
• Language: English