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

## Abstract

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.

- Authors:

- University of Sao Paulo
- San Francisco State University
- University of Adelaide, York University
- Autonomous University of Barcelona

- Publication Date:

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1495814

- Grant/Contract Number:
- SC0013682

- Resource Type:
- Published Article

- Journal Name:
- SciPost Physics Proceedings

- Additional Journal Information:
- Journal Name: SciPost Physics Proceedings Journal Issue: 1

- Publisher:
- Stichting SciPost

- Country of Publication:
- Country unknown/Code not available

- Language:
- English

### Citation Formats

```
Boito, Diogo, Golterman, Maarten, Maltman, Kim, and Peris, Santiago. Determining $\alpha_s$ from hadronic $\tau$ decay: the pitfalls of truncating the OPE. Country unknown/Code not available: N. p., 2019.
Web. doi:10.21468/SciPostPhysProc.1.053.
```

```
Boito, Diogo, Golterman, Maarten, Maltman, Kim, & Peris, Santiago. Determining $\alpha_s$ from hadronic $\tau$ decay: the pitfalls of truncating the OPE. Country unknown/Code not available. doi:10.21468/SciPostPhysProc.1.053.
```

```
Boito, Diogo, Golterman, Maarten, Maltman, Kim, and Peris, Santiago. Fri .
"Determining $\alpha_s$ from hadronic $\tau$ decay: the pitfalls of truncating the OPE". Country unknown/Code not available. doi:10.21468/SciPostPhysProc.1.053.
```

```
@article{osti_1495814,
```

title = {Determining $\alpha_s$ from hadronic $\tau$ decay: the pitfalls of truncating the OPE},

author = {Boito, Diogo and Golterman, Maarten and Maltman, Kim and Peris, Santiago},

abstractNote = {We discuss sum-rule determinations of \alpha_s α s from non-strange hadronic \tau τ -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 τ 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 α s , including a representation of duality violations is unavoidable if one wishes to avoid uncontrolled theoretical errors.},

doi = {10.21468/SciPostPhysProc.1.053},

journal = {SciPost Physics Proceedings},

number = 1,

volume = ,

place = {Country unknown/Code not available},

year = {2019},

month = {2}

}

DOI: 10.21468/SciPostPhysProc.1.053