# Tau-decay determination of the strong coupling

### Submission summary

 As Contributors: Antonio Pich Preprint link: scipost_201811_00029v1 Date accepted: 2019-01-15 Date submitted: 2018-11-18 01:00 Submitted by: Pich, Antonio Submitted to: SciPost Physics Proceedings Proceedings issue: The 15th International Workshop on Tau Lepton Physics (Amsterdam, 2018-09) Academic field: Physics Specialties: High-Energy Physics - Experiment High-Energy Physics - Phenomenology Approach: Theoretical

### Abstract

We review the current status of the determination of the strong coupling from tau decay. Using the most recent release of the ALEPH data, a very comprehensive phenomenological analysis has been performed, exploring all strategies previously considered in the literature and several complementary approaches. Once their actual uncertainties are properly assessed, the results from all adopted methodologies are in excellent agreement, leading to a very robust and reliable value of the strong coupling, $\alpha_s^{(n_f=3)}(m_\tau^2) = 0.328\pm 0.013$, which implies $\alpha_s^{(n_f=5)}(M_Z^2) = 0.1197\pm 0.0015$.

Published as SciPost Phys. Proc. 1, 036 (2019)

### Submission & Refereeing History

Submission scipost_201811_00029v1 on 18 November 2018

## Reports on this Submission

### Anonymous Report 1 on 2018-12-9 (Invited Report)

• Cite as: Anonymous, Report on arXiv:scipost_201811_00029v1, delivered 2018-12-09, doi: 10.21468/SciPost.Report.721

### Strengths

1. The analysis reported in this paper is based on convincing scientific arguments and the strategy is well thought.
2. The paper is very nicely written, and all relevant aspects are clearly discussed.
3. I find the analysis in the Appendix of crucial importance in order to assess the validity of recent claims, Ref [24] in this paper, on the importance of duality violations in tau-decay determinations of the QCD coupling. In fact, the appendix shows clearly the limitations of the model-dependent description of the duality violations when the analysis is extended to larger ranges of $s$ values.

### Report

This contribution is very clearly written and addresses with solid scientific arguments a relevant topic that has recently been the subject of lively debates among phenomenologists.

I am of the opinion that this debate must be resolved soon, in order to avoid generating further confusion in the scientific community, and that it can be resolved on the basis of current evidences, like the ones reported in this contribution.

### Requested changes

No changes are requested.

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