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Tau-decay determination of the strong coupling

by Antonio Pich

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Submission summary

Authors (as registered SciPost users): Antonio Pich
Submission information
Preprint Link: scipost_201811_00029v1  (pdf)
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 (TAU2018)
Ontological classification
Academic field: Physics
  • High-Energy Physics - Experiment
  • High-Energy Physics - Phenomenology
Approach: Theoretical


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)

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


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.


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.

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