$\alpha_s$ in 2016 from the (revised) ALEPH data for $\tau$ decay

TL;DR

This paper compares two methods for determining the strong coupling constant _s at the tau mass scale, concluding that the Duality Violation model is more reliable than the truncated Operator Product Expansion model.

Contribution

It provides a critical evaluation of existing strategies for extracting _s from tau decay data, favoring the Duality Violation approach based on passing all current tests.

Findings

The truncated Operator Product Expansion model fails key tests.

The Duality Violation model passes all known tests.

The paper recommends the Duality Violation model as the reliable method.

Abstract

We summarize a comparison of the two strategies which are currently available in the literature for determining the value of $\alpha_s(m_\tau)$. We will refer to these as the truncated Operator Product Expansion model and the Duality Violation model. After describing the main features of both approaches, we explain why the former fails to pass crucial tests. The latter, on the other hand, passes all the tests known up to date and, therefore, should be currently considered the only reliable method.