Updated determination of chiral couplings and vacuum condensates from hadronic tau decay data

TL;DR

This paper refines the determination of chiral couplings and vacuum condensates using updated tau decay data, applying spectral moments and operator product expansion with rigorous uncertainty analysis.

Contribution

It provides the most recent precise extraction of low-energy chiral couplings and vacuum condensates from tau decay spectral functions, incorporating comprehensive uncertainty assessments.

Findings

Updated values for L10 and C87 couplings.

Refined estimates of vacuum condensates.

Quantified uncertainties including duality violations.

Abstract

We analyze the lowest spectral moments of the left-right two-point correlation function, using all known short-distance constraints and the recently updated ALEPH V-A spectral function from tau decays. This information is used to determine the low-energy couplings L10 and C87 of chiral perturbation theory and the lowest-dimensional contributions to the Operator Product Expansion of the left-right correlator. A detailed statistical analysis is implemented to assess the theoretical uncertainties, including violations of quark-hadron duality.