A new determination of α_s (M_τ²) and higher-order QCD corrections to hadronic τ decays

2025/10/17 by Abbas, Gauhar, Singh, Vartika
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph)

paper · doi:10.48550/arxiv.2510.16119

Abstract

We employ Levin-type sequence transformations to accelerate the convergence of the perturbative fixed-order expansion of the QCD correction δ⁽⁰⁾ in terms of the strong coupling α_s, and of the inverted series expressing α_s in powers of δ⁽⁰⁾. The method efficiently resums the divergent inverted series, yielding a stable and self-consistent determination of the strong coupling at the τ mass scale. It also provides reliable estimates of higher-order QCD corrections to hadronic τ decays, consistent with existing results. We find α_s^Levin-FOPT = 0.3159 ± 0.0018 ± 0.0023 , and predict c_5,1 = 269⁺⁴⁷_-45, c_6,1 = 3185⁺¹¹⁷_-279, c_7,1 = (1.9^+0.9_-0.8) × 10⁴. Our results demonstrate that Levin-type transformations provide an efficient framework for analyzing asymptotic perturbative series and improving the extraction of α_s(M_τ²) from hadronic τ decays.

Citations

• Estimating the strong coupling from τ decay using accelerating series convergence
• Precision physics with inclusive QCD processes
• The QCD renormalization group equation and the elimination of fixed-order scheme-and-scale ambiguities using the principle of maximum conformality
• Tau Decay Determination of the QCD Coupling
• On the determination of alpha_s from hadronic tau decays with contour-improved, fixed order and renormalon-chain perturbation theory
• Nonlinear sequence transformations for the acceleration of convergence and the summation of divergent series

Related

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• α_s from the updated ALEPH data for hadronic τ decays
• Compatibility of α_s(M_τ) with α_s(M_Z)
• α_s from the (revised) ALEPH data for τ decay
• QCD Tests from Tau Decays