Extraction of α_s using Borel-Laplace sum rules for tau decay data

2022/02/26 by César J. Ayala, Ayala, César, Gorazd Cvetič +3
Physics and Astronomy · #Advanced Frequency and Time Standards #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.2202.13178

openalex publication_date 2022/02/26 · openalex created_date 2022/04/03 · openalex updated_date 2026/07/28

Abstract

Double-pinched Borel-Laplace sum rules are applied to ALEPH τ-decay data. For the leading-twist (D=0) Adler function a renormalon-motivated extension is used, and the 5-loop coefficient is taken to be d₄=275 ± 63. Two D=6 terms appear in the truncated OPE (D ≤ 6) to enable cancellation of the corresponding renormalon ambiguities. Two variants of the fixed order perturbation theory, and the inverse Borel transform, are applied to the evaluation of the D=0 contribution. Truncation index N_t is fixed by the requirement of local insensitivity of the momenta a^(2,0) and a^(2,1) under variation of N_t. The averaged value of the coupling obtained is α_s(m_τ²)=0.3235^+0.0138_-0.0126 [α_s(M_Z²)=0.1191 ± 0.0016]. The theoretical uncertainties are significantly larger than the experimental ones.

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