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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Higher-order QCD corrections to hadronic tau decays from Pade approximants

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Boito, Diogo [1] ; Masjuan, Pere [2, 3] ; Oliani, Fabio [1]
Total Authors: 3
[1] Univ Sao Paulo, Inst Fis Sao Carlos, CP 369, BR-13560970 Sao Carlos, SP - Brazil
[2] Univ Autonoma Barcelona, Dept Fis, Grp Fis Teor, Campus UAB, E-08193 Bellaterra, Barcelona - Spain
[3] BIST, IFAE, Campus UAB, E-08193 Bellaterra, Barcelona - Spain
Total Affiliations: 3
Document type: Journal article
Source: Journal of High Energy Physics; n. 8 AUG 14 2018.
Web of Science Citations: 2

Perturbative QCD corrections to hadronic tau decays and e(+)e(-) annihilation into hadrons below charm are obtained from the Adler function, which at present is known in the chiral limit to five-loop accuracy. Extractions of the strong coupling, alpha(s), from these processes suffer from an ambiguity related to the treatment of unknown higher orders in the perturbative series. In this work, we exploit the method of Pade approximants and its convergence theorems to extract information about higher-order corrections to the Adler function in a systematic way. First, the method is tested in the large-beta(0) limit of QCD, where the perturbative series is known to all orders. We devise strategies to accelerate the convergence of the method employing renormalization scheme variations and the so-called D-log Pade approximants. The success of these strategies can be understood in terms of the analytic structure of the series in the Borel plane. We then apply the method to full QCD and obtain reliable model-independent predictions for the higher-order coefficients of the Adler function. For the six-, seven-, and eight-loop coefficients we find c(5,1) = 277 +/- 51, c(6,1) = 3460 +/- 690, and c(7)(,1) = (2.02 +/- 0.72) x10(4), respectively, with errors to be understood as lower and upper bounds. Our model-independent reconstruction of the perturbative QCD corrections to the tau hadronic width strongly favours the use of fixed-order perturbation theory (FOPT) for the renormalization-scale setting. (AU)

FAPESP's process: 16/01341-4 - Padé approximants and the QCD perturbative series for tau decays into hadrons
Grantee:Fabio Henrique Oliani
Support type: Scholarships in Brazil - Master
FAPESP's process: 15/20689-9 - Precise determination of fundamental QCD parameters
Grantee:Diogo Rodrigues Boito
Support type: Research Grants - Young Investigators Grants