Titel
Reconciling the contour-improved and fixed-order approaches for τ hadronic spectral moments. Part II. Renormalon norm and application in αs determinations
Autor*in
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Abstract
In a previous article, we have shown that the discrepancy between the fixed-order (FOPT) and contour-improved (CIPT) perturbative expansions for τ hadronic spectral function moments, which had affected the precision of αs determinations for many years, may be reconciled by employing a renormalon-free (RF) scheme for the gluon condensate (GC) matrix element. In addition, the perturbative convergence of spectral function moments with a sizeable GC correction can be improved. The RF GC scheme depends on an IR factorization scale R and the normalization Ng of the GC renormalon. In the present work, we use three different methods to determine Ng, yielding a result with an uncertainty of 40%. Following two recent state-of-the-art strong coupling determination analyses at O(α5s), we show that using the renormalon-free GC scheme successfully reconciles the results for αs(m2τ) based on CIPT and FOPT. The uncertainties due to variations of R and the uncertainty of Ng only lead to a small or moderate increase of the final uncertainty of αs(m2τ), and affect mainly the CIPT expansion method. The FOPT and CIPT results obtained in the RF GC scheme may be consistently averaged. The RF GC scheme thus constitutes a powerful new ingredient for future analyses of τ hadronic spectral function moments.
Stichwort
Higher-Order Perturbative CalculationsSpecific QCD Phenomenology
Objekt-Typ
Sprache
Englisch [eng]
Persistent identifier
phaidra.univie.ac.at/o:1678873
Erschienen in
Titel
Journal of High Energy Physics
Band
2022
Ausgabe
9
ISSN
1029-8479
Erscheinungsdatum
2022
Publication
Springer Science and Business Media LLC
Fördergeber
Erscheinungsdatum
2022
Zugänglichkeit
Rechte
Rechteangabe
© The Authors
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