2005/09/21 by Matthias Jamin · 1 citation
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-lat #hep-ph
paper · pdf · doi:10.1088/1126-6708/2005/09/058
published as JHEP 0509 (2005) 058 · 20 pages, 5 eps-figures; discussion on scale and scheme dependence added as compared to published journal version JHEP 09 (2005) 058
openalex publication_date 2005/09/21 · arxiv created 2005/09/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/29
The hadronic decay rate of the tau lepton serves as one of the most precise determinations of the QCD coupling alphas. The dominant theoretical source of uncertainty at present resides in the seeming disparity of two approaches to improving the perturbative expansion with the help of the renormalisation group, namely fixed-order and contour-improved perturbation theory. In this work it is demonstrated that in fact both approaches yield compatible results. However, the fixed-order series is found to oscillate around the contour-improved result with an oscillation frequency of approximately six perturbative orders, approaching it until about the 30th order, after which the expansion reveals its asymptotic nature. Additionally, the renormalisation scale and scheme dependencies of the perturbative series for the tau hadronic width are investigated in detail.