2009/04/11 by S. Menke, Menke, Sven · 4 citations
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.0904.1796
openalex publication_date 2009/04/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
One of the largest theoretical uncertainties assigned to the strong coupling constant alphas as determined from hadronic tau decays stems from the differences in the results for Fixed Order Perturbation Theory (FOPT), Contour Improved Perturbation Theory (CIPT) and Renormalon Chain Perturbation Theory (RCPT). It is often argued that the three methods differ in the treatment of higher orders only and therefore the full difference should be treated as theoretical error. Recently other arguments either in favor of FOPT, CIPT or RCPT have been given, but none of those is able to combine all three to a single value in the strong coupling constant. In this note I will show that FOPT alone has a much larger uncertainty than previously assumed and therefore agrees within error with CIPT. Furthermore a more appropriate matching of the different schemes used in RCPT reduces the difference to the CIPT result by a factor of 6. Together with recently published results for the 4th order term K4 this reduces the theoretical error on alphas by a factor of 2.5 compared to the previously assumed spread of the three perturbative approaches.