On the difference between FOPT and CIPT for hadronic tau decays
Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
2 Erwin Schrödinger International Institute for Mathematics and Physics, University of Vienna, Boltzmanngasse 9, 1090, Vienna, Austria
Accepted: 26 July 2021
Published online: 12 September 2021
In this article we review the results of our recent work on the difference between the Borel representations of hadronic spectral function moments obtained with the CIPT and FOPT methods. For the presentation of the theoretical results we focus on the large- approximation, where all expressions can be written down in closed form, and we comment on the generalization to full QCD. The results may explain the discrepancy in the behavior of the FOPT and CIPT series that has been the topic of intense discussions in previous literature and which represents a major part of the theoretical uncertainties in current strong coupling determinations from hadronic decays. The findings also imply that the OPE corrections for FOPT and CIPT differ and that the OPE corrections for CIPT do not have standard form.
© The Author(s) 2021
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