τ hadronic spectral function moments in a nonpower QCD perturbation theory

0540680 - FZÚ 2021 RIV NL eng C - Konferenční příspěvek (zahraniční konf.)
Abbas, G. - Ananthanarayan, B. - Caprini, I. - Fischer, Jan
τ hadronic spectral function moments in a nonpower QCD perturbation theory.
Nuclear and Particle Physics Proceedings. Vol. 273. Amsterdam: Elsevier Science BV, 2016, s. 2777-2779. ISSN 2405-6014.
[International Conference on High Energy Physics (ICHEP) /37./. Valencie (ES), 02.07.2014-09.07.2014]
Institucionální podpora: RVO:68378271
Klíčová slova: strong coupling * tau decays
Obor OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

The moments of the hadronic spectral functions are of interest for the extraction of the strong coupling and other QCD parameters from the hadronic decays of the τ lepton. We consider the perturbative behavior of these moments in the framework of a QCD nonpower perturbation theory, defined by the technique of series acceleration by conformal mappings, which simultaneously implements renormalization-group summation and has a tame large-order behavior. Two recently proposed models of the Adler function are employed to generate the higher order coefficients of the perturbation series and to predict the exact values of the moments, required for testing the properties of the perturbative expansions. We show that the contour-improved nonpower perturbation theories and the renormalization-group-summed nonpower perturbation theories have very good convergence properties for a large class of moments of the so-called “reference model”.

Trvalý link: http://hdl.handle.net/11104/0318298