Power corrections in the dispersive model for a determination of the strong coupling constant from the thrust distribution

Abstract

In the context of the dispersive model for non-perturbative corrections, we extend the leading renormalon subtraction to NNLO for the thrust distribution in $e^+e^-$ annihilation. Within this framework, using a NNLL+NNLO perturbative description and including bottom quark mass effects to NLO, we analyse data in the centre-of-mass energy range $\sqrt{s}=14-206$ GeV in view of a simultaneous determination of the strong coupling constant and the non-perturbative parameter $α_0$. The fits are performed by matching the resummed and fixed-order predictions both in the R and the log-R matching schemes. The final values in the R scheme are $α_s(M_Z) = 0.1131^{+0.0028}_{-0.0022}$, $α_0(2 {\rm GeV}) = 0.538^{+0.102}_{-0.047}$.

13 pages, 3 figures, 1 table. Two references updated and small textual changes in sections 4.1 and 6