Hadronization effects in event shape moments

Abstract

We study the moments of hadronic event shapes in $e^+e^-$ annihilation within the context of next-to-next-to-leading order (NNLO) perturbative QCD predictions combined with non-perturbative power corrections in the dispersive model. This model is extended to match upon the NNLO perturbative prediction. The resulting theoretical expression has been compared to experimental data from JADE and OPAL, and a new value for $α_s(M_Z)$ has been determined, as well as of the average coupling $α_0$ in the non-perturbative region below $μ_I=2$ GeV within the dispersive model: α_s(M_Z)&=0.1153\pm0.0017(\mathrm{exp})\pm0.0023(\mathrm{th}),α_0&=0.5132\pm0.0115(\mathrm{exp})\pm0.0381(\mathrm{th}), The precision of the $α_s(M_Z)$ value has been improved in comparison to the previously available next-to-leading order analysis. We observe that the resulting power corrections are considerably larger than those estimated from hadronization models in multi-purpose event generator programs.

23 pages, 5 figures, 15 tables. Few minor changes. Version accepted for publication in European Physical Journal C.