Non-perturbative contribution to the thrust distribution in e(+)e(-) annihilation

作者：Davison R A^*; Webber B R

来源：European Physical Journal C, 2009, 59(1): 13-25.

DOI：10.1140/epjc/s10052-008-0836-7

We re-evaluate the non-perturbative contribution to the thrust distribution in e(+) e(-) -> hadrons, in the light of the latest experimental data and the recent NNLO perturbative calculation of this quantity. By extending the calculation to NNLO+NLL accuracy, we perform the most detailed study to date of the effects of non-perturbative physics on this observable. In particular, we investigate how well a model based on a low-scale QCD effective coupling can account for such effects. We find that the difference between the improved perturbative distribution and the experimental data is consistent with a 1/Q-dependent nonperturbative shift in the distribution, as predicted by the effective coupling model. Best fit values of alpha(s) (91.2 GeV) = 0.1164(-0.0026)(+0.0028) and alpha(0)(2 GeV) = 0.59 +/- 0.03 are obtained with chi(2)/d.o.f. = 1.09. This is consistent with NLO+NLL results but the quality of fit is improved. The agreement in alpha(0) is non-trivial because a part of the 1/Q-dependent contribution (the infrared renormalon) is included in the NNLO perturbative correction.

• 出版日期2009-1