Matching NLLA plus NNLO for event shape distributions

We study the matching of the next-to-leading logarithmic approximation (NLLA) onto the fixed next-to-next-to-leading order (NNLO) calculation for event shape distributions in electron-positron annihilation. The resulting theoretical predictions combine all precision QCD knowledge on the distributions, and are theoretically reliable over an extended kinematical range. Compared to previously available matched NLLA + NLO and fixed order NNLO results, we observe that the effects of the combined NLLA + NNLO are small in the three-jet region, relevant for precision physics. (c) 2008 Elsevier B.V. All tights reserved.