Speaker
Description
We present a global analysis of the thrust distribution in $e^+e^-$ annihilation aimed at determining the strong coupling constant $\alpha_S$ together with the parameters describing non-perturbative QCD effects. The theoretical prediction is based on Sudakov resummation in the Laplace moment space at $N^3LL$ accuracy, matched to fixed-order $NNLO$ calculations. Non-perturbative effects are included through the Dokshitzer–Marchesini–Webber (DMW) model extended to incorporate power corrections up to second order.
The theoretical predictions are compared with experimental measurements over a wide range of center-of-mass energies. A simultaneous fit of $\alpha_S(m_Z)$ and the non-perturbative parameters is performed, allowing for a consistent description of the thrust distribution from low to high energies. The impact of higher-order non-perturbative corrections on the extraction of $\alpha_S$ and on the quality of the global fit is discussed.