Old and new observables for $α_S$ from $e^+e^-$ to hadrons

Abstract

We present a computation of energy-energy correlation in $e+e−$ annihilation at next-to-next-to-leading order accuracy in perturbative QCD matched with the next-to-next-to-leading logarithmic resummed calculation for the back-to-back limit. Using these predictions and state-of-the-art Monte Carlo tools to model hadronization corrections, we perform an extraction of the strong coupling from available data sets. We also show next-to-next-to-leading order results for soft-drop thrust, an observable specifically constructed to have reduced hadronization corrections. We study the impact of the soft drop on the convergence of the perturbative prediction and find that generally grooming improves perturbative stability. This improved stability, together with the reduced sensitivity to non-perturbative corrections makes soft-drop thrust a promising observable for precision measurements of the strong coupling at lepton colliders.