Soft-drop event shapes in electron-positron annihilation at next-to-next-to-leading order accuracy

TL;DR

This paper provides NNLO predictions for soft-drop event shapes in electron-positron annihilation, demonstrating improved perturbative convergence and reduced non-perturbative sensitivity, making them promising for precise strong coupling measurements.

Contribution

It offers the first NNLO calculations of soft-drop event shapes in electron-positron annihilation, showing enhanced perturbative stability due to grooming effects.

Findings

Grooming improves perturbative convergence of event shape distributions.

Soft-drop event shapes exhibit reduced sensitivity to non-perturbative effects.

Enhanced stability makes these observables suitable for precise strong coupling extraction.

Abstract

We present predictions for soft-drop event shapes of hadronic final states in electron-positron annihilation at next-to-next-to-leading order accuracy in perturbation theory obtained using the CoLoRFulNNLO subtraction method. We study the impact of the soft drop on the convergence of the perturbative expansion for the distributions of three event shape variables, the soft-drop thrust, the hemisphere jet and narrow jet invariant masses. We find that grooming generally improves perturbative convergence for these event shapes. This better perturbative stability, in conjunction with a reduced sensitivity to non-perturbative hadronization corrections makes soft-drop event shapes promising observables for the precise determination of the strong coupling at lepton colliders.