Electroweak corrections to hadronic event shapes and jet production in e+e- annihilation

TL;DR

This work provides the complete electroweak $O(\alpha^3 \alpha_s)$ corrections to three-jet production and related event-shape observables in $e^+e^-$ annihilation. The authors employ the complex-mass scheme to describe the $Z$-boson resonance, include higher-order initial-state radiation in the leading-logarithmic approximation, and account for photon isolation and hadronic fragmentation by implementing the quark-to-photon fragmentation function within both slicing and subtraction frameworks. They quantify EW effects on event-shape distributions and the three-jet rate, finding corrections at the few-percent level with remnants of radiative return persisting even after cuts. The results are implemented in a parton-level event generator and illustrated for LEP1, LEP2, and a future linear collider, highlighting the relevance of EW corrections for precision QCD studies and for accurate determinations of the strong coupling constant $\alpha_s$.

Abstract

We present a complete calculation of the electroweak O(alpha^3 alpha_s) corrections to three-jet production and related event-shape observables at electron--positron colliders. The Z-boson resonance is described within the complex-mass scheme, rendering the calculation valid both in the resonance and off-shell regions. Higher-order initial-state radiation is included in the leading-logarithmic approximation. We properly account for the corrections to the total hadronic cross section and for the experimental photon isolation criteria. To this end we implement contributions of the quark-to-photon fragmentation function both in the slicing and subtraction formalism. The effects of the electroweak corrections on various event-shape distributions and on the three-jet rate are studied. They are typically at the few-per-cent level, and remnants of the radiative return are found even after inclusion of appropriate cuts.