EERAD3 version 2: QCD corrections in hadronic colour-singlet decays

TL;DR

EERAD3 v2 delivers a unified, fixed-order QCD framework for hadronic colour-singlet decays, enabling NNLO predictions for $\gamma^*/Z \to 3j$ and NLO predictions for $H\to bb$ and $H\to gg$ in Higgs and Z decays. The package integrates a rigorous perturbative structure for event-shape observables with a major software overhaul, including a Python-based user interface and a broad set of observables. It introduces EERAD3hist to merge independent runs, combine perturbative contributions, and generate distributions in modern formats, facilitating reproducible, high-precision phenomenology for current and future lepton colliders. This work advances precision QCD and Higgs factory studies by delivering a flexible, extensible toolset for fixed-order calculations and robust histogram-based analyses.

Abstract

We present a major update of the publicly available EERAD3 package to calculate perturbative corrections in the strong coupling in hadronic Higgs and $Z$-boson decays. We describe the theoretical framework underlying the numerical implementation and provide a guide to the usage of the program.

Figures (1)

• Figure 1: Structure of EERAD3 v2.