Simplified Template Cross Sections -- Stage 1.1 and 1.2

TL;DR

This paper revises and details the definitions of the Simplified Template Cross Sections (STXS) stages 1.1 and 1.2, providing a standardized framework for Higgs measurements at the LHC to reduce uncertainties and enable data combination.

Contribution

It presents the complete, updated definitions of STXS kinematic bins for key Higgs production processes used in LHC Run 2 analyses, facilitating consistent measurements across experiments.

Findings

Revised STXS bin definitions for Higgs production modes.

Application of STXS in ATLAS and CMS Run 2 analyses.

Enhanced framework for combining Higgs measurements.

Abstract

Simplified Template Cross Sections (STXS) have been adopted by the LHC experiments as a common framework for Higgs measurements. Their purpose is to reduce the theoretical uncertainties that are directly folded into the measurements as much as possible, while at the same time allowing for the combination of the measurements between different decay channels as well as between experiments. We report the complete, revised definition of the STXS kinematic bins (stage 1.1 and stage 1.2), which have been used for the measurements by the ATLAS and CMS experiments using the full LHC Run 2 datasets. The main focus is on the four dominant Higgs production processes, namely gluon-fusion, vector-boson fusion, production in association with a vector boson and in association with a $t\bar t$ pair. We also comment briefly on the treatment of other production modes.