# Theoretical uncertainties for electroweak and Higgs-boson precision measurements at FCC-ee

## TL;DR

This paper assesses the necessary reduction in theoretical uncertainties for electroweak and Higgs measurements at FCC-ee to match future experimental precision, emphasizing multi-loop corrections and input parameter control.

## Contribution

It provides an estimate of the required improvements in theoretical calculations to support high-precision measurements at FCC-ee.

## Key findings

- Quantifies the impact of current theoretical uncertainties on FCC-ee measurements.
- Identifies the key areas where improved calculations are needed.
- Highlights the importance of multi-loop radiative corrections.

## Abstract

Due to the high anticipated experimental precision at the Future Circular Collider FCC-ee (or other proposed $e^+e^-$ colliders, such as ILC, CLIC, or CEPC) for electroweak and Higgs-boson precision measurements, theoretical uncertainties may have, if unattended, an important impact on the interpretation of these measurements within the Standard Model (SM), and thus on constraints on new physics. Current theory uncertainties, which would dominate the total uncertainty, need to be strongly reduced through future advances in the calculation of multi-loop radiative corrections together with improved experimental and theoretical control of the precision of SM input parameters. This document aims to provide an estimate of the required improvement in calculational accuracy in view of the anticipated high precision at the FCC-ee. For the most relevant electroweak and Higgs-boson precision observables we evaluate the corresponding quantitative impact.