Instrumental uncertainties in radiative corrections for the MUSE experiment

TL;DR

This paper assesses instrumental uncertainties in radiative corrections for the MUSE experiment, showing that these uncertainties are minimal for electrons and negligible for muons within the experiment's kinematic range.

Contribution

It provides a detailed estimation of instrumental uncertainties in radiative corrections using the ESEPP generator, specific to the MUSE experiment's conditions.

Findings

Angular-dependent uncertainties for electrons are below 0.4%.

Uncertainties for muons are negligible.

Results inform the precision of cross section measurements.

Abstract

The MUSE experiment at the Paul Scherrer Institute is measuring elastic lepton-proton scattering cross sections in a four-momentum transfer range from $Q^2$ of approximately 0.002 to 0.08 GeV$^2$ using positively and negatively charged electrons and muons. The extraction of the Born cross sections from the experimental data requires radiative corrections. Estimates of the instrumental uncertainties in those corrections have been made using the ESEPP event generator. The results depend in particular on the minimum lepton momentum that contributes to the experimental cross section and the fraction of events with hard initial-state radiation that is detected in the MUSE calorimeter and is excluded from the data. These results show that the angular-dependent instrumental uncertainties in radiative corrections to the electron cross section are better than 0.4 % and are negligible for the muon cross section.