Muon Tridents at FASER and NA64μ: Motivation, Predictions, and Prospects for Precision Measurements
Abstract
The intense flux of high-energy muons produced in the far-forward region of pp collisions at the LHC provides a unique opportunity to study rare electromagnetic interactions at TeV energies. In this work, we investigate the muon trident scattering in muon-nucleus interactions at the FASER experiment, which is expected to have recorded more than 105 such events. The theoretical description of the process is reviewed and improved. Predictions for the total event rates and differential distributions expected during Run~3 of the LHC are presented, taking into account realistic detector acceptance and the main background contributions. The dependence of the predictions on the treatment of the nuclear form factors and the impact of higher-order QED effects such as Coulomb corrections are investigated. Our results indicate that the muon trident process can be measured for the first time at TeV energies using FASER's spectrometer, with a projected precision on the cross-section at the percent level. We also extended our analysis to the NA64μ experiment and showed that, together with FASER, these experiments can probe the energy dependence of the muon trident cross-section over a broad unexplored energy range.
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BibTeX
@misc{francener2026muon,
title = {{Muon Tridents at FASER and NA64$μ$: Motivation, Predictions, and Prospects for Precision Measurements}},
author = {Reinaldo Francener and Victor P. Goncalves and Felix Kling and Gabriel Rabelo-Soares},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.33153},
eprint = {2610.33153},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.33153},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Muon Tridents at FASER and NA64μ: Motivation, Predictions, and Prospects for Precision Measurements
AU - Reinaldo Francener
AU - Victor P. Goncalves
AU - Felix Kling
AU - Gabriel Rabelo-Soares
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.33153
UR - https://arxiv.org/abs/2610.33153
AB - The intense flux of high-energy muons produced in the far-forward region of pp collisions at the LHC provides a unique opportunity to study rare electromagnetic interactions at TeV energies. In this work, we investigate the muon trident scattering in muon-nucleus interactions at the FASER experiment, which is expected to have recorded more than 10^5 such events. The theoretical description of the process is reviewed and improved. Predictions for the total event rates and differential distributions expected during Run~3 of the LHC are presented, taking into account realistic detector acceptance and the main background contributions. The dependence of the predictions on the treatment of the nuclear form factors and the impact of higher-order QED effects such as Coulomb corrections are investigated. Our results indicate that the muon trident process can be measured for the first time at TeV energies using FASER's spectrometer, with a projected precision on the cross-section at the percent level. We also extended our analysis to the NA64μ experiment and showed that, together with FASER, these experiments can probe the energy dependence of the muon trident cross-section over a broad unexplored energy range.
ER -