A study to suppress a sneaking cosmic muon background in the COMET experiment
Abstract
The COMET experiment, conducted at J-PARC, aims to search for muon-to-electron conversion with an unprecedentedly high sensitivity. One of the severest backgrounds in the Phase-I experiment originates from cosmic-ray muons. A cosmic muon sneaks into a detector solenoid magnet from a loophole, scattered and leaving a track in a cylindrical drift chamber. Among them, a positive muon track with reverse direction may mimic a signal electron of 105 MeV/. In order to suppress the sneaking cosmic positive muon background, we developed a method to discriminate the track direction by using track-fitting quality. We demonstrated that the positive muon background can be reduced by an order of magnitude. In this paper, we will report the methodology, a Monte Carlo simulation and results with prospects.
Cite
@article{arxiv.2508.15344,
title = {A study to suppress a sneaking cosmic muon background in the COMET experiment},
author = {Manabu Moritsu and Hai-Bo Li and Tianyu Xing and Ye Yuan and Yao Zhang},
journal= {arXiv preprint arXiv:2508.15344},
year = {2025}
}
Comments
8 pages, 5 figures, Proceedings of the 4th J-PARC Symposium 2024