Search for Visible Dark Photon Decays at the Future SHINE Facility with the DarkSHINE Experiment
Abstract
We study the sensitivity of the proposed DarkSHINE experiment to displaced dark photon decays, A'→ e+e-, using an 8~GeV electron beam incident on a tungsten target. We consider 2me<mA'<2mμ and assume a unit branching fraction to electron--positron pairs. Signal events generated at tree level with \textsc{CalcHEP} are propagated through a detailed \textsc{Geant4} detector simulation. A close tracker, graph-neural-network-based track reconstruction, and displaced vertex selections suppress prompt pair-production and photon-conversion backgrounds, while calorimeter and invariant-mass requirements render hadronic backgrounds negligible. Extrapolation of the residual prompt-background distribution yields 0.3 expected events for 9×1014 electrons on target. The median expected 90\% confidence-level exclusion covers masses of approximately 30--70~MeV and kinetic mixing parameters from approximately 5×10−5 to 2×10−4. This visible decay search complements DarkSHINE searches for invisible dark photon decays.
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BibTeX
@misc{lu2026search,
title = {{Search for Visible Dark Photon Decays at the Future SHINE Facility with the DarkSHINE Experiment}},
author = {Zejia Lu and Huayang Wang and Xiang Chen and Jiahui Wu and Yulei Zhang and Liang Li},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.18534},
eprint = {2609.18534},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.18534},
}
RIS
TY - UNPB
TI - Search for Visible Dark Photon Decays at the Future SHINE Facility with the DarkSHINE Experiment
AU - Zejia Lu
AU - Huayang Wang
AU - Xiang Chen
AU - Jiahui Wu
AU - Yulei Zhang
AU - Liang Li
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2609.18534
UR - https://arxiv.org/abs/2609.18534
AB - We study the sensitivity of the proposed DarkSHINE experiment to displaced dark photon decays, A'→ e^+e^-, using an 8~GeV electron beam incident on a tungsten target. We consider 2m_e<m_A'<2m_μ and assume a unit branching fraction to electron--positron pairs. Signal events generated at tree level with \textsc{CalcHEP} are propagated through a detailed \textsc{Geant4} detector simulation. A close tracker, graph-neural-network-based track reconstruction, and displaced vertex selections suppress prompt pair-production and photon-conversion backgrounds, while calorimeter and invariant-mass requirements render hadronic backgrounds negligible. Extrapolation of the residual prompt-background distribution yields 0.3 expected events for 9×10^14 electrons on target. The median expected 90\% confidence-level exclusion covers masses of approximately 30--70~MeV and kinetic mixing parameters from approximately 5×10^−5 to 2×10^−4. This visible decay search complements DarkSHINE searches for invisible dark photon decays.
ER -