Probing the dark axion portal via J/ψ decays at BESIII and STCF
Abstract
Large numbers of J/ψ mesons can be resonantly produced at BESIII and STCF at the center-of-mass energy √s=3.097~GeV. Such J/ψ mesons may undergo rare decays into an axionlike particle (ALP) a and a dark photon γ' through the dark axion portal. We investigate the exclusion reach of the existing BESIII dataset and the projected sensitivity of STCF, focusing on the mono-photon signature. We perform Monte Carlo simulations of the signal and estimate both the irreducible J/ψ→γνν̅ background and the continuum and resonant three-photon reducible backgrounds. Detector-induced migration of three-photon events into the mono-photon signal region is parameterized by the event-level leakage probability ε3γleak=0,10−6,10−4,10−3. In the zero- and sufficiently small-leakage benchmarks, the existing BESIII dataset could probe previously unexplored parameter space, while STCF can further improve the coupling reach. Increasing leakage probabilities progressively weaken these projections, highlighting the importance of detector-level three-photon rejection in realizing the projected reach.
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BibTeX
@misc{wang2026probing,
title = {{Probing the dark axion portal via $J/ψ$ decays at BESIII and STCF}},
author = {Zeren Simon Wang and Dazhuang He and Yu Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.01791},
eprint = {2606.01791},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.01791},
}
RIS
TY - UNPB
TI - Probing the dark axion portal via J/ψ decays at BESIII and STCF
AU - Zeren Simon Wang
AU - Dazhuang He
AU - Yu Zhang
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2606.01791
UR - https://arxiv.org/abs/2606.01791
AB - Large numbers of J/ψ mesons can be resonantly produced at BESIII and STCF at the center-of-mass energy √s=3.097~GeV. Such J/ψ mesons may undergo rare decays into an axionlike particle (ALP) a and a dark photon γ' through the dark axion portal. We investigate the exclusion reach of the existing BESIII dataset and the projected sensitivity of STCF, focusing on the mono-photon signature. We perform Monte Carlo simulations of the signal and estimate both the irreducible J/ψ→γνν̅ background and the continuum and resonant three-photon reducible backgrounds. Detector-induced migration of three-photon events into the mono-photon signal region is parameterized by the event-level leakage probability ε_3γ^leak=0,10^−6,10^−4,10^−3. In the zero- and sufficiently small-leakage benchmarks, the existing BESIII dataset could probe previously unexplored parameter space, while STCF can further improve the coupling reach. Increasing leakage probabilities progressively weaken these projections, highlighting the importance of detector-level three-photon rejection in realizing the projected reach.
ER -