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arXiv · 2601.08567

Where to find $X(17)$?

Jun Jiang·Cong-Feng Qiao·Yu-Han Zhao
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Abstract

The Atomki anomaly puts forward the hypothesis of an $X(17)$ particle to explain its observation. Utilizing experimental results from the Atomki experiments, measurements of the electron's anomalous magnetic moment, beam dump experiments, the KLOE-2 experiment, the PADME experiment, and the parity-violating M{\o}ller scattering experiment, we derive constraints on the $Xee$ coupling of the $X(17)$ boson to electrons. It is found that the scalar and pseudoscalar models can be excluded by Atomki experiments due to the parity conservation, and the pure axial-vector model is excluded at 98\% C.L. Meanwhile, the analyses in both pure vector and the vector $\pm$ axial-vector models consistently show that the $Xee$ coupling is of the vector type and has an almost fixed value, $\left(6.78 \pm 0.042\right) \times 10^{-4} \lesssim |\varepsilon_e^v| \lesssim \left(6.93 \pm 1.66\right) \times 10^{-4}$ in unit of electric charge $e$.

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Jun Jiang, Cong-Feng Qiao, Yu-Han Zhao. 2026-01-13. Where to find $X(17)$?. https://arxiv.org/abs/2601.08567

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