The Atomki anomaly puts forward the hypothesis of an X(17) particle to explain the observation. Utilizing experimental data 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 couplings of the X(17) boson to electrons. Our findings indicate that no viable parameter spaces exist for the pseudoscalar, scalar, vector, axial-vector, and vector±axial-vector models describing the couplings of X(17) to electrons. The Atomki anomaly may not correspond to signals of New Physics, but rather to some nuclear effect that remains poorly understood.
Cite
@article{arxiv.2601.08567,
title = {Where to find $X(17)$?},
author = {Jun Jiang and Cong-Feng Qiao and Yu-Han Zhao},
journal= {arXiv preprint arXiv:2601.08567},
year = {2026}
}
Comments
21 pages, 5 figures, 1 table; major changes applied in this update