Physical Review Letters
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Search for Sub-GeV Dark Particles in $η→{π}^{0}+\text{Invisible}$ Decay
Author(s): M. Ablikim et al. (BESIII Collaboration)
BESIII collaboration performs the first search for a sub-GeV dark scalar in η→π0S decays using over 10 billion J/ψ events, observing no signal. [Phys. Rev. Lett. 137, 031804] Published Thu Jul 16, 2026
