Elementary Particles and Fields and String Theory Commons^™

Protophobic Fifth-Force Interpretation Of The Observed Anomaly In 8Be Nuclear Transitions, Jonathan L. Feng, Bartosz Fornal, Iftah Galon, Susan Gardner, Jordan Smolinsky, Tim M. P. Tait, Philip Tanedo

Physics and Astronomy Faculty Publications

Recently a 6.8σ anomaly has been reported in the opening angle and invariant mass distributions of e⁺e⁻ pairs produced in ⁸Be nuclear transitions. The data are explained by a 17 MeV vector gauge boson X that is produced in the decay of an excited state to the ground state, ⁸Be^∗ → ⁸Be X, and then decays through X → e⁺e⁻. The X boson mediates a fifth force with a characteristic range of 12 fm and has millicharged couplings to up and down quarks and electrons, and a …