Probing Dark force at BES-III/BEPCII

Understand

We study an experimental search of a GeV scale vector boson at BES-III/BEPCII.

• It is responsible for mediating a new U(1)$_d$ interaction, as recently exploited in the context of weakly interacting massive particle dark matter.
• At low energy $e^+ e^-$ colliders this dark state can be efficiently probed.
• We discuss the direct productions of this light vector $U$ boson and the decay of this state with BES-III data and its foreseen larger data.