Search for dark sector by repurposing the UVX Brazilian synchrotron

Abstract

Abstract We propose the first Search for Dark Sector at the Brazilian Synchrotron Light Laboratory, site of Sirius, a fourth-generation storage ring. We show that UVX, Sirius predecessor, can be a promising dark sector detector, SeDS, with unprecedented sensitivity. The search is based on a $$1-3$$ 1 - 3 GeV positron beam impinging on a thick target leading the $$e^+ e^- \rightarrow \gamma A'$$ e + e - → γ A ′ reaction, followed by a missing mass spectrum event reconstruction. We show that SeDS has the potential to probe dark photons with masses up to 55 MeV and kinetic coupling down to $$\epsilon ^2 \sim 10^{-12}$$ ϵ 2 ∼ 10 - 12 . Therefore, such experiment would constitute the best dark photon probe worldwide in the $$10{-}55$$ 10 - 55 MeV mass range, being able to probe an unexplored region of parameter space.