Probing New Physics with Underground Accelerators and Radioactive Sources

Understand

New light, weakly coupled particles can be efficiently produced at existing and future high-intensity accelerators and radioactive sources in deep underground laboratories.

• Once produced, these particles can scatter or decay in large neutrino detectors (e.g Super-K and Borexino) housed in the same facilities.
• We discuss the production of weakly coupled scalars $\phi$ via nuclear de-excitation of an excited element into the ground state in two viable concrete reactions: the decay of the $0^+$ excited state of $^{16}$O populated via a $(p,\alpha)$ reaction on fluorine and from radioactive $^{144}$Ce decay where the scalar is produced in the de-excitation of $^{144}$Nd$^*$, which occurs along the decay chain.
• Subsequent scattering on electrons, $e(\phi,\gamma)e$, yields a mono-energetic signal that is observable in neutrino detectors.