Speaker
Description
The search for sub-MeV neutrinos via precision nuclear decay measurements is among the most powerful methods for BSM neutrino mass searches since it relies only on the existence of a heavy neutrino admixture to the active neutrinos, and not on the model-dependent details of their interactions. Within this context, the BeEST (Beryllium Electron-capture with Superconducting Tunnel junctions) experiment uses the decay-momentum reconstruction technique to precisely measure the low-energy $^7$Be$\rightarrow^7$Li recoil spectrum via $^7$Be ions implanted into high-rate superconducting quantum sensors. Here we outline the experimental concept of the currently running experiment, sensitivity to additional BSM physics scenarios, and future plans for scaling to 10,000 STJ pixels using new materials for ultra-high energy resolution detectors to probe keV-masses with neutrino couplings of $|U_{ei}|^2\leq10^{-9}$.
