Revealing new processes with superfluid liquid helium detectors: the coherent elastic neutrino atom scattering

The particle physics community is studying and building new technologies to detect processes never detected before. Among these, strong efforts are put into studying innovative He detectors based on the quantum evaporation process. The main outcome of such a detector is the possibility to detect light dark matter particles. However, they have enormous potentialities also for exploring neutrino properties. Indeed, we propose an experimental setup to observe coherent elastic neutrino-atom scattering (CEnAS) using electron antineutrinos from tritium decay and a liquid helium target. In this scattering process with the whole atom, that has not been observed so far, the electrons tend to screen the weak charge of the nucleus as seen by the electron antineutrino probe. In addition to this discovery, it may be possible to measure fundamental weak interaction parameters at very low energy scale, never reached before, and set very strong limits for the presence of electromagnetic properties of neutrinos.