Neutrinos in the Lab

Evidence of physics beyond the standard model

Neutrino oscillations have established without a doubt that they have mass, and how they come about it is an open question. New physics are at work, but we don't yet know enough to discriminate between competing theories. The same right-handed sterile neutrino theories that could give neutrinos mass, and potentially produce keV-scale dark matter candidates, could produce lighter, eV-scale neutrinos. Such neutrinos have been hinted at by several anomalies in measured reactor antineutrino rates, and in the results of the LSND, MiniBooNE, GALLEX and SAGE experiments, although there are several null experiments and the overall picture remains confusing. Whether these are due to new physics or to the complexities of neutrino measurements remains to be seen.

A new measurement channel

We are applying our detector technology to neutrino physics, specifically to measure coherent elastic neutrino-nucleus scattering (CEνNS), which is the same type of coherent recoil between the particle and the nucleus we seek in our WIMP searches. This is a neutral current channel, and is thus flavor blind. An oscillation disappearance measured through the CEνNS channel cannot be due to neutrinos oscillating into another known neutrino species, but would be a smoking-gun measurement of oscillation into a sterile state. That being said, measuring CEνNS is very challenging, and we are developing sensitive detectors to study this signal at a nuclear reactor as part of the Riocochet experiment.

Are neutrinos Majorana particles?

Part of the puzzle of what lies beyond the standard model is inextricably tied to the source of neutrino masses. It might also hold the key to why there is more matter than anti-matter in the Universe. We could begin to find answers to these questions if we could establish that neutrinos are Majorana particles; that is that they are their own anti-particle, and two neutrinos of the same type could annihilate each other. The CUPID experiment seeks to answer this question by looking for a very rare event called a neutrinoless double beta decay.

Next: Detector Technology