There is so much that we do not yet know about neutrinos. Neutrinos are very light, chargeless, and elusive particles that are involved in a process named beta decay and that can help us to understand the origin of matter in the universe. Beta decay is a type of radioactive decay that involves a neutron converting into a proton, emitting an electron and an antineutrino. Beta decay is very common– it occurs about a dozen of times per second in a banana. There might also be an ultra-rare kind of beta decay that emits two electrons but no neutrinos. Nuclear physicists around the world are searching for this neutrinoless-double beta decays (NLDBD) in different nuclei. The interest in these decays arises from their potential to reveal unsolved mysteries related to the Universe’s creation of matter. They can also provide hints towards our understanding of the currently unknown mass of neutrinos.
The Impact
The Cryogenic Underground Observatory for Rare Events (CUORE) can search for these rare NLDBD processes using different nuclei. Scientists rely on complementarity among searches using different nuclei to have a better understanding of the underlying physics in the process. Complementarity in physics involves theories that contrast with each other but that both explain part of the same phenomena. CUORE recently searched for NLDBD using a nucleus that had not previously been studied with CUORE, Tellurim-128. The researchers have so far found no evidence for NLDBD. However, they show that the half-life of Tellurim-128 to decay by NLDBD is longer than 3.6 septillion years (ultra-rare decays have very long half-lives). This lower limit is about 30 times higher than those from prior experiments using the same technique. This new search pushes forward scientists’ knowledge on these rare nuclear decays. This opens another path to our understanding of the origin of matter in our Universe.