They were recently used in an article in Nature to investigate the uranium and thorium content of the inner Earth.
It is unknown whether they are Majorana particles, and therefore it is unclear if they are released in double beta decays. They were recently used in an article in Nature to investigate the uranium and thorium content of the inner Earth. Found to oscillate between their different varieties by experiments conducted in Japanese mines, they were shown to not be massive enough to account for dark matter. However, the KamLAND and Super-Kamiokande experiments did show that, contrary to long-held suspicions, they do have mass.  FTP, name these uncharged leptons that come in electron, muon, and tau varieties.
It is unknown whether they are Majorana particles, and therefore it is unclear if they are released in double beta decays.
Neutrinos