Physicists compete to verify rare radioactive event

Nature : The race is on to verify a controversial 2001 report of neutrino-less double-β decay. The extremely rare phenomenon has important implications for physics because a definitive sighting would allow physicists to determine the neutrino’s mass and perhaps even help them understand why matter exists, writes Edwin Cartlidge for Nature. A decade ago, Hans Klapdor-Kleingrothaus and colleagues at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, claimed to have seen the phenomenon in a detector at Italy’s Gran Sasso National Laboratory. The experiment was closed down in 2003, and no other detector has had the sensitivity to test the team’s conclusions until now. A new generation of facilitiesâmdash;including the Enriched Xenon Observatory in New Mexico, KamLAND-Zen in Japan, and the Cryogenic Underground Observatory for Rare Events in Gran Sassoâmdash;has joined the search, and researchers hope to settle the issue possibly later this year.