Search for Neutrinoless Double Beta Decay with NEMO-3 and SuperNEMO Experiments

点击翻译按钮获取中文摘要

Neutrino oscillations not only demonstrate that neutrinos have mass but also imply the existence of new symmetries beyond the Standard Model. Natural conjectures suggest that deeper understanding of neutrinos may provide a glimpse onto phenomena at a Planck-scale energy level, could broaden our knowledge of the fundamental forces, could shed light onto the initial creation of leptons and baryons, and can help to improve our understanding of the early evolution of the Universe. These observations motivate further studies of the properties of neutrinos including investigating if they are Majorana- or Dirac-type. Majorana-type neutrinos lead to a neutrinoless double beta decay -- the second-order weak nuclear process for which an initial state nucleus with atomic weight and number (A, Z) is transformed into a nucleus with (A, Z + 2) with the emission of only two electrons. The two electrons in the final state carry a total energy equal to the energy of the nuclear transition. This seemingly simple principle provides the main observable for detecting neutrinoless double beta decay and poses an experimental challenge in searches for such transitions.This award will provide funding to continue this group's participation in the NEMO-3 data analysis and in the construction of the first SuperNEMO module (the 'Demonstrator'). The NEMO-3 data, collected at the Modane Underground Laboratory under the French-Italian Alps between 2003 and 2011, will be fully analyzed over the next couple of years. For SuperNEMO, the next three years will be a critical period for completing and commissioning the Demonstrator. This group has two new important commitments: to provide the high voltage system for all Demonstrator photomultipliers, and to coordinate the radio-purification of 82-Selenium and production of isotopic foils.Broader Impact: Proving or disproving that neutrinos are Majorana-type may shed light onto the early stages of the evolution of the Universe. This experiment will advance knowledge about some of the rarest phenomena in Nature. On the technical side, the group is developing a unique low background counting technique which may be applied outside of physics and be of general benefit to society. They plan to build on the UT campus an exhibit gallery illustrating the discovery, the underlying physics, and applications of natural radioactivity, cosmic rays, and related subatomic phenomena. It would 'tell a story' that would educate, entertain, fascinate to seek further information, and perhaps steer students or general audience towards the sciences.