Nemo3, désintégration double beta

par Zavier Sarazin (LAL)

lundi 24 oct. 2005, 14:00 → 15:00 Europe/Paris

Amphithéâtre

The neutrinoless double beta decay (bb0nu) is the most sensitive process for the search of leptonic number violation and its discovery would prove that the neutrino is a Majorana particle. This process may occur through several mechanisms. In particular the existence of the decay by light neutrino exchange would allow to determine the mass scale of the neutrinos. The NEMO 3 detector, searching for decay with 7 kg of 100Mo and 1 kg of 82Se, has been running reliably since February 2003. The first results after 1 year of data collection are presented: they have demonstrated that all the sources of backgrounds are well identified and understood and that the background reductions are at the expected levels for both internal and external backgrounds. The expected sensitivity of the NEMO 3 detector with 7 kg of 100Mo is T1/2(bb0nu) > 2 1024 years corresponding to a limit on the effective Majorana neutrino mass of m < 0.3 - 1.3 eV. Since the NEMO technique can be extrapolated for a larger mass detector, the NEMO collaboration proposes a R&D program in order to design a detector (SuperNEMO) with 100 kg of 82Se, coupling track reconstruction and calorimeter and sensitive to a period of few 1026 years.