Status of the NEMO (Neutrino Ettore Majorana Observatory) experiments: NEMO3 and beyond “Is the neutrino its own antimatter?”

Status of the NEMO (Neutrino Ettore Majorana Observatory) Experiments: NEMO3 and Beyond “Is the Neutrino its Own Antimatter?”

Dr. Corinne Augier
Laboratoire de l'Accélérateur Linéaire (LAL), Orsay
University of Paris

In the Standard Model, which describes elementary particles and fundamental interactions, neutrinos are exactly massless. The observation of neutrino oscillations has demonstrated that neutrinos have mass, and so this proves that there exists physics beyond the “Standard Model.”

A direct consequence of this new physics is the renewed interest in double beta decay (bb) experiments, which provide the only way to determine the fundamental nature of the neutrino: are neutrinos Dirac or Majorana particles? All the fermions in the Standard Model, with the exception of neutrinos, are charged particles with their antiparticles being their charge conjugates, with equal but opposite quantum numbers. Neutrinos, however, have an extra possibility due to their neutral charge. Neutrinos may have a Majorana mass, which would imply that the neutrino and antineutrino are effectively the same particle and cannot be distinguished.

The purpose of the NEMO experiments is to study bb processes. The neutrinoless double beta decay (bb0n) is the most sensitive process for the search of leptonic number violation, which is forbidden by the Standard Model, and its discovery would also prove that the neutrino is a Majorana particle.

After an introduction to neutrino physics and double beta processes, this seminar will present the status of the NEMO3 experiment, which is taking data in the Fréjus Underground Laboratory (LSM, Modane, France) since 2003, as well as the R&D program proposed by the collaboration in order to design SuperNEMO, a detector of future generation.