R2D2: a high pressure xenon TPC for neutrinoless double beta decay search, F. PICQUEMAL (LP2I – Bordeaux) – July 11th 2025 @2pm

The knowledge of the nature of the neutrino – is the neutrino its own anti-particle ? – is crucial for particle physics and cosmology. The most sensitive process to adress this question is the neutrinoless double beta decay decay. It exitence would prove unambugouisly that the neutrino is a Majorana particle. The R2D2 collaboration is developing a radial time projection chamber with a fiducial mass of half a tonne of 136Xe at high pressure able to identify the two emitted electrons to reach an unprecedented sensitivity. The final objective is to built a ton-scale experiment with zero background. The various developements like detector design, topological recognition of interactions, event energy reconstruction and radioactive background mitigation will be presented as well as the results obtained with the prototypes. The simulations for the full scale experiment show that he projected sensitivity after ten years of data taking yields a half-life limit exceeding 10^27 years, along with a constraint on the effective neutrino mass. With larger mass of Xe, The detector could exclude the inverted neutrino mass hierarchy region, depending on the final experimental background.

The seminar will be in English.