LABORATORI NAZIONALI DEL GRAN SASSO
To search for ??0?? decay with unprecedented sensitivity, the R2D2 collaboration is developing a radial time projection chamber with a fiducial mass of half a tonne of 136Xe at high pressure. The various approaches implemented to eliminate the radioactive background are presented in terms of detector design, topological recognition of interactions, and event energy reconstruction. The developed tools allow for the disentangling of the sought-after signal from the background, and the projected sensitivity after ten years of data taking yields a half-life limit exceeding 1027 years, along with a constraint on the effective neutrino mass m??, that could potentially exclude the inverted mass hierarchy region, depending on the final experimental background. ------ Anselmo Meregaglia French National Centre For Scientific Research (CNRS)

DATA: 03-03-2025