Ponente
Descripción
Neutrinoless double-beta decay is a hypothetical nuclear process, (A,Z) → (A,Z+2) + 2e⁻, that is not allowed by the Standard Model since it violates the total lepton number conservation by two units.
The discovery of 0νββ would have profound theoretical implications: it could help explain the matter-antimatter asymmetry in the universe and it is the only practical way to determine if the neutrino is its own antiparticle (a Majorana neutrino), providing important insight into the origin of neutrino mass and access to the absolute neutrino mass scale through the measurement of the effective Majorana mass.
An extensive experimental effort is underway worldwide, with numerous projects employing a variety of detection technologies to search for this rare transition.
One of the most promising international experimental projects dedicated to the search for neutrinoless double beta decay is the LEGEND (Large Enriched Germanium Experiment for Neutrinoless ββ Decay) experiment aiming to detect the 0νββ decay Germanium-76 (⁷⁶Ge).
Two phases are foreseen for this experimental project.
LEGEND-200, the initial phase, currently collecting data at the INFN Gran Sasso National Laboratory in Italy, has 142 kg of enriched germanium detectors installed and aims to achieve a half-life sensitivity for neutrinoless double-beta decay in 76Ge of approximately 10²⁷ years. This may be possible by a projected background index of 0.6 counts/(FWHM·t·yr) and a total exposure of 1 tonne·year.
The subsequent phase, LEGEND-1000, is designed to surpass a sensitivity of 10²⁸ years by operating 1 tonne of enriched germanium detectors, accumulating more than 10 tonne·years of exposure at a background index of about 0.025 counts/(FWHM·t·yr). With this level of sensitivity, LEGEND-1000 will be capable of probing the entire inverted neutrino mass ordering region.
