The search of neutrinoless double beta decay with the NEXT experiment

The NEXT experiment is trying to find the extremely rare neutrinoless double beta decay of ¹³⁶Xe using the technology of high pressure xenon gas time projection chambers with electroluminescent amplification. The detection of this process would imply that the neutrino is a Majorana particle and the total lepton number would not be conserved, which could be related to the cosmological asymmetry between matter and antimatter through leptogenesis. After the successful operation of the NEXT-White detector, which demonstrated the excellent energy resolution of 1% at Q_ββ, validated the reconstruction algorithms and the background model, made a measurement of the two-neutrino double beta decay of ¹³⁶Xe and performed a demonstration of the 0νββ search capabilities of the NEXT technology, the current phase holding around 100 kg of Xe is being constructed at the Laboratorio Subterráneo de Canfranc (Spain). NEXT-100 is expected to enhance the NEXT energy resolution and run with lower background and better event containment to reach a sensitivity of about 6 × 10²⁵ yr after a run of 3 effective years. It will also assess the background model and will serve as a preparation for the tonne-scale. In this talk, the results obtained with the NEXT-White detector, the NEXT-100 construction status and the prospects of future NEXT detectors will be reported.