Speaker
Description
The goal of the NEXT (Neutrino Experiment with a Xenon TPC) collaboration is the sensitive search of the neutrino-less double beta decay ($\beta\beta0\nu$) of $^{136}$Xe at the Laboratorio Subterraneo de Canfranc (LSC). The observation of such a lepton-number-violation process would prove the Majorana nature of neutrinos, providing also handles for an eventual measurement of the neutrino absolute mass. After a successful R\&D phase, a first large-scale prototype of a high-pressure gas-Xenon electroluminescent TPC is being operated at the LSC since 2016. NEXT-White is a 5-kg radiopure detector meant to understand the relevant backgrounds for the $\beta\beta0\nu$ search and to perform a measurement of the two neutrino mode of the double beta decay ($\beta\beta2\nu$). The operation of NEXT-White is setting the grounds for the construction of the NEXT-100 detector: a TPC holding 100 kg of $^{136}$Xe and reaching a sensitivity to the $\beta\beta0\nu$ half-life of 6$\times$10$^{25}$ y after 3 years of data taking. In this talk, the latest results from the NEXT-White detector will be presented. The calibration data have allowed to evaluate the performance of the NEXT technology in terms of the topology-based background rejection capabilities and the energy resolution. In particular, a world-leading resolution for a Xe TPC has been achieved ($<$1\% FWHM at 2.6 MeV). The radioactivity-induced backgrounds have also been measured using the data collected operating the detector with depleted xenon. These results validate the background model of the NEXT experiment, estimating less than 5$\times$10$^{-4}$ counts/keV/kg/year in the NEXT-100 detector. As NEXT-White is currently taking data with $^{136}$Xe, preliminary results on the measurement of the $\beta\beta2\nu$ half-life will be released in this talk. Finally, the status of NEXT-100 and future upgrades, like the Ba$^{++}$ tagging R\&D, will also be addressed.
