Abstract

The detection of neutrinoless double beta decay is the only practical way to establish if neutrinos are their own antiparticle, which implies that lepton number is not conserved. Violation of lepton number would have profound implications in physics and comsology, among which being the origin of the matter-antimatter asymmetry observed in the Universe. The NEXT experiment aims to observe the neutrinoless double beta decay of Xe-136 in a high-pressure gas xenon Time Projection Chamber using electroluminescence to amplify the signal from ionization. The two main advantages of this technology are a high energy resolution and the possibility of reconstructing the electron tracks in events with energies close to the Q-value of the decay to use it to distinguish signal (two electrons) from background (single electron). After a period of protoypes (2009-2014) NEXT has completed the construction of its first phase (NEW) in the Canfranc Underground Laboratory, in the Spanish Pyrenees and the first calibration run started in October 2016.