Backgrounds and sensitivity of the NEXT double beta decay experiment

Abstract

NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta (ββ0ν) decay experiment that will operate at the Canfranc Underground Laboratory (LSC). It is an electroluminescent high-pressure gaseous xenon Time Projection Chamber (TPC) with separate read-out planes for calorimetry and tracking. Energy resolution and background suppression are the two key features of any neutrinoless double beta decay experiment. NEXT has both good energy resolution (<1% FWHM) at the Q value of ${}^{136}$Xe and an extra handle for background identification provided by track reconstruction. With the background model of NEXT, based on the detector simulation and the evaluation of the detector radiopurity, we can determine the sensitivity to a measurement of the ββ2ν mode in NEW and to a ββ0ν search in NEXT100. In this way we can predict the background rate of $5\times 10^{-4}$counts/(keV kg yr), and a sensitivity to the Majorana neutrino mass down to 100 meV after a 5-years run of NEXT100.

3 pages, 3 figures, 2 tables. Proceedings from the poster session at the 37th International Conference on High Energy Physics (ICHEP, Valencia, Jul 2014)