Breakthrough improvement in track reconstruction in the NEXT experiment searching for neutrinoless double beta decay in xenon-136


  Lior Arazi  ,  Ander Simón Estévez  ,  Yair Ifergan  ,  Adam Redwine  
Ben-Gurion University of the Negev

The search for neutrinoless double beta decay is the most promising approach to determine whether the neutrino is its own antiparticle. If detected, it will be a first demonstration of lepton number violation, with far-reaching implications in particle physics and cosmology. Because of the extremely long half-lives of the decay (>10^26 years), a successful detection requires outstanding background suppression capability. The NEXT experiment searches for neutrinoless double beta decay in xenon-136, using a high-pressure gaseous xenon time projection chamber. While other experiments in the field rely predominantly on a high energy resolution for discriminating between candidate signal and background events, NEXT has in addition a unique capability to reconstruct the full topology of events in 3D and thus provide an extra handle for signal-background discrimination. In this talk we will present a new image reconstruction method recently developed at Ben-Gurion University, which allows for unprecedented accuracy in track reconstruction, resulting in a 4-5 fold improvement in background suppression. We will demonstrate the use of this method on real data from the experiment, showing – for the first time – sharp images of two-neutrino double beta decay candidate tracks.