Benjamin Jones

High Pressure Xenon Gas TPCs with Single Barium Ion 
Identification:  Progress Toward the first Ton-Scale, Background Free Neutrinoless Double Beta Decay Experiment


The goal of future neutrinoless double beta decay experiments is to achieve sufficient sensitivity to establish 
the Majorana nature of the neutrino, probing decay rates substantially smaller than 10-27 per year. Such a discovery 
would have major implications for cosmology and particle physics, but requires ton-scale detectors with backgrounds below 
1 count per ton per year in the signal ROI. This is a formidable technological challenge without a known solution. This 
talk will focus on a technology that shows particular promise: the High Pressure Xenon Gas TPC (HPGXe-TPC). In HPGXe-TPCs 
such as the US/Spanish led NEXT experiment, event topology and precise energy resolution provide particularly strong background 
rejection capabilities.  Ongoing work on SMFI-based barium tagging, combining techniques from biochemistry, microscopy and nuclear 
physics, may further suppress radioactive backgrounds, perhaps enabling the first background-free, ton-scale technology. This talk
will cover early results from the running NEXT-NEW demonstrator, and present new demonstrations of barium tagging methods developed
for NEXT with the unprecedented combination of single ion sensitivity and plausible scalability to large experiments.