The NEXT experiment will search for [beta][beta]0v in [sup.136]Xe using a high-pressure xenon gas (HPXe) time projection chamber (TPC) containing 100 kilograms of enriched gas, and called NEXT-100.
In particular, we will show that a sensitivity of 20 meV in [m.sub.[beta][beta]] is within the reach of a ton-scale HPXe detector.
The HPXe technology offers less efficiency than the other two but a much better resolution.
At the maximum exposure, the XeSci detectors reach a draw at ~32 meV, while the HPXe detector reaches 25 meV.
Particles interacting in the HPXe transfer their energy to the medium through ionization and excitation.