“WIMPS, 0-neutrino double beta-decay, and xenon”
David Nygren Physics Division, LBNL
14 June 2007

Abstract: I conclude that a high-pressure gaseous xenon (instead of liquid) 
xenon detector will offer much superior gamma-background rejection in the search 
for WIMPs and much superior energy resolution for the 0-neutrino double beta decay search 
in 136Xe. It appears that a relatively modest augmentation to the optimum 
detector for 0-neutrino double beta decay will lead to an attractive synergy for both 
purposes. If this scenario is correct, two identical HPXe TPCs differing 
only in isotopic content may provide significantly more robust evidence for 
the existence of either signal. In this case, the arguably optimum detector 
for both purposes is the same high-pressure xenon gas (HPXe) TPC. A simple 
analysis of important factors that limit energy resolution, especially the 
anomalously large fluctuations between scintillation and ionization in 
liquid xenon (LXe), is presented with the goal of defining an optimal 
design for next-generation HPXe-based searches at the few hundred kg 
level.  An unresolved issue is whether the WIMP and 136Xe 0-neutrino double beta decay 
communities might embrace such a common approach.