  The South Pole Telescope (SPT) has probed an expanded angular range of the
CMB temperature power spectrum. Their recent analysis of the latest
cosmological data prefers nonzero neutrino masses, mnu = 0.32+-0.11 eV. This
result, if confirmed by the upcoming Planck data, has deep implications on the
discovery of the nature of neutrinos. In particular, the values of the
effective neutrino mass involved in neutrinoless double beta decay (bb0nu) are
severely constrained for both the direct and inverse hierarchy, making a
discovery much more likely. In this paper, we focus in xenon-based bb0nu
experiments, on the double grounds of their good performance and the
suitability of the technology to large-mass scaling. We show that the current
generation, with effective masses in the range of 100 kg and conceivable
exposures in the range of 500 kg year, could already have a sizable opportunity
to observe bb0nu events, and their combined discovery potential is quite large.
The next generation, with an exposure in the range of 10 ton year, would have a
much more enhanced sensitivity, in particular due to the very low specific
background that all the xenon technologies (liquid xenon, high-pressure xenon
and xenon dissolved in liquid scintillator) can achieve. In addition, a
high-pressure xenon gas TPC also features superb energy resolution. We show
that such detector can fully explore the range of allowed effective Majorana
masses, thus making a discovery very likely.
