DAMA/NaI results on spontaneous transition of nuclei to a superdense state
Thanks to the deeper experimental site, to the much larger
exposure, to the effective shielding of the detectors and to the strong improvements
in the detectors' radiopurity, the present search has achieved a much larger
sensitivity than the pioneer experiment by Aleshin et al. in 1976.
In particular, lower limits of order of 1023 y have been obtained
on the lifetime of the process in 23Na and 127I (about
three orders of magnitude higher than the previously available ones); the lower
limits on the barrier potential U0, instead, have only been modestly
improved because of their logarithmic dependence on the lifetime of the processes.