DAMA/NaI results on spontaneous transition of nuclei to a superdense state
From the very beginning of nuclear physics it was debated the possible existence
of superdense nuclear states with density ρs larger
than the nuclear average density ρ0. The possible existence of
superdense states was also discussed in some pioneering works of Migdal and
others, in connection with the so called "pion condensation" phenomenon.
More recently this argument has been developed by many authors.
To realise the density transition ρ0 --> ρs, it must be overcome a potential barrier U0 whose shape and height cannot be reliably predicted on the basis of actual knowledge. In this framework a nucleus (or a part of a nucleus) can be metastable and spontaneously can go over to the superdense state.
2005 - The search has been carried out by using an exposure of 33834 kg x day. The exploited experimental approach consists in the search for γ-radiation accompaining the occurrence of a possible transition of Sodium and Iodine nuclei to a superdense state with an energy release ΔE larger than 10 MeV. For this purpose, events with multiplicity larger or equal to two and total energy - released in the nine 9.7 kg NaI(Tl) detectors - larger than 10 MeV have been considered.