At the International Conference "Neutrino Oscillations in Venice”, the DAMA collaboration today presented the results of the DAMA/LIBRA experiment on dark matter.
The DAMA/LIBRA experiment consists of 250 kg of sodium iodide in the form of 25 crystals with an extremely high radiopurity, which since March 2003 have been taking data at the laboratories of Italy’s National Institute of Nuclear Physics (INFN) in Gran Sasso.
The objective of the experiment is to study dark matter particles by measuring the flashes of light generated in the crystals as a result of interactions with the dark matter particles of the galactic halo.
The results confirm that there is an annual modulation in the signals counting rate, an evidence that is independent of the various theoretical models for the dark matter, which could be related to the Earth’s motion within the Galaxy’s dark matter halo. DAMA had previously revealed this modulation at Gran Sasso using an apparatus with a smaller mass than the current apparatus. It should be mentioned that, to date, the DAMA collaboration has produced the apparatuses with the greatest mass, the highest radiopurity and the longest measurement time.
This important confirmation will contribute to the heated debate which has been going on for several years regarding the nature and composition of dark matter, a debate that has been fueled by experiments of different kind, whose sensitivity is similar to that of DAMA yet which to date have not produced data that can be interpreted as indicative of the presence of dark matter.
This research has placed the INFN Laboratories in Gran Sasso at the centre of international attention, not only for the results obtained but also for the important experiments being developed, such as WARP and Xenon, which use cryogenic liquids, and CRESST, which uses crystals cooled to extremely low temperatures.
Additional results will be expected from the Large Hadron Collider at CERN in Geneva, which could directly produce the particles responsible for dark matter.
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