The international collaboration DAMA, operating at the INFN Gran Sasso National Laboratories, recently shared the first results obtained with the DAMA/LIBRA-Phase2 device. The experimental approach employed by the experiment is based on the study of the model independent markings of the annual modulation of dark matter’s signal, consequent to the Earth’s movement with respect to the dark matter particles in the galactic halo. DAMA/LIBRA-Phase2 is a detector equipped with an extremely radiopure device, whose sensitive part is a modular structure of 25 detectors of scintillating thallium-doped sodium iodide. The recent results are based on data acquired on 6 independent annual cycles and confirm the evidence of a signal that meets the requirements of an annual modulation marking, with a high level of confidence (9.5 sigma) in the energy region of the software threshold between 1 keV to 6 keV. Furthermore, by combining the experimental data, a confidence level equal to 12.9 sigma was reached in the energy region between 2 and 6 keV, where the data are also available from the earlier experiments DAMA/NaI and DAMA/LIBRA-Phase1. The Researchers of this collaboration have therefore explained that the measured modulation parameters are consistent with those expected for dark matter particles; that there are no available systematic effects or competing processes able to quantitatively account for the amplitude observed and to simultaneously satisfy all the requirements of the marking; that the model independent result is compatible with a wide zoology of theoretical and phenomenological models.
31 March 2018
