Annual modulation results from DAMA/LIBRA

Abstract

DAMA/LIBRA is an experiment investigating the presence of Dark Matter particles in the Galactic halo. The target detectors are ultra-radiopure NaI(Tl) crystal scintillators. They are placed inside a low-background set-up at the underground Gran Sasso National Laboratory (LNGS) of the I.N.F.N.. DAMA/LIBRA has been in operation in two phases by pursuing the annual modulation as signature to point-out in a model-independent way the presence and the features of the Dark Matter (DM) signal in the counting rate. In its second phase of measurement, DAMA/LIBRA–phase2, it has been working with a lower software energy threshold with respect to DAMA/LIBRA–phase1. DAMA/LIBRA–phase2 confirms the evidence of a signal that meets all the requirements of the model independent Dark Matter annual modulation signature, at 11.8 [Formula: see text] C.L. in the energy region (1–6) keV. In the energy region (2–6) keV, where data are also available from DAMA/NaI and DAMA/LIBRA–phase1, the achieved C.L. for the full exposure (2.86 ton × yr, 22 annual cycles) is 13.7 [Formula: see text]; the modulation amplitude of the single-hit scintillation events is: [Formula: see text] cpd/kg/keV, and the measured period and phase are well in agreement with those expected for DM particles. Detailed studies have excluded that the observed modulation is due to systematics or side reaction. In this proceedings the results achieved so far by the DAMA/LIBRA experiment and the new ones corresponding to two new annual cycles of data will be presented. Future perspectives of the experiment will be addressed.