Final model independent result of DAMA/LIBRA-phase1

TL;DR

The DAMA/LIBRA-phase1 experiment reports a highly significant annual modulation signal consistent with dark matter particles in the galactic halo, based on 7 years of data with NaI(Tl) detectors, confirming previous findings with increased exposure.

Contribution

This paper provides the final, model-independent result of DAMA/LIBRA-phase1, confirming dark matter detection evidence with an extended dataset and improved statistical significance.

Findings

7.5 sigma evidence for dark matter in DAMA/LIBRA data

Modulation amplitude of (0.0112 ± 0.0012) cpd/kg/keV in (2-6) keV

Measured phase and period consistent with dark matter expectations

Abstract

The results obtained with the total exposure of 1.04 ton x yr collected by DAMA/LIBRA-phase1 deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N. during 7 annual cycles (i.e. adding a further 0.17 ton x yr exposure) are presented. The DAMA/LIBRA-phase1 data give evidence for the presence of Dark Matter (DM) particles in the galactic halo, on the basis of the exploited model independent DM annual modulation signature by using highly radio-pure NaI(Tl) target, at 7.5 sigma C.L.. Including also the first generation DAMA/NaI experiment (cumulative exposure 1.33 ton x yr, corresponding to 14 annual cycles), the C.L. is 9.3 sigma and the modulation amplitude of the single-hit events in the (2-6) keV energy interval is: (0.0112 \pm 0.0012) cpd/kg/keV; the measured phase is (144 \pm 7) days and the measured period is (0.998 \pm 0.002) yr, values well in agreement with those expected for DM particles. No systematic or side reaction able to mimic the exploited DM signature has been found or suggested by anyone over more than a decade.