Dark matter particles in the galactic halo: DAMA/LIBRA results and perspectives

Abstract

Most of the Universe is Dark and a large fraction of it should be made of relic particles; many possibilities are open on their nature and interaction types. Thus, their investigation is an outstanding issue in the field; for this purpose experiments offering a model independent signature for the presence of Dark Matter (DM) particles in the Galactic halo are mandatory. In this paper the DAMA/LIBRA results are described. In particular, the DAMA/LIBRA experiment is mainly devoted to the investigation of DM particles in the Galactic halo by exploiting the model independent DM annual modulation signature. The present DAMA/LIBRA and the former DAMA/NaI (exposed masses:250 kg and 100 kg of highly radiopure NaI(Tl), respectively) experiments have released so far a total exposure of 1.17 ton × yr collected over 13 annual cycles; they provide a model independent evidence of the presence of DM particles in the galactic halo at 8.9 σ C.L.. Future perspectives are mentioned.

Production Yield of Muon-Induced Neutrons in Lead

“…The DAMA [109,116] experiment claims a discovery of galactic dark matter interacting with their target based on an annual modulation of the count rate statistic. As stated above, this is extracted without specifying the kind of interaction on an event-by-event base.…”

“…The DAMA project searched, with two experimental set-ups, for WIMP signatures in NaI(Tl) crystals at the Laboratori Nazionali del Gran Sasso (LNGS, Italy) at a depth of 3600 mwe [109,117]. Until July 2002, the DAMA/NaI set-up collected in 7 years [111] 107,731 kg.d exposure with nine crystals of 9.7 kg mass [112].…”

“…This modulation persisted in the combined exposure of DAMA/NaI and DAMA/LIBRA (1.17 t.yr) at a significance of 8.9σ CL, spanning 13 annual cycles [109]. According to the DAMA collaboration, possible modulated backgrounds, like muon-induced neutrons, can not explain the observed topology of the events and amplitude of the modulation [109,116,117]. Therefore, the DAMA collaboration claims evidence for a dark matter induced signal [109,116].…”

Dark matter and dark force in the type-I inert 2HDM with local U(1) H gauge symmetry

“…In case we assume that there exist another dark matter particles which contribute to the dark matter relic density, we impose the bound Ω IDM ≤ 0.1280. On the other hand, dark matter may interact with atomic nuclei in a detector, and it can be detected by underground experiments, such as the DAMA [50], CoGeNT [51], CRESST [52], XENON [53,54], CDMS [55], LUX [56] and etc. The CoGeNT, DAMA, CRESST-II, and CDMS-II experiments show some excesses in the light dark matter region with the dark matter mass of about 10 GeV and the spin-independent cross section for the WIMP-nucleon scattering is predicted to be σ SI ∼ 10 −40 − 10 −42 cm 2 [55].…”

Search for magnetic inelastic dark matter with XENON100

“…A plethora of experiments based on different techniques aim at the direct detection of dark matter in sensitive underground detectors [2][3][4]. However, the limits on the dark matter-ordinary matter scattering cross section derived by these experiments are in strong conflict with the long-standing dark matter detection claim by DAMA/LIBRA [5], especially if their 9.3 σ modulation signal is interpreted within the usual framework of Weakly Interacting Massive Particles (WIMPs) [6]. Several alternatives to the classical WIMP scenario have been proposed in order to reconcile the null results of other experiments with DAMA/LIBRA.…”