DARK MATTER PARTICLES IN THE GALACTIC HALO: RESULTS AND IMPLICATIONS FROM DAMA/NaI

Abstract

The DAMA/NaI experiment (≃ 100 kg highly radiopure NaI(Tl)) was proposed, designed and realised to effectively investigate in a model independent way the presence of a Dark Matter particle component in the galactic halo by exploiting the annual modulation signature. With a total exposure of 107731 kg · day, collected over seven annual cycles deep underground at the Gran Sasso National Laboratory of the I.N.F.N., it has pointed out -at 6.3 σ C.L. -an effect which satisfies all the peculiarities of the signature and neither systematic effects nor side reactions able to mimic the signature were found. Moreover, several (but still few with respect to the possibilities) corollary model dependent quests for the candidate particle have been carried out. In this paper the obtained results are summarized and some perspectives are discussed at some extent.

New results and perspectives of DAMA/LIBRA

“…Thus, again evidence of annual modulation with proper features as required by the DM annual modulation signature is present in the single-hit residuals (events class to which the DM particle induced events belong), while it is absent in the multiple-hit residual rate (event class to which only background events belong). Similar results were also obtained for the last two annual cycles of the DAMA/NaI experiment [17]. Since the same identical hardware and the same identical software procedures have been used to analyse the two classes of events, the obtained result offers an additional strong support for the presence of a DM particle component in the galactic halo.…”

“…The residuals of the DAMA/NaI data (0.29 ton × yr) are given in Ref. [2,8,16,17]. We remind that these residual rates are calculated from the measured rate of the single-hit events after subtracting the constant part: < r i jk − f lat jk > jk .…”

“…The presently running DAMA/LIBRA [1][2][3][4][5][6][7][8][9][10][11] experiment, as the former DAMA/NaI [12][13][14][15][16][17][18][19][20][21][22][23][24][25], has the main aim to investigate the presence of DM particles in the galactic halo by exploiting the model independent DM annual modulation signature (originally suggested in Ref. [26]).…”

Dark Matter Annual Modulation Results by DAMA/LIBRA

“…in refs. [4][5][6][7][8][9][10][11]. On the other hand, one should stress that it does not exist any approach in direct and indirect DM searches which can offer information on the nature of the candidate in a model independent way, that is without assuming any astrophysical, nuclear and particle Physics scenarios.…”

“…It is based on the development and use of low background scintillators. The main experimental set-ups are: i) DAMA/NaI ( 100 kg of highly radiopure NaI(Tl)) that took data for 7 annual cycles and completed its data taking on July 2002 [1][2][3][4][5][6][7][8][9][10][11][12]; ii) DAMA/LXe, 6.5 kg liquid Kr-free Xenon enriched either in 129 Xe or in 136 Xe [13]; iii) DAMA/R&D, a facility dedicated to tests on prototypes and to perform experiments developing and using various kinds of low background crystal scintillators to investigate various rare processes [14]; iv) DAMA/Ge, where a e-mail: pierluigi.belli@roma2.infn.it DOI: 10.1051/ C Owned by the authors, published by EDP Sciences, 2014 , / sample measurements are carried out and where dedicated measurements on rare events are performed [15]; v) the second generation DAMA/LIBRA set-up, 250 kg highly radiopure NaI(Tl)) [16][17][18][19][20] mainly devoted to the investigation of the presence of Dark Matter (DM) particles in the Galactic halo. Profiting of the low background features of these set-ups, many rare processes have been studied.…”