Investigating halo substructures with annual modulation signature

Abstract

Galaxy hierarchical formation theories, numerical simulations, the discovery of the Sagittarius Dwarf Elliptical Galaxy (SagDEG) in 1994 and more recent investigations suggest that the dark halo of the Milky Way can have a rich phenomenology containing non thermalized substructures. In the present preliminary study, we investigate the case of the SagDEG (the best known satellite galaxy in the Milky Way crossing the solar neighbourhood) analyzing the consequences of its dark matter stream contribution to the galactic halo on the basis of the DAMA/NaI annual modulation data. The present analysis is restricted to some WIMP candidates and to some of the astrophysical, nuclear and particle Physics scenarios. Other candidates such as e.g. the light bosonic ones, we discussed elsewhere, and other non thermalized substructures are not yet addressed here.

Annual Modulation of Dark Matter in the Presence of Streams

“…[52,53]; DAMA also examined the possibility of streams in Ref. [54]. The presence of an energy cutoff due to a stream in this modulation signal would provide a "smoking gun" for WIMPs.…”

New results and perspectives of DAMA/LIBRA

“…For completeness, we recall that a slight energy dependence of the phase could be expected in case of possible contributions of non-thermalized DM components to the galactic halo, such as e.g. the SagDEG stream [19,29,30] and the caustics [31].…”

“…In this case the signal can be written as: conditions hold for most of the dark halo models; however, as mentioned above, slight differences can be expected in case of possible contributions from non-thermalized DM components, such as e.g. the SagDEG stream [19,29,30] and the caustics [31]. Considering cumulatively the data of DAMA/NaI and DAMA/LIBRA-phase1 (exposure 1.33 ton × yr) the obtained 2σ contours in the plane (S m , Z m ) for the (2-6) keV and (6-14) keV energy intervals are shown in Fig.…”

“…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

“…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.…”