Ref HAL: hal-00777643_v1
Ref Arxiv: 1205.1004
DOI: 10.1016/j.crhy.2012.05.001
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29 citations
Comments: Invited review submitted to Comptes Rendus de l'Academie des Sciences, special issue on "Dark matter and dark energy" (Eds. C. Boehm and P. Brax). 82 pages. V2: matches the published version Journal: Comptes Rendus Physique, Volume 13, Issue 6, p. 740-782 (2012)

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Ref Arxiv: 1204.4121
DOI: 10.1103/PhysRevD.86.063524
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6 citations
Comments: 6 pages, 3 figures. V2: minor changes to match the published version Journal: Phys. Rev. D 86, 063524 (2012)

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Ref Arxiv: 1203.1488
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Comments: 243 pages, report of the Les Houches 2011 New Physics Group

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Ref Arxiv: 1108.1128
DOI: 10.1016/J.NUCLPHYSB.2011.09.020
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26 citations
Abstract:

The CoGeNT experiment, dedicated to direct detection of dark matter, has recently released excess events that could be interpreted as elastic collisions of ˜10 GeV dark matter particles, which might simultaneously explain the still mysterious DAMA/LIBRA modulation signals, while in conflict with results from other experiments such as CDMS, XENON-100 and SIMPLE. It was shown that 5-15 GeV singlino-like dark matter candidates arising in singlet extensions of minimal supersymmetric scenarios can fit these data; annihilation then mostly proceeds into light singlet-dominated Higgs (pseudo-)scalar fields. We develop an effective Lagrangian approach to confront these models with the existing data on cosmic-ray antiprotons, including the latest PAMELA data. Focusing on a parameter space consistent with the CoGeNT region, we show that the predicted antiproton flux is generically in tension with the data whenever the produced (pseudo-)scalars can decay into quarks energetic enough to produce antiprotons, provided the annihilation S-wave is significant at freeze out in the early universe. In this regime, a bound on the singlino annihilation cross section is obtained, <σv>≲10‑26 cm3/s, assuming a dynamically constrained halo density profile with a local value of ρ=0.4 GeV/cm3. Finally, we provide indications on how PAMELA or AMS-02 could further constrain or detect those configurations producing antiprotons which are not yet excluded.

Ref HAL: hal-00628256_v1
Ref Arxiv: 0908.0195
DOI: 10.1103/PHYSREVD.83.023518
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102 citations
Abstract:

We study the prospects for detecting the annihilation products of dark matter (DM) in the framework of the two highest-resolution numerical simulations currently available, i.e., Via Lactea II and Aquarius. We propose a strategy to determine the shape and size of the region around the Galactic center that maximizes the probability of observing a DM signal, and we show that, although the predicted flux can differ by a factor of 10 for a given DM candidate in the two simulation setups, the search strategy remains actually unchanged, since it relies on the angular profile of the annihilation flux, not on its normalization. We present mock γ-ray maps that keep into account the diffuse emissions produced by unresolved halos in the Galaxy, and we show that, in an optimistic DM scenario, a few individual clumps can be resolved above the background with the Fermi-LAT. Finally, we calculate the energy-dependent boost factors for positrons and antiprotons and show that they are always of O(1), and, therefore, they cannot lead to the large enhancements of the antimatter fluxes required to explain the recent PAMELA, ATIC, Fermi, and HESS data. Still, we show that the annihilation of 100 GeV weakly interacting massive particles into charged lepton pairs may contribute significantly to the positron budget.

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Ref Arxiv: 1008.5124
DOI: 10.1103/PHYSREVD.82.083521
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2 citations
Abstract:

We study the Sunyaev-Zel'dovich effect potentially generated by relativistic electrons injected from dark matter annihilation or decay in the Galaxy, and check whether it could be observed by Planck or the Atacama Large Millimeter Array (ALMA), or even imprint the current CMB data as, e.g., the specific fluctuation excess claimed from an recent reanalysis of the WMAP-5 data. We focus on high-latitude regions to avoid contamination of the Galactic astrophysical electron foreground, and consider the annihilation or decay coming from the smooth dark matter halo as well as from subhalos, further extending our analysis to a generic modeling of spikes arising around intermediate-mass black holes. We show that all these dark Galactic components are unlikely to produce any observable Sunyaev-Zel'dovich effect. For a self-annihilating dark matter particle of 10 GeV with canonical properties, the largest optical depth we find is τe≲10-7 for massive isolated subhalos hosting intermediate-mass black holes. We conclude that dark matter annihilation or decay on the Galactic scale cannot lead to significant Sunyaev-Zel'dovich distortions of the CMB spectrum.

Ref HAL: hal-00628252_v1
Ref Arxiv: 0907.5589
DOI: 10.1088/1475-7516/2010/02/005
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8 citations
Abstract:

We revisit the prospects for detecting the Sunyaev Zel'dovich (SZ) effect induced by dark matter (DM) annihilation or decay. We show that with standard (or even extreme) assumptions for DM properties, the optical depth associated with relativistic electrons injected from DM annihilation or decay is much smaller than that associated with thermal electrons, when averaged over the angular resolution of current and future experiments. For example, we find: τDM ~ 10-9-10-5 (depending on the assumptions) for mχ = 1 GeV and a density profile ρproptor-1 for a template cluster located at 50 Mpc and observed within an angular resolution of 10'', compared to τth ~ 10-3-10-2. This, together with a full spectral analysis, enables us to demonstrate that, for a template cluster with generic properties, the SZ effect due to DM annihilation or decay is far below the sensitivity of the Planck satellite. This is at variance with previous claims regarding heavier annihilating DM particles. Should DM be made of lighter particles, the current constraints from 511 keV observations on the annihilation cross section or decay rate still prevent a detectable SZ effect. Finally, we show that spatial diffusion sets a core of a few kpc in the electron distribution, even for very cuspy DM profiles, such that improving the angular resolution of the instrument, eg with ALMA, does not necessarily improve the detection potential. We provide useful analytical formulæ parameterized in terms of the DM mass, decay rate or annihilation cross section and DM halo features, that allow quick estimates of the SZ effect induced by any given candidate and any DM halo profile.