Anisotropic dark matter distribution functions and impact on WIMP direct detection

Journal Article · Sun Dec 01 04:00:00 EST 2013 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2013/12/050· OSTI ID:22369839

Bozorgnia, Nassim; Schwetz, Thomas ^[1]; Catena, Riccardo ^[2]

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1. Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, Heidelberg, 69117 (Germany)
2. Institut für Theoretische Physik, Friedrich-Hund-Platz 1, Göttingen, 37077 (Germany)

Dark matter N-body simulations suggest that the velocity distribution of dark matter is anisotropic. In this work we employ a mass model for the Milky Way whose parameters are determined from a fit to kinematical data. Then we adopt an ansatz for the dark matter phase space distribution which allows to construct self-consistent halo models which feature a degree of anisotropy as a function of the radius such as suggested by the simulations. The resulting velocity distributions are then used for an analysis of current data from dark matter direct detection experiments. We find that velocity distributions which are radially biased at large galactocentric distances (up to the virial radius) lead to an increased high velocity tail of the local dark matter distribution. This affects the interpretation of data from direct detection experiments, especially for dark matter masses around 10 GeV, since in this region the high velocity tail is sampled. We find that the allowed regions in the dark matter mass-cross section plane as indicated by possible hints for a dark matter signal reported by several experiments as well as conflicting exclusion limits from other experiments shift in a similar way when the halo model is varied. Hence, it is not possible to improve the consistency of the data by referring to anisotropic halo models of the type considered in this work.

• OSTI ID: 22369839
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 12 Vol. 2013; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
CROSS SECTIONS
DISTANCE
DISTRIBUTION FUNCTIONS
GEV RANGE
MASS
MILKY WAY
NONLUMINOUS MATTER
PHASE SPACE
RADIATION DETECTION
SIGNALS
SIMULATION
VELOCITY