Complementarity of Dark Matter Direct Detection Targets

Physical review D: Particles and fields 12/2010; DOI: 10.1103/PhysRevD.83.083505
Source: arXiv

ABSTRACT We investigate the reconstruction capabilities of Dark Matter mass and
spin-independent cross-section from future ton-scale direct detection
experiments using germanium, xenon or argon as targets. Adopting realistic
values for the exposure, energy threshold and resolution of Dark Matter
experiments which will come online within 5 to 10 years, the degree of
complementarity between different targets is quantified. We investigate how the
uncertainty in the astrophysical parameters controlling the local Dark Matter
density and velocity distribution affects the reconstruction. For a 50 GeV
WIMP, astrophysical uncertainties degrade the accuracy in the mass
reconstruction by up to a factor of $\sim 4$ for xenon and germanium, compared
to the case when astrophysical quantities are fixed. However, combination of
argon, germanium and xenon data increases the constraining power by a factor of
$\sim 2$ compared to germanium or xenon alone. We show that future direct
detection experiments can achieve self-calibration of some astrophysical
parameters, and they will be able to constrain the WIMP mass with only very
weak external astrophysical constraints.

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    ABSTRACT: Fitting the model "A" to dark matter direct detection data, when the model that underlies the data is "B", introduces a theoretical bias in the fit. We perform a quantitative study of the theoretical bias in dark matter direct detection, with a focus on assumptions regarding the dark matter interactions, and velocity distribution. We address this problem within the effective theory of isoscalar dark matter-nucleon interactions mediated by a heavy spin-1 or spin-0 particle. We analyze 24 benchmark points in the parameter space of the theory, using frequentist and Bayesian statistical methods. First, we simulate the data of future direct detection experiments assuming a momentum/velocity dependent dark matter-nucleon interaction, and an anisotropic dark matter velocity distribution. Then, we fit a constant scattering cross section, and an isotropic Maxwell-Boltzmann velocity distribution to the simulated data, thereby introducing a bias in the analysis. The best fit values of the dark matter particle mass differ from their benchmark values up to 2 standard deviations. The best fit values of the dark matter-nucleon coupling constant differ from their benchmark values up to several standard deviations. We conclude that common assumptions in dark matter direct detection are a source of potentially significant bias.
    Journal of Cosmology and Astroparticle Physics 07/2014; 2014(09). DOI:10.1088/1475-7516/2014/09/049 · 5.88 Impact Factor
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    ABSTRACT: Directional detection of WIMPs, in which the energies and directions of the recoiling nuclei are measured, currently presents the only prospect for probing the local \textit{velocity} distribution of Galactic dark matter. We investigate the extent to which future directional detectors would be capable of probing dark matter substructure in the form of streams. We analyse the signal expected from a Sagittarius-like stream and also explore the full parameter space of stream speed, direction, dispersion and density. Using a combination of non-parametric directional statistics, a profile likelihood ratio test and Bayesian parameter inference we find that within acceptable exposure times ($\mathcal{O}(10)$ kg yr for cross sections just below the current exclusion limits) future directional detectors will be sensitive to a wide range of stream velocities and densities. We also examine and discuss the importance of the energy window of the detector.
    Physical Review D 10/2014; 90(12). DOI:10.1103/PhysRevD.90.123511 · 4.86 Impact Factor
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    ABSTRACT: Cosmological observations and the dynamics of the Milky Way provide ample evidence for an invisible and dominant mass component. This so-called dark matter could be made of new, colour and charge neutral particles, which were non-relativistic when they decoupled from ordinary matter in the early universe. Such weakly interacting massive particles (WIMPs) are predicted to have a non-zero coupling to baryons and could be detected via their collisions with atomic nuclei in ultra-low background, deep underground detectors. Among these, detectors based on liquefied noble gases have demonstrated tremendous discovery potential over the last decade. After briefly introducing the phenomenology of direct dark matter detection, I will review the main properties of liquified argon and xenon as WIMP targets and discuss sources of background. I will then describe existing and planned argon and xenon detectors that employ the so-called single- and dual-phase detection techniques, addressing their complementarity and science reach.
    09/2014; DOI:10.1016/j.dark.2014.07.001


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