Optimized velocity distributions for direct dark matter detection

Ibarra, Alejandro; Rappelt, Andreas

doi:10.1088/1475-7516/2017/08/039

Cited by 26 publications

(34 citation statements)

References 108 publications

(153 reference statements)

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“…This involves writing the rescaled velocity integral as a series of monotonically decreasing steps (which is physically equivalent to the velocity distribution being composed of a series of streams with different densities and velocities) and finding the optimum step properties [123,[133][134][135]138]. It is also possible to make astrophysics independent comparisons of direct detection experiments and neutrino telescopes [138,139].…”

Section: A Astrophysics Independent Methodsmentioning

confidence: 99%

Astrophysical uncertainties on the local dark matter distribution and direct detection experiments

Green¹

2017

J. Phys. G: Nucl. Part. Phys.

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The differential event rate in Weakly Interacting Massive Particle (WIMP) direct detection experiments depends on the local dark matter density and velocity distribution. Accurate modelling of the local dark matter distribution is therefore required to obtain reliable constraints on the WIMP particle physics properties. Data analyses typically use a simple Standard Halo Model which might not be a good approximation to the real Milky Way (MW) halo. We review observational determinations of the local dark matter density, circular speed and escape speed and also studies of the local dark matter distribution in simulated MW-like galaxies. We discuss the effects of the uncertainties in these quantities on the energy spectrum and its time and direction dependence. Finally we conclude with an overview of various methods for handling these astrophysical uncertainties.

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Section: A Astrophysics Independent Methodsmentioning

confidence: 99%

Astrophysical uncertainties on the local dark matter distribution and direct detection experiments

Green¹

2017

J. Phys. G: Nucl. Part. Phys.

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“…Clearly, as ∆ increases, the support of the function f Cmax (v) is restricted to a smaller and smaller interval left-bounded by v = 0, and tends to f Cmax (v) = δ(v) as ∆ → ∞. Again, this is a consequence of the fact that in this limit the optimization problem is only subject to the normalization constraint, and therefore the optimized velocity distribution is composed of a single delta-function [79]. The velocity distribution giving the smallest capture rate corresponds to…”

Section: Impact On Limits From Neutrino Telescopesmentioning

confidence: 99%

“…Reference [79] (hereafter referred to as IR17) developed a new fully halo-independent approach to comparing direct detection and neutrino telescope experiments. Noting that the nuclear scattering rate (in the case of direct detection) and solar capture rate (relevant for neutrino telescopes) are both linear in the DM velocity distribution f ( v), IR17 showed that the techniques of linear programming can be applied to optimize the signal in one experiment, subject to the constraints imposed by another experiment.…”

Section: Introductionmentioning

confidence: 99%

Bracketing the impact of astrophysical uncertainties on local dark matter searches

Ibarra

Kavanagh

Rappelt

2018

J. Cosmol. Astropart. Phys.

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The theoretical interpretation of dark matter (DM) experiments is hindered by uncertainties on the dark matter density and velocity distribution inside the Solar System. In order to quantify those uncertainties, we present a parameter that characterizes the deviation of the true velocity distribution from the standard Maxwell-Boltzmann form, and we then determine for different values of this parameter the most aggressive and most conservative limits on the dark matter scattering cross section with nuclei; uncertainties in the local dark matter density can be accounted for trivially. This allows us to bracket, in a model independent way, the impact of astrophysical uncertainties on limits from direct detection experiments and/or neutrino telescopes. We find that current limits assuming the Standard Halo Model are at most a factor of ∼ 2 weaker than the most aggressive possible constraints. In addition, combining neutrino telescope and direct detection constraints (in a statistically meaningful way), we show that limits on DM in the mass range ∼ 10 − 1000 GeV cannot be weakened by more than around a factor of 10, for all possible velocity distributions. We finally demonstrate that our approach can also be employed in the event of a DM discovery, allowing us to avoid bias in the reconstruction of the DM properties.

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“…Refs. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43], this often comes at the cost of greater complexity and less overall constraining power.…”

Section: Introductionmentioning

confidence: 99%

Refinement of the standard halo model for dark matter searches in light of the Gaia Sausage

Evans

O’Hare

McCabe³

2019

Phys. Rev. D

179

165

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Predicting signals in experiments to directly detect dark matter (DM) requires a form for the local DM velocity distribution. Hitherto, the standard halo model (SHM), in which velocities are isotropic and follow a truncated Gaussian law, has performed this job. New data, however, suggest that a substantial fraction of our stellar halo lies in a strongly radially anisotropic population, the 'Gaia Sausage'. Inspired by this recent discovery, we introduce an updated DM halo model, the SHM ++ , which includes a 'Sausage' component, thus better describing the known features of our galaxy. The SHM ++ is a simple analytic model with five parameters: the circular speed, local escape speed and local DM density, which we update to be consistent with the latest data, and two new parameters: the anisotropy and the density of DM in the Sausage. The impact of the SHM ++ on signal models for WIMPs and axions is rather modest since the multiple changes and updates have competing effects. In particular, this means that the older exclusion limits derived for WIMPS are still reasonably accurate. However, changes do occur for directional detectors, which have sensitivity to the full three-dimensional velocity distribution.

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Optimized velocity distributions for direct dark matter detection

Cited by 26 publications

References 108 publications

Astrophysical uncertainties on the local dark matter distribution and direct detection experiments

Astrophysical uncertainties on the local dark matter distribution and direct detection experiments

Bracketing the impact of astrophysical uncertainties on local dark matter searches

Refinement of the standard halo model for dark matter searches in light of the Gaia Sausage

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