| 1. |
- Bergström, Lars, et al.
(författare)
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Complementarity of direct dark matter detection and indirect detection through gamma rays
- 2011
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 83:4, s. 045024-
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Tidskriftsartikel (refereegranskat)abstract
- We show, by using an extensive sample of viable supersymmetric models as templates, that indirect detection of dark matter through gamma rays may have a large potential for identifying the nature of dark matter. This is, in particular, true also for models that give too weak dark matter-nucleon scattering cross sections to be probed by present and planned direct detection experiments. Also models with a mass scale too high to be accessible at CERN's LHC accelerator may show up in next-generation imaging Cherenkov telescope arrays. Based on our findings, we therefore suggest to view indirect searches as genuine particle physics experiments, complementing other strategies to probe so far unknown regions in the parameter space of e.g. supersymmetric models, and propose a new approach that would make use of telescopes dedicated for dark matter searches. As a concrete example for the potential of such an approach, we consider an array of imaging air Cherenkov telescopes, the Dark Matter Array (DMA), and show that such an experiment could extend present-day limits by several orders of magnitude, reaching a large class of models that would remain undetected in both direct detection experiments and searches at the LHC. In addition, in a sizable part of the parameter space, signals from more than one type of dark matter detection experiment would be possible, something that may eventually be necessary in order to identify the dark matter candidate.
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| 2. |
- Bergström, Lars, et al.
(författare)
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New Limits on Dark Matter Annihilation from Alpha Magnetic Spectrometer Cosmic Ray Positron Data
- 2013
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 111:17
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Tidskriftsartikel (refereegranskat)abstract
- The Alpha Magnetic Spectrometer experiment onboard the International Space Station has recently provided cosmic ray electron and positron data with unprecedented precision in the range from 0.5 to 350 GeV. The observed rise in the positron fraction at energies above 10 GeV remains unexplained, with proposed solutions ranging from local pulsars to TeV-scale dark matter. Here, we make use of this high quality data to place stringent limits on dark matter with masses below similar to 300 GeV, annihilating or decaying to leptonic final states, essentially independent of the origin of this rise. We significantly improve on existing constraints, in some cases by up to 2 orders of magnitude.
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| 3. |
- Bringmann, Torsten, et al.
(författare)
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Improved constraints on the primordial power spectrum at small scales from ultracompact minihalos
- 2012
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Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 85:12, s. 125027-
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Tidskriftsartikel (refereegranskat)abstract
- For a Gaussian spectrum of primordial density fluctuations, ultracompact minihalos (UCMHs) of dark matter are expected to be produced in much greater abundance than, e.g., primordial black holes. Forming shortly after matter-radiation equality, these objects would develop very dense and spiky dark matter profiles. In the standard scenario where dark matter consists of thermally produced, weakly interacting massive particles, UCMHs could thus appear as highly luminous gamma-ray sources or leave an imprint in the cosmic microwave background by changing the reionization history of the Universe. We derive corresponding limits on the cosmic abundance of UCMHs at different epochs and translate them into constraints on the primordial power spectrum. We find the resulting constraints to be quite severe, especially at length scales much smaller than what can be directly probed by the cosmic microwave background or large-scale structure observations. We use our results to provide an updated compilation of the best available constraints on the power of density fluctuations on all scales, ranging from the present-day horizon to scales more than 20 orders of magnitude smaller.
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