http://arxiv.org/abs/2301.03624
We propose a new method to hunt for dark matter using dark forest/absorption features across the whole electromagnetic spectrum from radio to gamma rays, especially in the bands where there is a desert i.e. regions where no strong lines from baryons are expected. Such novel signatures can arise for dark matter models with a composite nature and internal electromagnetic transitions. The photons from a background source can interact with the dark matter resulting in an absorption signal in the source spectrum. In the case of a compact source, such as a quasar, such interactions in the dark matter halos can produce a series of closely spaced absorption lines, which we call the dark forest. We show that the dark forest feature is a sensitive probe of the dark matter self-interactions and the halo mass function, especially at the low mass end. Moreover, the absorption of CMB photons by dark matter gives rise to a global absorption signal in the CMB spectrum. For dark matter transition energies in the range $2.5\times 10^{-4} \text{eV}$-$5\times 10^{3}$ eV, such absorption features result in spectral distortions of the CMB in the COBE/FIRAS band of 60-600 GHz. If the dark matter transition frequency is $\sim$156 GHz, we show that the absorption of CMB photons by dark matter can provide an explanation for the anomalous absorption feature detected by the EDGES collaboration in 50-100 MHz range.
A. Ganguly, R. Khatri and T. Roy
Wed, 11 Jan 23
75/80
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