Co-Scattering Dark Matter. (arXiv:1902.02348v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Liu_J/0/1/0/all/0/1">Jia Liu</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Wang_X/0/1/0/all/0/1">Xiao-Ping Wang</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Xue_W/0/1/0/all/0/1">Wei Xue</a>
We propose a novel mechanism that, in two-component dark matter models, the
subdominant one can thermalize the dominant one in galaxies, and leads to core
density profiles. We take ultralight dark photons and
$mathrm{GeV}$-$mathrm{TeV}$ Dirac fermions as an example, with a $U(1)$
coupling between the two dark matter candidates. This mechanism is
significantly different from the self-interacting dark matter, due to three
effects: 1) large occupation number enhancement, 2) forward-backward scattering
cancellation, and 3) multiple scatterings required for the heavy dark matter.
Unlike the fuzzy dark matter solution to the small structure problems having
tension with Lyman-$alpha$, the ultralight dark photons with mass $gtrsim
10^{-21}$ eV can have a core profile through interactions with $psi$ and are
not constrained by other astrophysical observations.
We propose a novel mechanism that, in two-component dark matter models, the
subdominant one can thermalize the dominant one in galaxies, and leads to core
density profiles. We take ultralight dark photons and
$mathrm{GeV}$-$mathrm{TeV}$ Dirac fermions as an example, with a $U(1)$
coupling between the two dark matter candidates. This mechanism is
significantly different from the self-interacting dark matter, due to three
effects: 1) large occupation number enhancement, 2) forward-backward scattering
cancellation, and 3) multiple scatterings required for the heavy dark matter.
Unlike the fuzzy dark matter solution to the small structure problems having
tension with Lyman-$alpha$, the ultralight dark photons with mass $gtrsim
10^{-21}$ eV can have a core profile through interactions with $psi$ and are
not constrained by other astrophysical observations.
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