Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Free streaming in mixed dark matter   Free streaming in a \emph{mixture} of collisionless non-relativistic dark
matter (DM) particles is studied by implementing methods from the theory of
multicomponent plasmas. The mixture includes Fermionic, condensed and non
condensed Bosonic particles decoupling in equilibrium while relativistic, heavy
non-relativistic thermal relics (WIMPs), and sterile neutrinos that decouple
\emph{out of equilibrium} when they are relativistic. The free-streaming length
$\lambda_{fs}$ is obtained from the marginal zero of the gravitational
polarization function, which separates short wavelength Landau-damped from long
wavelength Jeans-unstable \emph{collective} modes. At redshift $z$ we find $
\frac{1}{\lambda^2_{fs}(z)}= \frac{1}{(1+z)} \big[\frac{0.071}{\textrm{kpc}}
\big]^2 \sum_{a}\nu_a g^{2/3}_{d,a}({m_a}/{\mathrm{keV}})^2 I_a $,where $0\leq
\nu_a \leq 1$ are the \emph{fractions} of the respective DM components of mass
$m_a$ that decouple when the effective number of ultrarelativistic degrees of
freedom is $g_{d,a}$, and $I_a$ only depend on the distribution functions at
decoupling, given explicitly in all cases. If sterile neutrinos produced either
resonantly or non-resonantly that decouple near the QCD scale are the
\emph{only} DM component,we find $\lambda_{fs}(0) \simeq 7 \mathrm{kpc}
(\mathrm{keV}/m)$ (non-resonant), $\lambda_{fs}(0) \simeq 1.73 \mathrm{kpc}
(\mathrm{keV}/m)$ (resonant).If WIMPs with $m_{wimp} \gtrsim 100 \mathrm{GeV}$
decoupling at $T_d \gtrsim 10 \mathrm{MeV}$ are present in the mixture with
$\nu_{wimp} \gg 10^{-12}$,$\lambda_{fs}(0) \lesssim 6.5 \times 10^{-3}
\mathrm{pc}$ is \emph{dominated} by CDM. If a Bose Einstein condensate is a DM
component its free streaming length is consistent with CDM because of the
infrared enhancement of the distribution function.

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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-th
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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The categories of this paper are: chem-ph