Hidden Inflaton Dark Matter. (arXiv:1811.09640v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Almeida_J/0/1/0/all/0/1">Juan P. Beltrán Almeida</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Bernal_N/0/1/0/all/0/1">Nicolás Bernal</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Rubio_J/0/1/0/all/0/1">Javier Rubio</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Tenkanen_T/0/1/0/all/0/1">Tommi Tenkanen</a>
If cosmic inflation was driven by an electrically neutral scalar field stable
on cosmological time scales, the field necessarily constitutes all or part of
dark matter (DM). We study this possibility in a scenario where the inflaton
field $s$ resides in a hidden sector, which is coupled to the Standard Model
sector through the Higgs portal $lambda_{hs}
s^2mathcal{H}^daggermathcal{H}$ and non-minimally to gravity via $xi_s s^2
R$. We study scenarios where the field $s$ first drives inflation, then reheats
the Universe, and later constitutes all DM. We consider two benchmark scenarios
where the DM abundance is generated either by production during reheating or
via non-thermal freeze-in. In both cases, we take into account all production
channels relevant for DM in the mass range from keV to PeV scale. On the
inflationary side, we perform the analysis for the full two-field case ($s$ and
$mathcal{H}$), comparing the dynamics and the relevant observables in two
different but well-motivated theories of gravity (metric and Palatini), as well
as taking into account the non-perturbative nature of particle production
during reheating. We find that, depending on the couplings and the DM mass, the
scenario works well especially for large DM masses, $10^2~{rm GeV} lesssim
m_{s}lesssim 10^6~rm{GeV}$, although there are also small observationally
allowed windows at the keV and MeV scales. We discuss how the model can be
tested through astrophysical observations.
If cosmic inflation was driven by an electrically neutral scalar field stable
on cosmological time scales, the field necessarily constitutes all or part of
dark matter (DM). We study this possibility in a scenario where the inflaton
field $s$ resides in a hidden sector, which is coupled to the Standard Model
sector through the Higgs portal $lambda_{hs}
s^2mathcal{H}^daggermathcal{H}$ and non-minimally to gravity via $xi_s s^2
R$. We study scenarios where the field $s$ first drives inflation, then reheats
the Universe, and later constitutes all DM. We consider two benchmark scenarios
where the DM abundance is generated either by production during reheating or
via non-thermal freeze-in. In both cases, we take into account all production
channels relevant for DM in the mass range from keV to PeV scale. On the
inflationary side, we perform the analysis for the full two-field case ($s$ and
$mathcal{H}$), comparing the dynamics and the relevant observables in two
different but well-motivated theories of gravity (metric and Palatini), as well
as taking into account the non-perturbative nature of particle production
during reheating. We find that, depending on the couplings and the DM mass, the
scenario works well especially for large DM masses, $10^2~{rm GeV} lesssim
m_{s}lesssim 10^6~rm{GeV}$, although there are also small observationally
allowed windows at the keV and MeV scales. We discuss how the model can be
tested through astrophysical observations.
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