Primordial black holes and induced gravitational waves in Galileon inflation. (arXiv:2102.05651v1 [astro-ph.CO])

Primordial black holes and induced gravitational waves in Galileon inflation. (arXiv:2102.05651v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Solbi_M/0/1/0/all/0/1">Milad Solbi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Karami_K/0/1/0/all/0/1">Kayoomars Karami</a>

Recent observational constraints indicate that primordial black holes (PBHs)
with the mass scale $sim 10^{-12}M_{odot}$ can explain most of dark matter in
the Universe. To produce this kind of PBHs, we need an enhance in the
primordial scalar curvature perturbations to the order of
${mathcal{O}(10^{-2})}$ at the scale $ k sim 10^{12}~rm Mpc^{-1}$. Here, we
investigate the production of PBHs and induced gravitational waves (GWs) in the
framework of Galileon inflation. To this aim, we consider the Galileon term
$G(X)=X/M^3$ as well as the $alpha$-attractor base potential modified by a
small local Gaussian bump. We solve numerically the Mukhanov-Sasaki equation to
obtain the primordial scalar power spectrum. In addition, we estimate the PBHs
abundance $f_{text{PBH}}^{text{peak}}$ as well as the energy density
parameter $Omega_{rm GW,0}$ of induced GWs. Interestingly enough is that for
a special set of model parameters, we estimate the mass scale and the abundance
of PBHs as $sim{cal O}(10^{-12})M_{odot}$ and
$f_{text{PBH}}^{text{peak}}=0.92$, respectively. This confirms that the
mechanism of PBHs production in Galileon inflation can justify most of dark
matter. Furthermore, we evaluate the GWs energy density parameter and conclude
that it behaves like a power-law function $Omega_{rm GW}sim (f/f_c)^n$ where
in the infrared limit $fll f_{c}$, the power index reads $n=3-2/ln(f_c/f)$.

Recent observational constraints indicate that primordial black holes (PBHs)
with the mass scale $sim 10^{-12}M_{odot}$ can explain most of dark matter in
the Universe. To produce this kind of PBHs, we need an enhance in the
primordial scalar curvature perturbations to the order of
${mathcal{O}(10^{-2})}$ at the scale $ k sim 10^{12}~rm Mpc^{-1}$. Here, we
investigate the production of PBHs and induced gravitational waves (GWs) in the
framework of Galileon inflation. To this aim, we consider the Galileon term
$G(X)=X/M^3$ as well as the $alpha$-attractor base potential modified by a
small local Gaussian bump. We solve numerically the Mukhanov-Sasaki equation to
obtain the primordial scalar power spectrum. In addition, we estimate the PBHs
abundance $f_{text{PBH}}^{text{peak}}$ as well as the energy density
parameter $Omega_{rm GW,0}$ of induced GWs. Interestingly enough is that for
a special set of model parameters, we estimate the mass scale and the abundance
of PBHs as $sim{cal O}(10^{-12})M_{odot}$ and
$f_{text{PBH}}^{text{peak}}=0.92$, respectively. This confirms that the
mechanism of PBHs production in Galileon inflation can justify most of dark
matter. Furthermore, we evaluate the GWs energy density parameter and conclude
that it behaves like a power-law function $Omega_{rm GW}sim (f/f_c)^n$ where
in the infrared limit $fll f_{c}$, the power index reads $n=3-2/ln(f_c/f)$.

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