Primordial black holes from a cosmic phase transition: The collapse of Fermi-balls. (arXiv:2106.00111v3 [astro-ph.CO] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Kawana_K/0/1/0/all/0/1">Kiyoharu Kawana</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xie_K/0/1/0/all/0/1">Ke-Pan Xie</a>
We propose a novel primordial black hole (PBH) formation mechanism based on a
first-order phase transition (FOPT). If a fermion species gains a huge mass in
the true vacuum, the corresponding particles get trapped in the false vacuum as
they do not have sufficient energy to penetrate the bubble wall. After the
FOPT, the fermions are compressed into the false vacuum remnants to form
non-topological solitons called Fermi-balls, and then collapse to PBHs due to
the Yukawa attractive force. We derive the PBH mass and abundance, showing that
for a $mathcal{O}({rm GeV})$ FOPT the PBHs could be $sim10^{17}$ g and
explain all of dark matter. If the FOPT happens at higher scale, PBHs are
typically overproduced and extra dilution mechanism is necessary to satisfy
current constraints.
We propose a novel primordial black hole (PBH) formation mechanism based on a
first-order phase transition (FOPT). If a fermion species gains a huge mass in
the true vacuum, the corresponding particles get trapped in the false vacuum as
they do not have sufficient energy to penetrate the bubble wall. After the
FOPT, the fermions are compressed into the false vacuum remnants to form
non-topological solitons called Fermi-balls, and then collapse to PBHs due to
the Yukawa attractive force. We derive the PBH mass and abundance, showing that
for a $mathcal{O}({rm GeV})$ FOPT the PBHs could be $sim10^{17}$ g and
explain all of dark matter. If the FOPT happens at higher scale, PBHs are
typically overproduced and extra dilution mechanism is necessary to satisfy
current constraints.
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