https://doi.org/10.1140/epjc/s10052-024-13246-y
Regular Article - Theoretical Physics
Primordial black holes and scalar-induced gravitational waves in radiative hybrid inflation
1
Department of Physics, Quaid-i-Azam University, 45320, Islamabad, Pakistan
2
Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093, Warsaw, Poland
Received:
4
July
2024
Accepted:
13
August
2024
Published online:
27
September
2024
We study the possibility that primordial black holes (PBHs) can be formed from large curvature perturbations generated during the waterfall phase transition due to the effects of one-loop radiative corrections of Yukawa couplings between the inflaton and a dark fermion in a non-supersymmetric hybrid inflationary model. We obtain a spectral index 
, and a tensor-to-scalar ratio r, consistent with the current Planck data. Our findings show that the abundance of PBHs is correlated to the dark fermion mass 
and peak in the GW spectrum. We identify parameter space where PBHs can be the entire dark matter (DM) candidate of the universe or a fraction of it. Our predictions are consistent with any existing constraints of PBH from microlensing, BBN, CMB, etc. Moreover, the scenario is also testable via induced gravitational waves (GWs) from first-order scalar perturbations detectable in future observatories such as LISA and ET. For instance, with inflaton mass 
GeV, 
GeV, we obtain PBHs of around 
mass that can explain the entire abundance of DM and predict GWs with amplitude 
with peak frequency f
0.1 Hz in LISA. By explicitly estimating fine-tuning we show that the model has very mild tuning. We discuss successful reheating at the end of the inflationary phase via the conversion of the waterfall field into standard model (SM) particles. We also briefly speculate a scenario where the dark fermion can be a possible heavy right-handed neutrino (RHN) which is responsible for generating the SM neutrino masses via the seesaw mechanism. The RHN can be produced due to waterfall field decay and its subsequent decay may also explain the observed baryon asymmetry in the universe via leptogenesis. We find the reheat temperature 
GeV that explains the matter-anti-matter asymmetry of the universe.
© The Author(s) 2024
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