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Kayoomars Karami

Kayoomars Karami

Academic rank: Professor
ORCID:
Education: PhD.
ScopusId: 22979495000
Faculty: Faculty of Science
Address: Department of Physics, University of Kurdistan Pasdaran St., P.O.Box: 66177-15175 Sanandaj - Iran
Phone:

Research

Title
Mechanism of primordial black holes production and secondary gravitational waves in α-attractor Galileon inflationary scenario
Type
JournalPaper
Keywords
gravitational waves, theory, inflation, primordial black holes
Year
2021
Journal JOURNAL of COSMOLOGY and ASTROPARTICLE PHYSICS
DOI
Researchers Zeinab Teimoori ، Kazem Rezazadeh Sarab ، mariwan Ahmad rasheed ، Kayoomars Karami

Abstract

We study the process of the Primordial Black Holes (PBHs) production in the novel framework, namely α-attractor Galileon inflation (G-inflation) model. In our framework, we take the Galileon function asG(ϕ)=GI(ϕ)(1+GII(ϕ)), where the partGI(ϕ) is motivated from the α-attractor inflationary scenario in its original non-canonical frame, and it ensures for the model to be consistent with the Planck 2018 observations at the CMB scales. The part GII(ϕ) is invoked to enhance the curvature perturbations at some smaller scales which in turn gives rise to PBHs formation. By fine-tuning of the model parameters, we find three parameter sets which successfully produce a sufficiently large peak in the curvature power spectrum. We show that these parameter sets produce PBHs with masses Script O(10)M☉, Script O(10-5)M☉, and Script O(10-13)M☉ which can explain the LIGO events, the ultrashort-timescale microlensing events in OGLE data, and around 0.98% of the current Dark Matter (DM) content of the universe, respectively. Additionally, we study the secondary Gravitational Waves (GWs) in our setup and show that our model anticipates the peak of their present fractional energy density as ΩGW0 ∼ 10-8 for all the three parameter sets, but at different frequencies. These predictions can be located well inside the sensitivity region of some GWs detectors, and therefore the compatibility of our model can be assessed in light of the future data. We further estimate the tilts of the included GWs spectrum in the different ranges of frequency, and confirm that spectrum follows the power-law relation ΩGW0 ∼ fn in those frequency bands.