Primordial black hole formation in $α$-attractor models: an analysis using optimized peaks theory [CEA]

http://arxiv.org/abs/2103.15957


In this paper, the formation of primordial black holes (PBHs) is reinvestigated using inflationary $\alpha$-attractors. Instead of using the conventional Press-Schechter theory to compute the abundance, the optimized peaks theory is used, which was developed in Ref. \cite{Yoo:2018kvb,Yoo:2020dkz}. This method takes into account how curvature perturbations play a rôle in modifying the mass of primordial black holes. Analyzing the model proposed in \cite{Mahbub:2019uhl} it is seen that the horizon mass of the collapsed Hubble patch is larger by $\mathcal{O}(10^2)$ compared to the usual computation. Moreover, PBHs can be formed from curvature power spectrum, $\mathcal{P}_{\zeta}(k)$, peaked at lower values using numerically favored threshold overdensities. As a result of the generally larger masses predicted, the peak of the power spectrum can be placed at $k>10^{15}\text{Mpc}^{-1}$ with which potential future constraints on the primordial power spectrum through gravitational waves (GWs) can be evaded.

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R. Mahbub
Wed, 31 Mar 2021
33/62

Comments: 13 pages, 8 captioned figures