Negative non-Gaussianity as a salvager for PBHs with PTAs in bounce

Fuente: arXiv
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Main Authors: Choudhury, Sayantan, Dey, Kritartha, Ganguly, Siddhant, Karde, Ahaskar, Singh, Swapnil Kumar, Tiwari, Pranjal
Format: Preprint
Published: 2024
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author Choudhury, Sayantan
Dey, Kritartha
Ganguly, Siddhant
Karde, Ahaskar
Singh, Swapnil Kumar
Tiwari, Pranjal
author_facet Choudhury, Sayantan
Dey, Kritartha
Ganguly, Siddhant
Karde, Ahaskar
Singh, Swapnil Kumar
Tiwari, Pranjal
contents Non-Gaussianity in the primordial curvature perturbation is a crucial element of the early universe due to its significant impact on the primordial black hole (PBH) production. In this work, we focus on the effects of negative non-Gaussianity on PBH abundance through the lens of the compaction function criterion for PBH formation. Our setup utilizes an effective field theory of non-singular bounce, including the standard slow-roll inflation with an ultra-slow roll phase for amplifying the curvature perturbations to form PBHs. We investigate with two separate values of the non-Gaussianity parameter, $f_{\rm NL}=(-39.95,-35/8)$, found within the ekpyrotic contraction and the matter bounce scenarios, respectively, and show that a negatively large amount of $f_{\rm NL}$ can provide sizeable abundance, $10^{-3}\leq f_{\rm PBH}\leq 1$, and completely mitigates the PBH overproduction issue. We also highlight that the case with the effective sound speed $c_{s}=1$, coupled with $f_{\rm NL}=-39.95$, provides an agreement under $1σ$ for the scalar-induced gravitational wave explanation of the latest PTA (NANOGrav15 and EPTA) signal. Lastly, we extract an upper bound on the most negative value of, $f_{\rm NL}\sim -60$, below which we show breaching of the underlying perturbativity constraints on the power spectrum amplitude.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18983
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Negative non-Gaussianity as a salvager for PBHs with PTAs in bounce
Choudhury, Sayantan
Dey, Kritartha
Ganguly, Siddhant
Karde, Ahaskar
Singh, Swapnil Kumar
Tiwari, Pranjal
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
Non-Gaussianity in the primordial curvature perturbation is a crucial element of the early universe due to its significant impact on the primordial black hole (PBH) production. In this work, we focus on the effects of negative non-Gaussianity on PBH abundance through the lens of the compaction function criterion for PBH formation. Our setup utilizes an effective field theory of non-singular bounce, including the standard slow-roll inflation with an ultra-slow roll phase for amplifying the curvature perturbations to form PBHs. We investigate with two separate values of the non-Gaussianity parameter, $f_{\rm NL}=(-39.95,-35/8)$, found within the ekpyrotic contraction and the matter bounce scenarios, respectively, and show that a negatively large amount of $f_{\rm NL}$ can provide sizeable abundance, $10^{-3}\leq f_{\rm PBH}\leq 1$, and completely mitigates the PBH overproduction issue. We also highlight that the case with the effective sound speed $c_{s}=1$, coupled with $f_{\rm NL}=-39.95$, provides an agreement under $1σ$ for the scalar-induced gravitational wave explanation of the latest PTA (NANOGrav15 and EPTA) signal. Lastly, we extract an upper bound on the most negative value of, $f_{\rm NL}\sim -60$, below which we show breaching of the underlying perturbativity constraints on the power spectrum amplitude.
title Negative non-Gaussianity as a salvager for PBHs with PTAs in bounce
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
High Energy Physics - Phenomenology
High Energy Physics - Theory
url https://arxiv.org/abs/2409.18983