New probe of non-Gaussianities with primordial black hole induced gravitational waves

• DOI: 10.1016/j.physletb.2024.138997
• Publication Date: 2024-09-03T16:30:29Z
• Authors: Theodoros Papanik...; Xin-Chen He; Xiao-Han Ma; Yi-Fu Cai; Emmanuel N. Sarid...; Misao Sasaki
• Keywords: Primordial black hole; Black hole (networking)

We propose a new probe of primordial non-Gaussianities (NGs) through the observation gravitational waves (GWs) induced by ultra-light (MPBH<109g) black holes (PBHs). Interestingly enough, existence NG can leave imprints on clustering properties PBHs and spectral shape GW signals. Focusing scale-dependent local-type NG, we identify distinct double-peaked energy spectrum that, contingent upon MPBH abundance at time formation, denoted as ΩPBH,f, may fall into frequency bands upcoming observatories, including LISA, ET, SKA, BBO. Thus, such signal serve novel portal for probing NGs. Intriguingly, combining BBN bounds amplitude, find first joint limit product effective non-linearity parameter tri-spectrum, τ¯NL, curvature perturbation power PR(k), which reads τ¯NLPR(k)<4×10−20ΩPBH,f−17/9(MPBH104g)−17/9.