Primordial black hole formation from non-Gaussian curvature perturbations

Abstract: We consider several early Universe models that allow for production of large curvature perturbations at small scales. As is well known, such perturbations can lead to formation of primordial black holes (PBHs). We briefly review the today's situation with PBH constraints and then focus on two models in which strongly non-Gaussian curvature perturbations are predicted: the hybrid inflation waterfall model and the curvaton model. We show that PBH constraints on the values of curvature perturbation power spectrum amplitude are strongly dependent on the shape of perturbations and can significantly (by two orders of magnitude) deviate from the usual Gaussian limit ${\cal P}_\zeta \lesssim 10^{-2}$. We give examples of PBH mass spectra calculations for both inflationary models.