Hybrid $\hat{I}\pm$-attractors, primordial black holes and gravitational wave backgrounds

Abstract

We investigate the two-stage inflation regime in the theory of hybrid cosmological $\hat{I}\pm$-attractors. The spectrum of inflationary perturbations is compatible with the latest Planck/BICEP/Keck results, thanks to the attractor properties of the model. However, at smaller scales, it may have a very high peak of controllable width and position, leading to a copious production of primordial black holes (PBH) and generation of a stochastic background of gravitational waves (SGWB).

39 pages, 12 figures, v2: references added, minor modifications, matches JCAP version