Black hole formation by the waterfall field of hybrid inflation.
Lyth, David (Lancaster University)

A contribution to the curvature perturbation will be generated by the waterfall field of hybrid inflation. Following our earlier work arXiv:1012.4617, we identify the region of parameter space within which this contribution leads to the overproduction of primordial black holes. Our finding is applied to well-motivated models, including GUT hybrid inflation.