Can massive primordial black holes be produced in mild waterfall hybrid inflation?

Abstract

We studied the possibility whether the massive primordial black holes (PBHs)\nsurviving today can be produced in hybrid inflation. Though it is of great\ninterest since such PBHs can be the candidate for dark matter or seeds of the\nsupermassive black holes in galaxies, there have not been quantitatively\ncomplete works yet because of the non-perturbative behavior around the critical\npoint of hybrid inflation. Therefore, combining the stochastic and $\\delta N$\nformalism, we numerically calculated the curvature perturbations in a\nnon-perturbative way and found, without any specific assumption of the types of\nhybrid inflation, PBHs are rather overproduced when the waterfall phase of\nhybrid inflation continues so long that the PBH scale is well enlarged and the\ncorresponding PBH mass becomes sizable enough.\n