Primordial cosmological collapse to regular black holes with finite-mass extremal endpoints

We investigate how short-distance regularization may affect primordial-black-hole (PBH) dark matter at both formation and late times. On the formation side, we develop an effective model of primordial collapse to regular black holes during radiation domination by promoting static Hayward-, Bardeen- and Dymnikova-type mass profiles to local excess-mass prescriptions within the Misner–Sharp and compaction-function framework. The resulting regular core suppresses short-distance compaction and raises the threshold for horizon-bearing collapse; in the Hayward case, the leading correction scales as ( ²/Rₘ²), where (ℓ) is the regularization scale and (Rm) is the radius of maximum compaction. The common sign is a feature of the three effective maps studied here, whereas the magnitude of the true nonlinear collapse-threshold shift is model dependent. On the late-time side, we adopt the Hayward, Bardeen and Dymnikova geometries as benchmark evaporation completions and show that their finite-mass extremal endpoints obey the universal geometric scaling (TH∝(M − M*)1/2). Within the Stefan–Boltzmann vacuum approximation, this implies asymptotically slow evaporation, (M(t) − M*∝t−1), and motivates a transport framework for evolving PBH populations and their gamma-ray signal. Short-distance regularization therefore acts in opposite directions on PBH dark matter, suppressing primordial production while enhancing late-time survival. We argue that any realistic assessment of nonsingular PBH dark matter should treat these two sectors simultaneously. The physical-unit evolution, however, establishes no observationally allowed dark-matter region; it provides only branch-consistent mass-flow and single-energy emission diagnostics.