  Supermassive black holes and intermediate mass black holes are believed to
exist in the Universe. There is no established astrophysical explanation for
their origin and considerations have been made in the literature that those
massive black holes (MBHs) may be primordial black holes (PBHs), black holes
which are formed in the early universe (well before the matter-radiation
equality) due to the direct collapse of primordial overdensities. This paper
aims at discussing the possibility of excluding the PBH scenario as the origin
of the MBHs. We first revisit the constraints on PBHs obtained from the CMB
distortion that the seed density perturbation causes. By adopting a recent
computation of the CMB distortion sourced by the seed density perturbation and
the stronger constraint on the CMB distortion set by the COBE/FIRAS experiment
used in the literature, we find that PBHs in the mass range $6\times
10^4~M_\odot \sim 5 \times 10^{13}~M_\odot$ are excluded. Since PBHs lighter
than $6 \times 10^4~M_\odot$ are not excluded from the non-observation of the
CMB distortion, we propose a new method which can potentially exclude smaller
PBHs as well. Based on the observation that large density perturbations
required to create PBHs also result in the copious production of ultracompact
minihalos (UCMHs), compact dark matter halos formed at around the
recombination, we show that weakly interacting massive particles (WIMPs) as
dark matter annihilate efficiently inside UCMHs to yield cosmic rays far
exceeding the observed flux. Our bound gives severe restriction on the
compatibility between the particle physics models for WIMPs and the PBH
scenario as the explanation of MBHs.
