相关论文: Extragalactic neutrino background from PBHs evapor…
We revisit the constraints on evaporating primordial black holes (PBHs) from the isotropic X-ray and soft gamma-ray background in the mass range $10^{16}-10^{18}$ g. We find that they are stronger than usually inferred due to two neglected…
The explorations of alternative dark matter (DM) candidates beyond WIMP motivated primordial black holes (PBHs) or sub-GeV DM particle in the Milky Way. Neutrinos from PBH evaporation at the present times play as a novel medium boosting…
We investigate the constraint on the abundance of primordial black holes (PBHs) and the spectral index $n$ of primeval density perturbations given by the ionizing photon background at the epoch of reionization. Within the standard…
Light primordial black holes (PBHs) may have originated in the early Universe, and could contribute to the dark matter in the Universe. Their Hawking evaporation into particles could eventually lead to the production of antinuclei, which…
We study the Primordial Black Hole (PBH) reheating scenario, where PBHs originate in a general cosmological background. In this scenario, ultralight PBHs with masses $M\lesssim 10^8$g temporarily dominate the Universe and reheat it via…
Large-amplitude density perturbations may have collapsed during the radiation dominated epoch of the Universe to form primordial black holes (PBHs). There are several constraints to the abundance of PBHs that stem from evaporation or…
At times prior to Big Bang Nucleosynthesis, the universe could show a primordial structure formation period if dominated by a fast oscillating inflaton field during reheating. In this context, we have postulated a new mechanism of…
The spectrum of neutrinos produced by the outflow of high temperature matter surrounding microscopic black holes is calculated for neutrino energies between one GeV and the Planck energy. The results may be applicable for the last few hours…
Primordial black holes (PBHs) are a potential dark matter candidate whose masses can span over many orders of magnitude. If they have masses in the $10^{15}-10^{17}$ g range, they can emit sizeable fluxes of MeV neutrinos through…
The amount of late decaying massive particles (e.g., gravitinos, moduli) produced in the evaporation of primordial black holes (PBHs) of mass $\Mbh\la10^9 $g is calculated. Limits imposed by big-bang nucleosynthesis on the abundance of…
We present precision calculations of dark radiation in the form of gravitons coming from Hawking evaporation of spinning primordial black holes (PBHs) in the early Universe. Our calculation incorporates a careful treatment of extended spin…
We determine the abundance of primordial black holes (PBHs) formed in the context of non-gaussian models with primordial density perturbations. We consider models with a renormalized $\chi^2$ probability distribution function parametrized…
Sterile neutrinos ($\nu_s$s) are well-motivated and actively searched for hypothetical neutral particles that would mix with the Standard Model active neutrinos. They are considered prime warm dark matter (DM) candidates, typically when…
The quantum gravity scale within the dark dimension scenario ($M_* \sim 10^{9}~{\rm GeV}$) roughly coincides with the energy scale of the KM3-230213A neutrino ($E_\nu \sim 10^{8}~{\rm GeV}$). We propose an interpretation for this intriguing…
Observational constraints on the abundance of primordial black holes (PBHs) constrain the allowed amplitude of the primordial power spectrum on both the smallest and the largest ranges of scales, covering over 20 decades from $1-10^{20}/…
Evidences for the primordial black holes (PBH) presence in the early Universe renew permanently. New limits on their mass spectrum challenge existing models of PBH formation. One of the known model is based on the closed walls collapse…
The fraction of the Universe going into primordial black holes (PBHs) with initial mass M_* \approx 5 \times 10^{14} g, such that they are evaporating at the present epoch, is strongly constrained by observations of both the extragalactic…
Possibilities of an experimental search for gamma-ray bursts from primordial black hole (PBH) evaporations in space are reconsidered. It is argued that the corresponding constraints which can be obtained in experiments with cosmic ray…
The existence (and abundance) of primordial black holes (PBHs) is governed by the power spectrum of primordial perturbations generated during inflation. So far no PBHs have been observed, and instead, increasingly stringent bounds on their…
We consider the possibility of primordial black hole, PBH, formation sourced by a rise in the power spectrum. The power spectrum becomes large at late times due to decay of the inflaton into vectors through a $\phi F \tilde{F}$ coupling.…