arXiv subjects

Amane Takeshita

Publications and source records attributed to Amane Takeshita.

2 recordsLinked to original sources

arXiv2026

WIMP/FIMP dark matter and primordial black holes with memory burden effect

The lifetime of primordial black holes (PBHs), which formed in the early universe, can be extended by the memory burden effect. Light PBHs may exist today and be candidates for dark matter (DM). We assume that DM is made of thermally produced weakly interacting massive particles (WIMPs), WIMPs produced via the Hawking radiation of PBHs, and PBHs that survived Hawking evaporation via the memory burden effect. Feebly interacting massive particles (FIMPs) are alternatives to WIMPs. Focusing on parameter regions where thermal production dominates and PBHs never dominate the energy density of the Universe, we identify a sufficient condition under which DM particles emitted from PBHs do not thermalize with the thermal bath. In this regime, the total DM relic abundance can be consistently obtained as the sum of the three components. In addition, we show that the contribution from gravitational freeze-in via graviton exchange remains subdominant within the parameter space considered.

hep-ph↗

arXiv2025

Interstellar medium gas heating by primordial black holes and dark matter particles

The Leo T dwarf galaxy has been utilized to investigate the heating of interstellar medium gas by both primordial black holes (PBHs) and dark matter (DM) particles. Previous studies have typically assumed that either PBHs or DM particles are responsible for heating the interstellar medium gas. In contrast, this study considers the simultaneous contribution of both PBHs and DM particles to the heating process. If both PBHs and dark photons heat the gas in Leo T, a stringent constraint on the PBH fraction, $f_{\rm PBH}=ρ_{\rm PBH}/ρ_{\rm DM}$ is obtained for $4 \lesssim M_{\rm PBH}/M_\odot \lesssim 10^2$, where $ρ_{\rm PBH}$, $ρ_{\rm DM}$, represent the energy densities of PBHs and DM, respectively, and $M_{\rm PBH}$, and $M_\odot$ denote the masses of PBHs and Sun, respectively. Conversely, if both PBHs and millicharged particles heat the gas, it becomes challenging to impose a more significant constraint on the PBH fraction than previously achieved, due to the very small allowed values of charge parameters within the model.

hep-ph↗