%0 Generic %1 carr2020black %A Carr, Bernard %A Kuhnel, Florian %A Visinelli, Luca %D 2020 %K journal_club %T Black Holes and WIMPs: All or Nothing or Something Else %U http://arxiv.org/abs/2011.01930 %X We consider constraints on primordial black holes (PBHs) in the mass range $( 10^-18$ - $10^15 )\,M_ødot$ if the dark matter (DM) comprises weakly interacting massive particles (WIMPs) which form halos around them and generate $\gamma$-rays by annihilations. The observed extragalactic $\gamma$-ray background then implies that the PBH DM fraction is $f^_PBH łesssim 10^-10\,( m_\chi / TeV )^1.1$ in the mass range $2 \times 10^-11\,M_ødot\,( m_\chi / TeV )^-3.2 M 3 10^11\,M_ødot\,( m_\chi / TeV )^1.1$, where $m_\chi$ and $M$ are the WIMP and PBH masses, respectively. This limit is independent of $M$ and therefore applies for any PBH mass function.For $M 2\times 10^-11\,M_ødot\,( m_\chi / TeV )^-3.2$, the constraint on $f^_PBH$ is a decreasing function of $M$ and PBHs could still make a significant DM contribution at very low masses. We also consider constraints on WIMPs if the DM is mostly PBHs. If the merging black holes recently discovered by LIGO/Virgo are of primordial origin, this would rule out the standard WIMP DM scenario. More generally, the WIMP DM fraction cannot exceed $10^-4$ for $M > 10^-9\,M_ødot$ and $m_\chi >10\,$GeV. There is a region of parameter space, with $M 10^-11\,M_ødot$ and $m_\chi łesssim 100\,$GeV, in which WIMPs and PBHs can both provide some but not all of the DM, so that one requires a third DM candidate.

@misc{carr2020black, abstract = {We consider constraints on primordial black holes (PBHs) in the mass range $( 10^{-18}$ - $10^{15} )\,M_{\odot}$ if the dark matter (DM) comprises weakly interacting massive particles (WIMPs) which form halos around them and generate $\gamma$-rays by annihilations. The observed extragalactic $\gamma$-ray background then implies that the PBH DM fraction is $f^{}_{\rm PBH} \lesssim 10^{-10}\,( m_{\chi} / {\rm TeV} )^{1.1}$ in the mass range $2 \times 10^{-11}\,M_{\odot}\,( m_{\chi} / {\rm TeV} )^{-3.2} \lesssim M \lesssim 3 \times 10^{11}\,M_{\odot}\,( m_{\chi} / {\rm TeV} )^{1.1}$, where $m_{\chi}$ and $M$ are the WIMP and PBH masses, respectively. This limit is independent of $M$ and therefore applies for any PBH mass function.For $M \lesssim 2\times 10^{-11}\,M_{\odot}\,( m_{\chi} / {\rm TeV} )^{-3.2}$, the constraint on $f^{}_{\rm PBH}$ is a decreasing function of $M$ and PBHs could still make a significant DM contribution at very low masses. We also consider constraints on WIMPs if the DM is mostly PBHs. If the merging black holes recently discovered by LIGO/Virgo are of primordial origin, this would rule out the standard WIMP DM scenario. More generally, the WIMP DM fraction cannot exceed $10^{-4}$ for $M > 10^{-9}\,M_{\odot}$ and $m_{\chi} >10\,$GeV. There is a region of parameter space, with $M \lesssim 10^{-11}\,M_{\odot}$ and $m_{\chi} \lesssim 100\,$GeV, in which WIMPs and PBHs can both provide some but not all of the DM, so that one requires a third DM candidate.}, added-at = {2020-11-09T07:05:56.000+0100}, author = {Carr, Bernard and Kuhnel, Florian and Visinelli, Luca}, biburl = {https://www.bibsonomy.org/bibtex/262bc2668740687ef9dca94fcd41a397b/bhvzchhn}, description = {[2011.01930] Black Holes and WIMPs: All or Nothing or Something Else}, interhash = {8966ac286022b1275015935b8bbcd650}, intrahash = {62bc2668740687ef9dca94fcd41a397b}, keywords = {journal_club}, note = {cite arxiv:2011.01930Comment: 12 pages, 4 figures and one table}, timestamp = {2020-11-09T07:05:56.000+0100}, title = {Black Holes and WIMPs: All or Nothing or Something Else}, url = {http://arxiv.org/abs/2011.01930}, year = 2020 }