Oct 2023 - Sep 2024

Evaporating (and exploding) Primordial Black Holes

by Quim Iguaz Juan



I will revisit the constraints on evaporating primordial black holes (PBHs) from the isotropic soft $\gamma$-ray background and the diffuse soft $\gamma$-ray emission towards the inner Galaxy in the mass range $10^{16}$− $10^{18}$ g. For the first set of bounds (isotropic), we find that they are stronger than usually inferred due to two neglected effects: i) The contribution of the annihilation radiation due to positrons emitted in the evaporation process. ii) The high-latitude, Galactic contribution to the measured isotropic flux. For the second set (galactic), we analyze 16 years of data taken by the INTEGRAl satellite and implement a spatial template fit and an improved instrumental background model. No PBH signal is detected, and we set the strongest limit on PBH DM for masses up to $4 \times 10^{17}$ g, significantly closing in into the so-called asteroid mass range. I will also discuss how the results are modified for non-spinning PBHs and for extended mass functions. In the last part of the talk, I will briefly discuss the possibility of detecting an exploding PBH with current experimental facilities (HAWC) and the conditions needed to detect such an unprecedented event.