"Dark" Series Colloquium 6# Dark Radiation and Superheavy Dark Matter from Hawking Evaporation of Primordial Black Holes

by Prof. Dan Hooper (The University of Chicago & Fermilab)

Thursday 14 Oct 2021, 10:00 → 11:00 Asia/Shanghai

If even a relatively small number of black holes were created in the early universe, they will constitute an increasingly large fraction of the total energy density as space expands. It is thus well-motivated to consider scenarios in which the early universe included an era in which primordial black holes dominated the total energy density. Within this context, we consider Hawking radiation as a mechanism to produce both dark radiation and dark matter. If the early universe included a black hole dominated era, we find that Hawking radiation will produce dark radiation at a level of delta N_eff ~0.03-0.2 for each light and decoupled species of spin 0, 1/2, or 1. This range is well suited to relax the tension between late and early-time Hubble determinations, and is within the reach of upcoming CMB experiments. The dark matter could also originate as Hawking radiation in a black hole dominated early universe, although such dark matter candidates must be very heavy (m_DM > 10^11 GeV) if they are to avoid exceeding the measured abundance. Zoom： https://zoom.com.cn/j/96357968034?pwd=K2REeGF0V2dqOElRd09hVGVRcDk4Zz09 or https://cern.zoom.us/j/96357968034?pwd=K2REeGF0V2dqOElRd09hVGVRcDk4Zz09 Meeting ID: 963 5796 8034 Password: 125125