PBH Bounds from Gas Cooling and PBH Formation in High Temperature QCD Transitions

by Dr Philip Lu (Seoul National University)

Tuesday 9 May 2023, 14:00 → 15:30 Asia/Seoul

1423 in building 1 (KIAS)

Title: PBH Bounds from Gas Cooling and PBH Formation in High Temperature QCD Transitions

Speaker: Philip Lu (Seoul National University)

Abstract: I will introduce a set of bounds on the primordial black hole (PBH) mass density. By considering stable gas clouds in thermal equilibrium, we can calculate the cooling rate and impose constraints on possible heating processes. Intermediate mass black holes, which can form efficient accretion disks, and light black holes, which emit Hawking radiation, would generate significant amounts of thermal energy. We set limits on the dark matter fraction of PBH as a result and briefly explore the possible contributions from jets. In the second half of the talk, I will discuss a PBH formation model from critical collapse that involves a high temperature QCD transition. A first order QCD transition softens the equation of state parameter and facilitates PBH formation. By considering a higher-temperature QCD transition, we can generate the relevant mass scales for the claimed OGLE and HSC microlensing detections as well as a dark matter population in the mass window.

PBH_ Cloud Cooling Bounds and High Temperature QCD Formation.pdf

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