The Minimum Primordial Black Hole Mass Surviving to the Present Day

Evaporation divides the primordial black hole population into two classes with entirely different observational lives. Objects heavy enough to survive to the present day can constitute dark matter and are hunted by lensing and dynamics; objects lighter than the survival mass have already vanished, and their only legacy is the radiation and particles they injected into the universe, hunted instead through background light, nucleosynthesis, and the microwave background. The headline computed values are: M star g = 3.144e+14; M star kg = 3.144e+11. The work is computational throughout: assumptions are stated, the arithmetic is deposited, and no result is presented as a measurement.