Speaker
Description
Primordial black holes form with an extended mass function whose shape encodes the physics of their formation. As the universe ages, Hawking evaporation reshapes that function, eroding it from below and thereby fixing the distribution that present observational constraints actually probe. An analytic parametrization of this object underlies every downstream analysis, yet the fitting forms in current use are tied to specific formation scenarios, lose accuracy in the tails that dominate observations, and surrender their shape the moment evaporation begins. In this talk I present a single analytic family with four parameters that spans the standard formation scenarios and repairs all of these failures at once. The mass functions of common practice arise as exact limits or boundaries of this family, so nothing already established is discarded. More surprisingly, the family is not merely compatible with evaporation but selected by it. When primordial black holes lose mass through Hawking emission governed by a power law, a subfamily fixed by that law is exactly invariant, evolution across it reduces to the linear drift of a single scale together with an elementary survival factor, and whatever accuracy a fit achieves at formation it retains at every later epoch. A numerical survey spanning lognormal, critical collapse and power law progenitors quantifies the general case and distills the results into a practical prescription for constraint work.