Femtolensing by Dark Matter

by Wei Xue (CERN)

Tuesday, 30 October 2018 from to (Europe/Vienna)
at HEPHY ( Library )
Femtolensing of gamma ray bursts (GRBs) has been put forward as an exciting possibility to probe exotic astrophysical objects with masses below 10^−13 solar masses such as small primordial black holes or ultra-compact dark matter minihalos, made up for instance of QCD axions. In this talk I will review this idea, properly taking into account the extended nature of the source as well as wave optics effects. I will demonstrate that most GRBs are inappropriate for femtolensing searches due to their large sizes. This removes the previous femtolensing bounds on primordial black holes, implying that vast regions of parameter space for primordial black hole dark matter are not robustly constrained.