BSM PANDEMIC Delta Series: Anna-Maria Taki (Oregon) and Marios Galanis (Stanford)

by Anna-Maria Taki (University of Oregon), Marios Galanis (Stanford University)



Anna-Maria Taki:   Astrophysical Uncertainties in Dark Matter-Electron Scattering & How to Evade Them

Abstract:   Dark matter-electron scattering calculations are sensitive to the choice of the underlying dark matter halo velocity distribution and its associated astrophysical parameters. In this talk, I will give a brief overview of the leading halo models and the parameters which enter them and show how astrophysical uncertainties impact the interpretation of experimental results. I will also introduce work from an ongoing effort to analyze and present data from dark matter-electron experiments in a halo-independent manner, without invoking any astrophysical assumptions.


Marios Galanis:   Black hole superradiance

Abstract:   Black hole superradiance is a powerful probe of bosonic, light, weakly-coupled hidden sector particles. Particles with a Compton wavelength comparable to the black hole’s radius lead to an instability, extracting mass and angular momentum from the black hole. Many ultralight candidates, such as axions, generically have self-interactions that can influence the evolution of the superradiant instability.  Self-interactions lead to energy exchange between bound levels and particle emission to infinity; for large self-couplings, superradiant growth is saturated at a quasi-equilibrium configuration of reduced level occupation numbers. In this talk, I will review the basic aspects of black hole superradiance and give a qualitative picture of how it changes when quartic self-interactions are present. Finally, I will discuss possible signatures, which include coherent, monochromatic gravitational and axion waves that can be probed in current or future experiments.