Improving Axion Signal Models Through N-Body Simulations

Abstract

The QCD axion is a well-motivated candidate for solving both the strong CP and dark matter problems. A great deal would be revealed about physics both on the level of fundamental particles and astronomy if the axion were detected to be the primary component of dark matter. A number of experimental searches for dark matter axions are currently operating under a weakly-motivated signal shape, which degrades the significance of their findings. Modern structure-formation simulations are capable of producing robust estimates of potential axion signals, and further may resolve a standing question in the literature: do axions form unique structures on galactic scales due to their unique state as a highly degenerate Bose fluid, or are they indistinguishable from a pressure-less fluid? This dissertation addresses the unique structure problem and provides a robust axion signal shape in the pressure-less fluid limit. These theoretical findings are then applied to the most recent data run of the Axion Dark Matter eXperiment, the world's most sensitive axion search. The narrower profile of the updated signal model drastically increases the discovery potential for ADMX. Preliminary findings also show that axions do contain the potential for unique structure formation on galactic scales.