The Hunt for Halo Axions
The hunt for dark matter continues. One plausible possibility is that a portion of the dark matter consists of hidden sector fields - low mass particles whose couplings to the baryonic sector are suppressed. The prototypical example is the axion - the Goldstone boson associated with breaking of the Peccei Quinn symmetry introduced to make QCD CP-conserving. Axions in our halo could be detected through Primakoff conversion into photons in a magnetic field, where the photons are detected in a resonant structure - typically a cavity threading the magnetic field region. I will describe the ADMX experiment and present recent results. I will then introduce a novel resonant structure that might replace the cavity, and show how this resonant feedback detector could significantly increase the search rate in ADMX, other axion searches, and any hidden sector experiment that uses a resonant detector.