Joint HEP/Theory Seminar: ABRACADABRA, A Broadband Search for Axion Dark Matter

ABRACADABRA is a proposed experiment to search for ultralight (10^-14 - 10^-6 eV) axion dark matter, with the ultimate goal of probing the QCD axion at the GUT scale. When ultralight axion dark matter encounters a static magnetic field, it sources an effective electric current that follows the magnetic field lines and oscillates at the axion Compton frequency. In the presence of axion dark matter, a large toroidal magnet will act like an oscillating current ring, whose induced magnetic flux can be measured by an external pickup loop inductively coupled to a SQUID magnetometer. The readout circuit can be broadband or resonant and both are considered. ABRACADABRA is fielding a 10-cm prototype in 2017 with the intention of scaling to a 1m^3 experiment. In this talk I will review the design, sources of noise, and sensitivity of the experiment. I will also discuss the proposed 10-cm prototype.