Danielle Speller
INVISIBLE WORLDS: Searching for Axion Dark Matter with the HAYSTAC Experiment
The nature of dark matter is one of the most elusive puzzles in modern physics. With the absence of the discovery of traditional candidates like the WIMP, there has been a strong resurgence of interest in low mass and very light candidates, such as the axion. The Haloscope At Yale Sensitive To Axion CDM (HAYSTAC) is a tunable microwave cavity axion search experiment sensitive to significant regions of the cosmologically relevant mass range for an axion dark matter candidate.  In 2017, the HAYSTAC experiment reached sensitivities of order 2x10-14 GeV-1 in the mass range 23.55 < m_a < 24.0 micro-eV, in a mass range unreached by previously existing haloscope limits.  HAYSTAC is now incorporating the improvements from the 2017 run with a new squeezed-state receiver system and significant upgrades to the cryogenics system in preparation for phase II.