ADAMOS: Axion Daily Modulation Searches for Dark Matter at 20 GHz

Abstract: The ADAMOS (Axion Daily Modulation Searches) project aims to explore the nature of dark matter (DM) through a novel axion haloscope experiment. We propose to construct a fixed-frequency cavity resonator operating at 20 GHz at the University of Hamburg, using an innovative "thin-shell" design that preserves a large detection volume at high frequencies. The experiment will be installed in an existing 14 T superconducting magnet and connected to a highly sensitive RF chain with continuous in situ calibration to eliminate temperature-dependent gain drifts, constituting an essential improvement based on lessons learned from previous attempts. ADAMOS will conduct simultaneous searches for three classes of axion signals: (1) conventional cold DM axions, (2) relativistic axions from axion quark nugget annihilations exhibiting daily modulations, and (3) transient enhancements from streaming DM. By targeting this unexplored frequency regime with a robust, calibrated, and versatile setup, ADAMOS will open new discovery channels in a previously unexplored region of the dark sector.