Searching for axion dark matter, the ADMX Collaboration acquired data from January to October 2018, over the mass range $2.81–3.31\mathrm{\mu }\mathrm{eV}$, corresponding to the frequency range 680–790 MHz. Using an axion haloscope consisting of a microwave cavity in a strong magnetic field, the ADMX experiment excluded Dine-Fischler-Srednicki-Zhitnisky (DFSZ) axions at 90% confidence level and 100% dark matter density over this entire frequency range, except for a few gaps due to mode crossings. This paper explains the full ADMX analysis for run 1B, motivating analysis choices informed by details specific to this run.

• Received 14 October 2020
• Accepted 4 January 2021

DOI:https://doi.org/10.1103/PhysRevD.103.032002