Search for non-virialized axions with 3.3-4.2 $\mu$eV mass at selected resolving powers

TL;DR

This study searches for narrow axion flows within a specific mass range using high spectral resolution, setting new limits on local axion dark matter density for certain coupling models.

Contribution

It provides the first constraints on non-virialized axion flows in the 3.3-4.2 μeV mass range with high spectral resolution measurements.

Findings

Excluded axion dark matter density above 0.03 GeV/cm^3 for Dine-Fischler-Srednicki-Zhitnitski coupling.

Excluded axion dark matter density above 0.004 GeV/cm^3 for Kim-Shifman-Vainshtein-Zakharov coupling.

Demonstrated the importance of spectral resolution in detecting low-velocity dispersion axion flows.

Abstract

The Axion Dark Matter eXperiment is sensitive to narrow axion flows, given axions compose a fraction of the dark matter with a non-negligible local density. Detecting these low-velocity dispersion flows requires a high spectral resolution and careful attention to the expected signal modulation due to Earth's motion. We report an exclusion on the local axion dark matter density in narrow flows of $\rho_a \gtrsim 0.03\,\mathrm{GeV/cm^3}$ and $\rho_a \gtrsim 0.004\,\mathrm{GeV/cm^3}$ for Dine-Fischler-Srednicki-Zhitnitski and Kim-Shifman-Vainshtein-Zakharov axion-photon couplings, respectively, over the mass range $3.3-4.2\,\mu\text{eV}$. Measurements were made at selected resolving powers to allow for a range of possible velocity dispersions.