Experimental Limits on Planetary Mass Primordial Black Hole Mergers

TL;DR

This paper reports on the MAGE experiment's efforts to detect high-frequency gravitational waves from primordial black hole mergers, setting new limits on merger rates and excluding certain background signals after 61 days of data collection.

Contribution

It introduces the MAGE experiment's methodology and results, providing the first bounds on primordial black hole merger rates in the MHz gravitational wave regime.

Findings

Set upper bounds on primordial black hole merger rates.

Excluded strong non-gravitational background signals.

Achieved sensitivity reaching the scale of the solar system.

Abstract

The multi-mode acoustic gravitational wave experiment (MAGE) is a high-frequency gravitational wave detection experiment featuring cryogenic quartz bulk acoustic wave resonators operating as sensitive strain antennas in the MHz regime. After 61 days of non-continuous data collection, we present bounds on the observable merger rate density of primordial black hole binary systems of chirp mass $1.2\times10^{-4}M_\odot<\mathcal{M}<1.7\times10^{-9}M_\odot$. The maximum achieved limit on the merger rate density is $\mathcal{R}>1.3\times10^{18}~\mathrm{kpc}^{-3}\mathrm{yr}^{-1}$ which corresponds to constraining yearly mergers to a distance of reach on the order of the solar system, or $1.0\times10^{-6}$ kpc during the observational period. In addition, we exclude significantly rare and strong events similar to those observed in previous predecessor experiments as non-gravitational background signals, utilising coincident analysis between multiple detectors.