Searching for dark photons with existing haloscope data

Sumita Ghosh,E P Ruddy,A F Leder,R H Maruyama,M J Jewell

doi:10.1103/physrevd.104.092016

Abstract

The dark (or hidden) photon is a massive U(1) gauge boson theorized as a dark force mediator and as a dark matter candidate. Dark photons can be detected with axion cavity haloscopes by probing for a power excess caused by the dark photon's kinetic mixing with Standard Model photons. Haloscope axion exclusion limits may therefore be converted into competitive dark photon parameter limits via the calculation of a corresponding dark photon to photon coupling factor. This calculation allows for an improvement in sensitivity of around four orders of magnitude relative to other dark photon exclusions and may be attained using existing data. We present how one converts haloscope axion search limits and a summary of relevant experimental parameters from published searches. In addition, we have included the code that can be used to generate our dark photon exclusion limits for the cases described in this paper. Finally, we present limits on the kinetic mixing coefficient between dark photons and the Standard Model photons based on existing haloscope axion searches.

Highlights

Astrophysical observations suggest that ∼85% of the matter in the Universe is dark matter [1]
In addition to being sensitive to axions, haloscopes are sensitive to another viable dark matter candidate: the massive dark photon [4,5]
Experiments that used magnetic veto to eliminate potential axion signals, wherein the magnetic field is turned off when a signal is found in order to eliminate it as an axion candidate, are hashed out but still reported; the eliminated candidates could have been the dark photon signal independent of a magnetic field

Summary

INTRODUCTION

Astrophysical observations suggest that ∼85% of the matter in the Universe is dark matter [1]. Cavity-based axion detectors, known as haloscopes, search for a weak, narrow band signal at a frequency corresponding to the axion’s currently unknown rest mass. This signal would manifest as a slight power excess in the cavity originating from the axion’s predicted coupling to electromagnetism. In addition to being sensitive to axions, haloscopes are sensitive to another viable dark matter candidate: the massive dark photon [4,5]. We describe a procedure to convert haloscope exclusions from axion parameter space into dark photon parameter space including the probabilistic distribution of dark photon polarizations in the case of a slowly varying polarized dark photon field. We will review the existing body of knowledge throughout the article

DARK PHOTONS AS DARK MATTER

SCALING HALOSCOPE EXCLUSIONS FOR DARK PHOTON SEARCHES

Cmnl QL β þ β ð2Þ

RESULTS

CONCLUSIONS