Enhancement of dark-photon haloscope sensitivity with degenerate modes: toward axion-level form factor and polarization determination

TL;DR

This paper proposes a novel method using three degenerate modes in resonant cavities to enhance dark photon detection sensitivity, aiming to match axion-level form factors and determine polarization, thereby enabling simultaneous dark matter searches.

Contribution

It introduces a technique employing three orthogonal degenerate modes in resonant cavities to improve dark photon detection sensitivity and polarization measurement, approaching axion-like form factors.

Findings

Maximum form factor achieved in cubic, spherical, and cylindrical cavities.

Coherent sum of signals enhances detection sensitivity.

Method enables simultaneous dark matter axion and dark photon searches.

Abstract

The dark photon has been postulated as a potential constituent of dark matter, exhibiting notable similarities to the axion. The primary distinction between the two particles lies in the nature of their respective fields: the dark photon field is a vector field with a polarization direction that remains undetermined. This work explores the prospect of utilizing three degenerate modes for scanning the three dimensions of space in order to mitigate the low form factor expected in the detection of the dark photon due to their unknown polarization. The employment of an haloscope with three orthogonal and degenerate modes in conjunction with the coherent sum of signals is demonstrated in this work in order to enhance the dark photon form factor up to the axion form factor, and to determine the direction of the dark photon polarization vector. We show in this manuscript that the maximum form factor is achieved in cavities of cubic, spherical, and cylindrical geometries, considering the introduction of tuning elements. To achieve this adequately, some conditions reviewed in this article must be fulfilled in the resonant cavity, leading to uncertainties in the final measurement. Finally, this technique can allow the simultaneous search for dark matter axions and dark photons, and to the knowledge of the authors, the method shown in this work is the most effective one for detecting dark photon with microwave resonant cavities.