The asymmetry and the diurnal variation in axionic dark matter searches

TL;DR

This paper investigates how Earth's motion causes annual and diurnal variations in the resonance width in axion dark matter searches, highlighting potential directional effects and time-dependent signatures.

Contribution

It introduces the concept of time-dependent effects, including annual modulation and diurnal variation, in resonant cavity axion searches, emphasizing the importance of directional experiments.

Findings

Resonance width varies annually due to Earth's orbit.

Directional experiments show large asymmetries in observed widths.

Diurnal variation arises from Earth's rotation affecting measurements.

Abstract

In the present work we study possible time dependent effects in Axion Dark Matter searches employing resonant cavities. We find that the width of the resonance, which depends on the axion mean square velocity in the local frame, will show an annual variation due to the motion of the Earth around the sun (modulation). Furthermore, if the experiments become directional, employing suitable resonant cavities, one expects large asymmetries in the observed widths relative to the sun's direction of motion. Due to the rotation of the Earth around its axis, these asymmetries will manifest themselves as a diurnal variation in the observed width.