# Directional axion detection

**Authors:** Stefan Knirck, Alexander J. Millar, Ciaran A. J. O'Hare, Javier Redondo, Frank D. Steffen  
**arXiv:** [1806.05927](https://arxiv.org/abs/1806.05927)  
**Date:** 2018-06-15  
**Summary page:** https://www.summarizepaper.com/en/paper/1806.05927v1/

## Key points

- Formalism for describing extensions of axion haloscope designs with directional sensitivity
- Experiments designed with dimensions approaching coherence length can measure directional sensitivity
- Directional sensitivity enhances potential of axion detection experiments to probe local dark matter velocity distribution
- Applied formalism to resonant cavities and dielectric disk haloscopes
- Experiments capable of measuring daily modulation of dark matter signal and reconstructing three-dimensional velocity distribution
- Measurement of Solar peculiar velocity, investigation of anisotropy of dark matter velocity ellipsoid, and identification of cold substructures such as streams near Earth
- Ability to identify features over shorter timescales, potentially mapping debris from axion miniclusters
- Incorporating directional sensitivity significantly enhances capabilities in probing and understanding local dark matter velocity distribution.

## Summary

The paper titled "Directional axion detection" presents a formalism for describing extensions of existing axion haloscope designs that have directional sensitivity to incoming dark matter axion velocities. The authors demonstrate that if experiments are designed with dimensions approaching the typical coherence length for the local axion field, the effects of directional sensitivity can be measured. This directional sensitivity greatly enhances the potential of axion detection experiments to probe the local dark matter velocity distribution. The formalism developed in this study is applied to specific experimental designs, namely resonant cavities and dielectric disk haloscopes. The authors show that these experiments are capable of measuring the daily modulation of the dark matter signal and using it to reconstruct the three-dimensional velocity distribution. This allows for the measurement of the Solar peculiar velocity, investigation of anisotropy of the dark matter velocity ellipsoid, and identification of cold substructures such as recently discovered streams near Earth. Furthermore, directional experiments have the ability to identify features over much shorter timescales, potentially enabling mapping of debris from axion miniclusters. Overall, this research highlights how incorporating directional sensitivity into axion detection experiments can significantly enhance their capabilities in probing and understanding the local dark matter velocity distribution.