Spectral signatures of axionlike dark matter

Understand

We derive spectral line shapes of the expected signal for a haloscope experiment searching for axionlike dark matter.

• The knowledge of these line shapes is needed to optimize an experimental design and data analysis procedure.
• We extend the previously known results for the axion-photon and axion-gluon couplings to the case of gradient (axion-fermion) coupling.
• A unique feature of the gradient interaction is its dependence not only on magnitudes but also on directions of velocities of galactic halo particles, which leads to the directional sensitivity of the corresponding haloscope.