Axionlike particle production at beam dump experiments with distinct nuclear excitation lines

This is the authors' abstract. We don't add key points for this paper.

Searches for axionlike particles (ALPs) are motivated by the strong $CP$ problem in particle physics and by unexplained dark matter in astrophysics. In this paper, we discuss novel ALP searches using monoenergetic nuclear deexcitation photons from a beam dump, using the isotope decay-at-rest (IsoDAR) experiment as an example. We show that IsoDAR can set limits that close a gap in traditional QCD axion searches using the ALP-photon coupling, as well as provide sensitivity to large regions of new parameter space in models where ALPs couple to nucleons and electrons. We also show how isotope decay-at-rest experiments may be designed to improve potential ALP production and optimize detection sensitivity.