We discuss the discovery potential of the Dark-photons & Axion-Like particles Interferometer (DALI) in this letter. The apparatus, currently in a design and prototyping phase, will probe axion dark matter from the Teide Observatory, an environment protected from terrestrial microwave sources, reaching Dine--Fischler--Srednicki--Zhitnitsky-like axion sensitivity in the range 25--250 $\mu$eV of mass. The experimental approach shows a potential to probe dark sector photons of kinetic mixing strength in excess of several $10^{-16}$, and to establish new constraints to a stochastic gravitational wave background in its band. We identify different branches, including cosmology, stellar, and particle physics, where this next-generation halo-telescope may play a role in coming years.
Comment: As accepted by PRD [8 pages, 5 figures + Supplemental Material 4 pages, 3 figures]. https://journals.aps.org/prd/accepted/1f074Q62Pa91023535875f66ca556bf86dda6f468