WISP Dark Matter eXperiment and Prospects for Broadband Dark Matter Searches in the $1\mu$eV--$10$meV Mass Range

Light cold dark matter consisting of weakly interacting slim (or sub-eV) particles (WISPs) has been in the focus of a large number of studies made over the past two decades. The QCD axion and axion-like particles with masses in the $0.1\mu$eV–$100$meV are strong candidates for the dark matter particle, together with hidden photons with masses below $\lesssim 100$meV. This motivates several new initiatives in the field, including the WISP Dark Matter eXperiment (WISPDMX) and novel conceptual approaches for broad-band WISP searches using radiometry measurements in large volume chambers. First results and future prospects for these experiments are discussed in this contribution.