WIMPs are implied by extensions of the Standard Model of partcle physics such as supersymmetry. These models suggest WIMPs of 100s GeV mass, or hundreds of billions of electron-volts. Experimental searches for DM have been strongly motivated by the WIMP paradigm. So far WIMPs have eluded detection. Also, no evidence for the supporting supersymmetry theory has yet been found at the Large Hadron Collider.
The scientific community is thus re-evaluating the WIMP paradigm, recognizing that dark matter particles may be lighter and have different interaction properties than previously thought. In particular, a dark photon, an invisible, massive version of the ordinary photon, could be a fundamental component of DM, or act as mediator of DM interactions. Candidates for particles in this so-called dark or hidden sector span over a large range of masses, down to the single electron-volt, and are largely unconstrained by current experiments.
Dark matter scatters through a heavy (left) and light (right) mediator A. Theoretical models are shown as thick yellow lines [arxiv:2003.09497]
An R&D phase has taken place in 2013 - 2016 at SNOLAB underground laboratory in Canada. In 2016 we installed a 40-g prototype (DAMIC) at the SNOLAB underground laboratory. The detector performance, the background characterisation and the dark matter search capabilities have been successfully proven (Publications).
The next challenge is the construction of a kg-size detector, which will be installed at the Laboratoire Souterrain de Modane in France. The DAMIC-M (DAMIC at Modane) experiment will feature the most massive CCDs ever built and a novel concept for signal readout. With this unprecedented sensitivity DAMIC-M will take a leap forward of several orders of magnitude in the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called “hidden sector” which may have well so far escaped detection.
