New Ideas in Dark Matter Detection
The search for new particle physics has traditionally focused on accelerating particles to higher energies in search of new states. While dark matter dominates the dynamics of our Universe, it interacts only very weakly with ordinary matter, making identifying its underlying nature an open question; the answer to this question will change our understanding of the Universe. Sensitive underground detectors look for rare interactions of dark matter (focused on weakly interacting massive particles (WIMPs)) with target nuclei. The standard WIMP theory is becoming increasingly stretched thin by experimental constraints.
However, dark matter may reside in a low energy hidden sector. I have proposed qualitatively new types of theories for dark matter and their detection. (I gave an overview of these ideas in this Scientific American article.) These concepts have inspired new experimental efforts, particularly with superfluid helium and polar materials. A review can be found here. Our current work explores how the symmetry properties of these materials (e.g. in magnetic and Dirac targets) can be exploited to broaden the interactions probed. This work has brought our group into close collaboration with condensed matter and applied physicists and engineers.
In addition, while we carry out precision studies searching for new physics in terrestrial experiments, the cosmos provides a natural laboratory through stars and galaxies. One can learn about the nature of dark matter through the formation of structure. Our group has collaborated closely with astronomers making precision measurements of gravitational waves, joining the NANOGrav collaboration to learn about the nature of dark matter substructure.