Seeing in the Dark

Harvard University, Cambridge MA

Investigators

Abstract

This award funds the research activities of Professor Lisa Randall at Harvard University. Professor Randall's research explores fundamental physics at the smallest scales probed thus far as well as the nature of the as-yet unidentified dark matter. Understanding the nature of dark matter and its distribution in the Milky Way is essential for experimental and observational probes. Professor Randall's research will contribute significantly to this effort, opening up avenues for dark-matter research that have not yet been explored. This research program is also highly interdisciplinary, drawing from particle physics, cosmology, and astronomy, with additional potential connections to geology, paleontology, and chemistry. As such, this research contributes to the national interest by furthering the development of fundamental scientific knowledge within the United States. This research is also envisioned to have significant broader impacts. It will not only involve students and postdocs, thereby helping them develop a broad skill set, but also serves as a rich backdrop for introducing scientific ideas --- particularly those in particle physics --- to the general public. The PI's presence in the public sphere also encourages women and other under-represented groups to pursue science, while the PI's recent book "Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe" has provided an ideal platform for bringing science to the general public and has led to numerous media appearances. These activities are expected to continue under the current award. More technically, in spite of tremendous progress in particle physics over the last decade, many important questions remain unanswered, including the origin of the electroweak scale and the nature of dark matter. For example, we still do not know what dark matter is, or how its share of the cosmic energy density can be understood. The PI will investigate these questions within the framework of "Partially Interacting Dark Matter", and within one particular realization known as "Double Disk Dark Matter", where a small fraction of dark matter particles have interesting interactions beyond the gravitational. This feature can give rise to new testable signatures that can potentially affect structure formation. Another generic possibility is "Flooded Dark Matter", which provides a natural way to dilute the entropy in the dark sectors. This mechanism expands the model-building possibilities for dark-matter physics. Finally, Professor Randall plans to investigate new mechanisms for understanding the origin of the weak scale and will study their experimental implications.