CAREER: Searching for New Physics from a Dark Sector Using Optically Levitated Microspheres

Yale University, New Haven CT

Investigators

Abstract

Astrophysical observations indicate that the majority of the matter in the universe consists of dark matter. Identifying the nature of dark matter is a central goal of fundamental physics in the coming years. This award provides support to develop a novel set of techniques to search for dark matter by observing the possible presence of new forces under which dark matter interacts. If present, these new forces could lead to small, but observable, deviations in the electromagnetic interactions of normal matter. The techniques planned here will enable novel searches for dark matter that are largely complementary to existing searches. These searches will provide more than an order of magnitude improvement in sensitivity to a well-motivated class of dark matter models, relative to the best existing laboratory constraints. Since no single search can probe all viable dark matter models, a wide variety of complementary techniques will likely be needed to identify the nature of dark matter or fully constrain its properties. This award will provide educational opportunities related to the scientific and technical aspects of this research to the New Haven and Yale University communities. In particular, the Pathways to Science program serves the local school districts in New Haven and reflects the diversity of the public schools in this area. Through the activities supported by this award, middle and high school students from groups that are underrepresented in physics and STEM-based fields will have the opportunity to learn about the physics and techniques underlying this research. A new class of force sensors based on optically levitated dielectric microspheres in high vacuum will be used to search for the effects of such new forces. These techniques can allow the detection of Newtonian forces smaller than 10^-18 N acting on nanogram-sized objects. An experimental apparatus optimized for searches for deviations from Coulomb's law at sub-mm distances will be developed in the course of this work, which will enable a search for new interactions mediated by dark photons with masses between 0.1 meV and 1 eV. In addition, the same force sensors can be used to search for "milli-charged particles," which have tiny fractional electric charges (q << 1 e). In certain dark matter models, such particles could have been produced in the early universe and formed stable bound states with atoms that can be searched for in terrestrial matter today.