Exploring Portals to the Dark Sector

It is widely believed that most of the matter in the universe consists of new fundamental particles beyond those comprising familiar matter. So far, the evidence for this "dark matter" comes from purely gravitational phenomena. Therefore, a basic open question is whether dark matter has non-gravitational interactions with the known elementary particles. Even if dark matter does not experience the other known forces of nature (strong, weak, and electromagnetic), it may still interact through a so-called "portal" interaction connecting the dark sector to ordinary matter. In this talk I will introduce the basic theoretical framework for dark sectors and portals. I will also highlight the growing experimental program to search for a variety of novel phenomena associated with portals and dark sectors.