Discoverable Matter: an Optimist’s View of Dark Matter and How to Find It

An abundance of evidence from diverse cosmological times and scales demonstrates that85% of the matter in the Universe is comprised of nonluminous, non-baryonic dark matter.Discovering its fundamental nature has become one of the greatest outstanding problemsin modern science. Other persistent problems in physics have lingered for decades, amongthem the electroweak hierarchy and origin of the baryon asymmetry. Little is known aboutthe solutions to these problems except that they must lie beyond the Standard Model. Thefirst half of this dissertation explores dark matter models motivated by their solution tonot only the dark matter conundrum but other issues such as electroweak naturalness andbaryon asymmetry. The latter half of this dissertation approaches the dark matter enigmafrom a different vantage point inspired by the null results at dark matter direct detectionexperiments. The theory community has explored alternative dark matter candidates andproduction mechanisms while the experimental program has made progress on larger andmore sensitive experiments. In this dissertation, we take a complementary approach byinvestigating signals of novel dark matter models which may have been overlooked in currentexperiments.