This award funds the research activities of Professor Peisi Huang at the University of Nebraska-Lincoln.<br/><br/>There has never been a more exciting time for particle physics and cosmology. Ongoing and forthcoming experimental efforts are transforming our understanding of fundamental physics. Despite the remarkable success of modern physics, many mysteries of the Universe suggest there is an entire realm of “new physics” that lies beyond our current understanding. Professor Huang's research aims to utilize current and future experimental probes to advance our understanding of new physics through theoretical studies. Specifically, Professor Huang will study black holes, the imbalance between matter and antimatter, and possible changes in the history of the Universe. As such, Professor Huang's research advances the national interest by promoting the progress of science in one of its most fundamental directions: the discovery and understanding of new physical laws. This project is also envisioned to have significant broader impacts. The proposed research will provide training opportunities for a diverse group of graduate and undergraduate students. Professor Huang also aims to increase participation in STEM by making a special effort to involve women, other underrepresented minorities, and first-generation college students.<br/><br/>More technically, Professor Huang will first propose new formation mechanisms and probes for primordial black holes, which are hypothetical black holes formed right after the Big Bang. She will study formation mechanisms through first-order phase transitions. Second, Professor Huang will investigate the imbalance between matter and antimatter by suggesting possible mechanisms, such as models with sub-GeV singlets, that could have created this imbalance and identifying ways to test these theories experimentally. Third, Professor Huang will study potential modifications to the history of the Universe and their implications, including the role of dark matter, though a novel scenario where a dark sector particle couples to a scalar undergoing a strong first-order PT through higher-dimensional operators. This might lead to periods of so-called “early matter domination”.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.