Understanding the mechanism of electroweak symmetry breaking and uncovering the particle-physics origins of dark matter and dark energy are some of the most fundamental questions in our quest to understand the Universe at both microscopic and cosmological scales. The PI's on this project will investigate a wide range of innovative ideas in particle physics and cosmology: theoretical descriptions of the mechanisms of the electroweak symmetry breaking (EWSB), such as supersymmetry and extra dimensions; collider phenomenology; grand unified theories and quantum gravity; dark matter and particle cosmology. Much of this research will be of direct relevance for the Large Hadron Collider (LHC) which recently started its operations et the European Organization for Nuclear Research (CERN), as well as for several other upcoming landmark experiments.
This proposal is also envisioned to have significant broader impacts. The HEP Theory group at UC Irvine plans to play an essential role in UC Irvine's QuarkNet program, where high school teachers and their students are introduced to current research in high energy physics. These efforts will be complemented by additional public outreach activities, the training of postdoctoral researchers and graduate students, and professional service.
The last several years have witnessed significant progress in our understanding of particle physics, crowned by the discovery of the Higgs boson at the Large Hadron Collider (LHC). Furthermore, LHC experiments have began an extensive search for new physical phenomena beyond the Standard Model of particle physics. In addition, this period witnessed significant experimental and theoretical progress in the search for the identity of dark matter. Experimental measurements of neutrino mixing parameters have also evolved rapidly. These measurements suggest the potential of discovering in the upcoming neutrino oscillation experiments a new source of Charge-Parity (CP) violation, a neccessary condition for explaining the cosmological matter-antimatter asymmetry in the universe. Investigators contributing to research supported by "Particle Physics and Cosmology in the LHC Era" award obtained a number of significant theoretical results in the study of physics beyond the Standard Model, most notably study of supersymmetry (symmetry between particles with different spins) and dark matter, as well as the origin of flavor and CP violation for quarks and leptons, including the neutrinos. In the course of the project participants investigated several plausible supersymmetric models and their experimental signatures at the LHC. This work contributed to an ability of experimentalists to significantly constraint parameters of supersymmetric models and rule out a number of possible new physics scenarios. Project participants analyzed new experimental constraints and their implications for supersymmetry. They showed that several classes of supersymmetric models are not yet excluded by the experiment and clarified types of signatures to be searched for during future LHC runs. The project participants also investigated several different possible theoretical frameworks, including grand unified theories and flavor symmetries at the TeV scale, in which the observed patterns of masses and mixing angles of quarks and leptons can be explained. The project participants constructed novel models based on these frameworks. They showed that these models give rise to testable signatures at neutrino experiments, the LHC, and underground experiments for nucleon decay searches. In addition, the observed cosmological matter-antimatter asymmetry can be explained in these models.
