Topics in Particle Theory

College Of William And Mary, Williamsburg VA

Investigators

Abstract

The PI proposes to investigate a number of topics in particle theory. One is Family Unification in Extra Dimensions. Family unification models combine gauge and horizontal symmetry groups while embedding all three standard model generations into a single irreducible representation. Extra dimensions allow one to eliminate unwanted mirror family zero modes in such models via the appropriate choice of boundary conditions on the fields. This provides a new framework for constructing and studying the phenomenology of realistic family unified theories. The PI proposes to investigate a number of issues related to the phenomenology of noncommutative field theories, which can be realized as a low-energy limit of string theories. He will consider the only known consistent and complete noncommutative generalization of the standard model and will determine the bounds from low-energy searches for the violation of Lorentz invariance. Lorentz-violating effective operators induced at tree-level, one-loop and two-loops will be evaluated. In addition, the PI will study noncommutative quantum mechanical theories with minimum length uncertainty relations, and determine new bounds from atomic and molecular physics. Theories that attempt to explain fermion masses and mixing angles in the standard model generally include new matter and Higgs fields at a flavor scale, MF, which is much higher than the electroweak scale. A high flavor scale is necessary to avoid new contributions to flavor changing neutral current processes. The PI proposes to investigate whether realistic models with smaller MF can be constructed by arranging for a suppression of the higher-dimensional wave functions of certain flavor-sector fields at points where ordinary matter is located. The broader implications are that the PI is deeply involved in the education of undergraduate and PhD research students at William and Mary.