MPS: Particle Physics and Cosmology in the Experimental Age

Harvard University, Cambridge MA

Investigators

Abstract

This award funds the research of the PI Lisa Randall in a number of areas of particle physics and cosmology which are related to the phenomenological consequences of warped extra dimensions. Chief among these are LHC-related research along with model building and research related to Dark Matter. Many models Randall discusses are designed to address the hierarchy problem. The hierarchy problem remains one of the outstanding motivations for believing that interesting Beyond-the-Standard Model physics should exist at the weak scale. The question of why there is such a large separation between the Planck scale and the weak scale, or even how a theory incorporating quantum mechanics and special relativity can consistently maintain two such very different mass scales without a highly unlikely fine-tuning remains the major theoretical issue today for weak scale particle physics. Warped extra-dimensional geometry can potentially resolve the hierarchy problem. In this scenario, the cut-off varies over an extra dimension so that although the cut-off of a five dimensional theory is of order of the Planck scale, the local cut-off on a brane (which we will call the TeV brane) is of order a TeV. Randall is also guided by connections to general relativity solutions, string theory, and cosmology. Some work will be devoted to particular models, such as Randall-Sundrum (RS) warped geometry and its experimental signatures, supersymmetry and search strategy and model building, Higgs physics, and flavor physics. In addition Randall and colleagues will consider other models for comparison and consider potentially interesting signatures. With dark matter they will investigate new classes of models and consider possible implications for the various experiments of different types of models. In addition Randall plans to engage in more theoretical work related to general relativity and cosmological solutions. The project also has many broader impacts. With the onset of the LHC there are many opportunities to explain particle physics and science in general to the interested public. The activities in which Randall is and will be involved include numerous public lectures and interdisciplinary conference talks, magazine and newspaper articles, including pieces Randall has written and articles Randall was interviewed for as well as appearances on TV, radio, and in documentaries.