High-Energy Physics Theory

The theoretical high-energy physics group conducts research covering a broad range of topics centered on exploring the properties of, and the physics beyond, the Standard Model.  Our theoretical pursuits include electroweak symmetry breaking, Higgs boson physics, top quark physics, supersymmetry, and large extra dimensions.  The phenomenological studies include the strong interaction, collider searches for new particles, neutrino physics, and dark matter searches. A variety of tools are developed and employed in the research, including novel perturbative and nonperturbative methods of quantum field theory and statistical mechanics, model building, lattice field theory, effective field theory, and automated calculational packages for collider physics.

High-Energy Physics Experiments

The aim of the experimental particle physics is to understand the fundamental constituents of matter by searching for new subatomic particles and by measuring precisely the properties of the known particles and interactions. The data that will be collected at the LHC are expected to help answer important questions about fundamental forces and the evolution of the universe right after the Big Bang. The ATLAS group is involved in the studies of heavy quark physics and the search for supersymmetric particles and leptoquarks, hypothetical particles predicted by new physics models. Similar issues also are addressed from another perspective by studying neutrinos. Precision measurements of the fundamental properties of neutrinos such as mass and mixing angles are major goals of the neutrino group. The discovery of neutrino oscillations/masses in 1998 and the close connection between neutrino properties and cosmology have made neutrino physics a vibrant field of research.

Cosmology and Astrophysics

Observational Cosmology and Astrophysics efforts within PITT PACC focus primarily on the use of large survey datasets, augmented with data from large telescopes both on the ground and in space.  Faculty currently utilize the Sloan Digital Sky Survey, SDSS-III, Pan-STARRS, DEEP2, DEEP3, AEGIS, and CANDELS surveys in their research, and are playing a major role in planning the Large Synoptic Survey Telescope (LSST) and the BigBOSS redshift survey.  Key areas of focus include efforts to determine the nature of the "dark energy" causing the expansion of the Universe to accelerate; studies of the formation and evolution of galaxies; and investigations of the distribution and composition of gas in the local and distant universe via quasar absorption lines.   One key area of focus is investigations of the properties of supernovae and their progenitor populations; the 2011 Nobel Prize in Physics was awarded for the discovery of dark energy via supernova studies. In addition to work with the PITT PACC theory group, these efforts draw on collaborations with statisticians and computer scientists to better make use of these vast datasets.

Theoretical Cosmology and Astrophysics at PITT PACC encompasses a wide range of topics, from the physics of the early Universe, to the formation of the Milky Way Galaxy, to Supernovae and Stellar Physics.  Our research is unified by a pursuit of a greater understanding of the fundamental laws that govern the Universe and more detailed knowledge of the evolution of our particular patch of the Universe.  Particular problems that the group focuses on are understanding the nature and origin of dark matter and dark energy, and developing more detailed knowledge of the origin and evolution of galaxies, such as our own Milky Way.  A significant portion of the theoretical work of the PITT PACC Cosmology and Astrophysics Theory Group is aimed at making contact with data from existing and forthcoming experimental and observational projects, much of which is being collected by PITT PACC colleagues.  The techniques employed in this work vary greatly from perturbative treatments of cosmological structure growth, to numerical modeling of stars, to large-scale computer simulations of the formation and evolution of galaxies. This work lies along interfaces between stellar astrophysics, gravitational dynamics, particle physics, and cosmology and requires amalgamating diverse research topics into a coherent picture of the evolution of the Universe.