The High Energy Elementary Particle Physics Group
Faculty: Bigi - Delgado - Hildreth - Jessop - Kolda - Lannon - LoSecco - Martin - Ruchti - Wayne
Research Faculty: Karmgard - Marinelli
Visiting and Other Faculty: Baumbaugh - Lincoln - Loughran
Emeritus Faculty: Bose - Cason - McGlinn - Shephard
Postdocs, Visiting Scholars and Other Visitors: Bramante - Raj - Smith - Taroni
How Notre Dame physicists are helping us understand our universe: YouTube video link (written and produced by Don Lincoln)
An understanding of the fundamental constituents of matter and the forces with which they interact is sought in high energy physics experimental programs that are performed at colliding beam accelerator facilities of two complementary types: Hadron colliders and electron-positron colliders. Each of these programs has a current, operating experiment and a future experiment in either the construction phase or the research and development phase.
The hadron collider program is based upon the currently operating Tevatron 2 Collider and DØ experiment at Fermilab to be followed (starting in 2007) by the CMS experiment at the CERN Large Hadron Collider (LHC). The physics objectives of this program are to study top and beauty physics, electroweak bosons W and Z, QCD processes, and to search for evidence of electroweak symmetry breaking (such as Higgs bosons or technicolor), supersymmetry, extra (hidden) spatial dimensions, and other new phenomena. This program has provided many important physics results over the last decade, among them the discovery of the top quark in 1995. Notre Dame graduate students have written dissertations in all these research areas. Additionally, Notre Dame has been involved in the recent upgrade of the DØ detector to magnetic tracking, being a pioneering group in the development of scintillating-fiber tracking technology. Notre Dame manages the operation of the Central Fiber Tracker for DØ, directs the offline track reconstruction effort for the experiment, and is involved in the building of an improved level-1 track trigger processor for enhanced detector performance at increased luminosity. Fiber-optic techniques are also critical to the operation of the CMS hadron calorimeters at the LHC, and Notre Dame has been extensively involved in the design and construction of key elements of the electro-optical readout of these CMS detector subsystems, and has been engaged in R and D on new scintillator and waveshifter materials for improved calorimetry performance under high luminosity operation.
The electron-positron collider program is based upon the currently operating BaBar experiment at SLAC. This program, too has provided remarkable physics results, notably the observation by BaBar of CP violation in the b-quark system in 2000 - the first observation of CP violation outside of K L decays, which were discovered in 1964. Physics goals include systematic study of CP violating effects in a variety of decay modes in the b-system as well as studies of rare decays of beauty and charm mesons. Luminosity increases for the BaBar experiment are planned, and Notre Dame is engaged in refinements of the readout electronics of the central tracking chamber to improve track reconstruction.
A variety of R&D projects are underway for the future Linear Collider including, for detectors: scintillator and waveshifter development for fast triggering, calorimetry, muon detection, and tracking; and for accelerators: beam controls and diagnostics systems.
In theoretical high energy physics, refinements are pursued in the phenomenology of the standard model as well as 'new' physics beyond the standard model, particularly supersymmetry. This new physics can be manifested by its presence in CP asymmetries like the one recently measured at SLAC, the first new CP measurement in 40 years. Also being analyzed is supersymmetry and other attempts to tie the electroweak symmetry breaking in the standard model to a more fundamental understanding of nature, including connections to cosmology such as the dark matter and dark energy. Baryo- and lepto-genesis in the Universe is also studied as well as scenarios with extra space dimensions and even multidimensional time.