An Introduction to the University of Illinois High Energy Physics Group

The Illinois High Energy Physics group comprises fifteen faculty, ten postdoctoral research associates, seventeen graduate students, and eight technical support staff. The experimental group is involved in a number of projects at Fermilab, CESR (an e+e- collider at Cornell), and the proposed LHC (Large Hadron Collider) at CERN. Our group has strengths in both hardware and software/analysis tasks. We build major subsystems for detectors, write analysis software, and extract physics that interests us from our data. In a way, the work we do is analogous to the atomic physics done in 1929: many of our experiments are tests of the Standard Model. We'd like to see if its predictions are consistent with our experimental measurements. Discrepancies would point to new physics which might explain the origin of particle masses, and help us understand why the particles we see in our experiments are so much lighter than the Planck scale.

The theoretical group is involved in lattice studies of QCD, electroweak symmetry breaking and top quark physics, as well as formal studies of supersymmetric gauge theories, duality and string theory.

Members of the HEP Group

Experimental faculty	Theoretical faculty	Experimental res. assoc.	Theoretical res. assoc.
Bob Eisenstein	Aida El-Khadra	Jesse Ernst	Moshe Rozali
Debbie Errede	John Kogut	Eric Gottschalk	Jim Simone
Steve Errede	Rob Leigh	Randal Hans	Tim Stelzer
Gary Gladding	John Stack	Inga Karliner	Misha Stephanov
George Gollin	Scott Willenbrock	Mark Palmer
Lee Holloway		Rob Roser
Tony Liss
Mats Selen
Jon Thaler
Jim Wiss

Experimental students	Theoretical students	Engineering support
Tim Bergfeld	Michael Chavel	Fred Cogswell
Jill Buckley	Rafal Filipczyk	Bob Downing
Chris Cawlfield	Martin Smith	Mike Haney
Len Christofek	Costas Strouthos	Dave Lesny
Jake Costello	Zack Sullivan	Todd Moore
Ed Johnson	Thao Tran	Larry Nelson
Mike Marsh		Harold Scott
Kee-Su Park		Vaidas Simaitis
Charles Plager
Amir Rahimi
Chris Sedlack
John Strologas
Jeremy Williams

CLEO at CESR

The High Energy Physics group of the University of Illinois has a strong commitment to the CLEO experiment at CESR, the Cornell Electron Storage Ring. This experiment, dedicated largely to the study of heavy quarks and leptons, has accumulated more data for this purpose than any other facility in the world, and is leading the field in several areas. We use the CLEO detector to study the properties of particles containing charmed and bottom quarks, and to measure the characteristics of t leptons. CLEO has recently installed a silicon microstrip vertex detector which will provide us with resolutions of 0.1 psec in measurements of particle lifetimes. Illinois faculty working on CLEO include Bob Eisenstein, Gary Gladding, George Gollin, Mats Selen, and Jon Thaler.

High Energy Photoproduction: E687 and FOCUS at Fermilab

The discovery of states containing the 4th (charmed) quark played a pivotal role in the formulation of the generational structure of the Standard Model of subatomic physics. Charm studies continue to provide surprises as they refine theoretical models describing heavy particle spectroscopy, lifetimes, decay mechanisms, and production dynamics. Our group studies the properties of charm particles produced by an intense beam of very high energy (l = 5¥10-18 m) photons interacting with a metal target. The charmed states are isolated from background sources by tagging their short, but finite (picosecond) lifetimes through precision solid state detectors. The U of I group, consisting of faculty member Jim Wiss and graduate students Amir Rahimi, Christopher Cawlfield, and Kee-Su Park, is presently involved with the first run of the FOCUS experiment at Fermilab. Our principle contribution to the hardware for this new run is the construction of a 350 element scintillation counter array to be used to identify cleanly muons produced when charmed particles decay. Our group has traditionally had a dominant role in data analysis and the development of the software used to identify and study photoproduced charmed particles.

The Collider Detector at Fermilab

The Collider Detector at Fermilab (CDF) studies interactions of high energy protons and antiprotons. The superconducting particle accelerator at Fermilab is used to store beams of protons and antiprotons at 1000 GeV, the world's highest energy. The CDF group has built a large detector to investigate the nature of the interactions that occur when these beams collide head-on. Precise measurements of the properties of the W boson, top quark, and other elementary particles are being made. Studies of the nature of the trilinear gauge couplings of the W and Z bosons are also in progress. Faculty collaborating on CDF include Debbie Errede, Steve Errede, Lee Holloway, and Tony Liss.

CDF is currently undergoing a major upgrade in preparation for the next collider run. The Illinois group is responsible for upgrading the central muon system's front end electronics as well as electronics for the levels 1 and 2 triggers. We are participating in the construction of the new central tracking chamber.

BTeV Detector at Fermilab

The BTeV experiment will study heavy quark physics in the C0 collision hall at Fermilab. Comprising a compact detector optimized for heavy quark studies, the specialized BTeV experiment will have physics capabilities unmatched by the other Fermilab collider experiments. Faculty involved in BTeV include Mats Selen and Jim Wiss.

ATLAS Experiment at the Large Hadron Collider

The ATLAS experiment at the LHC will study very high energy proton-proton collisions to provide insight into the nature of electroweak symmetry breaking. Illinois faculty participating in ATLAS include Debbie Errede, Steve Errede, and Jon Thaler. Present efforts include construction of hadron calorimeter modules and studies of the performance of photomultiplier tubes to be used in the readout of the calorimeter.

Lattice Field Theory

Faculty member John Kogut and postdoctoral research associate Misha Stephanov use simulation techniques on a space-time lattice to calculate properties of strongly interacting systems. New methods for dealing with fermions in lattice gauge theories have been developed by this group and are now being extensively exploited to study chiral symmetry restoration and quark deconfinement at finite temperatures.

Precision Studies of Quantum Chromodynamics Through Lattice Calculations

It has become possible to make accurate predictions of some aspects of the strong interaction by performing Lattice QCD calculations. Recent results include calculation of a precise value for the strong coupling constant. Faculty member Aida El-Khadra and postdoctoral research associate Jim Simone are involved in this effort.

String Theory and Duality

Recent results in supersymmetric quantum field theory make it possible to study non-perturbative behaviour analytically. Professor Rob Leigh and postdoctoral research associate Moshe Rozali investigate the non-perturbative properties of quantum field theories and their duality properties, as well as similar phenomena in superstring theories.

Top Physics and Electroweak Symmetry Breaking

Efforts to understand the mechanism of electroweak symmetry breaking, responsible for the masses of W and Z bosons, as well as studies of the physics of the top quark, are the focus of Professor Scott Willenbrock and postdoctoral research associate Tim Stelzer.

Studies of the Confinement Mechanism in Quantum Chromodynamics

The old idea of explaining confinement in QCD by magnetic monopoles has in recent years become an active area of investigation in lattice gauge theory. Faculty member John Stack and students have performed calculations for an SU(2) gauge group, which use magnetic monopoles to give a quantitative explanation of the heavy quark potential and glueball spectrum.