The SMU High Energy Particle Physics group studies the properties of the most fundamental constituents of matter and the laws governing their behavior. Some of the most important questions today concern: the origin of elementary particle masses, the apparent asymmetry between matter and anti-matter in the universe, and the nature of dark matter and dark energy. Several large, accelerator based experiments address these questions. SMU physicists work on the ATLAS experiment at the Large Hadron Collider at CERN in Geneva, Switzerland and on the D0 and NOνA experiments based at the Fermi National Accelerator Laboratory in Batavia, Illinois. D0 collects data from proton-antiproton collisions at 2 TeV that is the highest accelerator energy possible today. In 2007 ATLAS will start study of proton-proton interactions at an even higher energy of 14 TeV. NOνA is a proposed experiment to study neutrino oscillations.
In 2006, most of SMU activities are concentrated on the commissioning of the ATLAS experiment and preparations for the data analysis. Analysis of the D0 data, the R&D work for ATLAS detector and its readout electronics upgrade, and the R&D work on the NOνA detector and the development of new electronics and new particle detection techniques, are also actively pursued.
For the ATLAS project, SMU physicists designed and built elements of readout electronics for the electromagnetic calorimeter system including a 1600 channel optical link system with a total data rate of about 2.7 terabits per second. In 2006, most of the effort is devoted to the commissioning of the 220,000 detector channels and creation of the control software. We are also strongly involved in designing the software architecture to monitor the experiment in real-time. Preparations for the physics studies include searches for new phenomena: the Higgs boson responsible for particle masses, supersymmetry, extra dimensions, magnetic monopoles and others. The R&D program for the future detector upgrade is pursued together with the Electrical Engineering Department to develop very fast opto-electronics components that can work in a very high radiation environment. Faculty members involved in ATLAS are Robert Kehoe, Stephen Sekula, Ryszard Stroynowski and Jingbo Ye.
Quarks lie at the fundamental stratum of nature's constituents. The most recently discovered quark, the top quark, has some of the most mysterious properties of this particle family. Its large mass makes it a crucial probe of the yet undiscovered Higgs boson in particle physics. The Higgs particle is at the heart of our current understanding of the origin of mass, so it is extremely important that we fully understand its properties. Until it is discovered, possibly at the LHC, study of the top quark is the best way to gain this understanding. A primary purpose of the D0 experiment is the measurement of the top quark's properties. Through Kehoe's efforts, SMU has been engaged in these studies primarily by measuring the top quark mass in two-lepton ('dilepton') events that have naturally low backgrounds. We have also been involved in the maintenance and upgrade of the hardware calorimeter trigger.
There is compelling evidence that neutrinos change flavor, implying that neutrinos are massive and that leptons mix. SMU, under the direction of Thomas Coan, is a member of the international NOνA collaboration that proposes to study the oscillation of muon neutrinos produced at Fermilab into electron neutrinos detected by a massive 25~kiloton detector in northern Minnesota. Key experimental goals of this second generation neutrino experiment are establishing the "mass hierarchy" of the neutrino mass eigenstates, measuring the electron component in the singlet mass eigenstate, and detecting CP violation in the neutrino sector. Coan is currently developing novel instrumentation for quality assurance of the NOνA's 18.5 kilotons of liquid scintillator.
Between 1992 and 2006, SMU group participated the CLEO experiment at the Cornell Electron-positron Storage Ring (CESR) located at Cornell University in Ithaca, NY. The goal of CLEO is to study the properties of beauty, charm quarks and tau lepton. The SMU group was responsible for the construction of the radiator of CLEO III Ring Image Cherenkov Detector (RICH). The SMU group members have been responsible for many CLEO publications on B, charm and Tau physics.
works on lightcone quantization and its applications in QCD to hadronic physics, including generalised parton distributions, chiral symmetry breaking, relativistic string representations. In particular, he continues to develop transverse lattice gauge theory as a quantitative tool for computing the lightcone wavefunctions of hadrons.
applies nonperturbative computational methods to study quantum field theories, especially quantum chromodynamics (QCD), the theory of the strong interactions. He is part of the HPQCD collaboration, which seeks to employ improved actions defined on a spacetime lattice to make high-precision comparisons of QCD with experimental data for heavy-quark systems. One specific interest is the development of methods to include dynamical light quarks in these calculations. Past research, as part of the NRQCD collaboration, produced accurate calculations of the strong coupling constant, the mass of the b quark, and the spectra of the upsilon and charm systems.
works on theoretical computations describing scattering of elementary particles at modern colliders. He is also involved in the multi-variate statistical analysis of diverse experimental data with the goal to understand the internal structure of protons and neutrons. He contributes to the determination of widely used CTEQ parton density functions and collaborates with experimentalists on adapting theoretical methods for measurements at the Fermilab Tevatron collider and CERN Large Hadron Collider. Nadolsky is an author of 50+ research publications, including highly cited papers on CTEQ6.x sets of parton distributions and transverse momentum resummation. He is a recipient of a prestigious 2008 LHC Theory Initiative Travel and Computing Award.
is active in the CTEQ collaboration and he spent the 1997-98 year on sabbatical at Fermilab to expand research ties with both theorists and experimentalists in the NuTeV, DØ, and CDF collaborations. He is also a member of the LHC ATLAS collaboration. He developed the ACOT scheme for computing processes involving heavy quarks, and this has been used in the analysis of deeply inelastic scattering data. Encouraged by the leptoproduction results, this work was extended to the hadroproduction case applicable for Fermilab Run II and LHC. On the theoretical side, a "Simplified-ACOT" formalism has been developed to facilitate higher order calculations. These tools are being used to analyze heavy quark data, and are being incorporated into the CTEQ global analysis code which generates the widely used parton distribution functions. In 2005 he was elected an APS Fellow for "For significant contributions to understanding nucleon structure and heavy quark production in perturbative quantum chromodynamics."
works on composite operator renormalization in perturbative QCD, heavy quark hadroproduction, and heavy quark leptoproduction. With Olness, he uses heavy quark parton distribution functions to resum badly behaved perturbation series, yielding cross section calculations with reduced theoretical uncertainty due to factorization scale dependence. He is the creator and maintainer of the CTEQ collaboration's world wide web page at http://cteq.org -- the primary distribution site for the CTEQ parton distribution functions, the Handbook of Perturbative QCD, and CTEQ summer school information.
is our resident Higgs hunter, he has been active in refining search strategies for Higgs discovery at an upgraded Tevatron, the LHC, and the Next Linear Collider. His interests include SUSY as well as Non-SUSY models of electroweak symmetry breaking. More recently Vega has been involved in the study of Effective Lagrangians for the model independent parametrization of physics beyond the standard model. He is also working on novel approaches for determining neutrino masses. His collaborators include D.A. Dicus (UT Austin), J.F. Gunion (UC Davis), and J. Wudka (UC Riverside).