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Duals for SU(N) SUSY Gauge Theories with an Antisymmetric Tensor: Five Easy Flavors

Description: I consider N = 1 supersymmetric SU(N{sub c}) gauge theories with matter fields consisting of one antisymmetric representation, five flavors, and enough antifundamental representations to cancel the gauge anomaly. Previous analyses are extended to the case of even N{sub c} with no superpotential. Using holomorphy I show that the theory has an interacting infrared fixed point for sufficiently large N{sub c}. These theories are interesting due to the fact that in going from five to four flavors the theory goes from a non-trivial infrared fixed point to confinement, in contradistinction to SUSY QCD, but in analogy to the behavior expected in non-SUSY QCD.
Date: December 16, 1997
Creator: Terning, John
Partner: UNT Libraries Government Documents Department

National Computational Infrastructure for Lattice Gauge Theory

Description: In this document we describe work done under the SciDAC-1 Project National Computerational Infrastructure for Lattice Gauge Theory. The objective of this project was to construct the computational infrastructure needed to study quantim chromodynamics (QCD). Nearly all high energy and nuclear physicists in the United States working on the numerical study of QCD are involved in the project, as are Brookhaven National Laboratory (BNL), Fermi National Accelerator Laboratory (FNAL), and Thomas Jefferson National Accelerator Facility (JLab). A list of the serior participants is given in Appendix A.2. The project includes the development of community software for the effective use of the terascale computers, and the research and development of commodity clusters optimized for the study of QCD. The software developed as part of this effort is pubicly available, and is being widely used by physicists in the United States and abroad. The prototype clusters built with SciDAC-1 fund have been used to test the software, and are available to lattice guage theorists in the United States on a peer reviewed basis.
Date: May 30, 2008
Creator: Reed, Daniel, A
Partner: UNT Libraries Government Documents Department

"Quantum Field Theory and QCD"

Description: This grant partially funded a meeting, "QFT & QCD: Past, Present and Future" held at Harvard University, Cambridge, MA on March 18-19, 2005. The participants ranged from senior scientists (including at least 9 Nobel Prize winners, and 1 Fields medalist) to graduate students and undergraduates. There were several hundred persons in attendance at each lecture. The lectures ranged from superlative reviews of past progress, lists of important, unsolved questions, to provocative hypotheses for future discovery. The project generated a great deal of interest on the internet, raising awareness and interest in the open questions of theoretical physics.
Date: February 25, 2006
Creator: Jaffe, Arthur M.
Partner: UNT Libraries Government Documents Department

Resolving exceptional configurations

Description: In lattice QCD with Wilson fermions, exceptional configurations arise in the quenched approximation at small quark mass. The origin of these large previously uncontrolled lattice artifacts is identified. A simple well-defined procedure (MQA) is presented which removes the artifacts while preserving the correct continuum limit.
Date: October 1, 1997
Creator: Bardeen, W.; Eichten, E.; Duncan, A. & Thacker, H.
Partner: UNT Libraries Government Documents Department

Quark confinement and surface critical phenomena

Description: Surface critical phenomena and the related onset of Goldstone modes probe the fundamental properties of the confining flux in Quantum Chromodynamics. New ideas on surface roughening and their implications for lattice studies of quark confinement are presented. Problems with the oversimplified string description of the Wilson flux sheet are discussed.
Date: October 20, 1999
Creator: K.J. Juge, J. Kuti and C.J. Morningstar
Partner: UNT Libraries Government Documents Department

Quark confinement in a constituent quark model

Description: On the level of an effective quark theory, we define confinement by the absence of quark anti-quark thresholds in correlation function. We then propose a confining Nambu-Jona-Lasinio-type model. The confinement is implemented in analogy to Anderson localization in condensed matter systems. We study the model`s phase structure as well as its behavior under extreme conditions, i.e. high temperature and/or high density.
Date: July 1, 1995
Creator: Langfeld, K. & Rho, M.
Partner: UNT Libraries Government Documents Department

Phases of QCD: Summary of the Rutgers Long Range Plan Town Meeting, January 12-14, 2007

Description: This White Paper summarizes the outcome of the Town Meeting on Phases of QCD that took place January 12-14, 2007 at Rutgers University, as part of the NSAC 2007 Long Range Planning process. The meeting was held in conjunction with the Town Meeting on Hadron Structure, including a full day of joint plenary sessions of the two meetings. Appendix A.1 contains the meeting agenda. This Executive Summary presents the prioritized recommendations that were determined at the meeting. Subsequent chapters present the essential background to the recommendations. While this White Paper is not a scholarly article and contains few references, it is intended to provide the non-expert reader
Date: May 14, 2007
Creator: Jacobs, Peter; Kharzeev, Dmitri; Muller, Berndt; Nagle, Jamie; Rajagopal, Krishna & Vigdor, Steve
Partner: UNT Libraries Government Documents Department

Transverse Spin Physics: Recent Developments

Description: Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD dynamics in transverse spin physics.
Date: December 10, 2008
Creator: Yuan, Feng
Partner: UNT Libraries Government Documents Department

Substructure of High-pT Jets at the LHC

Description: We study high-p{sub T} jets from QCD and from highly-boosted massive particles such as tops, W,Z and Higgs, and argue that infrared-safe observables can help reduce QCD backgrounds. Jets from QCD are characterized by different patterns of energy flow compared to the products of highly-boosted heavy particle decays, and we employ a variety of jet shapes, observables restricted to energy flow within a jet, to explore this difference. Results from Monte Carlo generators and arguments based on perturbation theory support the discriminating power of the shapes we refer to as planar flow and angularities. We emphasize that for massive jets, these and other observables can be analyzed perturbatively.
Date: July 2, 2008
Creator: Almeida, L.G.; Lee, S.J.; Perez, G.; Sterman, G.; Sung, I. & Virzi, J.
Partner: UNT Libraries Government Documents Department

Recent Progress in Weakly-Coupled Heterotic String Phenomenology

Description: Some recent developments in the weakly-coupled heterotic string phenomenology are reviewed. We discuss several important issues such as dilaton/moduli stabilization, supersymmetry breaking (by hidden-sector gaugino condensation), gauge coupling unification (or the Newton's constant), the QCD axion, as well as cosmological problems involving the dilaton/moduli and the axion.
Date: July 28, 1997
Creator: Wu, Yi-Yen
Partner: UNT Libraries Government Documents Department

{pi}-{eta} mixing from QCD sum rules

Description: The q{sub 2} dependence of the {pi}-{eta} mixing amplitude is examined with the use of QCD sum rules. The linear slope of the mixing function {theta}(q{sup 2}) is found to be much smaller than that for {rho}-{omega} mixing. Thus the mixing amplitude is approximately the same in the space-like region as in the time-like one, and one may neglect the q{sup 2} dependence of the mixing. A comparison between a hadron-meson, an effective chiral model, and the QCD sum rules approaches is made.
Date: March 1, 1994
Creator: Chan, C. T.; Henley, E. M. & Meissner, T.
Partner: UNT Libraries Government Documents Department

The gluon propagator in momentum space

Description: We consider quenched QCD on a 16{sup 3}{times}40 lattice at {beta}=6.0. We give preliminary numerical results for the lattice gluon propagator evaluated both in coordinate and momentum space. Our findings are compared with earlier results in the literature at zero momentum. In addition, by considering nonzero momenta we attempt to extract the form of the propagator and compare it to continuum predictions formulated by Gribov and others.
Date: December 31, 1992
Creator: Bernard, C.; Parrinello, C. & Soni, A.
Partner: UNT Libraries Government Documents Department

Measurement of the Three-jet Mass Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV

Description: This thesis describes the measurement of the inclusive three-jet cross section in proton-antiproton collisions at √s = 1.96 TeV measured at the D0 experiment at the Fermilab Tevatron Collider in the Fermi National Accelerator Laboratory, Batavia, Illinois, USA. The cross section as a function of three-jet invariant mass is provided in three regions of the third jet transverse momentum and three regions of jet rapidities. It utilizes a data sample collected in the so called Run IIa data taking period (2002-2006) corresponding to the integrated luminosity of about 0.7 fb<sup>-1</sup>. The results are used to test the next-to-leading order predictions of Quantum chromodynamics computed using the latest parton distribution functions.
Date: June 1, 2010
Creator: Hubacek, Zdenek
Partner: UNT Libraries Government Documents Department

Weak matrix elements on the lattice - Circa 1995

Description: Status of weak matrix elements is reviewed. In particular, e{prime}/e, B {yields} K*{gamma}, B{sub B} and B{sub B}, are discussed and the overall situation with respect to the lattice effort and some of its phenomenological implications are summarised. For e{prime}/e the need for the relevant matrix elements is stressed in view of the forthcoming improved experiments. For some of the operators, (e.g. O{sub 6}), even bound on their matrix elements would be very helpful. On B {yields} K{degrees}{gamma}, a constant behavior of T{sub 2} appears disfavored although dependence of T{sub 2} could, of course, be milder than a simple pole. Improved data is badly needed to settle this important issue firmly, especially in view of its ramification for extractions of V{sub td} from B {yields} {rho}{gamma}. On B{sub {kappa}}, the preliminary result from JLQCD appears to contradict Sharpe et al. JLQCD data seems to fit very well to linear {alpha} dependence and leads to an appreciably lower value of B{sub {kappa}}. Four studies of B{sub {kappa}} in the {open_quotes}full{close_quotes} (n{sub f} = 2) theory indicate very little quenching effects on B{sub {kappa}}; the full theory value seems to be just a little less than the quenched result. Based on expectations from HQET, analysis of B-parameter (B{sub h}{ell}) for the heavy-light mesons via B{sub h}{ell}) = constant + constants{prime}/m{sub h}{ell} is suggested. A summary of an illustrative sample of hadron matrix elements is given and constraints on CKM parameters (e.g. V{sub td}/V{sub ts}, on the unitarity triangle and on x{sub s}/x{sub d}, emerging from the lattice calculations along with experimental results are briefly discussed. In quite a few cases, for the first time, some indication of quenching errors on weak matrix elements are now becoming available.
Date: October 3, 1995
Creator: Soni, A.
Partner: UNT Libraries Government Documents Department

Light hadron spectroscopy

Description: I review the progress that has been made in light hadron spectroscopy from lattice QCD, since the LATTICE`94 conference in Bielefeld.
Date: December 31, 1995
Creator: Sinclair, D.K.
Partner: UNT Libraries Government Documents Department

Prospects for the Precision Measurement of {alpha}{sub s}

Description: The prospects for the measurement of the strong coupling constant {alpha}{sub MS}(M{sub Z}) to a relative uncertainty of 1 % are discussed. Particular emphasis is placed on the implications relating to future High Energy Physics facilities.
Date: December 1996
Creator: Burrows, P. N.; Dixon, L. & El-Khadra, A. X.
Partner: UNT Libraries Government Documents Department

Unitarity-based techniques for one-loop calculations in QCD

Description: Perturbative QCD, and jet physics in particular, have matured sufficiently that rather than being merely subjects of experimental studies, they are now tools in the search for new physics. This role can be seen in the search for the top quark, as well as in recent speculations about the implications of supposed high-E{sub T} deviations of the inclusive-jet differential cross section at the Tevatron. One of the important challenges to both theorists and experimenters in coming years will be to hone jet physics as a tool in the quest for physics underlying the standard model. As such, it will be important to measurements of parameters of the theory or of non-perturbative quantities such as the parton distribution functions, as well as to searches for new physics at the LHC. Jet production, or jet production in association with identified photons or electroweak vector bosons, appears likely to provide the best information on the gluon distribution in the proton, and may also provide useful information on the strong coupling {alpha}{sub s}. In order to make use of these final states, the authors need a wider variety of higher-order calculations of matrix elements. Indeed, as the authors shall review, next-to-leading order calculations are in a certain sense the minimal useful ones. On the other hand, these calculations are quite difficult with conventional Feynman rules. In the following sections, the authors will discuss some of the techniques developed in recent years to simplify such calculations.
Date: June 1, 1996
Creator: Bern, Z.; Dixon, L. & Kosower, D.A.
Partner: UNT Libraries Government Documents Department

Power corrections, renormalons and resummation

Description: I briefly review three topics of recent interest concerning power corrections, renormalons and Sudakov resummation: (a) 1/Q corrections to event shape observables in e(+)e(-) annihilation, (b) power corrections in Drell-Yan production and (c) factorial divergences that arise in resummation of large infrared (Sudakov) logarithms in moment or `real` space.
Date: August 1, 1996
Creator: Beneke, M.
Partner: UNT Libraries Government Documents Department

Strings and supersymmetry as tools for perturbative QCD

Description: We review techniques simplifying the analytic calculation of one-loop QCD amplitudes with many external legs, for use in next-to-leading-order corrections to multi-jet processes. We explain how a supersymmetry-inspired organization works well in conjunction with other tools, namely the color and helicity decompositions of amplitudes, and the constraints imposed by perturbative unitarity and collinear singularities. String theory seems most useful as a heuristic guide. Using these techniques, the complete set of one-loop five-parton QCD amplitudes, as well as certain sequences of special helicity amplitudes with an arbitrary number of external gluons, have been obtained.
Date: July 1, 1995
Creator: Dixon, L.
Partner: UNT Libraries Government Documents Department


Description: We present results at {beta} = 6.0 and 6.2 for the O(a) improvement and renormalization constants for bilinear operators using axial and vector Ward identities. We discuss the extraction of the mass dependence of the renormalization constants and the coefficients of the equation of motion operators.
Date: December 1, 2000
Partner: UNT Libraries Government Documents Department

Charmed meson and onium production at the Tevatron

Description: The authors report recent results of D*{sup {+-}} meson, J/{psi} and {Upsilon} production at the Fermilab Tevatron. They observe about 8,000 D*{sup {+-}} mesons reconstructed in the decay chain of D* {r_arrow} D{sub {pi}}{sup 0}, D{sup 0} {r_arrow} K{mu}+X. They measure the integrated D*{sup +} production cross section to be 347 {+-} 65(stat.) {+-} 58(sys.) nb for the rapidity range {vert_bar}{eta}(D*{sup +}){vert_bar} &lt; 1.0 and the transverse momentum range p{sub T} (D*{sup +}) &gt; 10 GeV/c. The measurement is slightly higher than the theoretical prediction, especially at lower pT range. We also measure the polarization of J/{psi} at production and find that the measured transverse polarization is not well explained by the color-octet model proposed to explain the anomalously high J/{psi} production cross section. We also present a new result on {Upsilon} production and polarization. Production of the {Upsilon} is consistent with being unpolarized.
Date: December 20, 2000
Creator: Nakaya, T.
Partner: UNT Libraries Government Documents Department

The pooltable analogy to axion physics

Description: An imaginary character named TSP finds himself in a playroom whose floor is tilted to one side. However, the pooltable in the playroom is horizontal. TSP wonders how this can be. In doing so, he embarks upon an intellectual journey which parallels that which has been travelled during the past two decades by physicists interested in the Strong CP Problem and axion physics.
Date: January 1, 1996
Creator: Sikivie, P.
Partner: UNT Libraries Government Documents Department