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in subjects: "Extended Particle Model"

open access

Two exercises in supersymmetry: a low-energy supergravity model and free string field theory

The new features of a supersymmetric standard model in the presence of heavy families are studied. The minimal set of Higgs fields, the desert between the electroweak and the grand unification scale and perturbative values of the dimensionless parameters throughout this region are assumed. Using the numerical as well as the approximate analytic solution of the renormalization group equations, the evolution of all the parameters of the theory are studied in the case of large Yukawa couplings for… more

Date: September 1, 1986

Creator: Preitschopf, C.R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Bag model, the hyperspherical formalism and the heavy baryons

The bag model framework is used to discuss the heavy baryons, triple flavored objects like ccc, cbb, etc. A nonrelativistic picture seems justified. It is insisted that the long-range interaction consist of a genuine three-body force. Once the potential energy of the three quarks is determined, the three-body Schroedinger equation is solved by the method of hyperspherical expansion. 1 table. (RWR)

Date: January 1, 1980

Creator: Richard, J. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Potential energy for quarks

It is argued on theoretical and phenomenological grounds that confinement of quarks is intrinsically a many-body interaction. The Born-Oppenheimer approximation to the bag model is shown to give rise to a static potential energy that consists of a sum of two-body Coulomb terms and a many-body confining term. Following the success of this potential in heavy Q anti Q systems it is being applied to Q/sup 2/ anti Q/sup 2/. Preliminary calculations suggest that dimeson bound states with exotic flavo… more

Date: January 1, 1985

Creator: Heller, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The geometry of the Virasoro group for physicists

Diff(S/sup 1/), the group of reparametrizations of the circle, is known as the Virasoro group in string theory. Reparametrizations keeping fixed a point of the circle form the quotient space Diff(S/sup 1/)S/sup 1/. The geometry of this space is relevant for string theory and string field theory. We describe this space as an infinite dimensional complex manifold with a Kaehler metric and compute ist Riemann tensor and its Ricci tensor. 7 refs

Date: November 1, 1987

Creator: Zumino, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Gaugino masses in superstring inspired models

Contributions to the masses of the gauginos in models arising as low energy limits of superstring theories are considered.

Date: August 1, 1986

Creator: Dawson, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Gauge invariant description of heavy quark bound states in quantum chromodynamics

A model for a heavy quark meson is proposed in the framework of a gauge-invariant version of quantum chromodynamics. The field operators in this formulation are taken to be Wilson loops and strings with quark-antiquark ends. The fundamental differential equations of point-like Q.C.D. are expressed as variational equations of the extended loops and strings. The 1/N expansion is described, and it is assumed that nonleading effects such as intermediate quark pairs and nonplanar gluonic terms can b… more

Date: August 1, 1980

Creator: Moore, S. E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Fragmentation model applied to exclusive final states in photon-photon collisions

Monte Carlo calculations with the Lund string fragmentation model are compared to experimental results on the reactions ..gamma gamma -->..2..pi../sup +/2..pi../sup -/, ..gamma gamma -->..K/sup +/K/sup -/..pi../sup +/..pi../sup -/ and ..gamma gamma -->..p anti p..pi../sup +/..pi../sup -/. It is found, that when the parameters of the Lund model are tuned to low energy, inclusive multi hadron production in photon-photon collisions, the cross sections of exclusive processes near threshold are qual… more

Date: July 1, 1986

Creator: Buijs, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Introduction to conformal field theory and string theory

These lectures are meant to provide a brief introduction to conformal field theory (CFT) and string theory for those with no prior exposure to the subjects. There are many excellent reviews already available, and most of these go in to much more detail than I will be able to here. 52 refs., 11 figs.

Date: December 1, 1989

Creator: Dixon, L.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Normalizing the renormalization group in deep inelastic leptoproduction. CTP No. 878

The quark-bag model is used to calculate the nucleon matrix elements of local twist-two operators. Bag matrix elements applicable to low Q/sup 2/ are evolved by use of QCD perturbation theory to a value of Q/sup 2/ large enough that the data can be expected to be dominated by twist-two. Nonsinglet moments of F/sub 3/ are plotted. Although only twist-two was studied, the work has implications for higher twist. It is concluded that either the twist-two operator matrix element is Q/sup 2/ dependen… more

Date: September 1, 1980

Creator: Jaffe, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Difficult states in the quark model: glueballs and the pion. CTP No. 874

Work on the spectroscopy of glueballs and on the pion is reviewed.

Date: August 1, 1980

Creator: Donoghue, J. F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Jets in e/sup +/e/sup -/ annihilation

We have a simple perturbative picture of the production of hadrons from e/sup +/e/sup -/ annihilations which works quite well in predicting the main features of this interaction. It explains the magnitude of the total cross-section, the basic two-jet structure, and the final state angular distributions. It is also consistent with our present ideas about the structure of hadronic matter and the requirement that at high enough energies, the corrections due to strong interactions are small and hen… more

Date: October 1, 1983

Creator: Hollebeek, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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(Research in the theory of condensed matter and elementary particles. ) Progress report

Progress is summarized in these areas: a new formulation of two dimensional critical phenomena and string theory, supersymmetric critical phenomena and string compactification, conformal field theory on orbifolds, Gaussian models with twisted boundary conditions, modular invariance and supersymmetric critical phenomena, critical indices, conformal invariance, and current algebra, renormalization group fixed points and the string equation of motion, fermionic string field theory, N = 2 super Rie… more

Date: January 1, 1986

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Gauge invariant actions for string models

String models of unified interactions are elegant sets of Feynman rules for the scattering of gravitons, gauge bosons, and a host of massive excitations. The purpose of these lectures is to describe the progress towards a nonperturbative formulation of the theory. Such a formulation should make the geometrical meaning of string theory manifest and explain the many ''miracles'' exhibited by the string Feynman rules. There are some new results on gauge invariant observables, on the cosmological c… more

Date: June 1, 1986

Creator: Banks, T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Theoretical particle physics

We have carried out research in lattice gauge theory, superstring theory, supersymmetry, the solar neutrino puzzle, QCD perturbation theory, and phenomenological models of hadrons. In this report, we summarize our work in each of these areas.

Date: April 1, 1992

Creator: Gottlieb, S.A.; Hendry, A.W.; Kostelecky, V.A. & Lichtenberg, D.B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Inclusive. pi. /sup + -/, K/sup + -/, and p, anti p production in e/sup +/e/sup -/ annihilation at. sqrt. s = 29 GeV

Measurements of ..pi../sup + -/, K/sup + -/ and p, anti p inclusive cross sections and fractions in e/sup +/e/sup -/ annihilation at ..sqrt..s = 29 GeV are presented. The momentum interval covered corresponds to 0.01 < z < 0.90, where z = pp/sub beam/. The analysis is based on approximately 70 pb/sup -1/ of data collected between 1984 and 1986 with the TPC2..gamma.. detector at PEP. Charged particles are identified by a simultaneous measurement of momentum and ionization energy loss (dEdx). The… more

Date: January 1, 1988

Creator: Cowan, G.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Momentum-dependent mean field and the nuclear equation of state

We study the momentum distribution of nucleons in nuclear matter and calculate the incompressibility analytically in the presence of a momentum-dependent mean field. An equivalent mass is introduced for calculational purposes. The effect of the momentum-dependence of the mean field on the hadronic equation of state is examined and the conditions for equilibrium with a quark phase described by a bag model equation of state are investigated. 12 refs., 4 figs.

Date: 1991-01~

Creator: Csernai, László P.; Fai, George; Gale, Charles & Osnes, Eivind

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Particle Cosmology Comes of Age

The application of modern ideas in particle physics to astrophysical and cosmological settings is a continuation of a fruitful tradition in astrophysics which began with the application of atomic physics, and then nuclear physics. In the past decade particle cosmology and particle astrophysics have been recognized as 'legitimate activities' by both particle physicists and astrophysicists and astronomers. During this time there has been a high level of theoretical activity producing much specula… more

Date: December 1, 1987

Creator: Turner, M. S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Resonant enhancement of flavor-changing neutrino interactions

The resonant amplification of neutrino oscillations in the presence of flavor-changing neutrino interactions with matter is analyzed. It is shown that a significant {mu}-flavor conversion can take place even in the absence of neutrino mixing in vacuum. To account for the solar neutrino deficit, the strength of the new interactions should be {approximately} 10{sup {minus}2}G{sub F} and the resulting neutrino suppression and spectrum is similar to that in the ordinary MSW effect. I discuss some e… more

Date: October 1, 1991

Creator: Roulet, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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(Topics in theoretical physics). Progress report

Progress is reported in these areas: supersymmetry and conformal invariance and new structures in two dimensional critical phenomena; spinor fields and new applications and techniques for studying Ising model correlation factors; superstring compactification and high energy physics applications for novel two dimensional critical points; ordered and disordered spatial structure in dynamical systems; and fermion-boson mass relations in BCS type theories. Research is proposed in covariant formulat… more

Date: January 1, 1985

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Meson radiation from quark-gluon plasma

Meson formation and radiation at the surface of quark-gluon plasma are studied by making use of the chromoelectric flux tube model. The effect of the surface meson radiation on the hydroexpansion of the plasma fluid is also discussed.

Date: November 1, 1983

Creator: Matsui, T.; Banerjee, B. & Glendenning, N.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quantum cosmology on the worldsheet

Two-dimensional quantum gravity coupled to conformally invariant matter central c > 25 provides a toy model for quantum gravity in four dimensions. Two-dimensional quantum cosmology can thus be studied in terms of string theory in background fields. The large scale cosmological constant depends on non-linear dynamics in the string theory target space and does not appear to be suppressed by wormhole effects. 13 refs.

Date: August 1, 1991

Creator: Cooper, A.R.; Susskind, L. & Thorlacius, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Theoretical high energy physics research at the University of Chicago, Task A

This report discusses research conducted at the University of Chicago in theoretical high energy physics. Some of the areas included in this report are: cp violation and cabibbo-kobayashi-maskawa matrix; radiative corrections and electroweak observables; heavy quark symmetry; heavy meson spectroscopy; hadronic string theory; composite models of quarks and leptons; and pedagogical effects. (LSP)

Date: April 1, 1992

Creator: Rosner, J.L.; Martinec, E.J. & Sachs, R.G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Relativistic heavy ions physics

Central nuclear collisions at energies far above 1 GeV/nucleon may provide for conditions, where the transition from highly excited hadronic matter into quark matter or quark-gluon plasma can be probed. We review current ideas about the nature of, and signals for, this transition, and we discuss the (hadronic) string model approach to the nuclear collisions dynamics. At even higher energies in the TeV/nucleon range peripheral nuclear collisions may become a laboratory for electroweak physics at… more

Date: January 1, 1989

Creator: Mueller, B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comparison of q anti qg and q anti q. gamma. events in e/sup +/e/sup -/ annihilation at PEP

In comparing the particle flow in the event plane of three-jet (q anti qg) events and of radiative annihilation events (q anti q..gamma..) for similar kinematic configurations, two PEP experiments find a significant decrease in particle density in the angular region opposite to the gluon jet in q anti qg events, relative to the particle density in the region opposite to the photon in q anti q..gamma.. events. The effect is predicted both by QCD and by phenomenological string models. 5 refs., 5 … more

Date: July 1, 1986

Creator: Hofmann, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department