34 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Unified-Field Theories 645400* -- High Energy Physics-- Field Theory"

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

Top quark and light Higgs scalar mass bounds in no-scale supergravity

No-scale supergravity theories with the minimal low-energy particle content are shown to become untenable for a top quark mass m/sub T/ much less than 40 GeV. For m/sub T/ < 55 GeV, a stringent upper bound operates on the mass of the lowest-lying Higgs scalar. Further, the Higgs pseudoscalar is constrained to be nearly a quarter as massive as the gluino.

Date: August 29, 1986

Creator: Roy, P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The physics of heavy flavors

We review the physics of heavy quark flavors, including weak decays, onium, tau leptons, mixing, the Kobayashi-Maskawa matrix, and CP violation in B decay. 36 refs., 12 figs.

Date: December 1, 1987

Creator: Gilman, Frederick J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Exotic signatures from supersymmetry

Minor changes to the standard supersymmetric model, such as soft flavor violation and R parity violation, cause large changes in the signatures. The origin of these changes and the resulting signatures are discussed. 15 refs., 7 figs., 2 tabs.

Date: August 1, 1989

Creator: Hall, L. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Monopole catalysis: an overview

A summary of the talks presented in the topological workshop on monopole catalysis at this conference is given. We place special emphasis on the conservation laws which determine the allowed monopole-fermion interactions and on catalysis as a probe of the structure of a grand unified theory. 11 references.

Date: November 1, 1983

Creator: Dawson, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Beyond the supersymmetric standard model

The possibility of baryon number violation at the weak scale and an alternative primordial nucleosynthesis scheme arising from the decay of gravitations are discussed. The minimal low energy supergravity model is defined and a few of its features are described. Renormalization group scaling and flavor physics are mentioned.

Date: February 1, 1988

Creator: Hall, L.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Physics at the Planck scale

Effective supergravity theories suggested by superstrings can be explored to determine their potential for successfully describing both observed physics at zero temperature and an inflationary cosmology. An important ingredient in this study is the dynamics of gaugino condensation, which has been the subject of recent activity. 33 refs., 2 figs.

Date: December 6, 1990

Creator: Gaillard, M.K. (Lawrence Berkeley Lab., CA (USA) California Univ., Berkeley, CA (USA). Dept. of Physics)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effective theories and thresholds in particle physics

The role of effective theories in probing a more fundamental underlying theory and in indicating new physics thresholds is discussed, with examples from the standard model and more speculative applications to superstring theory. 38 refs.

Date: June 7, 1991

Creator: Gaillard, M. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Low-energy structure of four-dimensional superstrings

The N = 1, d = 4 supergravity theories derived as the low-energy limit of four-dimensional superstrings are discussed, focusing on the properties of their effective potentials. Gauge symmetry breaking is possible along several flat directions. A class of superpotential modifications is introduced, which describes supersymmetry breaking with vanishing cosmological constant and Str M{sup 2} = 0 at any minimum of the tree level potential. Under more restrictive assumptions, there are minima with b… more

Date: May 1, 1988

Creator: Zwirner, F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Diffraction theory in QCD and beyond

A study of the Pomeron in QCD is briefly outlined. Implications for the production of W/sup +/W/sup -/ and Z/sup 0/Z/sup 0/ pairs are described and the possibility that the electroweak scale is a major strong-interaction threshold discussed. The application of Pomeron phase-transition theory to SU(5) dynamical symmetry breaking is suggested and the related ''strong-interaction'' properties of the photon briefly mentioned.

Date: December 11, 1987

Creator: White, A.R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The standard model and colliders

Some topics in the standard model of strong and electroweak interactions are discussed, as well as how these topics are relevant for the high energy colliders which will become operational in the next few years. The radiative corrections in the Glashow-Weinberg-Salam model are discussed, stressing how these corrections may be measured at LEP and the SLC. CP violation is discussed briefly, followed by a discussion of the Higgs boson and the searches which are relevant to hadron colliders are the… more

Date: March 1, 1987

Creator: Hinchliffe, I.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Physics with ultra-low energy antiprotons

The experimental observation that all forms of matter experience the same gravitational acceleration is embodied in the weak equivalence principle of gravitational physics. However no experiment has tested this principle for particles of antimatter such as the antiproton or the antihydrogen atom. Clearly the question of whether antimatter is in compliance with weak equivalence is a fundamental experimental issue, which can best be addressed at an ultra-low energy antiproton facility. This paper… more

Date: January 1, 1989

Creator: Holtkamp, D. B.; Holzscheiter, M. H. & Hughes, R. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Gravitational properties of antimatter

Quantum gravity is at the forefront of modern particle physics, yet there are no direct tests, for antimatter, of even the principle of equivalence. We note that modern descriptions of gravity, such as fibre bundles and higher dimensional spacetimes, allow violations of the commonly stated form of the principle of equivalence, and of CPT. We review both indirect arguments and experimental tests of the expected gravitational properties of CPT-conjugate states. We conclude that a direct experimen… more

Date: January 1, 1985

Creator: Goldman, T. & Nieto, M.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Standard model and beyond

The ''standard'' SU(3)/sub C/ x SU(2)/sub L/ x U(1) model of strong and electroweak interactions elegantly incorporates all the proven symmetries and successes of the quark model, quantum electrodynamics, and the Four-Fermi theory. It correctly predicted weak neutral currents as well as the existence and properties of W/sup + -/, Z and gluons. ''Only'' the predicted Higgs scalar boson remains undiscovered. At this time there are no solid experimental results that cannot be accommodated by the s… more

Date: January 1, 1985

Creator: Marciano, William J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Superworlds/hyperworlds

Some simple exercises are carried out which clarify the physics of a 5-dimensional world in which one dimension is curled up to a radius R. A technical problem necessary to generalize this discussion to d dimensions is considered - the determination of the sizes of spinors in higher dimensions. The origin of eigenmodes of a higher-dimensional field with exactly zero energy is explored, using as examples conventional models of field theory. General relativity is then reviewed, formulated as a ga… more

Date: March 1, 1986

Creator: Peskin, M.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Problems in unification and supergravity

Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented. (WHK)

Date: January 1, 1984

Creator: Farrar, G. & Henyey, F. (eds.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The standard model and beyond

In these lectures, my aim is to present a status report on the standard model and some key tests of electroweak unification. Within that context, I also discuss how and where hints of new physics may emerge. To accomplish those goals, I have organized my presentation as follows. I survey the standard model parameters with particular emphasis on the gauge coupling constants and vector boson masses. Examples of new physics appendages are also commented on. In addition, I have included an appendix… more

Date: May 1, 1989

Creator: Marciano, William J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Stable Compactifications

We show that compactifications of theories with extra dimensions are unstable if due to monopole configurations of an antisymmetric tensor field balanced against one-loop Casimir corrections. In the case of ten dimensional supergravity, it is possible, at least for a portion of the phase space, to achieve a stable compactification without fine-tuning by including the contribution of fermionic condensates to the monopole configurations. 23 refs., 2 figs.

Date: March 1, 1986

Creator: Accetta, F. S.; Gleiser, M.; Holman, R. & Kolb, E. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Standard model and beyond

The SU(3)/sub c/ circle crossSU(2)/sub L/circle crossU(1)/sub Y/ gauge theory of ineractions among quarks and leptons is briefly described, and some recent notable successes of the theory are mentioned. Some shortcomings in our ability to apply the theory are noted, and the incompleteness of the standard model is exhibited. Experimental hints that Nature may be richer in structure than the minimal theory are discussed. 23 references.

Date: September 1, 1984

Creator: Quigg, C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Testing the surrogate zeta-function method

Use of the surrogate zeta-function method was crucial in calculating the Casimir energy in non-Abelian Kaluza-Klein theories. We establish the validity of this method for the case that the background metric is (Euclidean space)x(N-sphere). Our techniques do not apply to the case where the background is (Minkowski-space)x(N-sphere).

Date: October 1, 1985

Creator: Chodos, A. & Myers, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Grand unification: quo vadis domine

The present theoretical and experimental situation with grand unification is summarized. The issues of proton decay and the Weinberg angle are addressed, going through the predictions of both the standard SU(5) theory and its supersymmetric extension. The SO(10) theory, which provides a minimal one family model, is then studied. The gravitational characteristics of domain walls and strings are then discussed. It is argued that there is a need to go beyond SO(10) in order to incorporate a unifie… more

Date: January 1, 1985

Creator: Senjanovic, G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effective nonrenormalizable theories at one loop

The paper focuses on a nonrenormalizable theory that is more closely related to those suggested by superstrings, namely a gauged nonlinear delta-model, but one which can also be obtained analytically in a particular limit of a parameter (m/sub H/ ..-->.. infinity) of the standard, renormalizable electroweak theory. This will provide another laboratory for testing the validity of calculations using the effective theory. We find (as for certain superstring inspired models to be discussed later) f… more

Date: October 12, 1987

Creator: Gaillard, M. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Supersymmetry, grand unification and proton decay

In this talk, some phenomenological issues were reviewed pertaining to supersymmetric grand unified theories (SUSY GUTs), with special emphasis on new features for proton decay. 18 refs.

Date: January 1, 1982

Creator: Rudaz, S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Hypermultiplet couplings in N = 2 supergravity

An arbitrary number of massless spin (0,/sup 1///sub 2/) multiplets are coupled to N = 2 supergravity, and the scalar fields are found to lie on a negatively curved quaternionic manifold. 6 references.

Date: August 1, 1984

Creator: Bagger, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department