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Dynamics of N = 2 Supersymmetric Gauge Theories in Three Dimensions

Description: We study the structure of the moduli spaces of vacua and superpotentials of N = 2 supersymmetric gauge theories in three dimensions. By analyzing the instanton corrections, we compute the exact superpotentials and determine the quantum Coulomb and Higgs branches of the theories in the weak coupling regions. We find candidates for non-trivial N = 2 superconformal field theories at the singularities of the moduli spaces. The analysis is carried out explicitly for gauge groups U(N{sub c}) and SU(N{sub c}) with N{sub f} flavors. We show that the field theory results are in complete agreement with the intersecting branes picture. We also compute the exact superpotentials for arbitrary gauge groups and arbitrary matter content.
Date: March 21, 1997
Creator: de Boer, J.; Hori, K. & Oz, Y.
Partner: UNT Libraries Government Documents Department

Diffeomorphism groups and anyon fields

Description: We make use of unitary representations of the group of diffeomorphisms of the plane to construct an explicit field theory of anyons. The resulting anyon fields satisfy q-commutators, where q is the well-known phase shift associated with a single counterclockwise exchange of a pair of anyons. Our method uses a realization of the braid group by means of paths in the plane, that transform naturally under diffeomorphisms of R{sup 2}.
Date: September 1, 1995
Creator: Goldin, G.A. & Sharp, D.H.
Partner: UNT Libraries Government Documents Department

Field Theory On the World Sheet: Mean Field Expansion And Cutoff Dependence

Description: Continuing earlier work, we apply the mean field method to the world sheet representation of a simple field theory. In particular, we study the higher order terms in the mean field expansion, and show that their cutoff dependence can be absorbed into a running coupling constant. The coupling constant runs towards zero in the infrared, and the model tends towards a free string. One cannot fully reach this limit because of infrared problems, however, one can still apply the mean field method to the high energy limit (high mass states) of the string.
Date: January 10, 2007
Creator: Bardakci, Korkut
Partner: UNT Libraries Government Documents Department

Massive Supergravity and Deconstruction

Description: We present a simple superfield Lagrangian for massive supergravity. It comprises the minimal supergravity Lagrangian with interactions as well as mass terms for the metric superfield and the chiral compensator. This is the natural generalization of the Fierz-Pauli Lagrangian for massive gravity which comprises mass terms for the metric and its trace. We show that the on-shell bosonic and fermionic fields are degenerate and have the appropriate spins: 2, 3/2, 3/2 and 1. We then study this interacting Lagrangian using goldstone superfields. We find that achiral multiplet of goldstones gets a kinetic term through mixing, just as the scalar goldstone does in the non-supersymmetric case. This produces Planck scale (Mpl) interactions with matter and all the discontinuities and unitarity bounds associated with massive gravity. In particular, the scale of strong coupling is (Mpl m^4)^1/5, where m is the multiplet's mass. Next, we consider applications of massive supergravity to deconstruction. We estimate various quantum effects which generate non-local operators in theory space. As an example, we show that the single massive supergravity multiplet in a 2-site model can serve the function of an extra dimension in anomaly mediation.
Date: March 23, 2004
Creator: Gregoire, Thomas; Schwartz, Matthew D. & Shadmi, Yael
Partner: UNT Libraries Government Documents Department

Noncommutative Dipole Field Theories And Unitarity

Description: We extend the argument of Gomis and Mehen for violation of unitarity in field theories with space-time noncommutativity to dipole field theories. In dipole field theories with a timelike dipole vector, we present 1-loop amplitudes that violate the optical theorem. A quantum mechanical system with nonlocal potential of finite extent in time also shows violation of unitarity.
Date: October 24, 2003
Creator: Chiou, Dah-Wei & Ganor, Ori J.
Partner: UNT Libraries Government Documents Department

Conformal field theory on affine Lie groups

Description: Working directly on affine Lie groups, we construct several new formulations of the WZW model, the gauged WZW model, and the generic affine-Virasoro action. In one formulation each of these conformal field theories (CFTs) is expressed as a one-dimensional mechanical system whose variables are coordinates on the affine Lie group. When written in terms of the affine group element, this formulation exhibits a two-dimensional WZW term. In another formulation each CFT is written as a two-dimensional field theory, with a three- dimensional WZW term, whose fields are coordinates on the affine group. On the basis of these equivalent formulations, we develop a translation dictionary in which the new formulations on the affine Lie group are understood as mode formulations of the conventional formulations on the Lie group. Using this dictionary, we also express each CFT as a three-dimensional field theory on the Lie group with a four-dimensional WZW term. 36 refs.
Date: April 1, 1996
Creator: Clubok, K.S.
Partner: UNT Libraries Government Documents Department

Phase transitions: An overview with a view

Description: The dynamics of phase transitions plays a crucial role in the so- called interface between high energy particle physics and cosmology. Many of the interesting results generated during the last fifteen years or so rely on simplified assumptions concerning the complex mechanisms typical of nonequilibrium field theories. After reviewing well-known results concerning the dynamics of first and second order phase transitions, I argue that much is yet to be understood, in particular in situations where homogeneous nucleation theory does not apply. I present a method to deal with departures from homogeneous nucleation, and compare its efficacy with numerical simulations. Finally, I discuss the interesting problem of matching numerical simulations of stochastic field theories with continuum models.
Date: October 1, 1997
Creator: Gleiser, M.
Partner: UNT Libraries Government Documents Department

Regularization for effective field theory with two heavy particles

Description: A regularization for effective field theory with two propagating heavy particles is constructed. This regularization preserves the low-energy analytic structure, implements a low-energy power counting for the one-loop diagrams, and preserves symmetries respected by dimensional regularization.
Date: January 1, 2001
Creator: Goity, J.L.; Lehmann, D.; Prezeau, G. & Saez, J.
Partner: UNT Libraries Government Documents Department

Research in theoretical elementary particle physics at the University of Florida: Task A. Annual progress report

Description: This is the Annual Progress Report of the theoretical particle theory group at the University of Florida under DOE Grant DE-FG05-86ER40272. At present our group consists of four Full Professors (Field, Ramond, Thorn, Sikivie), one Associate Professor (Woodard), and two Assistant Professors (Qiu, Kennedy). In addition, we have four postdoctoral research associates and seven graduate students. The research of our group covers a broad range of topics in theoretical high energy physics including both theory and phenomenology. Included in this report is a summary of the last several years, an outline of our current research program.
Date: December 1994
Creator: Field, R. D.; Ramond, P. M.; Sikivie, P. & Thorn, C. B.
Partner: UNT Libraries Government Documents Department

Supersymmetry and Superstring Phenomenology

Description: We briefly cover the early history of supersymmetry, describe the relation of SUSY quantum field theories to superstring theories and explain why they are considered a likely tool to describe the phenomenology of high energy particle theory beyond the Standard Model.
Date: May 5, 2008
Creator: Gaillard, Mary K; Gaillard, Mary K. & Zumino, Bruno
Partner: UNT Libraries Government Documents Department

Instabilities of higher dimensional compactifications

Description: Various schemes for cosmological compactification of higher dimensional theories are considered. Possible instabilities which drive the ground state with static internal space to de Sitter-like expansion of all dimensions are discussed. These instabilities are due to semiclassical barrier penetration and classical thermal fluctuations. For the case of the ten dimensional Chapline-Manton action, it is possible to avoid such difficulties by balancing one-loop Casimir corrections against monopole contributions from the field strength H/sub MNP/ and fermionic condensates. 10 refs.
Date: February 1, 1987
Creator: Accetta, F.S.
Partner: UNT Libraries Government Documents Department

Gravitinos as the cold dark matter in an. cap omega. = 1 universe

Description: In attempts to simultaneously have galaxy formation with adiabatic fluctuations, dark galactic halos and a critical ..cap omega.. = 1, recent models have been proposed with a heavy (cold) species which decays and a lighten (hot or warm) one which is stable. Surprisingly enough, these models are very constraining. Independent of the particle physics model, the decay width of the heavy particle must be 0(10/sup -40/) GeV. Such a scale is only natural in theories involving gravity where one expects GAMMA - M/sub H//sup 3//M/sub p//sup 2/, where M/sub H/ is the mass of the heavy particle and M/sub p/ is the planck mass. In this paper, we suggest that the heavy particle might be the gravitino which is present in all supergravity theories. This model would then require that the gravitino decay products not include photons, indicating that the lightest supersymmetric particle (LSP) must be something other than the photino. An acceptable candidate for the LSP might be the axino, the supersymmetric partner of the axion.
Date: November 1, 1984
Creator: Olive, K.A.; Schramm, D.N. & Srednicki, M.
Partner: UNT Libraries Government Documents Department

Collective enhancement of inclusive cross sections at large transverse momentum in stochastic-field multiparticle theory

Description: A stochastic-field calculus, previously discussed in connection with Regge intercepts and instability questions, is applied to inclusive cross sections, and is shown to predict a growth with energy of large-P/perpendicular/ to inclusives. (auth)
Date: January 1, 1976
Creator: Arnold, R.C.
Partner: UNT Libraries Government Documents Department

Local discrete symmetries from superstring derived models

Description: Discrete and global symmetries play an essential role in many extensions of the Standard Model, for example, to preserve the proton lifetime, to prevent flavor changing neutral currents, etc. An important question is how can such symmetries survive in a theory of quantum gravity, like superstring theory. In a specific string model the author illustrates how local discrete symmetries may arise in string models and play an important role in preventing fast proton decay and flavor changing neutral currents. The local discrete symmetry arises due to the breaking of the non-Abelian gauge symmetries by Wilson lines in the superstring models and forbids, for example dimension five operators which mediate rapid proton decay, to all orders of nonrenormalizable terms. In the context of models of unification of the gauge and gravitational interactions, it is precisely this type of local discrete symmetries that must be found in order to insure that a given model is not in conflict with experimental observations.
Date: October 1, 1996
Creator: Faraggi, A.E.
Partner: UNT Libraries Government Documents Department

No strings attached potential vs. interaction energy in QCD

Description: In infrared-stable fixed-point field theories, the interaction energy of a test particle is proportional to the non-relativistic (heavy source) coordinate-space potential derived from the field strength produced by that source. This is no longer true in ultraviolet-stable fixed-point field theories (UVSFPFT) as they may not have a finite infrared fixed point. This leads to the possibility that UVSFPFTs may have quite conventional field strength distributions despite the unusual spatial dependence expected for the interaction energy.
Date: October 20, 1996
Creator: Goldman, T.
Partner: UNT Libraries Government Documents Department

Regularization and the potential of effective field theory in nucleon-nucleon scattering

Description: This paper examines the role that regularization plays in the definition of the potential used in effective field theory (EFT) treatments of the nucleon-nucleon interaction. The author considers N N scattering in S-wave channels at momenta well below the pion mass. In these channels (quasi-)bound states are present at energies well below the scale m{sub {pi}}{sup 2}/M expected from naturalness arguments. He asks whether, in the presence of such a shallow bound state, there is a regularization scheme which leads to an EFT potential that is both useful and systematic. In general, if a low-lying bound state is present then cutoff regularization leads to an EFT potential which is useful but not systematic, and dimensional regularization with minimal subtraction leads to one which is systematic but not useful. The recently-proposed technique of dimensional regularization with power-law divergence subtraction allows the definition of an EFT potential which is both useful and systematic.
Date: April 1, 1998
Creator: Phillips, D.R.
Partner: UNT Libraries Government Documents Department

Super-Galilei invariant field theories in 2+1 dimensions

Description: The authors extend the Galilei group of space-time transformations by gradation, construct interacting field-theoretic representations of this algebra, and show that non-relativistic Super-Chern-Simons theory is a special case. They also study the generalization to matrix valued fields, which are relevant to the formulation of superstring theory as a 1/N{sub c} expansion of a field theory. The authors find that in the matrix case, the field theory is much more restricted by the supersymmetry.
Date: December 31, 1995
Creator: Bergman, O. & Thorn, C.B.
Partner: UNT Libraries Government Documents Department

New Constraints on Chiral Gauge Theories

Description: Recently, a new constraint on the structure of a wide class of strongly coupled field theories has been proposed. It takes the form of an inequality limiting the number of degrees of freedom in the infrared description of a theory to be no larger than the number of underlying, ultraviolet degrees of freedom. Here we apply this inequality to chiral gauge theories. For some models we find that it is always satisfied, while for others we find that the assumption of the validity of the inequality implies a strong additional restriction on the spectrum of massless composite particles.
Date: April 27, 1999
Creator: Schmaltz, Martin
Partner: UNT Libraries Government Documents Department

The generic world-sheet action of irrational conformal field theory

Description: We review developments in the world-sheet action formulation of the generic irrational conformal field theory, including the non-linear and the linearized forms of the action. These systems form a large class of spin-two gauged WZW actions which exhibit exotic gravitational couplings. Integrating out the gravitational field, we also speculate on a connection with sigma models.
Date: May 1, 1995
Creator: Clubok, K. & Halpern, M.B.
Partner: UNT Libraries Government Documents Department

Potential motion for Thomas-Fermi non-topological solitons

Description: In the Thomas-Fermi approximation to theories of coupled fermions and scalars, the equations for spherically-symmetric non-topological solitons have the form of potential motion. This gives a straightforward method for proving the existence of non-topological solitons in a given theory and for finding the constant-density, saturating solutions.
Date: April 1, 1992
Creator: Bahcall, S. & Lynn, B.W.
Partner: UNT Libraries Government Documents Department

Six-dimensional supergravity on S3 x AdS3 and 2d conformal field theory

Description: In this paper we study the relation between six-dimensional supergravity compactified on S{sup 3} x AdS{sub 3} and certain two-dimensional conformal field theories. We compute the Kaluza-Klein spectrum of supergravity using representation theory; these methods are quite general and can also be applied to other compactifications involving anti-de Sitter spaces. A detailed comparison between the spectrum of the two-dimensional conformal field theory and supergravity is made, and we find complete agreement. This applies even at the level of certain non-chiral primaries, and we propose a resolution to the puzzle of the missing states recently raised by Vafa. As a further illustration of the method the Kaluza-Klein spectra of F-theory on M{sup 6} x S{sup 3} x AdS{sub 3} and of M-theory on M{sup 6} x S{sup 2} x AdS{sub 3} are computed, with M{sup 6} some Calabi-Yau manifold.
Date: June 20, 1998
Creator: de Boer, Jan
Partner: UNT Libraries Government Documents Department