It has recently been found that the \cal N=4 supersymmetric gauge theory describing the low-energy excitations of coincident D3-branes is equivalent to a IIB string theory in a background of the form AdS_5\times S^5. We consider extensions of this correspondence to the case in which the branes are located at singularities of the transverse space. This construction leads to holographic conjectures for a large class of \cal N=1 supersymmetric gauge theories. In particular, we study the singularities which arise as partial resolutions of orbifolds. For these singularities we are able to compute properties of the induced conformal field theories and make direct comparisons with the predictions of the AdS/CFT correspondence.
[UB07.02] U(1)' in gauge mediated supersymmetry breaking models
Paul Langacker, Nir Polonsky, Jing Wang
We investigate the possibility of realistic electroweak
symmetry breaking in the presence of an additional U(1)'
symmetry in models with gauge mediated supersymmetry
breaking associated with a scale \Lambda \sim 10^5~GeV.
Two scenarios are considered. One involves only one SM
singlet S charged under U(1)' with the coupling S
H_u\cdot H_d. The U(1)' breaking via the non-zero VEV
of S happens at the TeV scale to ensure a heavy Z',
and an effective \mu parameter is generated. A B term
also arises from the A term associated with the coupling
S H_u \cdot H_d. We found that in this scenario, due
to the large U(1)' D-term contribution to the scalar
potential and the small A parameter, the minimum takes
place at large \tan\beta\sim 30 and large \mu\sim
1~TeV. The other involves two singlets S_1 and S_2 with
U(1)' charges Q_1=-2Q_2. Hence, there is a U(1)'
D-flat direction formed by S_1, S_2 at a scale
below \Lambda, and their contributions to the D-term
vanish. Gauge invariance allows the coupling S_1 S_2^2, it
pushes the U(1)' breaking along the D-flat direction to
occur at \sim TeV scale. The A parameter associated with
S_1 H_u \cdot H_d can be larger than the previous
case; also the F- term from S_1 S_2^2 and S_1 H_u
\cdot H_d contributes to the effective B term. As a
result, the total effective B term is of order a few
\times 100~(GeV)^2. Hence, the minimum of the potential
occurs for reasonable \mu\sim a few \times 100~GeV and
\tan\beta \sim 10.
[UB07.03] Hamilton-Jacobi formalism of superstrings
Yutaka Hosotani (School of Physics and Astronomy, University of Minnesota), Ryuichi Nakayama (Department of Physics, Hokkaido University)
The Hamilton-Jacobi formalism of bosonic strings and
superstrings is given. Classical motion of strings is
described by local fields. Connection to quantum string
fields is also explored.
[UB07.04] Noncommutative Yang-Mills theories in Matrix model compactification
Yong-Shi Wu (Department of Physics, University of Utah), Pei-Ming Ho (Department of Physics, National Taiwan University)
We present a noncommutaive geometric framework for Matrix
theory compactified on a flat quotient space R^n/
\Gamma, with \Gamma a discrete group of Euclidean
motions. It results in Yang-Mills theories living on a
quantum space, which can be a noncommutative torus, orbifold
or orientifold. The information of the compactification is
encoded in the action of \Gamma on the Euclidean space
R^n and a projective representation U of \Gamma.
The choice of Hilbert space on which the algebra of U is
realized as an operator algebra corresponds to the choice of
a physical background for the compactification.
[UB07.05] Incorporating Lorentz-Violating Terms into the Standard Model
Don Colladay (The College of Wooster), V. Alan Kostelecký (Indiana University)
An extension of the standard model that incorporates small
Lorentz-breaking terms is presented. The terms are assumed
to arise through spontaneous symmetry breaking in a
fundamental theory underlying the standard model. A
consistent quantization of the theory is developed, and the
restriction to quantum electrodynamics is discussed.
Proposed bounds on the parameters using high precision
measurements are explored.
[UB07.06] Supermultiplets and relativistic equations
Marcos Moshinsky (Instituto de F'\isica, UNAM. Apdo. Postal 20-365, México, D. F.)
The word multiplet is frequently used to denote degeneracy of states associated with ordinary spin while supermultiplet, in nuclear physics, is related to degeneracy caused by both spin and isospin. In relativistic equations we can introduce the supermultiplet concept by replacing the \alpha's and \beta, or equivalently the \gamma's, in Dirac type equations in terms of direct products of ordinary spin and a new one which we denote by the name of sign spin. In this way nuclear physics methods can be applied to relativistic problems which now show SU(4) as symmetry group. We first discuss the application of this supermultiplet formulation to one particle relativistic equations, in which the spin can take arbitrary values, through the chain SU(4)\supsetSp(4), and as Sp(4) is isomorphic to O(5) we further characterize our states by the chain O(5)\supset O(4) \supsetO(3) \supsetO(2). We also consider many-body interacting relativistic particles, with special emphasis on the two body problem where supermultiplet states allow its representation in matrix form, suitable for variational calculations.
[UB07.07] Large Gauge Invariance at Finite Temperature
Gerald Dunne (University of Connecticut)
Recent work has shown the surprising result that finite
temperature perturbation theory is not invariant, at a given
order, under large gauge transformations (those with
non-zero winding number). Nevertheless, in certain cases it
is possible to re-sum perturbation theory to recover
invariance under large gauge transformations. This can be
illustrated most directly for planar fermionic theories for
which radiative quantum effects induce parity violating
terms. At zero temperature only a Chern-Simons term is
induced, but at non-zero temperature there are other parity
violating contributions to the effective action. For
particular backgrounds these contributions may be re-summed
to restore large gauge invariance. Some outstanding unsolved
problems and some implications for other systems with
discrete symmetries will also be discussed.
[UB07.08] A Cheshire Cat Classical Relativistic Interaction
Harry Woodcock (Philadelphia College of Textiles and Science)
Some approximately relativistic equations of motion in the special-relativistic classical mechanics of interacting point particles have been approached in at least two ways. These may be characterized as bottom up and top down. The former begins with a static Newtonian two-body potential energy and adds relativistic corrections to the Lagrangian in powers of (1/c) so as to have approximately Poincaré-invariant equations of motion. The latter begins by expanding in powers of (1/c) the integrand of a Poincaré-invariant Fokker-type variational principle describing two-body interactions in order to find the approximately relativistic Lagrangian. It has been suggested by Peter Havas that the latter approach could include a Galilei-invariant limit at which the interaction vanishes, while the exact interaction and the approximately relativistic corrections are non-zero. Such cases would be missed entirely by the former approach.
This paper explores the suggestion and finds that such interactions are indeed possible. Some examples are given.
[UB07.09] Massless Quantum Fields in the Spacetime Tangent Bundle
Howard E. Brandt (Army Research Laboratory, Adelphi, MD 20783)
Maximal-acceleration invariant quantum fields were recently
formulated in terms of the maximal acceleration group and
the differential geometric structure of the spacetime
tangent bundle [1,2]. The simple case was addressed of a
massive free scalar field in a flat Minkowski spacetime for
which the bundle is also flat. The field was shown to have
an automatic physically based regularization with an
exponential spectral cutoff at the Planck mass. In the
present work, massless quantum fields are considered as the
zero-mass limit of massive fields and are shown to have an
exponential spectral cutoff at the Planck frequency. [1] H.
E. Brandt, "Quantum Fields in the Spacetime Tangent Bundle,"
Found. Phys. Lett., Vol. 11, 265 (1998). [2] H. E. Brandt,
"Finslerian Fields in the Spacetime Tangent Bundle," invited
paper to appear in Journal of Chaos, Solitons and Fractals,
special issue on "Strings, M, F, S,...Theory" (1998).
[UB07.10] On the Existence of a Super Strong Interaction
M.E. De Souza (Departamento de F'\isica, UFS)
The interaction between two nucleons is described in terms of a mesonic field in the nuclear domain and by QCD when one deals with quarks. Both descriptions are quite successful in their domains but appear to be disconnected. Despite its great success, QCD leaves many questions unanswered, such as the number of quarks, the constitution of the quark sea, the generation of quark masses, asymptotic freedom, prediction of hadron levels, protons and deuterons stability, etc. This work proposes that each quark is composed of two prequarks that interact via a massive and vectorial superstrong field and a mesonic field. In this context QCD is a theory of an effective field which is the result of the strong and super strong fields together. It is shown that there is no major contradiction with QCD and that many of its features are, actually, evidences of the existence of the superstrong interaction. Moreover, the questions above mentioned are easily explained. Also, this new interaction allows us to make the necessary bridge between quark-quark interactions and nucleon-nucleon interactions in the domain of nuclear physics. We are able then to propose a reasonable spatial arrangement for nucleons in nuclei that agrees with the experimental data. By means of such arrangement we can explain the absence of nuclei with A=5 and the strange instability of 8Be. Furthermore, the superstrong interaction can explain the explosion of type II supernovae.
[UB07.11] An Introduction to UFP for Elementary Particles and Nuclei: Proposal of Singlon, Pairon, Triron Structures for Charged Leptons, Neutrinos, and Charged Pions
Shuichi Iida (Emeritus Professor, University of Tokyo)
This abstract not available.