1,406 research outputs found
On Local Dilatation Invariance
The relationship between local Weyl scaling invariant models and local
dilatation invariant actions is critically scrutinized. While actions invariant
under local Weyl scalings can be constructed in a straightforward manner,
actions invariant under local dilatation transformations can only be achieved
in a very restrictive case. The invariant couplings of matter fields to an
Abelian vector field carrying a non-trivial scaling weight can be easily built,
but an invariant Abelian vector kinetic term can only be realized when the
local scale symmetry is spontaneously broken.Comment: 3 page
Superspace Measures, Invariant Actions, and Component Projection Formulae for (2,2) Supergravity
In the framework of the prepotential description of superspace
two-dimensional supergravity, we discuss the construction of invariant
integrals. In addition to the full superspace measure, we derive the measure
for chiral superspace, and obtain the explicit expressions for going from
superspace actions to component actions. We consider both the minimal
and the extended theories.Comment: 22 pages, Late
Dynamical Symmetries in q-deformed Quantum Mechanics
The dynamical algebra of the q-deformed harmonic oscillator is constructed.
As a result, we find the free deformed Hamiltonian as well as the Hamiltonian
of the deformed oscillator as a complicated, momentum dependent interaction
Hamiltonian in terms of the usual canonical variables. Furthermore we construct
a well-defined algebra SU(1,1) with consistent conjugation properties and
comultiplication. We obtain non lowest weight representations of this algebra.Comment: 19 pages, latex, no figure
(Non)renormalizability of the D-deformed Wess-Zumino model
We continue the analysis of the -deformed Wess-Zumino model which was
started in the previous paper. The model is defined by a deformation which is
non-hermitian and given in terms of the covariant derivatives . We
calculate one-loop divergences in the two-point, three-point and four-point
Green functions. We find that the divergences in the four-point function cannot
be absorbed and thus our model is not renormalizable. We discuss possibilities
to render the model renormalizable.Comment: 19 pages; version accepted for publication in Phys.Rev.D; new section
with the detailed discussion on renormalizabilty added and a special choice
of coupling constants which renders the model renormalizable analyze
The Gravitino-Overproduction Problem in Inflationary Universe
We show that the gravitino-overproduction problem is prevalent among
inflation models in supergravity. An inflaton field \phi generically acquires
(effective) non-vanishing auxiliary field G_\phi, if the K\"ahler potential is
non-minimal. The inflaton field then decays into a pair of the gravitinos. We
extensively study the cosmological constraints on G_\phi for a wide range of
the gravitino mass. For many inflation models we explicitly estimate G_\phi,
and show that the gravitino-overproduction problem severely constrains the
inflation models, unless such an interaction as K = \kappa/2 |\phi|^2 z^2 +
h.c. is suppressed (here z is the field responsible for the supersymmetry
breaking). We find that many of them are already excluded or on the verge of,
if \kappa \sim O(1).Comment: 34 pages, 7 figures. v2: minor correction
Thermal Gravitino Production and Collider Tests of Leptogenesis
Considering gravitino dark matter scenarios, we obtain the full
gauge-invariant result for the relic density of thermally produced gravitinos
to leading order in the Standard Model gauge couplings. For the temperatures
required by thermal leptogenesis, we find gaugino mass bounds which will be
probed at future colliders. We show that a conceivable determination of the
gravitino mass will allow for a unique test of the viability of thermal
leptogenesis in the laboratory.Comment: 5 pages, 3 figures, revised version matches published versio
Minimal Walking Technicolor: Set Up for Collider Physics
Different theoretical and phenomenological aspects of the Minimal and
Nonminimal Walking Technicolor theories have recently been studied. The goal
here is to make the models ready for collider phenomenology. We do this by
constructing the low energy effective theory containing scalars, pseudoscalars,
vector mesons and other fields predicted by the minimal walking theory. We
construct their self-interactions and interactions with standard model fields.
Using the Weinberg sum rules, opportunely modified to take into account the
walking behavior of the underlying gauge theory, we find interesting relations
for the spin-one spectrum. We derive the electroweak parameters using the newly
constructed effective theory and compare the results with the underlying gauge
theory. Our analysis is sufficiently general such that the resulting model can
be used to represent a generic walking technicolor theory not at odds with
precision data.Comment: 42 pages, 3 figures. RevTex forma
Probing R-parity violating models of neutrino mass at the LHC via top squark decays
It is shown that the R-parity violating decays of the lighter top squarks
() triggered by the lepton number violating couplings
, where the lepton family index i = 1-3, can be
observed at the LHC via the dilepton di-jet channel even if the coupling is as
small as 10 or 10, which is the case in several models of
neutrino mass, provided it is the next lightest supersymmetric particle(NLSP)
the lightest neutralino being the lightest supersymmetric particle(LSP). We
have first obtained a fairly model independent estimate of the minimum
observable value of the parameter ()) at the LHC for an integrated
luminosity of 10fb as a function of \mlstop by a standard Pythia based
analysis. We have then computed the parameter in several
representative models of neutrino mass constrained by the neutrino oscillation
data and have found that the theoretical predictions are above the estimated
minimum observable levels for a wide region of the parameter space.Comment: 19 pages, 1 Figure and 11 Table
Topological Defects in Twisted Bundles of Two-Dimensionally Ordered Filaments
Twisted assemblies of filaments in ropes, cables and bundles are essential
structural elements in wide use in macroscopic materials as well as within the
cells and tissues of living organisms. We develop the unique, non-linear
elastic properties of twisted filament bundles that derive from generic
properties of two-dimensional line-ordered materials. Continuum elasticity
reveals a formal equivalence between the elastic stresses induced by bundle
twist and those induced by the positive curvature in thin, elastic sheets.
These geometrically-induced stresses can be screened by 5-fold disclination
defects in lattice packing, and we predict a discrete spectrum elastic energy
groundstates associated with integer numbers of disclinations in cylindrical
bundles. Finally, we show that elastic-energy groundstates are extremely
sensitive to defect position in the cross-section, with off-center
disclinations driving the entire bundle to buckle, adopting globally writhing
configurations.Comment: 4.1 pages; 3 figure
Supergravity and IOSp(3,1|4) gauge theory
A new formulation of simple D=4 supergravity in terms of the geometry of
superspace is presented. The formulation is derived from the gauge theory of
the inhomogeneous orthosymplectic group IOSp(3,1|4) on a (4,4)-dimensional base
supermanifold by imposing constraints and taking a limit. Both the constraints
and the limiting procedure have a clear {\it a priori} physical motivation,
arising from the relationship between IOSp(3,1|4) and the super Poincar\'{e}
group. The construction has similarities with the space-time formulation of
Newtonian gravity.Comment: 17 pages. Expanded version. To appear in Class. Quantum Gra
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