511 research outputs found
AdS-Carroll Branes
Coset methods are used to determine the action of a co-dimension one brane
(domain wall) embedded in (d+1)-dimensional AdS space in the Carroll limit in
which the speed of light goes to zero. The action is invariant under the
non-linearly realized symmetries of the AdS-Carroll spacetime. The
Nambu-Goldstone field exhibits a static spatial distribution for the brane with
a time varying momentum density related to the brane's spatial shape as well as
the AdS-C geometry. The AdS-C vector field dual theory is obtained.Comment: 47 page
Gauging Nonlinear Supersymmetry
Coset methods are used to construct the action describing the dynamics
associated with the spontaneous breaking of the local supersymmetries. The
resulting action is an invariant form of the Einstein-Hilbert action, which in
addition to the gravitational vierbein, also includes a massive gravitino
field. Invariant interactions with matter and gauge fields are also
constructed. The effective Lagrangian describing processes involving the
emission or absorption of a single light gravitino is analyzed.Comment: 20 pages, no figure
Nonlinear realization of local symmetries of AdS space
Coset methods are used to construct the action describing the dynamics
associated with the spontaneous breaking of the local symmetries of AdS_{d+1}
space due to the embedding of an AdS_d brane. The resulting action is an
SO(2,d) invariant AdS form of the Einstein-Hilbert action, which in addition to
the AdS_d gravitational vielbein, also includes a massive vector field
localized on the brane. Its long wavelength dynamics is the same as a massive
Abelian vector field coupled to gravity in AdS_d space.Comment: 17 page
Towards String Predictions
The aim of superstring phenomenology is to develop the tools and methodology
needed to confront string theory with experimental data. The first mandatory
task is to find string solutions which reproduce the observable data. The
subsequent goal is to extract potential signatures beyond the observable data.
Recently, by studying exact flat directions of non-Abelian singlet fields, we
demonstrated the existence of free fermionic heterotic-string models in which
the -charged matter spectrum, just below the
string scale, consists solely of the MSSM spectrum. In this paper we study the
possibility that the exact flat directions leave a symmetry
unbroken at the Planck scale. We demonstrate in a specific example that such
unbroken is in general expected to be not of the GUT type but
of intrinsic stringy origin. We study its phenomenological characteristics and
the consequences in the case that remains unbroken down to
low energies. We suggest that observation in forthcoming colliders of a
, with universal couplings for the two light generations but
different couplings for the heavy generation may provide evidence for the
orbifold which underlies the free fermionic models.Comment: 18 pages. Standard Latex. References adde
Superconformal Symmetry, The Supercurrent And Non-BPS Brane Dynamics
The Noether currents associated with the non-linearly realized
super-Poincare' symmetries of the Green-Schwarz (Nambu-Goto-Akulov-Volkov)
action for a non-BPS p=2 brane embedded in a N=1, D=4 target superspace are
constructed. The R symmetry current, the supersymmetry currents, the
energy-momentum tensor and the scalar central charge current are shown to be
components of a world volume supercurrent. The centrally extended
superconformal transformations are realized on the Nambu-Goldstone boson and
fermion fields of the non-BPS brane. The superconformal currents form
supersymmetry multiplets with the world volume conformal central charge current
and special conformal current being the primary components of the supersymmetry
multiplets containing all the currents. Correspondingly the superconformal
symmetry breaking terms form supersymmetry multiplets the components of which
are obtainable as supersymmetry transformations of the primary currents'
symmetry breaking terms.Comment: 27 pages, LaTeX, Summary Tables Adde
Non-BPS Brane Dynamics And Dual Tensor Gauge Theory
The action for the long wavelength oscillations of a non-BPS p=3 brane
embedded in N=1, D=5 superspace is determined by means of the coset method. The
D=4 world volume Nambu-Goldstone boson of broken translation invariance and the
two D=4 world volume Weyl spinor Goldstinos of the completely broken
supersymmetry describe the excitations of the brane into the broken space and
superspace directions. The resulting action is an invariant synthesis of the
Akulov-Volkov and Nambu-Goto actions. The D=4 antisymmetric tensor gauge theory
action dual to the p=3 brane action is determined.Comment: 15 pages, no figure
Colliders and Brane Vector Phenomenology
Brane world oscillations manifest themselves as massive vector gauge fields.
Their coupling to the Standard Model is deduced using the method of nonlinear
realizations of the spontaneously broken higher dimensional space-time
symmetries. Brane vectors are stable and weakly interacting, and therefore
escape particle detectors unnoticed. LEP and Tevatron data on the production of
a single photon in conjunction with missing energy are used to delineate
experimentally excluded regions of brane vector parameter space. The additional
region of parameter space accessible to the LHC as well as a future lepton
linear collider is also determined by means of this process.Comment: 12 pages, 13 figure
Remotely‐sensed slowing down in spatially patterned dryland ecosystems
Environmental Biolog
Remotely‐sensed slowing down in spatially patterned dryland ecosystems
Environmental Biolog
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