1,049 research outputs found
Tri-N-ification
We consider a natural generalization of trinification to theories with 3N
SU(3) gauge groups. These theories have a simple moose representation and a
gauge boson spectrum that can be interpreted via the deconstruction of a 5D
theory with unified symmetry broken on a boundary. Although the matter and
Higgs sectors of the theory have no simple extra-dimensional analog, gauge
unification retains features characteristic of the 5D theory. We determine
possible assignments of the matter and Higgs fields to unified multiplets and
present theories that are viable alternatives to minimal trinified GUTs.Comment: 21 pages LaTeX, 6 eps figure
The gallery as therapeutic venue: exploring visitor perceptions in a contemporary space
This prospective qualitative study explored the social and psychological impact of an exhibition at a contemporary art gallery. Three focus groups, including 8 people aged 45-69, were held following a guided tour of an exhibition at Nottingham Contemporary gallery. The exhibition Uneven Geographies featured the works of a variety of international artists focussing upon the politics of globalisation through different media including film, installation and photography. Focus group transcripts were analysed using Braun and Clarke’s 6-phase model of thematic analysis. Three themes were identified: 1) ’It’s almost like a piece of a jigsaw puzzle’, 2) Interpreting the Message and 3) Dissolving Social Barriers. Results indicated that the exhibition helped participants make sense of a variety of experiences, art interpretation was a key educational skill, and attending the gallery promoted social inclusion. These findings build on previous studies that indicate the potential for cultural institutions, such as art galleries and museums, to promote education, health and wellbeing at individual and societal levels
An algorithm for correcting CoRoT raw light curves
We introduce the CoRoT detrend algorithm (CDA) for detrending CoRoT stellar
light curves. The algorithm CDA has the capability to remove random jumps and
systematic trends encountered in typical CoRoT data in a fully automatic
fashion. Since enormous jumps in flux can destroy the information content of a
light curve, such an algorithm is essential. From a study of 1030 light curves
in the CoRoT IRa01 field, we developed three simple assumptions which upon CDA
is based. We describe the algorithm analytically and provide some examples of
how it works. We demonstrate the functionality of the algorithm in the cases of
CoRoT0102702789, CoRoT0102874481, CoRoT0102741994, and CoRoT0102729260. Using
CDA in the specific case of CoRoT0102729260, we detect a candidate exoplanet
around the host star of spectral type G5, which remains undetected in the raw
light curve, and estimate the planetary parameters to be Rp=6.27Re and P=1.6986
days.Comment: 8 pages, 13 figure
Holographic Electroweak Symmetry Breaking from D-branes
We observe several interesting phenomena in a technicolor-like model of
electroweak symmetry breaking based on the D4-D8-D8bar system of Sakai and
Sugimoto. The benefit of holographic models based on D-brane configurations is
that both sides of the holographic duality are well understood. We find that
the lightest technicolor resonances contribute negatively to the
Peskin-Takeuchi S-parameter, but heavy resonances do not decouple and lead
generically to large, positive values of S, consistent with standard estimates
in QCD-like theories. We study how the S parameter and the masses and decay
constants of the vector and axial-vector techni-resonances vary over a
one-parameter family of D8-brane configurations. We discuss possibilities for
the consistent truncation of the theory to the first few resonances and suggest
some generic predictions of stringy holographic technicolor models.Comment: REVTeX, 25 pages, 8 eps figures, version published in PR
Towards a quantum field theory description of nonlocal spacetime defects
We propose an ansatz for encoding the physics of nonlocal spacetime defects
in the Green's functions for a scalar field theory defined on a causal set.
This allows us to numerically study the effects of nonlocal spacetime defects
on the discrete Feynman propagator of the theory defined on the causal set in
1+1 dimensions, and to compare to the defect-free limit. The latter approaches
the expected continuum result, on average, when the number of points becomes
large. When defects are present, two points with the same invariant spacetime
interval can have different propagation amplitudes, depending on whether the
propagation is between two ordinary spacetime points, two defects, or a defect
and an ordinary point. We show that a coarse-grained description that is only
sensitive to the average effect of the defects can be interpreted as a
defect-induced mass and wave-function renormalization of the scalar theory.Comment: 23 pages, LaTeX, 8 figure
Higgsless GUT Breaking and Trinification
Boundary conditions on an extra-dimensional interval can be chosen to break
bulk gauge symmetries and to reduce the rank of the gauge group. We consider
this mechanism in models with gauge trinification. We determine the boundary
conditions necessary to break the trinified gauge group directly down to that
of the standard model. Working in an effective theory for the gauge
symmetry-breaking parameters on a boundary, we examine the limit in which the
GUT-breaking sector is Higgsless and show how one may obtain the low-energy
particle content of the minimal supersymmetric standard model. We find that
gauge unification is preserved in this scenario, and that the differential
gauge coupling running is logarithmic above the scale of compactification. We
compare the phenomenology of our model to that of four-dimensional trinified
theories.Comment: 22 pages, LaTeX, 2 eps figures (v3: discussion of mass scales
clarified
1/Nc Countings in Baryons
The power countings for baryon decays and configuration mixings are
determined by means of a non-relativistic quark picture. Such countings are
expected to be robust under changes in the quark masses, and therefore valid as
these become light. It is shown that excited baryons have natural widths of
. These dominant widths are due to the decays that proceed
directly to the ground state baryons, with cascade decays being suppressed to
. Configuration mixings, defined as mixings between states
belonging to different multiplets, are shown to be
sub-leading in an expansion in when they involve the ground
state baryons, while the mixings between excited states can be
.Comment: 19 pages, 1 figure An omission that changes the conclusions on
configuration mixings has been correcte
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