5,525 research outputs found
Living with the user: Design drama for dementia care through responsive scripted experiences in the home
Participation in forms of drama and narrative can provoke empathy and creativity in user-centred design processes. In this paper, we expand upon existing methods to explore the potential for responsive scripted experiences that are delivered through the combination of sensors and output devices placed in a home. The approach is being developed in the context of Dementia care, where the capacity for rich user participation in design activities is limited. In this case, a system can act as a proxy for a person with Dementia, allowing designers to gain experiences and insight as to what it is like to provide care for, and live with, this person. We describe the rationale behind the approach, a prototype system architecture, and our current work to explore the creation of scripted experiences for design, played out though UbiComp technologies.This research is funded by the Arts and Humanities Research Council UK, (AH/K00266X/1) and Horizon Digital Economy Research (RCUK grant EP/G065802/1)
Cosmology with a TeV mass GUT Higgs
The most natural way to break the GUT gauge symmetry is with a Higgs field
whose vacuum expectation value is of order 10^{16}\,\mbox{GeV} but whose mass
is of order to 10^3\,\mbox{GeV}. This can lead to a cosmological
history radically different from what is usually assumed to have occurred
between the standard inflationary and nucleosynthesis epochs, which may solve
the gravitino and Polonyi/moduli problems in a natural way.Comment: 4 pages, revte
A Model of Direct Gauge Mediation
We present a simple model of gauge mediation (GM) which does not have a
messenger sector or gauge singlet fields. The standard model gauge groups
couple directly to the sector which breaks supersymmetry dynamically. This is
the first phenomenologically viable example of this type in the literature.
Despite the direct coupling, the model can preserve perturbative gauge
unification. This is achieved by the inverted hierarchy mechanism which
generates a large scalar expectation value compared to the size of
supersymmetry breaking. There is no dangerous negative contribution to the
squark, slepton masses due to two-loop renormalization group equation. The
potentially non-universal supergravity contribution to the scalar masses can be
suppressed enough to maintain the virtue of the gauge mediation. The model is
completely chiral, and one does not need to forbid mass terms for the messenger
fields by hand. Beyond the simplicity of the model, it possesses cosmologically
desirable features compared to the original models of GM: an improved gravitino
and string moduli cosmology. The Polonyi problem is back unlike in the original
GM models, but is still much less serious than in hidden sector models.Comment: LaTeX, 12 page
Thermal Inflation and the Moduli Problem
In supersymmetric theories a field can develop a vacuum expectation value , even though its mass is of order to
. The finite temperature in the early Universe can hold such a
field at zero, corresponding to a false vacuum with energy density . When the temperature falls below , the thermal energy
density becomes negligible and an era of thermal inflation begins. It ends when
the field rolls away from zero at a temperature of order , corresponding to
of order 10 -folds of inflation which does not affect the density
perturbation generated during ordinary inflation. Thermal inflation can solve
the Polonyi/moduli problem if is within one or two orders of magnitude of
.Comment: Revised version to appear in Phys Rev D. Improved discussion of the
possible effect of parametric resonance. Latex, 31 page
Preheating, Supersymmetry Breaking and Baryogenesis
Fluctuations of scalar fields produced at the stage of preheating after
inflation are so large that they can break supersymmetry much stronger than
inflation itself. These fluctuations may lead to symmetry restoration along
flat directions of the effective potential even in the theories where the usual
high temperature corrections are exponentially suppressed. Our results show
that nonthermal phase transitions after preheating may play a crucial role in
the generation of the primordial baryon asymmetry by the Affleck-Dine
mechanism. In particular, the baryon asymmetry may be generated at the very
early stage of the evolution of the Universe, at the preheating era, and not
when the Hubble parameter becomes of order the gravitino mass.Comment: 4 pages, no figure
On the Moduli Problem and Baryogenesis in Gauge-mediated SUSY Breaking Models
We investigate whether the Affleck-Dine mechanism can produce sufficient
baryon number of the universe in the gauge-mediated SUSY breaking models, while
evading the cosmological moduli problem by late-time entropy production. We
find that the Q-ball formation renders the scenario very difficult to work,
irrespective of the detail mechanism of the entropy production.Comment: 11 pages, RevTeX, 5 postscript figures include
Spectrum of Background X-rays from Moduli Dark Matter
We examine the -ray spectrum from the decay of the dark-matter moduli with
mass keV, in particular, paying attention to the line
spectrum from the moduli trapped in the halo of our galaxy. It is found that
with the energy resolution of the current experiments (%) the line
intensity is about twice stronger than that of the continuum spectrum from the
moduli that spread in the whole universe. Therefore, in the future experiments
with higher energy resolutions it may be possible to detect such line photons.
We also investigate the -ray spectrum emitted from the decay of the
multi-GeV moduli. It is shown that the emitted photons may form MeV-bump in the
-ray spectrum. We also find that if the modulus mass is of the order of
10 GeV, the emitted photons at the peak of the continuum spectrum loses their
energy by the scattering and the shape of the spectrum is significantly
changed, which makes the constraint weaker than that obtained in the previous
works.Comment: 14 pages (RevTeX file) including four postscript figures, reviced
version to be published in Physical Review
The Cosmological Moduli Problem, Supersymmetry Breaking and Stability in Postinflationary Cosmology
A survey of solutions to the cosmological moduli problem in string theory.
The only extant proposal which may work is Intermediate Scale Inflation as
proposed by Randall and Thomas. Supersymmetry preserving dynamics which could
give large masses to the moduli is strongly constrained by cosmology and
requires the existence of string vacuum states possessing properties different
from those of any known vacuuum. Such a mechanism cannot give mass to the
dilaton unless there are cancellations between different exponentially small
contributions to the superpotential. Our investigation also shows that
stationary points of the effective potential with negative vacuum energy do not
correspond to stationary solutions of the equations of postinflationary
cosmology. This suggests that supersymmetry breaking is a requirement for a
successful inflationary cosmology.Comment: harvma
Naturally Large Cosmological Neutrino Asymmetries in the MSSM
A large neutrino asymmetry is an interesting possibility for cosmology, which
can have significant observable consequences for nucleosynthesis and the cosmic
microwave background. However, although it is a possibility, there is no
obvious reason to expect the neutrino asymmetry to be observably large. Here we
note that if the baryon asymmetry originates via the Affleck-Dine mechanism
along a d=4 flat direction of the MSSM scalar potential and if the lepton
asymmetry originates via Affleck-Dine leptogenesis along a d=6 direction,
corresponding to the lowest dimension directions conserving R-parity, then the
ratio n_{L}/n_{B} is naturally in the range 10^{8}-10^{9}. As a result, a
potentially observable neutrino asymmetry is correlated with a baryon asymmetry
of the order of 10^{-10}.Comment: 10 pages LaTeX. Final version to be published in Physical Review
Letter
Monitoring the CMS strip tracker readout system
The CMS Silicon Strip Tracker at the LHC comprises a sensitive area of approximately 200 m2 and 10 million readout channels. Its data acquisition system is based around a custom analogue front-end chip. Both the control and the readout of the front-end electronics are performed by off-detector VME boards in the counting room, which digitise the raw event data and perform zero-suppression and formatting. The data acquisition system uses the CMS online software framework to configure, control and monitor the hardware components and steer the data acquisition. The first data analysis is performed online within the official CMS reconstruction framework, which provides many services, such as distributed analysis, access to geometry and conditions data, and a Data Quality Monitoring tool based on the online physics reconstruction. The data acquisition monitoring of the Strip Tracker uses both the data acquisition and the reconstruction software frameworks in order to provide real-time feedback to shifters on the operational state of the detector, archiving for later analysis and possibly trigger automatic recovery actions in case of errors. Here we review the proposed architecture of the monitoring system and we describe its software components, which are already in place, the various monitoring streams available, and our experiences of operating and monitoring a large-scale system
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