62 research outputs found
Symmetry Breaking Patterns for the Little Higgs from Strong Dynamics
We show how the symmetry breaking pattern of the simplest little Higgs model,
and that of the smallest moose model that incorporates an approximate custodial
SU(2), can be realized through the condensation of strongly coupled fermions.
In each case a custodial SU(2) symmetry of the new strong dynamics limits the
sizes of corrections to precision electroweak observables. In the case of the
simplest little Higgs, there are no new light states beyond those present in
the original model. However, our realization of the symmetry breaking pattern
of the moose model predicts an additional scalar field with mass of order a TeV
or higher that has exactly the same quantum numbers as the Standard Model Higgs
and which decays primarily to third generation quarks.Comment: 5 pages, 3 figure
The Supersymmetric Higgs
In the Minimal Supersymmetric Standard Model (the MSSM), the electroweak
symmetry is restored as supersymmetry-breaking terms are turned off. We
describe a generic extension of the MSSM where the electroweak symmetry is
broken in the supersymmetric limit. We call this limit the "sEWSB" phase, short
for supersymmetric electroweak symmetry breaking. We define this phase in an
effective field theory that only contains the MSSM degrees of freedom. The
sEWSB vacua naturally have an inverted scalar spectrum, where the heaviest
CP-even Higgs state has Standard Model-like couplings to the massive vector
bosons; experimental constraints in the scalar Higgs sector are more easily
satisfied than in the MSSM.Comment: 34 pages, 5 figure
Perturbative, Non-Supersymmetric Completions of the Little Higgs
The little Higgs mechanism produces a light 100 GeV Higgs while raising the
natural cutoff from 1 TeV to 10 TeV. We attempt an iterative little Higgs
mechanism to produce multiple factors of 10 between the cutoff and the 100 GeV
Higgs mass in a perturbative theory. In the renormalizable sector of the
theory, all quantum corrections to the Higgs mass proportional to mass scales
greater than 1 TeV are absent -- this includes quadratically divergent,
log-divergent, and finite loops at all orders. However, even loops proportional
to scales just a factor of 10 above the Higgs (or any other scalar) mass come
with large numerical factors that reintroduce fine-tuning. Top loops, for
example, produce an expansion parameter of not 1/(4 pi) but 1/5. The geometric
increase in the number of fields at higher energies simply exacerbates this
problem. We build a complete two-stage model up to 100 TeV, show that direct
sensitivity of the electroweak scale to the cutoff is erased, and estimate the
tuning due to large numerical factors. We then discuss the possibility, in a
toy model with only scalar and gauge fields, of generating a tower of little
Higgs theories and show that the theory quickly becomes a large-N gauge theory
with ~ N fundamental scalars. We find evidence that at least this toy model
could successfully generate light scalars with an exponentially large cutoff in
the absence of supersymmetry or strong dynamics. The fine-tuning is not
completely eliminated, but evidence suggests that this result is model
dependent. We then speculate as to how one might marry a working tower of
fields of this type at high scales to a realistic theory at the weak scale.Comment: 26 (+1) pages, 9 figure
Poster Abstract: Bits and Watts: Improving energy disaggregation performance using power line communication modems
Non-intrusive load monitoring (NILM) or energy disaggregation, aims to
disaggregate a household's electricity consumption into constituent appliances.
More than three decades of work in NILM has resulted in the development of
several novel algorithmic approaches. However, despite these advancements, two
core challenges still exist: i) disaggregating low power consumption appliances
and ii) distinguishing between multiple instances of similar appliances. These
challenges are becoming increasingly important due to an increasing number of
appliances and increased usage of electronics in homes. Previous approaches
have attempted to solve these problems using expensive hardware involving high
sampling rates better suited to laboratory settings, or using additional number
of sensors, limiting the ease of deployment. In this work, we explore using
commercial-off-the-shelf (COTS) power line communication (PLC) modems as an
inexpensive and easy to deploy alternative solution to these problems. We use
the reduction in bandwidth between two PLC modems, caused due to the change in
PLC modulation scheme when different appliances are operated as a signature for
an appliance. Since the noise generated in the powerline is dependent both on
type and location of an appliance, we believe that our technique based on PLC
modems can be a promising addition for solving NILM
A Composite Twin Higgs Model
Twin Higgs models are economical extensions of the Standard Model that
stabilize the electroweak scale. In these theories the Higgs field is a pseudo
Nambu-Goldstone boson that is protected against radiative corrections up to
scales of order 5 TeV by a discrete parity symmetry. We construct, for the
first time, a class of composite twin Higgs models based on confining QCD-like
dynamics. These theories naturally incoporate a custodial isospin symmetry and
predict a rich spectrum of particles with masses of order a TeV that will be
accessible at the LHC.Comment: 6 pages, 1 figur
Anomaly-Free Sets of Fermions
We present new techniques for finding anomaly-free sets of fermions. Although
the anomaly cancellation conditions typically include cubic equations with
integer variables that cannot be solved in general, we prove by construction
that any chiral set of fermions can be embedded in a larger set of fermions
which is chiral and anomaly-free. Applying these techniques to extensions of
the Standard Model, we find anomaly-free models that have arbitrary quark and
lepton charges under an additional U(1) gauge group.Comment: 21 (+1) page
A Determination of the Hubble Constant from Cepheid Distances and a Model of the Local Peculiar Velocity Field
We present a measurement of the Hubble Constant based on Cepheid distances to
27 galaxies within 20 Mpc. We take the Cepheid data from published measurements
by the Hubble Telescope Key Project on the Distance Scale (H0KP). We calibrate
the Cepheid Period-Luminosity (PL) relation with data from over 700 Cepheids in
the LMC obtained by the OGLE collaboration; we assume an LMC distance modulus
of 18.50 mag (d=50.1 kpc). Using this PL calibration we obtain new distances to
the H0KP galaxies. We correct the redshifts of these galaxies for peculiar
velocities using two distinct velocity field models: the phenomenological model
of Tonry et al. and a model based on the IRAS density field and linear
gravitational instability theory. We combine the Cepheid distances with the
corrected redshifts for the 27 galaxies to derive H_0, the Hubble constant. The
results are H_0 = 85 +/- 5 km/s/Mpc (random error) at 95% confidence when the
IRAS model is used, and 92 +/- 5 km/s/Mpc when the phenomenological model is
used. The IRAS model is a better fit to the data and the Hubble constant it
returns is more reliable. Systematic error stems mainly from LMC distance
uncertainty which is not directly addressed by this paper. Our value of H_0 is
significantly larger than that quoted by the H0KP, H_0 = 71 +/- 6 km/s/Mpc.
Cepheid recalibration explains ~30% of this difference, velocity field analysis
accounts for ~70%. We discuss in detail possible reasons for this discrepancy
and future study needed to resolve it.Comment: 33 pages, 8 embedded figures. New table, 5 new references, text
revision
Radiopathological correlation of sellar and suprasellar masses: our experience
Background: The area immediately around the pituitary, the sellar and parasellar region is an anatomically complex area that represents a crucial crossroads for important adjacent structures. A number of diseases that affect the pituitary-hypothalamic axis can have profound clinical, endocrinological as well as neurological consequences. Aim of the study was to identify the MR imaging characteristics of sellar and suprasellar masses, to correlate the MRI findings with histopathological findings and to calculate the diagnostic accuracy of MR imaging.Methods: We reviewed the records of 116 patients with sellar and suprasellar masses for which preoperative MR imaging films or reports were available. Radiological appearances were correlated with intraoperative findings and post-operative histopathology.Results: Majority of patients in this study belonged to the age group 21-40 years. Most common mass lesion operated was pituitary macroadenoma comprising 58% of the total cases. The accuracy, sensitivity and specificity of MRI in diagnosing macroadenomas are 86%, 88%, and 83% respectively. MR was 93% accurate, 85% sensitive and 95% specific in diagnosing craniopharyngioma. MR was 93% accurate, 80% sensitive and 95% specific in diagnosing meningioma.Conclusions: MRI is the modality for characterizing sellar and suprasellar lesions, morphology of lesions, nature of contrast material enhancement and extent of lesions. Hence MRI is the modality of choice for diagnosing sellar and suprasellar masses with high accuracy, sensitivity and specificity
E-Learning: Case Studies in Web-Controlled Devices and Remote Manipulation
Chances are that distance learning will transparently extend colleges and institutes of education and could plausibly overtake and turn into a preferred choice of higher education, especially for adult and working students. The main idea in e-learning is to build adequate solutions that can assure educational training over the Internet, without requiring a personal presence at the degree offering institution. The advantages are immediate and of unique importance, to enumerate a few: Education costs can be reduced dramatically, both from a student's perspective and the institution's (no need for room and board, for example); The tedious immigration and naturalization issues common with international students are eliminated; The limited campus facilities, faculty members and course schedules an institution can offer are no longer a boundary; Working adults can consider upgrading skills without changing their lifestyles We are presenting through this material a sequence of projects developed at University of Bridgeport and than can serve well in distance learning education ranging from simple "hobby" style training to professional guidance material. The projects have an engineering / laboratory flavor and are being presented in an arbitrary order, topics ranging from vision and sensing to engineering design, scheduling, remote control and operation
- …