1,611 research outputs found
Scenarios for Gluino Coannihilation
We study supersymmetric scenarios in which the gluino is the next-to-lightest
supersymmetric particle (NLSP), with a mass sufficiently close to that of the
lightest supersymmetric particle (LSP) that gluino coannihilation becomes
important. One of these scenarios is the MSSM with soft supersymmetry-breaking
squark and slepton masses that are universal at an input GUT renormalization
scale, but with non-universal gaugino masses. The other scenario is an
extension of the MSSM to include vector-like supermultiplets. In both
scenarios, we identify the regions of parameter space where gluino
coannihilation is important, and discuss their relations to other regions of
parameter space where other mechanisms bring the dark matter density into the
range allowed by cosmology. In the case of the non-universal MSSM scenario, we
find that the allowed range of parameter space is constrained by the
requirement of electroweak symmetry breaking, the avoidance of a charged LSP
and the measured mass of the Higgs boson, in particular, as well as the
appearance of other dark matter (co)annihilation processes. Nevertheless, LSP
masses ~TeV with the correct dark matter density are quite
possible. In the case of pure gravity mediation with additional vector-like
supermultiplets, changes to the anomaly-mediated gluino mass and the threshold
effects associated with these states can make the gluino almost degenerate with
the LSP, and we find a similar upper bound.Comment: 25 pages, 22 figure
Beyond the CMSSM without an Accelerator: Proton Decay and Direct Dark Matter Detection
We consider two potential non-accelerator signatures of generalizations of
the well-studied constrained minimal supersymmetric standard model (CMSSM). In
one generalization, the universality constraints on soft supersymmetry-breaking
parameters are applied at some input scale below the grand unification
(GUT) scale , a scenario referred to as `sub-GUT'. The other
generalization we consider is to retain GUT-scale universality for the squark
and slepton masses, but to relax universality for the soft
supersymmetry-breaking contributions to the masses of the Higgs doublets. As
with other CMSSM-like models, the measured Higgs mass requires supersymmetric
particle masses near or beyond the TeV scale. Because of these rather heavy
sparticle masses, the embedding of these CMSSM-like models in a minimal SU(5)
model of grand unification can yield a proton lifetime consistent with current
experimental limits, and may be accessible in existing and future proton decay
experiments. Another possible signature of these CMSSM-like models is direct
detection of supersymmetric dark matter. The direct dark matter scattering rate
is typically below the reach of the LUX-ZEPLIN (LZ) experiment if is
close to , but may lie within its reach if
GeV. Likewise, generalizing the CMSSM to allow non-universal
supersymmetry-breaking contributions to the Higgs offers extensive
possibilities for models within reach of the LZ experiment that have long
proton lifetimes.Comment: 42 pages, 15 figure
A Minimal Supersymmetric SU(5) Missing-Partner Model
We explore a missing-partner model based on the minimal SU(5) gauge group
with , and Higgs representations,
assuming a super-GUT CMSSM scenario in which soft supersymmetry-breaking
parameters are universal at some high scale above the GUT scale
. We identify regions of parameter space that are consistent with
the cosmological dark matter density, the measured Higgs mass and the
experimental lower limit on . These constraints can be
satisfied simultaneously along stop coannihilation strips in the super-GUT
CMSSM with where the input gaugino mass ~TeV, corresponding after strong renormalization by the large GUT Higgs
representations between and to ~TeV and ~TeV, with the
light-flavor squarks significantly heavier. We find that ~yrs throughout the allowed range of parameter space,
within the range of the next generation of searches with the JUNO, DUNE and
Hyper-Kamiokande experiments.Comment: 30 pages, 13 figure
Leadership in Kansas Agriculture: Examining Organization CEOsâ Styles and Skills
This projectâs primary purpose was to identify and describe the leadership styles and skills emphases of current Kansas agricultural organization chief executive officers. Twenty-three current CEOs participated and were described in terms of their leadership styles, leadership-skills emphases, and demographics. Overall, they appeared to be rather âmiddle of the roadâ on each of the Multifactor Leadership Questionnaireâs nine leadership scales. Leadership styles were not significantly affected by demographics, with the exception of formal leadership training affecting transactional leadership and education level, organizational category, and staff size affecting passive-avoidant leadership. Participants generally rated the 50 leadership skills as important. Leadership styles did not significantly affect the skill emphases. In evaluating CEO candidates, an agricultural organization should design its process to gauge leadership styles and skills separately because, according to this project, they do not predict each other. Once a new CEO is hired, a formal leadership-training program should emphasize the transformational style over the transactional and, more so, passive-avoidant while still maintaining an appropriate balance between transformational and transactional
Supersymmetric Proton Decay Revisited
Encouraged by the advent of a new generation of underground detectors---JUNO,
DUNE and Hyper-Kamiokande---that are projected to improve significantly on the
present sensitivities to various baryon decay modes, we revisit baryon decay in
the minimal supersymmetric SU(5) GUT. We discuss the phenomenological
uncertainties associated with hadronic matrix elements and the value of the
strong coupling ---which are the most important---the weak mixing
angle , quark masses including one-loop renormalization effects,
quark mixing and novel GUT phases that are not visible in electroweak
interaction processes. We apply our analysis to a variety of CMSSM, super- and
sub-GUT scenarios in which soft supersymmetry-breaking parameters are assumed
to be universal at, above and below the GUT scale, respectively. In many cases,
we find that the next generation of underground detectors should be able to
probe models with sparticle masses that are ~TeV, beyond the
reach of the LHC.Comment: 53 pages, 17 figure
Multivariate discrimination and the Higgs + W/Z search
A systematic method for optimizing multivariate discriminants is developed
and applied to the important example of a light Higgs boson search at the
Tevatron and the LHC. The Significance Improvement Characteristic (SIC),
defined as the signal efficiency of a cut or multivariate discriminant divided
by the square root of the background efficiency, is shown to be an extremely
powerful visualization tool. SIC curves demonstrate numerical instabilities in
the multivariate discriminants, show convergence as the number of variables is
increased, and display the sensitivity to the optimal cut values. For our
application, we concentrate on Higgs boson production in association with a W
or Z boson with H -> bb and compare to the irreducible standard model
background, Z/W + bb. We explore thousands of experimentally motivated,
physically motivated, and unmotivated single variable discriminants. Along with
the standard kinematic variables, a number of new ones, such as twist, are
described which should have applicability to many processes. We find that some
single variables, such as the pull angle, are weak discriminants, but when
combined with others they provide important marginal improvement. We also find
that multiple Higgs boson-candidate mass measures, such as from mild and
aggressively trimmed jets, when combined may provide additional discriminating
power. Comparing the significance improvement from our variables to those used
in recent CDF and DZero searches, we find that a 10-20% improvement in
significance against Z/W + bb is possible. Our analysis also suggests that the
H + W/Z channel with H -> bb is also viable at the LHC, without requiring a
hard cut on the W/Z transverse momentum.Comment: 41 pages, 5 tables, 29 figure
Trauma Immediately Preceding REM-Behavior Disorder:A Valuable Prognostic Marker?
Background: The definition of rapid eye movement (REM) sleep behavior disorder (RBD) has varied over the years. Rapid eye movement sleep behavior disorder can be considered isolated or idiopathic or can occur in the context of other disorders, including trauma-associated sleep disorder (TSD) and overlap parasomnia. However, whether trauma in RBD carries any prognostic specificity is currently unknown.
Study Objectives: To test the hypothesis that RBD secondary to trauma is less likely to result in the development of neurodegeneration compared to idiopathic RBD (iRBD) without trauma in the general population.
Methods: A retrospective cohort study of 122 consecutive RBD patients (103 males) at two tertiary sleep clinics in Europe between 2005 and 2020 was studied. Patients were diagnosed as having iRBD by video polysomnography (vPSG) and had a semi-structured interview at presentation, including specifically eliciting any history of trauma. Patients with secondary RBD to recognized causes were excluded from the study. Patients with iRBD were categorized into three groups according to reported trauma history: (1) No history of trauma, (2) traumatic experience at least 12 months prior to RBD symptom onset, and (3) traumatic experience within 12 months of RBD symptom onset. Idiopathic RBD duration was defined as the interval between estimated onset of RBD symptoms and last hospital visit or death. Follow-up duration was defined as the interval between iRBD diagnosis and last hospital visit or death.
Results: In a follow-up period of up to 18 years, no patient who experienced trauma within 12 months preceding their iRBD diagnosis received a diagnosis of a neurodegenerative disorder (n = 35), whereas 38% of patients without trauma within the 12 months of symptom onset developed a neurodegenerative illness. These patients were also significantly more likely to have a family history of α-synucleinopathy or tauopathy.
Conclusions: The development of RBD within 12 months of experiencing a traumatic life event, indistinguishable clinically from iRBD, did not lead to phenoconversion to a neurodegenerative disorder even after 18 years (mean follow up 6 years). We suggest that a sub-type of RBD be established and classified as secondary RBD due to trauma. Additionally, we advocate that a thorough psychological and trauma history be undertaken in all patients presenting with dream enactment behaviors (DEB)
Pure Samples of Quark and Gluon Jets at the LHC
Having pure samples of quark and gluon jets would greatly facilitate the
study of jet properties and substructure, with many potential standard model
and new physics applications. To this end, we consider multijet and jets+X
samples, to determine the purity that can be achieved by simple kinematic cuts
leaving reasonable production cross sections. We find, for example, that at the
7 TeV LHC, the pp {\to} {\gamma}+2jets sample can provide 98% pure quark jets
with 200 GeV of transverse momentum and a cross section of 5 pb. To get 10 pb
of 200 GeV jets with 90% gluon purity, the pp {\to} 3jets sample can be used.
b+2jets is also useful for gluons, but only if the b-tagging is very efficient.Comment: 19 pages, 16 figures; v2 section on formally defining quark and gluon
jets has been adde
Automated Method for Detecting Acute Insomnia Using Multi-Night Actigraphy Data
In this paper we propose a new machine learning model for classification of nocturnal awakenings in acute insomnia and normal sleep. The model does not require sleep diaries or any other subjective information from the individuals who took part of the study. It is based on nocturnal actigraphy collected from pre-medicated individuals with acute insomnia and normal sleep controls. We have derived dynamical and statistical features from the actigraphy time series data. These features are combined using two machine learning techniques namely Random Forest (RF) and Support Vector Machine (SVM). RF shows better performance (accuracy-84%) than SVM (73%) in classifying individuals with insomnia from healthy sleepers. The developed model provides a signature of the condition of acute insomnia obtained from actigraphy only and is very promising as a tool to detect the condition in a non-invasive way and without sleep diaries or any other subjective information
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