23 research outputs found
Tree Level FCNC from Models with a Flavored Peccei-Quinn Symmetry
A Peccei-Quinn~(PQ) symmetry is proposed, in order to generate a realistic mass matrix ansatz with five texture-zeros for both quark and lepton sector in the Standard Model~(SM). Limiting our analysis to Hermitian mass matrices we show that this requires a minimum of 4 Higgs doublets.
The price we pay is to have Yukawa values in the lepton sector much lower than 1, but consistent with the experimental values. Since the PQ charges are non-universal the model features Flavor-Changing Neutral Currents~(FCNC) at the tree level. We calculate the FCNC couplings of the most general low-energy effective Lagrangian for the axion in a procedure valid for an arbitrary number of Higgs doublets. Finally, we report the allowed region in the parameter space obtained from the measurements of branching ratios of semileptonic meson decays
Dark matter in Inert Doublet Model with one scalar singlet and gauge symmetry
We study Dark Matter (DM) abundance in the framework of the extension of the
Standard Model (SM) with an additional gauge symmetry. One complex
singlet is included to break the gauge symmetry, meanwhile one of the
doublets is considered inert to introduce a DM candidate. The stability of the
DM candidate is analyzed with a continuous gauge symmetry as well as
discrete symmetry. We find allowed regions for the free model parameters
which are in agreement with the most up-to-date experimental results reported
by CMS and ATLAS collaborations, the upper limit on WIMP-nucleon cross section
imposed by XENON1T collaboration and the upper limit on the production
cross-section of a gauge boson times the branching ratio of the
boson decaying into . We also obtain allowed regions
for the DM candidate mass from the relic density reported by the PLANCK
collaboration including light, intermediate and heavy masses; depending mainly
on two parameters of the scalar potential, and
. We find that trough
production, it may only be possible for a
future hadron-hadron Circular Collider (FCC-hh) to be able to detect a DM
candidate within the range of masses 10-60 GeV.Comment: Accepted version to be published in EPJC, typos corrected, cites
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Agent of Change: NSF Sponsored Mathematics Curriculum Development
This article identifies factors that make it difficult for publishers of commercial textbooks to make significant changes
consistent with curricular visions put forth by the National Council of Teachers of Mathematics (NCTM). Central among these factors is the lack of consensus of state standards on what and when certain topics in mathematics should be addressed. The variability of grade placement of key mathematics learning goals across different state standards results in excessive repetition and superficial treatment of topics in school mathematics textbooks
Sedimentology of a 'non-actualistic' Middle Ordovician tidal-influenced reservoir in the Murzuq basin (Libya)
The subsurface of the highly productive Murzuq Basin in southwest Libya remains poorly understood. As a consequence, a need exists for detailed sedimentological studies of both the oil-prone Mamuniyat Formation and Hawaz Formation reservoirs in this area. Of particular interest in this case is the Middle Ordovician Hawaz Formation, interpreted as an excellent example of a 'nonactualistic,' tidally influenced clastic reservoir that appears to extend hundreds of kilometers across much of the North African or Saharan craton. The Hawaz Formation comprises 15 characteristic lithofacies grouped into 7 correlatable facies associations distributed in broad and laterally extensive facies belts deposited in a shallow marine, intertidal to subtidal environment. Three main depositional sequences and their respective systems tracts have also been identified. On this basis, a genetic-based stratigraphic zonation scheme has been proposed as a tool to improve subsurface management of this reservoir unit. A nonactualistic sedimentary model is proposed in this work with new ideas presented for marginal to shallow marine depositional environments during the Middle Ordovician in the northern margin of Gondwana
Digital twin hybrid modeling for enhancing guided wave ultrasound inspection signals in welded rails
Guided wave ultrasound (GWU) systems have been widely used for monitoring structures
such as rails, pipelines, and plates. In railway tracks, the monitoring process involves the complicated
propagation of waves over several hundred meters. The propagating waves are multi-modal and
interact with discontinuities differently, increasing complexity and leading to different response
signals. When the researcher wants to gain insight into the behavior of guided waves, predicting
response signals for different combinations of modes becomes necessary. However, the task can
become computationally costly when physics-based models are used. Digital twins can enable a
practitioner to deal systematically with the complexities of guided wave monitoring in practical or
user-specified settings. This paper investigates the use of a hybrid digital model of an operational
rail track to predict response signals for varying user-specified settings, specifically, the prediction
of response signals for various combinations of modes of propagation in the rail. The digital twin
hybrid model employs a physics-based model and a data-driven model. The physics-based model
simulates the wave propagation response using techniques developed from the traditional 3D finite
element method and the 2D semi-analytical finite element method (FEM). The physics-based model
is used to generate virtual experimental signals containing different combinations of modes of
propagation. These response signals are used to train the data-driven model based on a variational
auto-encoder (VAE). Given an input baseline signal containing only the most dominant mode excited
by a transducer, the VAE is trained to predict an inspection signal with increased complexity according
to the specified combination of modes. The results show that, once the VAE has been trained, it can
be used to predict inspection signals for different combinations of propagating modes, thus replacing
the physics-based model, which is computationally costly. In the future, the VAE architecture will be
adapted to predict response signals for varying environmental and operational conditions.http://www.mdpi.com/journal/mcaMechanical and Aeronautical EngineeringSDG-09: Industry, innovation and infrastructureSDG-11:Sustainable cities and communitie