1,120 research outputs found
The CP-Violating 2HDM in Light of a Strong First Order Electroweak Phase Transition and Implications for Higgs Pair Production
We investigate the strength of the electroweak phase transition (EWPT) within
the CP-violating 2-Higgs-Doublet Model (C2HDM). By applying a renormalisation
scheme which allows efficient scans of the C2HDM parameter space, we analyse
the possibility of a strong first order EWPT required for baryogenesis and
study its phenomenological implications for the LHC. Like in the CP-conserving
(real) 2HDM (R2HDM) we find that a strong EWPT favours mass gaps between the
non-SM-like Higgs bosons. These lead to prominent final states comprised of
gauge+Higgs bosons or pairs of Higgs bosons. In contrast to the R2HDM, the
CP-mixing of the C2HDM also favours approximately mass degenerate spectra with
dominant decays into SM particles. The requirement of a strong EWPT further
allows us to distinguish the C2HDM from the R2HDM using the signal strengths of
the SM-like Higgs boson. We additionally find that a strong EWPT requires an
enhancement of the SM-like trilinear Higgs coupling at next-to-leading order
(NLO) by up to a factor of 2.4 compared to the NLO SM coupling, establishing
another link between cosmology and collider phenomenology. We provide several
C2HDM benchmark scenarios compatible with a strong EWPT and all experimental
and theoretical constraints. We include the dominant branching ratios of the
non-SM-like Higgs bosons as well as the Higgs pair production cross section of
the SM-like Higgs boson for every benchmark point. The pair production cross
sections can be substantially enhanced compared to the SM and could be
observable at the high-luminosity LHC, allowing access to the trilinear Higgs
couplings
and the wrong-sign limit of the Two-Higgs-Doublet Model
We point out the importance of the decay channels and in
the wrong-sign limit of the Two-Higgs-Doublet Model (2HDM) of type II. They can
be the dominant decay modes at moderate values of , even if the
(pseudo)scalar mass is above the threshold where the decay into a pair of top
quarks is kinematically open. Accordingly, large cross sections
and are obtained and currently probed by the LHC experiments,
yielding conclusive statements about the remaining parameter space of the
wrong-sign limit. In addition, mild excesses - as recently found in the ATLAS
analysis - could be explained. The wrong-sign limit makes
other important testable predictions for the light Higgs boson couplings.Comment: 19 pages, 6 figures, v2: journal versio
Phenomenological Comparison of Models with Extended Higgs Sectors
Beyond the Standard Model (SM) extensions usually include extended Higgs
sectors. Models with singlet or doublet fields are the simplest ones that are
compatible with the parameter constraint. The discovery of new non-SM
Higgs bosons and the identification of the underlying model requires dedicated
Higgs properties analyses. In this paper, we compare several Higgs sectors
featuring 3 CP-even neutral Higgs bosons that are also motivated by their
simplicity and their capability to solve some of the flaws of the SM. They are:
the SM extended by a complex singlet field (CxSM), the singlet extension of the
2-Higgs-Doublet Model (N2HDM), and the Next-to-Minimal Supersymmetric SM
extension (NMSSM). In addition, we analyse the CP-violating 2-Higgs-Doublet
Model (C2HDM), which provides 3 neutral Higgs bosons with a pseudoscalar
admixture. This allows us to compare the effects of singlet and pseudoscalar
admixtures. Through dedicated scans of the allowed parameter space of the
models, we analyse the phenomenologically viable scenarios from the view point
of the SM-like Higgs boson and of the signal rates of the non-SM-like Higgs
bosons to be found. In particular, we analyse the effect of
singlet/pseudoscalar admixture, and the potential to differentiate these models
in the near future. This is supported by a study of couplings sums of the Higgs
bosons to massive gauge bosons and to fermions, where we identify features that
allow us to distinguish the models, in particular when only part of the Higgs
spectrum is discovered. Our results can be taken as guidelines for future LHC
data analyses, by the ATLAS and CMS experiments, to identify specific benchmark
points aimed at revealing the underlying model.Comment: Matches journal version; figures for NMSSM changed; conclusions
unchange
Sox2, Tlx, Gli3, and Her9 converge on Rx2 to define retinal stem cells in vivo
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs
4.0 License.-- et al.Transcriptional networks defining stemness in adult neural stem cells (NSCs) are largely unknown. We used the proximal cis-regulatory element (pCRE) of the retina-specific homeobox gene 2 (rx2) to address such a network. Lineage analysis in the fish retina identified rx2 as marker for multipotent NSCs. rx2-positive cells located in the peripheral ciliary marginal zone behave as stem cells for the neuroretina, or the retinal pigmented epithelium. We identified upstream regulators of rx2 interrogating the rx2 pCRE in a trans-regulation screen and focused on four TFs (Sox2, Tlx, Gli3, and Her9) activating or repressing rx2 expression. We demonstrated direct interaction of the rx2 pCRE with the four factors in vitro and in vivo. By conditional mosaic gain- and loss-of-function analyses, we validated the activity of those factors on regulating rx2 transcription and consequently modulating neuroretinal and RPE stem cell features. This becomes obvious by the rx2-mutant phenotypes that together with the data presented above identify rx2 as a transcriptional hub balancing stemness of neuroretinal and RPE stem cells in the adult fish retina.DI received fellowships from the Human Frontier Science Program (HFSP) and the Japan Society for the Promotion of Science (JSPS); TT received a fellowship of the Hartmut Hoffmann Berling International Graduate School (HBIGS) in Heidelberg. The project was supported by the Collaborative Research Center SFB 873 (J.W.) of the German Research Foundation (DFG).Peer Reviewe
DEVELOPMENT OF PRACTICAL APPLICATIONS FOR REPRAP STYLE 3-D PRINTERS IN ENGINEERING
The current rise in popularity of consumer level 3-D printers introduces a need to understand the application and material property capabilities of the technology. Presented here is data demonstrating the ability for the average U.S. consumer to recuperate the cost of a 3-D printer within one year of ownership. Additionally, using a consumer level 3-D printer, multiple photovoltaic (PV) racking systems were printed and produced with much lower cost compared to commercially available aluminum racking. Additionally, mechanical testing on 3-D printed components showed a temperature dependence on both percent crystallinity and ultimate tensile strength. Conclusions are drawn using the information to describe the potential uses and applications of RepRap (Self Replicating Rapid Prototyper) style 3-D printers and their validity as an engineering tool
A global survey identifies novel upstream components of the Ath5 neurogenic network
Regulators of vertebrate Ath5 expression were identified by high-throughput screening; extending the current gene regulatory model network controlling retinal neurogenesis
Efficient activation of gene expression using a heat-shock inducible Gal4/Vp16-UAS system in medaka
BACKGROUND: Genetic interference by DNA, mRNA or morpholino injection is a widely used approach to study gene function in developmental biology. However, the lack of temporal control over the activity of interfering molecules often hampers investigation of gene function required during later stages of embryogenesis. To elucidate the roles of genes during embryogenesis a precise temporal control of transgene expression levels in the developing organism is on demand. RESULTS: We have generated a transgenic Gal4/Vp16 activator line that is heat-shock inducible, thereby providing a tool to drive the expression of specific effector genes via Gal4/Vp16. Merging the Gal4/Vp16-UAS system with the I-SceI meganuclease and the Sleeping Beauty transposon system allows inducible gene expression in an entirely uniform manner without the need to generate transgenic effector lines. Combination of this system with fluorescent protein reporters furthermore facilitates the direct visualization of transgene expressing cells in live embryos. CONCLUSION: The combinatorial properties of this expression system provide a powerful tool for the analysis of gene function during embryonic and larval development in fish by ectopic expression of gene products
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