scholarly journals Wrong sign bottom Yukawa coupling in low energy supersymmetry

2018 ◽  
Vol 97 (11) ◽  
Author(s):  
Nina M. Coyle ◽  
Bing Li ◽  
Carlos E. M. Wagner
Keyword(s):  
Yukawa Coupling ◽  
Low Energy ◽  
Wrong Sign

scholarly journals Generalized 2HDM with wrong-sign lepton-Yukawa coupling, in light of $$g_{\mu }-2$$ and lepton flavor violation at the future LHC

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Nivedita Ghosh ◽  
Jayita Lahiri
Keyword(s):  
Parameter Space ◽  
Yukawa Coupling ◽  
Higgs Doublet ◽  
Lepton Flavor Violation ◽  
Model Parameter ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Artificial Neural Network Analysis ◽  
Two Higgs Doublet Model ◽  
Wrong Sign

AbstractTo explain the observed muon anomaly and simultaneously evade bounds from lepton flavor violation in the same model parameter space is a long-cherished dream. In view of a generalized Two Higgs Doublet Model, with a Yukawa structure as a perturbation of Type-X, we are able to get substantial parameter space satisfying these criteria. In this work, we focus on a region with “wrong-sign” lepton-Yukawa coupling which gives rise to interesting phenomenological consequences. Performing a simple cut-based analysis, we show that at 14 TeV run of the LHC with $$300 \mathrm{{fb}}^{-1}$$ 300 fb - 1 integrated luminosity, part of the model parameter space can be probed with significance "Equation missing" which further improves with Artificial Neural Network analysis.

scholarly journals Probing loop effects in wrong-sign Yukawa coupling region of Type-II 2HDM

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Wei Su
Keyword(s):  
Parameter Space ◽  
Yukawa Coupling ◽  
Higgs Mass ◽  
Precision Measurements ◽  
Tree Level ◽  
Type Ii ◽  
Coupling Region ◽  
Loop Level ◽  
Wrong Sign

AbstractIn the framework of 2HDM, we explore the wrong-sign Yukawa region with direct and indirect searches up to one-loop level. The direct searches include the latest $$H/A \rightarrow f{\bar{f}}, VV, Vh, hh$$ H / A → f f ¯ , V V , V h , h h reports at current LHC, and the study of indirect Higgs precision measurements works with current LHC, future HL-LHC and CEPC. At tree level of Type-II 2HDM, for degenerate heavy Higgs mass $$m_A=m_H=m_{H^\pm }<800$$ m A = m H = m H ± < 800 GeV, the wrong-sign Yukawa regions are excluded largely except for the tiny allowed region around $$\cos (\beta -\alpha )\in (0.2,0.3)$$ cos ( β - α ) ∈ ( 0.2 , 0.3 ) under the combined Higgs constraints. The excluded region is also nearly independent of parameter $$m_{12}$$ m 12 or $$\lambda v^2=m_A^2-m_{12}^2/(\sin \beta \cos \beta )$$ λ v 2 = m A 2 - m 12 2 / ( sin β cos β ) . The situation changes a lot after including loop corrections to the indirect searches, for example $$m_A=1500 \text {~GeV}$$ m A = 1500 GeV , the region with $$\lambda v^2<0$$ λ v 2 < 0 will be stronger constrained to be totally excluded. Whilst parameter space with $$\lambda v^2>0$$ λ v 2 > 0 would get larger survived wrong-sign region for $$m_A=800 ~\text {~GeV}$$ m A = 800 GeV compared to it at tree level. We also conclude Higgs direct searches works better on constraining $$\lambda v^2 \approx 0$$ λ v 2 ≈ 0 GeV range than theoretical constraints. We also find that the loop-level wrong-sign Yukawa limit only occurs at mass decoupling scale.

scholarly journals Gravitational positivity bounds

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Junsei Tokuda ◽  
Katsuki Aoki ◽  
Shin’ichi Hirano
Keyword(s):  
Dispersion Relation ◽  
Effective Field Theories ◽  
Imaginary Part ◽  
Higher Order ◽  
Effective Field ◽  
Low Energy ◽  
Field Theories ◽  
Loop Level ◽  
Regge Behavior ◽  
Wrong Sign

Abstract We study the validity of positivity bounds in the presence of a massless graviton, assuming the Regge behavior of the amplitude. Under this assumption, the problematic t-channel pole is canceled with the UV integral of the imaginary part of the amplitude in the dispersion relation, which gives rise to finite corrections to the positivity bounds. We find that low-energy effective field theories (EFT) with “wrong” sign are generically allowed. The allowed amount of the positivity violation is determined by the Regge behavior. This violation is suppressed by $$ {M}_{\mathrm{pl}}^{-2}\alpha^{\prime } $$ M pl − 2 α ′ where α′ is the scale of Reggeization. This implies that the positivity bounds can be applied only when the cutoff scale of EFT is much lower than the scale of Reggeization. We then obtain the positivity bounds on scalar-tensor EFT at one-loop level. Implications of our results on the degenerate higher-order scalar-tensor (DHOST) theory are also discussed.

scholarly journals Doped holographic fermionic system

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Wenjun Huang ◽  
Guoyang Fu ◽  
Dan Zhang ◽  
Zhenhua Zhou ◽  
Jian-Pin Wu
Keyword(s):  
Yukawa Coupling ◽  
Energy Band ◽  
Current Model ◽  
High Energy ◽  
Spectral Weight ◽  
Low Energy ◽  
Gauge Fields ◽  
Fermionic System ◽  
Universal Properties ◽  
Scalar Hair

Abstract We construct a two-current model. It includes two gauge fields, which introduce the doping effect, and a neutral scalar field. And then we numerically construct an AdS black brane geometry with scalar hair. Over this background, we study the fermionic system with the pseudoscalar Yukawa coupling. Some universal properties from the pseudoscalar Yukawa coupling are revealed. In particular, as the coupling increases, there is a transfer of the spectral weight from the low energy band to the high energy band. The transfer is over low energy scales but not over all energy scales. The peculiar properties are also explored. The study shows that with the increase of the doping, the gap opens more difficult. It indicates that there is a competition between the pseudoscalar Yukawa coupling and the doping.

Dissociated Σ=27 boundaries in silicon

1988 ◽  
Vol 46 ◽  
pp. 624-625
Author(s):  
A. Garg ◽  
W.A.T. Clark ◽  
J.P. Hirth
Keyword(s):  
Electron Diffraction ◽  
Local Minimum ◽  
Boundary Energy ◽  
Coincidence Site Lattice ◽  
Boundary Plane ◽  
Low Energy ◽  
Theoretical Understanding ◽  
Site Lattice ◽  
Kikuchi Pattern ◽  
Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

Transfer optics for high spatial resolution electron spectroscopy

1988 ◽  
Vol 46 ◽  
pp. 666-667
Author(s):  
G. G. Hembree ◽  
Luo Chuan Hong ◽  
P.A. Bennett ◽  
J.A. Venables
Keyword(s):  
Magnetic Field ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Objective Lens ◽  
State University ◽  
Arizona State University ◽  
Initial Field ◽  
Resolution Electron ◽  
Scanning Transmission ◽  
Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 354-355
Author(s):  
Bertholdand Senftinger ◽  
Helmut Liebl
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Field Strength ◽  
Numerical Aperture ◽  
Low Energy ◽  
Energy Electron ◽  
High Resolution Imaging ◽  
Lens System ◽  
Resolution Imaging ◽  
Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

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