5 research outputs found
Exploring Non-Holomorphic Soft Terms in the Framework of Gauge Mediated Supersymmetry Breaking
It is known that in the absence of a gauge singlet field, a specific class of
supersymmetry (SUSY) breaking non-holomorphic (NH) terms can be soft breaking
in nature so that they may be considered along with the Minimal Supersymmetric
Standard Model (MSSM) and beyond. There have been studies related to these
terms in minimal supergravity based models. Consideration of an F-type SUSY
breaking scenario in the hidden sector with two chiral superfields however
showed Planck scale suppression of such terms. In an unbiased point of view for
the sources of SUSY breaking, the NH terms in a phenomenological MSSM (pMSSM)
type of analysis showed a possibility of a large SUSY contribution to muon
, a reasonable amount of corrections to the Higgs boson mass and a drastic
reduction of the electroweak fine-tuning for a higgsino dominated
in some regions of parameter space. We first investigate
here the effects of the NH terms in a low scale SUSY breaking scenario. In our
analysis with minimal gauge mediated supersymmetry breaking (mGMSB) we probe
how far the results can be compared with the previous pMSSM plus NH terms based
study. We particularly analyze the Higgs, stop and the electroweakino sectors
focusing on a higgsino dominated and
, a feature typically different from what appears in
mGMSB. The effect of a limited degree of RG evolutions and vanishing of the
trilinear coupling terms at the messenger scale can be overcome by choosing a
non-minimal GMSB scenario, such as one with a matter-messenger interaction.Comment: 27 pages, 9 figures, some text added, results and conclusion
unchanged, Accepted in JHE
New physics implications of VBF searches exemplified through the Georgi-Machacek model
LHC searches for nonstandard scalars in vector boson fusion (VBF) production
processes can be particularly efficient in probing scalars belonging to triplet
or higher multiplet representations of the Standard Model gauge
group. They can be especially relevant for models where the additional scalars
do not have any tree-level couplings to the Standard Model fermions, rendering
VBF as their primary production mode at the LHC. In this work, we employ the
latest LHC data from VBF resonance searches to constrain the properties of
nonstandard scalars, taking the Georgi-Machacek model as a prototypical
example. We take into account the theoretical constraints on the potential from
unitarity and boundedness-from-below as well as indirect constraints coming
from the signal strength measurements of the 125 GeV Higgs boson at the LHC. To
facilitate the phenomenological analysis we advocate a convenient
reparametrization of the trilinear couplings in the scalar potential. We derive
simple correlations among the model parameters corresponding to the decoupling
limit of the model. We explicitly demonstrate how a combination of theoretical
and phenomenological constraints can push the GM model towards the decoupling
limit. Our analysis suggests that the VBF searches can provide key insights
into the composition of the electroweak vacuum expectation value.Comment: 17 pages, 7 figure
EFFICIENCY AND RADIATIVE RECOMBINATION RATE ENHANCEMENT IN GAN/ALGAN MULTI-QUANTUM WELL-BASED ELECTRON BLOCKING LAYER FREE UV-LED FOR IMPROVED LUMINESCENCE
In this paper, an electron blocking layer (EBL) free GaN/AlGaN light emitting diode (LED) is designed using Atlas TCAD with graded composition in the quantum barriers of the active region. The device has a GaN buffer layer incorporated in a c-plane for better carrier transportation and low efficiency droop. The proposed LED has quantum barriers with aluminium composition graded from 20% to ~2% per triangular, whereas the conventional has square barriers. The resulted structures exhibit significantly reduced electron leakage and improved hole injection into the active region, thus generating higher radiative recombination. The simulation outcomes exhibit the highest internal quantum efficiency (IQE) (48.4%) indicating a significant rise compared to the conventional LED. The designed EBL free LED with graded quantum barrier structure acquires substantially minimized efficiency droop of ~7.72% at 60 mA. Our study shows that the proposed structure has improved radiative recombination by ~136.7%, reduced electron leakage, and enhanced optical power by ~8.084% at 60 mA injected current as compared to conventional GaN/AlGaN EBL LED structure