7,923 research outputs found
Natural NMSSM confronting with the LHC7-8
The natural supersymmetry (SUSY) requires that stop, sbottom, and gluino be
around one TeV or lighter. By using the direct SUSY search bounds from both
ATLAS and CMS Collaborations, we examine the constraints on the natural SUSY in
the Next to Minimal Supersymmetric Standard Model (NMSSM). We consider two
cases of interpretations for the Higgs boson data: (1) the Standard Model (SM)
like Higgs boson is the lightest CP-even Higgs boson; (2) the SM like Higgs
boson is the second lightest CP-even Higgs boson. We find that the direct SUSY
searches at the LHC impose a strong constraint on the light gluino scenarios,
and in both cases the gluino can not be lighter than 1.1 TeV with sbottom mass
up to 600 GeV and stop mass up to 550 GeV.Comment: 43 pages, 13 figure
Discovery potential of Higgs boson pair production through 4+ final states at a 100 TeV collider
We explore the discovery potential of Higgs pair production at a 100 TeV
collider via full leptonic mode. The same mode can be explored at the LHC when
Higgs pair production is enhanced by new physics. We examine two types of fully
leptonic final states and propose a partial reconstruction method. The
reconstruction method can reconstruct some kinematic observables. It is found
that the variable determined by this reconstruction method and the
reconstructed visible Higgs mass are important and crucial to discriminate the
signal and background events. It is also noticed that a new variable, denoted
as which is defined as the mass difference of two possible
combinations, is very useful as a discriminant. We also investigate the
interplay between the direct measurements of couplings and other
related couplings and trilinear Higgs coupling at hadron colliders and
electron-positron colliders
Higgs Pair Production: Improved Description by Matrix Element Matching
Higgs pair production is crucial for measuring the Higgs boson self-coupling.
The dominant channel at hadron colliders is gluon fusion via heavy-quark loops.
We present the results of a fully exclusive simulation of gluon fusion Higgs
pair production based on the matrix elements for hh + 0, 1 partons including
full heavy-quark loop dependence, matched to a parton shower. We examine and
validate this new description by comparing it with (a) Higgs Effective Theory
predictions, (b) exact hh + 0-parton sample showered by pythia, and (c) exact
hh+1-parton distributions, by looking at the most relevant kinematic
distributions, such as PTh, PThh, Mhh spectra, and jet rate as well. We find
that matched samples provide an state-of-the-art accurate exclusive description
of the final state. The relevant LHE files for Higgs pair productions at the
LHC can be accessed via http://hepfarm02.phy.pku.edu.cn/foswiki/CMS/HH, which
can be used for relevant experimental analysis.Comment: accepted version in Phys. Rev. D. arXiv admin note: substantial text
overlap with arXiv:1110.172
Efficient Numerical Evaluation of Feynman Integral
Feynman loop integrals are a key ingredient for the calculation of higher
order radiation effects, and are responsible for reliable and accurate
theoretical prediction. We improve the efficiency of numerical integration in
sector decomposition by implementing a quasi-Monte Carlo method associated with
the CUDA/GPU technique. For demonstration we present the results of several
Feynman integrals up to two loops in both Euclidean and physical kinematic
regions in comparison with those obtained from FIESTA3. It is shown that both
planar and non-planar two-loop master integrals in the physical kinematic
region can be evaluated in less than half a minute with
accuracy, which makes the direct numerical approach viable for precise
investigation of higher order effects in multi-loop processes, e.g. the
next-to-leading order QCD effect in Higgs pair production via gluon fusion with
a finite top quark mass.Comment: 8 pages, 5 figures, published in Chinese Physics
CP Violation and Extra Dimensions
It is shown that the new sources of CP violation can be generated in the
models with more than one extra dimensions. In the supersymmetric models on the
space-time , where the radius moduli have auxiliary vacuum
expectation values and the supersymmetry breaking is mediated by the
Kaluza-Klein states of gauge supermultiplets, we analyze the gaugino masses and
trilinear couplings for two scenarios and obtain that there exist relative CP
violating phases among the gaugino masses and trilinear couplings.Comment: Latex, 7 page
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