4,013 research outputs found
LHC Coverage of RPV MSSM with Light Stops
We examine the sensitivity of recent LHC searches to signatures of
supersymmetry with R-parity violation (RPV). Motivated by naturalness of the
Higgs potential, which would favor light third-generation squarks, and the
stringent LHC bounds on spectra in which the gluino or first and second
generation squarks are light, we focus on scenarios dominated by the pair
production of light stops. We consider the various possible direct and cascade
decays of the stop that involve the trilinear RPV operators. We find that in
many cases, the existing searches exclude stops in the natural mass range and
beyond. However, typically there is little or no sensitivity to cases dominated
by UDD operators or LQD operators involving taus. We propose several ideas for
searches which could address the existing gaps in experimental coverage of
these signals.Comment: 41 pages, 12 figures; v2: included new searches (see footnote 10),
minor corrections and improvement
Energy dependence on fractional charge for strongly interacting subsystems
The energies of a pair of strongly-interacting subsystems with arbitrary
noninteger charges are examined from closed and open system perspectives. An
ensemble representation of the charge dependence is derived, valid at all
interaction strengths. Transforming from resonance-state ionicity to ensemble
charge dependence imposes physical constraints on the occupation numbers in the
strong-interaction limit. For open systems, the chemical potential is evaluated
using microscopic and thermodynamic models, leading to a novel correlation
between ground-state charge and an electronic temperature.Comment: 4 pages, 3 figs.; as accepted (Phys. Rev. Lett.
Squark anti-squark pair production at the LHC: the electroweak contribution
We present the complete NLO electroweak contribution of
to the production of diagonal
squark--anti-squark pairs in proton--proton collisions. Compared to the
lowest-order electroweak terms, the
NLO contributions are also significant. We discuss the LO and NLO electroweak
effects in cross sections and distributions at the LHC for the production of
squarks different from top squarks, in various supersymmetric benchmark
scenarios.Comment: 38 pages, 21 figures. Replaced with the version published in JHE
NLO electroweak contributions to gluino pair production at hadron colliders
We calculate the full corrections to the
process of gluino pair production at hadron colliders in the framework of the
real MSSM. We show that these contributions can be neglected at the LHC
performing a scan over a wide region of the parameter space. The impact of
these corrections in the parameter range investigated at the Tevatron is small.Comment: 26 pages, 12 figure
Absorbing systematic effects to obtain a better background model in a search for new physics
This paper presents a novel approach to estimate the Standard Model
backgrounds based on modifying Monte Carlo predictions within their systematic
uncertainties. The improved background model is obtained by altering the
original predictions with successively more complex correction functions in
signal-free control selections. Statistical tests indicate when sufficient
compatibility with data is reached. In this way, systematic effects are
absorbed into the new background model. The same correction is then applied on
the Monte Carlo prediction in the signal region. Comparing this method to other
background estimation techniques shows improvements with respect to statistical
and systematical uncertainties. The proposed method can also be applied in
other fields beyond high energy physics
Dark matter searches at LHC
Besides Standard Model measurements and other Beyond Standard Model studies,
the ATLAS and CMS experiments at the LHC will search for Supersymmetry, one of
the most attractive explanation for dark matter. The SUSY discovery potential
with early data is presented here together with some first results obtained
with 2010 collision data at 7 TeV. Emphasis is placed on measurements and
parameter determination that can be performed to disentangle the possible SUSY
models and SUSY look-alike and the interpretation of a possible positive
supersymmetric signal as an explanation of dark matter.Comment: 15 pages, 14 figures, Invited plenary talk given at DISCRETE 2010:
Symposium On Prospects In The Physics Of Discrete Symmetries, 6-11 Dec 2010,
Rome, Ital
Three-body decays of sleptons in models with non-universal Higgs masses
We compute the three-body decays of charged sleptons and sneutrinos into
other sleptons. These decays are of particular interest in SUSY-breaking models
with non-universal Higgs mass parameters, where the left-chiral sleptons can be
lighter than the right-chiral ones, and lighter than the lightest neutralino.
We present the formulas for the three-body decay widths together with a
numerical analysis in the context of gaugino-mediated SUSY breaking with a
gravitino LSP.Comment: Version published in JHEP. See http://cern.ch/kraml/papers/ for
high-res figure
Neural NILM: Deep Neural Networks Applied to Energy Disaggregation
Energy disaggregation estimates appliance-by-appliance electricity
consumption from a single meter that measures the whole home's electricity
demand. Recently, deep neural networks have driven remarkable improvements in
classification performance in neighbouring machine learning fields such as
image classification and automatic speech recognition. In this paper, we adapt
three deep neural network architectures to energy disaggregation: 1) a form of
recurrent neural network called `long short-term memory' (LSTM); 2) denoising
autoencoders; and 3) a network which regresses the start time, end time and
average power demand of each appliance activation. We use seven metrics to test
the performance of these algorithms on real aggregate power data from five
appliances. Tests are performed against a house not seen during training and
against houses seen during training. We find that all three neural nets achieve
better F1 scores (averaged over all five appliances) than either combinatorial
optimisation or factorial hidden Markov models and that our neural net
algorithms generalise well to an unseen house.Comment: To appear in ACM BuildSys'15, November 4--5, 2015, Seou
Constraining parameter space in type-II two-Higgs doublet model in light of a 126 GeV Higgs boson
We explore the implications of a 126 GeV Higgs boson indicated by the recent
LHC results for two-Higgs doublet model (2HDM). Identifying the 126 GeV Higgs
boson as either the lighter or heavier of CP even neutral Higgs bosons in 2HDM,
we examine how the masses of Higgs fields and mixing parameters can be
constrained by the theoretical conditions and experimental constraints. The
theoretical conditions taken into account are the vacuum stability,
perturbativity and unitarity required to be satisfied up to a cut-off scale. We
also show how bounds on the masses of Higgs bosons and mixing parameters depend
on the cut-off scale. In addition, we investigate whether the allowed regions
of parameter space can accommodate particularly the enhanced di-photon signals,
ZZ* and WW* decay modes of the Higgs boson, and examine the prediction of the
signal strength of Z{\gamma} decay mode for the allowed regions of the
parameter space.Comment: To be published in JHEP, 20 pages, 11 figures, Figures and results
are updated for the recent LHC result
Minimal dark matter in type III seesaw
We explore the possibility of a new dark matter candidate in the
supersymmetric type III seesaw mechanism where a neutral scalar component of
the Y=0 triplet can be the lightest supersymmetric particle. Its thermal
abundance can be in the right range if non-standard cosmology such as kination
domination is assumed. The enhanced cross-section of the dark matter
annihilation to W+W- can leave detectable astrophysical and cosmological
signals whose current observational data puts a lower bound on the dark matter
mass. The model predicts the existence of a charged scalar almost degenerate
with the dark matter scalar and its lifetime lies between 5.5 cm and 6.3 m. It
provides a novel opportunity of the dark mater mass measurement by identifying
slowly-moving and highly-ionizing tracks in the LHC experiments. If the
ordinary lightest supersymmetric particle is the usual Bino, its decay leads to
clean signatures of same-sign di-lepton and di-charged-scalar associated with
observable displaced vertices which are essentially background-free and can be
fully reconstructed.Comment: 3 figures, 12 pages; An error in the antiproton limit corrected; the
lower bound on the dark matter mass strengthened; references added; typos
correcte
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