8,065 research outputs found
Search for anomalous gauge couplings in semi-leptonic decays of and in pp collisions at 8 TeV
A study of the Standard Model (SM) three electroweak boson production,
where V = W or Z gauge boson, is presented concerning events with a
leptonically decaying W boson accompanied by a photon and two or more jets. We
are using the full 2012 dataset, of proton-proton collisions at a
center-of-mass energy of 8 TeV and an integrated luminosity of 19.3
fb, collected by the CMS detector at the Large Hadron Collider (LHC).
production final states may be sensitive to anomalous
and quartic couplings. In light of the recent
discovery of a Higgs-like particle, we investigate, in a model independent way,
any deviation of gauge boson couplings with respect to the SM prediction by
setting limits on the anomalous quartic gauge couplings (aQGC) for
and . Upper limits at 95% confidence level are
obtained, with and without a form factor.Comment: "Presentation at the DPF 2013 Meeting of the American Physical
Society Division of Particles and Fields, Santa Cruz, California, August
13-17, 2013.
Current-induced electroresistance in Nd0.5Ca0.5Mn0.95Ni0.05O3
We have investigated the dc and pulsed current-induced electroresistance in
phase separated manganite Nd0.5Ca0.5Mn0.95Ni0.05O3 (NCMONi05) as a function of
temperature and magnetic field. It is shown that the negative differential
resistance which appears above a threshold current (Ic) and hysteresis in the
V-I progressively vanish with increasing period of the current pulses. However
a strong non-linearity in V-I exists even for a pulse period of 6s. The peak
voltage at Ic decreases in magnitude and shifts towards higher current values
with increasing strength of the magnetic field. The strong nonlinear behavior
and the negative differential resistance in the dc current sweep are
accompanied by a rapid increase of the sample surface temperature and therefore
primarily arise from the Joule heating in the sample. While the Joule heating
assists electroresistance in the high dc current regime, the nonlinearity in
the pulsed current sweep and the resistivity switching between a high and low
value induced by controlling the width and period of pulses can not be
explained solely on the basis of Joule heating.Comment: 16 pages,5figures. to appear in Solid State Commu
Big Data Privacy Context: Literature Effects On Secure Informational Assets
This article's objective is the identification of research opportunities in
the current big data privacy domain, evaluating literature effects on secure
informational assets. Until now, no study has analyzed such relation. Its
results can foster science, technologies and businesses. To achieve these
objectives, a big data privacy Systematic Literature Review (SLR) is performed
on the main scientific peer reviewed journals in Scopus database. Bibliometrics
and text mining analysis complement the SLR. This study provides support to big
data privacy researchers on: most and least researched themes, research
novelty, most cited works and authors, themes evolution through time and many
others. In addition, TOPSIS and VIKOR ranks were developed to evaluate
literature effects versus informational assets indicators. Secure Internet
Servers (SIS) was chosen as decision criteria. Results show that big data
privacy literature is strongly focused on computational aspects. However,
individuals, societies, organizations and governments face a technological
change that has just started to be investigated, with growing concerns on law
and regulation aspects. TOPSIS and VIKOR Ranks differed in several positions
and the only consistent country between literature and SIS adoption is the
United States. Countries in the lowest ranking positions represent future
research opportunities.Comment: 21 pages, 9 figure
Prospects for and measurements at the FCC-ee
We study the possibilities for the measurement of two-photon production of
the Higgs boson (in the decay channel), and of pairs
(decaying into four jets) in collisions at the the Future Circular
Collider (FCC-ee). The processes are simulated with the PYTHIA and MADGRAPH 5
Monte Carlo codes, using the effective photon approximation for the
photon fluxes, at center-of-mass energies 160 GeV
and 240 GeV. The analyses include electron-positron tagging, realistic
acceptance and reconstruction efficiencies for the final-state jets, and
selection criteria to remove the backgrounds. Observation of both channels is
achievable with the expected few ab integrated luminosities at FCC-ee.Comment: Proceedings of the conference PHOTON 2015: International Conference
on the Structure and the Interactions of the Photon including the 21th
International Workshop on Photon-Photon Collisions and the International
Workshop on High Energy Photon Colliders, held at Budker Institute of Nuclear
Physics (BINP), Siberian Branch of Russian Academy of Science, Novosibirsk,
Russia, from 15 to 19 June, 201
Influence of length and measurement geometry on magnetoimpedance in La0.7Sr0.3MnO3
We show that ac magnetoresistance at room temperature in La0.7Sr0.3MnO3 is
extremely high (= 47% in H = 100 mT, f = 3-5 MHz), and magnetic field
dependence of reactance exhibits a double peak behavior. However, magnitudes of
the ac magnetoresistance and magnetoreactance for a fixed length of the sample
(li) decrease with decreasing separation (lv) between voltage probes unlike the
dc magnetoresistance. On the contrary, change in li has a negligible influence
on magnetoimpedance when lv is fixed. Our results indicate that high frequency
electrical transport is sensitive to local variations in the magnetic
permeability.Comment: 12 pages, 3 figure
A large magnetoinductance effect in La0.67Ba0.33MnO3
We report four probe impedance of La0.67Ba0.33MnO3 at f = 100 kHz under
different dc bias magnetic fields. The ac resistance (R) exhibits a peak around
Tp = 325 K which is accompanied by a rapid increase and a peak in the reactance
(X) in a zero field. The magnetoreactance exhibits a sharp peak close to Tp and
its magnitude (= 60% in H = 1 kG) exceeds that of the ac magnetoresistance (= 5
% inH = 1 kG). It is suggested that the magnetoreactance arises from changes in
the self inductance of the sample rather than the capacitance.Comment: 13 pages, 3 figures. accepted in Appl. Phys. Let
Sharpening the shape analysis for higher-dimensional operator searches
When the Standard Model is interpreted as the renormalizable sector of a
low-energy effective theory, the effects of new physics are encoded into a set
of higher dimensional operators. These operators potentially deform the shapes
of Standard Model differential distributions of final states observable at
colliders. We describe a simple and systematic method to obtain optimal
estimations of these deformations when using numerical tools, like Monte Carlo
simulations. A crucial aspect of this method is minimization of the estimation
uncertainty: we demonstrate how the operator coefficients have to be set in the
simulations in order to get optimal results. The uncertainty on the
interference term turns out to be the most difficult to control and grows very
quickly when the interference is suppressed. We exemplify our method by
computing the deformations induced by the operator in
production at the LHC, and by deriving a bound on using TeV
CMS data.Comment: 21 pages, 4 figures. v2: Minor corrections, references added, matches
journal versio
Prospects for Higgs observation in ultraperipheral ion collisions at the Future Circular Collider
We study the two-photon production of the Higgs boson, , at the Future Circular Collider (FCC) in ultraperipheral PbPb and pPb
collisions at and 63 TeV. Signal and background events are
generated with MADGRAPH 5, including fluxes from the proton and lead
ions in the equivalent photon approximation, yielding = 1.75 nb and 1.5 pb in PbPb and pPb collisions
respectively. We analyse the H decay channel including
realistic reconstruction efficiencies for the final-state -jets, showered
and hadronized with PYTHIA 8, as well as appropriate selection criteria to
reduce the dominant exclusive continuum background.
Observation of is achievable
in the first year with the expected PbPb integrated luminosities.Comment: 5 pages, 4 figures. PHOTON'17, CERN Proceedings, to appear.
References adde
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