1,382 research outputs found
Multi-Higgs boson production in the Standard Model and beyond
We present a calculation of the loop-induced processes gg -> HH and gg ->
HHH, and investigate the observability of multi-Higgs boson production at the
CERN Large Hadron Collider (LHC) in the Standard Model (SM) and beyond. While
the SM cross sections are too small to allow observation at the LHC, we
demonstrate that physics beyond the SM can lead to amplified, observable cross
sections. Furthermore, the applicability of the heavy top quark approximation
in two- and three-Higgs boson production is investigated. We conclude that
multi-Higgs boson production at the SuperLHC is an interesting probe of Higgs
sectors beyond the SM and warrants further study.Comment: 17 pages, 17 figure
Introducing TAXI: a Transportable Array for eXtremely large area Instrumentation studies
A common challenge in many experiments in high-energy astroparticle physics
is the need for sparse instrumentation in areas of 100 km2 and above, often in
remote and harsh environments. All these arrays have similar requirements for
read-out and communication, power generation and distribution, and
synchronization. Within the TAXI project we are developing a transportable,
modular four-station test-array that allows us to study different approaches to
solve the aforementioned problems in the laboratory and in the field.
Well-defined interfaces will provide easy interchange of the components to be
tested and easy transport and setup will allow in-situ testing at different
sites. Every station consists of three well-understood 1 m2 scintillation
detectors with nanosecond time resolution, which provide an air shower trigger.
An additional sensor, currently a radio antenna for air shower detection in the
100 MHz band, is connected for testing and calibration purposes. We introduce
the TAXI project and report the status and performance of the first TAXI
station deployed at the Zeuthen site of DESY.Comment: 4 pages, 3 figures, presented at ARENA 2014, Annapolis, MD, June 201
Structural optimization and biological evaluation of 2-substituted 5-hydroxyindole-3-carboxylates as potent inhibitors of human 5-lipoxygenase.
Pharmacological suppression of leukotriene biosynthesis by inhibitors of 5-lipoxygenase (5-LO) is a strategy to intervene with inflammatory and allergic disorders. We recently presented 2-amino-5-hydroxy-1H-indoles as efficient 5-LO inhibitors in cell-based and cell-free assays. Structural optimization led to novel benzo[g]indole-3-carboxylates exemplified by ethyl 2-(3-chlorobenzyl)-5- hydroxy-1H-benzo[g]indole-3-carboxylate (compound 11a), which inhibits 5-LO activity in human neutrophils and recombinant human 5-LO with IC50 values of 0.23 and 0.086 ÎŒM, respectively. Notably, 11a efficiently blocks 5-LO product formation in human whole blood assays (IC50 = 0.83-1.6 ÎŒM) and significantly prevented leukotriene B4 production in pleural exudates of carrageenan-treated rats, associated with reduced severity of pleurisy. Together, on the basis of their high potency against 5-LO and the marked efficacy in biological systems, these novel and straightforward benzo[g]indole-3-carboxylates may have potential as anti-inflammatory therapeutics
Next-to-leading order multi-leg processes for the Large Hadron Collider
In this talk we discuss recent progress concerning precise predictions for
the LHC. We give a status report of three applications of our method to deal
with multi-leg one-loop amplitudes: The interference term of Higgs production
by gluon- and weak boson fusion to order O(alpha^2 alpha_s^3) and the
next-to-leading order corrections to the two processes pp -> ZZ jet and u ubar
-> d dbar s sbar. The latter is a subprocess of the four jet cross section at
the LHC.Comment: 6 pages, 5 figures. Talk given at the 8th international Symposium on
Radiative Corrections (RADCOR), October 1-5 2007, Florence, Ital
Measurements and Simulation Studies of Piezoceramics for Acoustic Particle Detection
Calibration sources are an indispensable tool for all detectors. In acoustic
particle detection the goal of a calibration source is to mimic neutrino
signatures as expected from hadronic cascades. A simple and promising method
for the emulation of neutrino signals are piezo ceramics. We will present
results of measruements and simulations on these piezo ceramics.Comment: 5 pages, 5 figure
Plasmonic nanomeshes: Their ambivalent role as transparent electrodes in organic solar cells
In this contribution, the optical losses and gains attributed to periodic nanohole array electrodes in polymer solar cells are systematically studied. For this, thin gold nanomeshes with hexagonally ordered holes and periodicities (P) ranging from 202 nm to 2560 nm are prepared by colloidal lithography. In combination with two different active layer materials (P3HT:PC 61 BM and PTB7:PC 71 BM), the optical properties are correlated with the power conversion efficiency (PCE) of the solar cells. A cavity mode is identified at the absorption edge of the active layer material. The resonance wavelength of this cavity mode is hardly defined by the nanomesh periodicity but rather by the absorption of the photoactive layer. This constitutes a fundamental dilemma when using nanomeshes as ITO replacement. The highest plasmonic enhancement requires small periodicities. This is accompanied by an overall low transmittance and high parasitic absorption losses. Consequently, larger periodicities with a less efficient cavity mode, yet lower absorptive losses were found to yield the highest PCE. Nevertheless, ITO-free solar cells reaching âŒ77% PCE compared to ITO reference devices are fabricated. Concomitantly, the benefits and drawbacks of this transparent nanomesh electrode are identified, which is of high relevance for future ITO replacement strategies
Integration of Acoustic Detection Equipment into ANTARES
The ANTARES group at the University of Erlangen is working towards the
integration of a set of acoustic sensors into the ANTARES Neutrino Telescope.
With this setup, tests of acoustic particle detection methods and background
studies shall be performed. The ANTARES Neutrino Telescope, which is currently
being constructed in the Mediterranean Sea, will be equipped with the
infrastructure to accommodate a 3-dimensional array of photomultipliers for the
detection of Cherenkov light. Within this infrastructure, the required
resources for acoustic sensors are available: Bandwidth for the transmission of
the acoustic data to the shore, electrical power for the off-shore electronics
and physical space to install the acoustic sensors and to route the connecting
cables (transmitting signals and power) into the electronics containers. It
will be explained how the integration will be performed with minimal
modifications of the existing ANTARES design and which setup is foreseen for
the acquisition of the acoustic data.Comment: 5 pages, 1 figure, to appear in the proceedings of the 1st
International ARENA Workshop, May 17-19th, 2005, DESY Zeuthen (Germany
Development of Acoustic Sensors for the ANTARES Experiment
In order to study the possibility of acoustic detection of ultra-high energy
neutrinos in water, our group is planning to deploy and operate an array of
acoustic sensors using the ANTARES Neutrino telescope in the Mediterranean Sea.
Therefore, acoustic sensor hardware has to be developed which is both capable
of operation under the hostile conditions of the deep sea and at the same time
provides the high sensitivity necessary to detect the weak pressure signals
resulting from the neutrino's interaction in water. In this paper, two
different approaches to building such sensors, as well as performance studies
in the laboratory and in situ, are presented.Comment: 5 pages, 3 figures. Proceedings of the ARENA 2005 Worksho
Testing Thermo-acoustic Sound Generation in Water with Proton and Laser Beams
Experiments were performed at a proton accelerator and an infrared laser
acility to investigate the sound generation caused by the energy deposition of
pulsed particle and laser beams in water. The beams with an energy range of 1
PeV to 400 PeV per proton beam spill and up to 10 EeV for the laser pulse were
dumped into a water volume and the resulting acoustic signals were recorded
with pressure sensitive sensors. Measurements were performed at varying pulse
energies, sensor positions, beam diameters and temperatures. The data is well
described by simulations based on the thermo-acoustic model. This implies that
the primary mechanism for sound generation by the energy deposition of
particles propagating in water is the local heating of the media giving rise to
an expansion or contraction of the medium resulting in a pressure pulse with
bipolar shape. A possible application of this effect would be the acoustical
detection of neutrinos with energies greater than 1 EeV.Comment: 5 pages, 2 figures, to appear in the proceedings of the 1st
International ARENA Workshop, May 17-19th, 2005, DESY Zeuthe
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