1,336 research outputs found
NLO QCD corrections to ZZ+jet production at hadron colliders
A fully differential calculation of the next-to-leading order QCD corrections
to the production of Z-boson pairs in association with a hard jet at the
Tevatron and LHC is presented. This process is an important background for
Higgs particle and new physics searches at hadron colliders. We find sizable
corrections for cross sections and differential distributions, particularly at
the LHC. Residual scale uncertainties are typically at the 10% level and can be
further reduced by applying a veto against the emission of a second hard jet.
Our results confirm that NLO corrections do not simply rescale LO predictions.Comment: 15 pages, 4 figures, 4 tables; added 1 reference, version to appear
in Phys. Lett.
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
ADJUSTMENT OF FUNCTIONAL ELECTRICAL STIMULATION (FES) ACCORDING TO KNEE FLEXION ANGLE
To clarify the different results of our simulation and FES-cycling tests, measurements on a knee dynamometer were made. The m. quadriceps of 16 healthy test persons was activated both by FES and voluntary contraction. Stimulated with the same level of intensity in a knee flexion angle range from 5° to 105°, the diagrams showed a very unusual course. The knee torque shows its maximum at the knee flexion angle of approx. 30°. Additional isometric measurements using stimulation intensity on constant on-verge-to pain levels for different knee angles were made. The measured courses of the resulting knee torque as a function of the knee angle are much closer to the results of physiologically activated muscle. These measurements show that for optimum power release, the stimulation intensity must be regulated depending on the knee flexion angle
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
New one-loop techniques and first applications to LHC phenomenology
In this talk we describe our approach for the computation of multi-leg
one-loop amplitudes and present some first results relevant for LHC
phenomenology.Comment: 5 pages, to appear in the proceedings of the conference "Loops and
Legs", Eisenach, 200
Kosmische Strahlung
Das vorliegende Unterrichtsmaterial bietet Ihnen und Ihren Schülern Einblicke in das faszinierende Forschungsfeld der Astroteilchenphysik. Dabei steht die experimentelle Untersuchung von kosmischen Teilchen am Beispiel der Myonen im Vordergrund. In den KAPITELN 1 und 2 werden zunächst einige Hintergrundinformationen für Lehrkräfte, wie beispielsweise Anknüpfungspunkte an den Lehrplan, benötigte Vorkenntnisse der Schüler, Lernziele sowie fachliche und methodische Hinweise gegeben. KAPITEL 3 beschäftigt sich dann mit der kosmischen Strahlung an sich. Mit Hilfe der Betrachtung von Teilchen in einer Nebelkammer gelingt der Einstieg in das Thema der Astroteilchenphysik. Neben den Spuren bereits bekannter Teilchen wie z. B. Elektronen und Alpha-Teilchen begegnen den Schülern hier erstmalig auch Myonen. Mittels anderer Experimente werden diese dann genauer untersucht. Die Experimente und Fachtexte werden durch entsprechende Aufgaben ergänzt. Abschließend wird dann die Entstehung der Myonen thematisiert. In KAPITEL 4 finden sich die vollständigen Lösungen zu allen Aufgaben. KAPITEL 5 bietet einen Überblick über weiterführende Materialien zum Thema kosmische Strahlung
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