286 research outputs found
Physics at the LHC -- From Standard Model measurements to Searches for New Physics
The successful operation of the {\em Large Hadron Collider} (LHC) during the
past two years allowed to explore particle interaction in a new energy regime.
Measurements of important Standard Model processes like the production of
high-\pt\ jets, and bosons and top and -quarks were performed by the
LHC experiments. In addition, the high collision energy allowed to search for
new particles in so far unexplored mass regions. Important constraints on the
existence of new particles predicted in many models of physics beyond the
Standard Model could be established. With integrated luminosities reaching
values around 5 \ifb\ in 2011, the experiments reached as well sensitivity to
probe the existence of the Standard Model Higgs boson over a large mass range.
In the present report the major physics results obtained by the two
general-purpose experiments ATLAS and CMS are summarized.Comment: 53 pages, 42 figures, to be published in the proceedings of ESHEP
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Prospects for Higgs Boson Searches at the LHC
The investigation of the dynamics responsible for electroweak symmetry breaking is one of the prime tasks of experiments at the CERN Large Hadron Collider (LHC). The experiments ATLAS and CMS have been designed to be able to discover a Standard Model Higgs boson over the full mass range as well as Higgs bosons in extended models. In this talk, the prospects for Higgs boson searches at the LHC are reviewed
Stimulation and inhibition of human platelet membrane high-affinity GTPase by neomycin
AbstractThe effect of the inositol phospholipid-binding antibiotic neomycin was studied on high-affinity GTPase in human platelet membranes. At low concentrations (up to 1 mM), neomycin by itself stimulated a high-affinity GTPase. This GTPase stimulation was additive with that caused by the hormonal factors, prostaglandin E1 and epinephrine, but not with thrombin. At concentrations higher than 1 mM, neomycin reduced control GTPase activity and eliminated the stimulation caused by thrombin. The data suggest that neomycin by a presently unknown mechanism can regulate activity states of signal transducing GTP-binding proteins
The process gg -> WW as a background to the Higgs signal at the LHC
The production of W pairs from the one-loop gluon fusion process is studied.
Formulas are presented for the helicity amplitudes keeping the top mass finite,
but all other quark masses zero. The correlations among the leptons coming from
the W bosons are kept. The contribution of this background to the Higgs boson
search in the WW decay mode at the LHC is estimated by applying the cuts
foreseen in experimental searches using the PYTHIA Monte Carlo program.
Kinematic distributions for the final state leptons are compared to those of
the Higgs boson signal and of the q qbar -> WW background. After applying final
cuts, the gg background is found to be large, at the level of 35% of the q qbar
background.The characteristics of the gg background are very similar to those
of the signal. Therefore, an experimental normalization of this background
component appears to be very difficult and the uncertainty must largely be
determined by theory. As a result, the significance of a Higgs signal in the gg
-> H -> WW mode at the LHC is reduced.Comment: 24 pages, 4 figure
Testing the lattice Hamiltonian built from partitionings
We test a possible digitization of lattice gauge theories
based on partitionings of the sphere . In our construction the link
operators are unitary and diagonal, with eigenvalues determined by the vertices
of the partitioning. The canonical momenta are finite difference operators
approximating the Lie derivatives on the manifold. In this formalism we
implement the standard Wilson Hamiltonian. We show results for a 2-site
Schwinger-type model in 1D and a single-plaquette system in 2D. Our
calculations are performed on a classical computer, though in principle they
can be implemented also on a quantum device
Canonical Momenta in Digitized SU(2) Lattice Gauge Theory: Definition and Free Theory
Hamiltonian simulations of quantum systems require a finite-dimensional
representation of the operators acting on the Hilbert space H. Here we give a
prescription for gauge links and canonical momenta of an SU(2) gauge theory,
such that the matrix representation of the former is diagonal in H. This is
achieved by discretising the sphere isomorphic to SU(2) and the
corresponding directional derivatives. We show that the fundamental commutation
relations are fulfilled up to discretisation artefacts. Moreover, we directly
construct the Casimir operator corresponding to the Laplace-Beltrami operator
on and show that the spectrum of the free theory is reproduced again up
to discretisation effects. Qualitatively, these results do not depend on the
specific discretisation of SU(2), but the actual convergence rates do
Saatgutbehandlung mit Pochonia chlamydosporia an Phacelia tanacetifolia zur Bekämpfung von Meloidogyne hapla
Zur Reduktion von M. hapla wird P. chlamydosporia in Form einer Saatbehandlung an P. tanacetifolia eingesetzt. Durch P. chlamydosporia wird die Menge der M. hapla Eier und damit die Vermehrung von M. hapla in der Zwischenfrucht reduziert. Der Befallsdruck in der Folgekultur wird somit verringert
Liver resection or combined chemoembolization and radiofrequency ablation improve survival in patients with hepatocellular carcinoma
Background/ Aims: To evaluate the long-term outcome of surgical and non-surgical local treatments of patients with hepatocellular carcinoma (HCC). Methods: We stratified a cohort of 278 HCC patients using six independent predictors of survival according to the Vienna survival model for HCC (VISUM- HCC). Results: Prior to therapy, 224 HCC patients presented with VISUM stage 1 (median survival 18 months) while 29 patients were classified as VISUM stage 2 (median survival 4 months) and 25 patients as VISUM stage 3 (median survival 3 months). A highly significant (p < 0.001) improved survival time was observed in VISUM stage 1 patients treated with liver resection ( n = 52; median survival 37 months) or chemoembolization (TACE) and subsequent radiofrequency ablation ( RFA) ( n = 44; median survival 45 months) as compared to patients receiving chemoembolization alone (n = 107; median survival 13 months) or patients treated by tamoxifen only (n = 21; median survival 6 months). Chemoembolization alone significantly (p <= 0.004) improved survival time in VISUM stage 1 - 2 patients but not (p = 0.341) in VISUM stage 3 patients in comparison to those treated by tamoxifen. Conclusion: Both liver resection or combined chemoembolization and RFA improve markedly the survival of patients with HCC
Characterization of Passive CMOS Strip Sensors
Recent advances in CMOS imaging sensor technology , e.g. in CMOS pixel
sensors, have proven that the CMOS process is radiation tolerant enough to cope
with certain radiation levels required for tracking layers in hadron collider
experiments. With the ever-increasing area covered by silicon tracking
detectors cost effective alternatives to the current silicon sensors and more
integrated designs are desirable. This article describes results obtained from
laboratory measurements of silicon strip sensors produced in a passive p-CMOS
process. Electrical characterization and charge collection measurements with a
90Sr source and a laser with infrared wavelength showed no effect of the
stitching process on the performance of the sensor.Comment: 6 pages, 16 figure
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