Vienna University of Technology

About: Vienna University of Technology is a education organization based out in Vienna, Austria. It is known for research contribution in the topics: Laser & Cloud computing. The organization has 16723 authors who have published 49341 publications receiving 1302168 citations.

Search for a Higgs boson in the mass range from 145 to 1000 GeV decaying to a pair of W or Z bosons

Abstract: A search for a heavy Higgs boson in the H to WW and H to ZZ decay channels is reported. The search is based upon proton-proton collision data samples corresponding to an integrated luminosity of up to 5.1 inverse femtobarns at sqrt(s)=7 TeV and up to 19.7 inverse femtobarns at sqrt(s)=8 TeV, recorded by the CMS experiment at the CERN LHC. Several final states of the H to WW and H to ZZ decays are analyzed. The combined upper limit at the 95% confidence level on the product of the cross section and branching fraction exclude a Higgs boson with standard model-like couplings and decays in the range 145 < m[H] < 1000 GeV. We also interpret the results in the context of an electroweak singlet extension of the standard model.

Atomic electric fields revealed by a quantum mechanical approach to electron picodiffraction

Abstract: By focusing electrons on probes with a diameter of 50 pm, aberration-corrected scanning transmission electron microscopy (STEM) is currently crossing the border to probing subatomic details. A major challenge is the measurement of atomic electric fields using differential phase contrast (DPC) microscopy, traditionally exploiting the concept of a field-induced shift of diffraction patterns. Here we present a simplified quantum theoretical interpretation of DPC. This enables us to calculate the momentum transferred to the STEM probe from diffracted intensities recorded on a pixel array instead of conventional segmented bright-field detectors. The methodical development yielding atomic electric field, charge and electron density is performed using simulations for binary GaN as an ideal model system. We then present a detailed experimental study of SrTiO3 yielding atomic electric fields, validated by comprehensive simulations. With this interpretation and upgraded instrumentation, STEM is capable of quantifying atomic electric fields and high-contrast imaging of light atoms.

Energy calibration and resolution of the CMS electromagnetic calorimeter in pp collisions at √s = 7 TeV

Abstract: The article is the pre-print version of the final publishing paper that is available from the link below.

Fluid and solid phases of the Gaussian core model

Abstract: We study the structural and thermodynamic properties of a model of point particles interacting by means of a Gaussian pair potential first introduced by Stillinger (Stillinger F H 1976 J. Chem. Phys. 65 3968). By employing integral equation theories for the fluid state and comparing with Monte Carlo simulation results, we establish the limits of applicability of various common closures and examine the dependence of the correlation functions of the liquid on the density and temperature. We employ a simple, mean-field theory for the high-density domain of the liquid and demonstrate that at infinite density the mean-field theory is exact and that the system reduces to an 'infinite-density ideal gas', where all correlations vanish and where the hypernetted-chain (HNC) closure becomes exact. By employing an Einstein model for the solid phases, we subsequently calculate quantitatively the phase diagram of the model and find that the system possesses two solid phases, face-centred cubic and body-centred cubic, and also displays re-entrant melting into a liquid at high densities. Moreover, the system remains fluid at all densities when the temperature exceeds 1% of the strength of the interactions.