Ph.D. Theses

A search for heavy, neutral Higgs bosons produced in association with b quarks and decaying into a pair of b quarks is presented. It is based on LHC Run 2 data, produced at a center-of-mass energy of 13 TeV in pp collisions and collected by the CMS experiment in 2017, corresponding to an integrated luminosity of 36.02/fb.Several theories beyond the Standard Model predict additional Higgs bosons and, dependingon the specific model, the coupling to b quarks can be significantly enlarged. [...]

In this work, the challenge to further the fundamental understanding of nanoscale matter is tackled from the perspective of cluster science. More specifically the spatial transformation of gas phase silver nanoclusters during melting is investigated. [...]

Diese Arbeit stellt eine Messung des $W^+ W^−$ Produktionswirkungsquerschnitts in pp Kollisionen bei einer Schwerpunktenergie von $\sqrt{s} = 13$ TeV vor. Der verwendete Datensatz wurde mit dem ATLAS Detektor im Jahr 2015 aufgezeichnet und entspricht einer integrierten Luminosität von 3,16 fb$^{-1}$ [...]

Many models of dark matter place their dark matter candidate inside a broader dark sector with other particles and fields for theoretical and phenomenological reasons. The cosmological evolution of these dark sectors can differ significantly from standard scenarios, in particular due to their interplay with the Standard Model of particle physics. [...]

Nano-bainitic steels represent a new class of alloys, whose microstructure consists of nanostructured bainitic ferrite formed at low temperature with a high amount of retained austeniteleading to a high ductility and high tensile strength of the steel. Formation of nanobainite has been studied thoroughly in literature as well as tempering of nano-bainitic steels. [...]

In dieser Dissertation wird die Suche nach schweren neutralen pseudoskalaren A und skalaren H Higgs-Bosonen vorgestellt, die in gg-Fusionen erzeugt werden, und in ein Top-Antitop-Quark-Paar zerfallen. Gesucht wurde im vollständigen Datensatz von Proton–Proton-Kollisionen bei einer Schwerpunktsenergie von 8 TeV die vom ATLAS-Detektor am Large Hadron Collider aufgezeichnet wurde und einer integrierten Luminosität von 20.3 fb$^{−1}$ entspricht. [...]

The aim of this work was to explore the potential of a combined rheology and X-ray scattering approach on complex fluids. Shear rates between 0.9·10$^5$ s$^{−1}$ and 5.6·10$^5$ s$^{−1}$, which are magnitudes higher than found in classical rheometry studies, were applied to a suspension of colloidal silica nanoparticles by a microfluidic jet device. [...]

Water is commonly said to be the matrix of life. It is built from water molecules, which are connected via hydrogen bonds. [...]

This thesis presents work for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). The two main subjects are a search for Dark Matter events in final states with one lepton within two supersymmetry (SUSY) models and studies on the performance of the Hadron Outer (HO) calorimeter as a support for the muon system and the muon trigger. [...]

Diese Arbeit beschreibt die Suche nach assoziierter Produktion eines Higgsbosons und eines Top-Quark Paares in Proton-Proton Kollisionen bei einer Schwerpunktsenergie von 13 TeV. Für diese Analyse wurden Ereignisse analysiert, die exakt zwei Leptonen mit gleichem Ladungsvorzeichen oder exakt drei Leptonen enthalten und daher auf die Higgs Zerfallsmoden in H->WW, H->ZZ und H->tautau sensitiv sind. [...]