Ph.D. Theses

he properties of the scalar boson that was first found in 2012 by the ATLAS and CMS experiments at the LHC are so far consistent with those of the Higgs boson, predicted by the Standard Model of particle physics. Further investigations of the boson's properties with increased accuracy are of immediate interest, as any deviation from Standard Model predictions could lead the way to a more fundamental theory of nature. [...]

Tryptophan hydroxylase catalyzes the rate-limiting reaction in the biosynthesis pathway of serotonin, one of the most ubiquitous and multifunctional neurotransmitters. The influence of the serotonergic system extends over many functions of the human body, ranging from temperature and muscle tone control, to mood and sleep regulation [...]

The γ-TiAl alloys are characterized as high-temperature stable light metals. As material, they are used for blades in the low-pressure area of aircraft turbines [...]

Liquid crystals are fascinating self–assembled soft materials in which the molecules are orientationally ordered and partially positionally ordered. Liquid crystals easily response to small perturbations like the electric field, magnetic field, surface effect, etc. [...]

Due to the coexistence of liquid-like fluidity with conventional solidlike anisotropy, liquid crystals exhibit unique optical, dielectric or elasticproperties which make them suitable for a variety of technical andscientific applications, especially in display devices. The dielectric andelectro-optic properties of these materials, along with their phasebehaviour, are of immense importance from application perspective. [...]

Now-a-days displays have become a field of tremendous importance as they provide the best means for interface between man and machine. Large numbers of displays are presently available in the market, but among all these displays about 90% are controlled by the liquid crystal display (LCD) technology. [...]

Strong-field ionisation imaging offers elegant ways to measure and visualise molecular structure with picometre spatial and femtosecond temporal resolution. The underlying ionisation process is driven by an intense laser-electric field and allows to selectively extract a single electron from the outermost valence orbital(s) of the target molecule. [...]

A search for a pair of light bosons produced in decays of the 125 GeV Higgs boson, with one of the light states decaying into a pair of muons and the other into a pair of tau leptons, is presented. The search is based on a data sample corresponding to an integrated luminosity of 137.2 fb-1, collected with the CMS detector at the CERN Large Hadron Collider in the years 2016, 2017, and 2018 at a center-of-mass energy of 13 TeV. [...]

Die morphologischen und kristallographischen Eigenschaften vertikaler, freistehender Nanodrähte, welche mittels der Dampf-Flüssigkeits-Feststoff-Methode (VLS) gezüchtet werden, sind durch ein kompliziertes Wechselspiel der Wachstumsparameter während des Herstellungsprozesses beeinflusst. Das Verständnis und die Kontrolle dieser dynamischen Prozesse sind folglich Voraussetzung für die Herstellung von Nanodrähten mit maßgeschneiderten Eigenschaften. [...]

The first part of this thesis investigates the direct detection of axions in particle physics. A generalized matrix formalism for describing axion-photon mixing in multi-layer systems to all orders in the axion-photon coupling is developed and applied for studying light shinning through a wall (LSW) experiments with and without dielectric layers. [...]