Ph.D. Theses

This work presents several measurements of the inclusive top pair production cross sectionat a center of mass energy of√s = 13 TeV with the CMS detector. The cross section ismeasured using several data sets collected by the CMS detector in 2015 and 2016. [...]

The study of condensed matter dynamics on ultrafast timescales is one of the key topics in modern material science research. Hard X-ray free-electron laser sources with extreme peak brightness and ultra short pulses provide excellent conditions for studying ultrafast dynamics in the time domain by employing such techniques as X-ray pump-probe spectroscopy or X-ray photon correlation spectroscopy. [...]

This thesis deals with a systematic study of magnetic properties, i.e. saturation magnetization, exchange stiffness, anisotropy, interlayer exchange coupling, and average domains size, of ultrathin Co-based multilayer systems. [...]

This thesis is focused on the search for pair production of the supersymmetric $\tau$ lepton partners within the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). The search is performed using the data collected at a center-of-mass-energy $\sqrt{s} = 13$ TeV with the CMS detector in the years 2016-2017.One of the most popular extensions of the Standard Model (SM) is supersymmetry (SUSY). [...]

Bulk glass-forming alloy compositions are found in various noble-metal based systems. Their superior properties and their high noble metal content predestinate these alloy classes for the application as jewelry alloys [...]

The International Linear Collider (ILC) is a planned electron-positron collider with a first stage at a center-of-mass energy of 250 GeV. The electron beam will be polarized to 80% and the positron beam to 30%. [...]

Plasma wakefields are a promising approach for the acceleration of electrons with ultrahigh (10 to 100 GV/m) electric fields. Nowadays, high-intensity laser pulses are routinely utilized to excite these large-amplitude plasma waves. [...]

In this thesis we discuss modern mathematical tools for the perturbative analysis of supersymmetric Yang–Mills theories (abbreviated SYM). We apply contemporary and traditional computational techniques to two kind of problems. [...]

In this thesis a search for new physics is presented, based on events with two isolated same sign leptons (muons and electrons), jets, and missing transverse energy. The analyzed data corresponds to an integrated luminosity of 1.1 fb$^{-1}$ and is collected with the CMSdetector in proton-proton collisions at the LHC with a center-of-mass energy of 7TeV. [...]