Master Theses

This thesis presents a precision measurement of the CP properties of the Higgs tau Yukawa coupling, focusing on the H → τ τ → μa3pr 1 +3ν decay channel with ggF and VBF production.The study uses proton–proton collisions data recorded by CMS in 2022 and 2023 at √s = 13.6TeV, corresponding to an integrated luminosity of 62.4 fb−1. The CP-mixing angle αHττ is determined via the coplanarity angle ϕCP . [...]

Among other restrictions, vacuum stability is a theoretical constraint for vacuumconfigurations in BSM theories to be allowed or excluded. But due to multidimensionalfield spaces, computing the vacuum stability is a challenging task. [...]

As the search for physics beyond the Standard Model continues, this thesis presentsan analysis in the long-lived particle (LLP) supersymmetry sector. A Boosted DecisionTree (BDT) classifier was developed to enhance the search for long-lived supersymmetricpartner particles of the tau lepton (stau) particles in the muon-hadronic tau channel at theCMS detector in LHC, motivated by Gauge Mediated Supersymmetry Breaking (GMSB)scenarios. [...]

This thesis evaluates a b-tagging algorithm optimized to identify low pT (soft) b-hadrons in theATLAS experiment at the LHC. The algorithm, called the NewVrtSecInclusiveTool, reconstructssoft secondary vertices (SSVs), which can be connected to the decay of a soft b-hadron [...]

(di-Higgs) events using simulated data from the ATLAS detector at the Large Hadron Collider ata center-of-mass energy of √s = 13TeV and an integrated luminosity of 140 fb−1. In the studiedchannel, one Higgs boson decays into a bottom quark-antiquark pair (b¯b), the other into two photons(γγ) [...]

In the endeavour to understand the fundamental components of the universe, the search for newparticles beyond the Standard Model of particle physics is a pivotal task. Axion-like particles (ALPs)are among the prime targets of this search, arising in various theoretical frameworks, includingquantum chromodynamics, supersymmetric extensions of the Standard Model of particle physics orstring theory. [...]

Palladium nanoparticles are widely studied in various fields of science. In biology, Pd parti-cles are studied for possible medical applications, in chemistry the particles are often synthe-sised in solution and then applied to a support via, for example, spin coating. [...]

Catalysts have a wide field of applications, for example, they play an important rolein producing chemicals and for renewable energies. Thus it is of great interest tomake them more efficient and to increase their lifetime [...]