Measurement of the Inclusive Electron Cross-Section from Heavy-Flavour Decays and Search for Compressed Supersymmetric Scenarios with the Atlas Experi

The first part of this thesis presents the measurement of the inclusive cross-section for electron production from heavy-flavour decays in the electron transverse momentum range 7 GeV < pT < 26 GeV using 1.3 pb-1 of 7 TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the cross-section within the fiducial range of the analysis is σ_e^HF = 0.946 ± 0.020(stat.) ± 0.146(syst.) ± 0.032(lumi.) μb. Theoretical predictions are in good agreement with the measurement. The second part of this thesis is a search for compressed supersymmetric scenarios in events with missing transverse energy, jets and one isolated low-pT lepton in the final state using 4.7 fb-1 of ATLAS data collected at 7 TeV center-of-mass energy in 2011. No significant excess of events over the Standard Model expectation is observed and exclusion limits are derived for a number of supersymmetric models.

The author began his undergraduate studies in physics at the University of Hamburg, Germany. During a study-abroad year at the University of Melbourne, Australia, he specialized in experimental particle physics and subsequently concluded his Diploma in Physics with a study on background estimation in searches for Supersymmetry with the ATLAS experiment. During his PhD studies at the University of Geneva, Switzerland, he performed a measurement of the inclusive electron cross-section from heavy-flavour decays and a search for compressed super symmetric scenarios with ATLAS. At present he is employed as fellow at the European Organization for Nuclear Research (CERN).