Licentiate Thesis: Measurement of the ttZ and ttW production cross sections in ATLAS at √s = 8 TeV and The Electronic Noise in the Tile Calorimeter
Thursday 18 December 2014
to 15:00 at
Olga Bessidskaia Bylund (Stockholm University, Department of Physics)
The Large Hadron Collider (LHC) at CERN is the largest particle accelerator in the world. The world record of √s = 8 TeV collision energy was reached at the LHC in 2012, using proton-proton collisions. The particles produced in the collisions are detected and analyzed by diferent detectors, of which the ATLAS experiment is the largest. In the frst part of this thesis, the Tile Calorimeter in ATLAS is described and the modelling of electronic noise in it is studied. In the second part, the measurement of the ttZ and ttW production cross sections in ATLAS, using √s = 8
TeV data with 20.3 fb−1 integrated luminosity, is presented. The background only hypothesis for the two processes is excluded with 2.7σ for ttZ and with 3.1σ for ttW.
This is one of the frst measurements where these processes have been observed.