Master thesis defense by Christian Caeser – University of Copenhagen

Forward this page to a friend Resize Print kalender-ikon Bookmark and Share

Discovery Center > Discovery calendar > Calendar 2013 > Master thesis defense ...

Master thesis defense by Christian Caeser

Measurement of Hard Double-Parton Interactions in Z -> llbar + 2 jet Events with the ATLAS Detector at sqrt(s) = 7 TeV.

Abstract: The aim of this thesis was the examination of multiple parton interactions (MPI) in Z -> l lbar + 2 jet processes at the hadron level. The determination of MPI in real data samples taken by the ATLAS detector at the LHC in 2011 (sqrt(s) = 7 TeV) was the main focus of this study. Minimum bias data corresponding to an integrated luminosity of 440.89 pb^-1 and preselected muons data corresponding to an integrated luminosity of 161.31 pb^-1 were used to perform the analysis. Events passing several selection criteria have been used to measure the fraction of MPI events f_{DP} by using the pT balance between pairs of jets. To do this different Monte Carlo (MC) generators were used, namely Pythia and Sherpa. Eventually the amount of MPI in the data samples was extracted by using a template method. Additionally, in order to check the behaviour of the MC generators several properties were compared to real data properties.
The result for the fraction of MPI obtained here can confirm an earlier study conducted in 2012 on W -> l nu + 2 jet events.