Muons in early ATLAS Data - from first collisions to W+W- production

In March 2010 the ATLAS experiment at the Large Hadron Collider (LHC) at CERN started its long anticipated data-taking phase. It is one of mankind's most ambitioned experiments, recording proton-proton collisions with energies more than 3 times higher than any experiment before. The presented work starts with improving the identification of muons in the collisions. Muons are charged elementary particles, similar to electrons but 200 times more heavy. Subsequently, we use the first recorded data to measure the muon identification efficiencies. Based on the results, we select muons in the ATLAS data recorded in 2011 to extract the production rate at which a W-boson-pair is produced at the given collision energy at the LHC, which already gives a hint of the just discovered Higgs boson.