Search for new physics in proton-proton collision events with a lepton and missing transverse energy

The production of a single lepton with opposing missing transverse energy is a distinct signa- ture and provides an interesting opportunity to search for physics not explained by the stan- dard model. The 8 TeV run of the CERN LHC in 2012 improved the discovery range for such a signal. In this thesis collisions of the CMS experiment corresponding to 19.7 fb−1 with an electron or a muon are examined. The data are interpreted in terms of a number of different models. The sequential standard model W′ boson, the helicity nonconserving contact interaction model, and a model with pair- produced dark matter are all expected to be discoverable in this framework. No significant deviation of the data from the standard model expectation is observed. A limit of 3.28 TeV on the W′ boson mass in the sequential standard model is determined. In the contact interaction model an interaction scale below 12.4 TeV is excluded. In the dark matter model limits in terms of the mass of the dark matter particle and the scale of the considered theory are determined. The three models are also evaluated to determine the future potential of the high luminosity LHC run with 3000 fb−1 at √ s = 14 TeV. A sequential standard model with a mass of 7 TeV is expected to be discoverable with such a configuration. In case a significant deviation of the data compared to the standard model expectation occurs, competing models describing the signal must be discriminated. In this context the distinction potential is determined, providing a measure of how well two models can be distinguished. The integrated luminosity required to discriminate different models is determined using this measure.