Search for heavy vector bosons W' in the tau decay channel using pp collisions at 8 TeV

The Large Hadron Collider has successfully taken a huge amount of data in the year 2012 at an unprecedented center of mass energy of 8 TeV making it the ideal discovery machine for new physics processes at highest energies. In this thesis, a search for a new heavy vector boson W ′ is performed with 12.1 fb−1 data taken with the CMS detector in the tau decay channel. The W ′ boson is predicted by many theories extending the Standard Model, and various searches have been performed in the past in the electron and muon channels. The current world‘s best limit excludes a W ′ boson in a Sequential Standard Model with masses below M(W′) = 3.35 TeV at 95 % CL[1]. In this thesis, for the first time, the tau decay channel of the W ′ is investigated where the tau subsequently decays hadronically. Although the sensitivity in the tau channel is lower than in the two other channels, this channel is important to gain the full picture of a hypothetical W ′ boson. An additional theory is investigated in this analysis where the coupling of the W ′ boson to the different fermion families is nonuniversal and depends on a parameter of this model. The analysis of the tau decay channel allows to study a parameter range of this model where the electron and muon channel are not sensitive. Since the decay of the W ′ gives rise to tau leptons at very high momenta which cause special and challenging requirements on the object reconstruction of these particles, a detailed study on tau identification and energy reconstruction at high momenta is performed first.