Estimation and modelling of Standard Model backgrounds in the search for W' gauge bosons with ATLAS (µ channel)

This thesis discusses the estimation and modelling of the Standard Model background contribution to the search for heavy W' gauge boson resonance in the W' -> µν channel. Smearing techniques for the Monte Carlo simulations to match data are explored, followed by a data driven technique to estimate the QCD contribution to the background using sidebands. And finally a next-to-leading-order cross-section correction factor to the electroweak background from higher order QCD and EW diagrams is pursued. We find the QCD background contribution is small in high transverse mass (mT) tails of the Standard Model background. We also find the higher order cross-section correction factors for the background can be significant.