Measurement of W-boson mass with the ATLAS detector at the LHC

This thesis describes the measurement of the W boson mass using the ATLAS detector based on the 2017 data-set recorded at a centre-of-mass energy of √s = 5 TeV, corresponding to 256.827 pb−1 of integrated luminosity. Special runs with a low number of interactions per bunch crossing were conducted to improve the experimental resolution of the recoil measurement and the reconstruction of missing transverse momentum and transverse mass. The primary emphasis of this research is on the leptonic decays of the W boson, specifically focusing on the channel W+ → e+νe. Additionally, the statistical uncertainty of the W boson mass measurement is evaluated in this study. Keywords: W boson mass, ATLAS, LHC, Standard Model