| Summary: | The mass of the W boson, mW, is an important fundamental constant of nature, which
is also potentially sensitive to a plethora of physics beyond the Standard Model. In this
thesis, we discuss the precision measurement of mW with the CMS detector at the LHC in
proton-proton collisions at √s = 13 TeV. The phenomenology of W bosons produced in pp
collisions, the CMS detector characteristics, and other relevant factors are examined to justify
the overall strategy to measure mW from the muon transverse momentum and pseudorapidity
spectrum [formula] in the W → µν channel with a part of the 2016 data corresponding
to an integrated luminosity of 16.8 fb⁻¹. Dedicated studies aiming to reduce systematic
uncertainties related to the muon transverse momentum calibration, the muon reconstruction
and background rejection efficiencies, and the modeling of the W boson production and decay
kinematics are presented. A profiled maximum-likelihood fit of MC templates to observed
data incorporating over 4,000 nuisance parameters is employed to extract the central value
and the total uncertainty on m_W. The result of this measurement is m_W = 80, 360.2 ± 2.4 (stat.) ± 9.6 (syst.) MeV,= 80, 360.2 ± 9.9 MeV, which is consistent with the standard model prediction m(SM/W) = 80, 354.5 ± 5.7 MeV.
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