Alexander Gude's PhD Thesis

Abstract

Measurements of the Z boson transverse momentum (QT) spectrum serve as both precision tests of non-perturbative QCD and help to reduce the uncertainty in the measurement of the W boson mass. However, QT is limited at its lowest values by detector resolution, and so a new variable, phistar, which performs better in the low QT region, is used instead. This thesis presents the first measurement of the normalized differential cross section of Z bosons decaying to electron pairs in terms of phistar at sqrt(s) = 8 TeV. The data used in this measurement were collected by the CMS detector at the LHC in 2012 and totaled 19.7/fb of integrated luminosity. The results are compared to predictions from simulation, which are found to provide a poor description of the data.