The effect of hadronization on the φ ∗ distribution of the Z boson in simulation compared to data from the CMS experiment at √ s = 8 TeV

Abstract

Measurements of the distribution of the Z boson decay are in disagreement with the theoretical distribution. This disagreement is of importance in its relationship to the transverse momentum of the Z boson (QT). This disagreement may be due to the hadronization step of the simulation, which attempts to describe QCD interactions involved in the event. If the hadronizer can be changed to remove this disagreement those changes can be applied to W simulations which would allow for the uncertainty of the W mass measurement to be decreased. This thesis presents normalized results of both measurements and rapidity measurements of the Z boson at a center-of-mass energy of 8 TeV along with multiple simulation results using changes to the hadronizer in an attempt to better match the data. The data used was collected by the CMS detector at the LHC in 2012. This data totaled 19.7 fb􀀀1 of integrated luminosity. Although changes to the hadronizer had a major eect on the simulated results, it was found that none of the changes could fully resolve the disagreement between data and theory.