000004241 001__ 4241
000004241 005__ 20240415163408.0
000004241 037__ $$aBELLE2-MTHESIS-2024-010
000004241 041__ $$aeng
000004241 100__ $$aLukas Grussbach
000004241 245__ $$aMeasuring the Weinberg Angle at the Belle II Experiment
000004241 260__ $$aMunich$$bInstitute for Hadronic Structure and Fundamental Symmetries$$c2022
000004241 300__ $$amult. p
000004241 500__ $$aPresented on 15 11 2022
000004241 502__ $$aMSc$$bMunich, Technical University of Munich$$c2022
000004241 520__ $$aThe Weinberg angle is known precisely only at high energies around the Z0 mass. At Belle II, we have the opportunity to measure it at much lower energies via e+e− → μ+μ− as a process. A measurement could solve the issue of the deviation observed by the NuTeV experiment. I calculate the differential cross section for this process at tree-level to relate the Weinberg angle to the polar angle distribution of the muons. This calculation is used in a dedicated software that I developed to fit the differential cross section to the polar angle distribution and extract the Weinberg angle. I study different background sources and criteria to select signal events and reject background events. By calculating muon detection efficiencies, I study the muon identification performance of Belle II in the process e+e− → μ+μ−γ both in recorded data and using simulation. The ratio of the efficiencies in recorded data and simulation allows us to correct differences between recorded and simulated data and provides systematic uncertainties related to these corrections.
000004241 700__ $$aStephan Paul$$edir.
000004241 700__ $$aDaniel Greenwald$$edir.
000004241 8560_ $$flukas.grussbach@tum.de
000004241 8564_ $$uhttps://docs.belle2.org/record/4241/files/BELLE2-MTHESIS-2024-010.pdf
000004241 980__ $$aTHESIS