E_6 modellerinde ekstra ayar bozonlari

The decay width of the extra Z' boson is calculated numerically in effective rank 5 models for different mixing angles theta of the model and for different mass values of the extra Z' boson. The decay width of the Z' boson to the Standard Model (SM) fermions is found to be between 4.42 and 19.36 GeV and the full decay width of Z' boson to all particles is found to be between 20.87 and 37.15 GeV. In this thesis after giving the basics of the Standard Model, Supersymmetry (SUSY), Minimal Supersymmetric Standard Model (MMSM) and Extra Gauge Bosons; we calculated the decay width for the Standard Model Z boson and then the decay width to the SM fermions for E_6 boson Z'(theta) for different mixing angles theta and masses. Finally, we calculated the full decay width at the angle theta~0 for Z' and Z_2--->Z' .Key Words: Standard Model, Minimal Supersymmetric Standard Model, Supersymmetry, Extra Gauge Bosons, Z' Mass in E_6 Models.