Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Physics and Astronomy


In the minimal standard model, the difference between the tree-level and one-loop-corrected predictions for the gauge-boson masses, known as the mass shifts, are of the order of 4%. The domi- nant contribution is from light-fermion loops. The Higgs-dependent terms are small, even if the Higgs boson is heavy;We have analyzed the mass shifts for models with a more compli- cated Higgs sector. We use the on-shell renormalization scheme, in which the parameters of the theory are the physical masses and couplings. We have considered the 2-doublet, n-doublet, triplet and doublet-triplet models. We have found that the Z-boson mass pre- diction has a strong dependence on the charged-Higgs mass. In the limit that the charged Higgs is much heavier than the gauge bosons, the Higgs-dependent terms become significant, and may even cancel the light-fermion terms. In the models with a Higgs triplet, there is also a strong dependence of the neutral-Higgs masses, although this contribution tends to be suppressed in realistic models. The W-boson mass shift does not have a strong Higgs dependence;If we use the Z mass as input in determining the parameters of the theory, a scenario which will become attractive as the mass of the Z is accurately measured in the next few years, we find that the W-boson mass shift exhibits the same sort of behavior, differing from the minimal model for the case of the charged Higgs being heavy;We have found that when the radiative corrections are taken into account, models with extended Higgs sectors may differ significantly from the minimal standard model in their predictions for the gauge-;boson masses. Thus, an accurate measurement of the masses will help shed light on the structure of the Higgs sector; *DOE Report IS-T-1173. This work was performed under contract No. W-7405-Eng-82 with the U.S. Department of Energy.



Digital Repository @ Iowa State University,

Copyright Owner

Stephen Richard Moore



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212 pages