Fine tuning in the constrained exceptional supersymmetric standard model
King, S. F.
High Energy Physics - Phenomenology
arxiv: High Energy Physics::Phenomenology | High Energy Physics::Experiment
Supersymmetric unified models in which the Z ? couples to the Higgs doublets, as in the E 6 class of models, have large fine tuning dominated by the experimental mass limit on the Z ? . To illustrate this, we investigate the degree of fine tuning throughout the parameter space of the constrained exceptional supersymmetric standard model (cE 6 SSM ) that is consistent with a Higgs mass m h ?125??GeV . Fixing tan?=10 , and taking specific values of the mass of the Z ? boson, with M Z ? ?2–4??TeV , we find that the minimum fine tuning is set predominantly from the mass of Z ? and varies from ?200 to 400 as we vary M Z ? from ?2 to 4 TeV. However, this is significantly lower than the fine tuning in the constrained minimal supersymmetric standard model, of O(1000) , arising from the large stop masses required to achieve the Higgs mass.