Comparison of mixed-Higgs scenarios in the NMSSM and the MSSM

We study scenarios in the minimal and next-to-minimal supersymmetric models in which the lightest CP-even Higgs boson can have mass below the 114 GeV standard model LEP limit by virtue of reduced ZZ coupling due to substantial mixing among the Higgs bosons. We pay particular attention to the size of corrections from superpartners needed for these scenarios to be viable and point to boundary conditions at large scales which lead to these scenarios while at the same time keeping electroweak fine-tuning modest in size. We find that naturalness of electroweak symmetry breaking in the mixed-Higgs scenarios of both models points to the same region of soft supersymmetry breaking terms as in the decoupled scenarios with mass of the CP even Higgs boson above 114 GeV, namely those leading to large mixing in the stop sector at the electroweak scale, especially if we also require that the lightest CP-even Higgs explains the Higgs-like LEP events at ~98 GeV.

©2008 The American Physical Society