Tevatron Higgs Mass Bounds: Projecting U(1)' Models to LHC Domain

We study Higgs boson masses in supersymmetric models with an extra U(1) symmetry to be called U(1)$^{\prime}$. Such extra gauge symmetries are urged by the $\mu$ problem of the MSSM, and they also arise frequently in low-energy supersymmetric models stemming from GUTs and strings. We analyze mass of the lightest Higgs boson and various other particle masses and couplings by taking into account the LEP bounds as well as the recent bounds from Tevatron experiments. We find that the $\mu$-problem motivated generic low-energy U(1)$^{\prime}$ model yields Higgs masses as large as $\sim 200\ {\rm GeV}$ and violate the Tevatron bounds for certain ranges of parameters. We analyze correlations among various model parameters, and determine excluded regions by both scanning the parameter space and by examining certain likely parameter values. We also make educated projections for LHC measurements in light of the Tevatron restrictions on the parameter space. We further analyze certain benchmark models stemming from E(6) breaking, and find that they elevate Higgs boson mass into Tevatron's forbidden band when U(1)$^{\prime}$ gauge coupling takes larger values than the one corresponding to one-step GUT breaking.