Implications of a heavy gauge boson

We study the implications of neutral heavy gauge bosons to electroweak (EW) baryogenesis, neutrino physics and the discovery limits at the Tevatron and LHC. For baryogenesis, we construct two anomaly free supersymmetric U(1)′ models with secluded U(1) ′-breaking sectors. In the framework of the one with E6 embedding, we study the one-loop effective potential at finite temperature, and show that there exist strong enough first order EW phase transition (EWPT) because of the large trilinear terms in the tree-level Higgs potentials. Unlike the Minimal Supersymmetric Standard Model (MSSM), the stop masses can be very heavy. We discuss possible large tree-level CP violation associated with the Higgs sector. Numerical calculations show that the contribution purely from the thin wall regime is big enough to explain the observed baryon number asymmetry for some of the parameter space. Our model is free of domain wall problems and does not introduce new contributions to electric dipole moments (EDM). Secondly, we consider various possibilities for generating neutrino masses in supersymmetric models with an additional U(1)′ gauge symmetry. One class of models involves two extra U (1)′ × U(1)″ gauge symmetries, with U(1)″ breaking at an intermediate scale and yielding small Dirac masses through higher-dimensional operators. The right-handed neutrinos [special characters omitted] can naturally decouple from the low energy U(1) ′, avoiding cosmological constraints. We secondly consider models with a pair of heavy triplets which couple to left-handed neutrinos. After integrating out the heavy triplets, a small neutrino Majorana mass matrix can be generated by the induced non-renormalizable terms. We also study models involving the double-see-saw mechanism, in which heavy Majorana masses are associated with the TeV-scale of U(1)′ breaking. We finally study how the exotic particles and supersymmetric partners would affect the discovery limit at the Tevatron and LHC for neutral gauge bosons in generic E6 models. We examine the Z′ decay in the extreme case that all of the particles are massless, then consider how the masses of non-standard model particles will affect the discovery limit