Abstract :
I discuss supersymmetric extensions of the Standard Model containing an extra U(1)′ gauge symmetry which provide a solution to the μ -problem and at the same time protect the proton from decaying via dimension 4 operators. Moreover, all fields are protected by chirality and supersymmetry from acquiring high scale masses. The additional requirements of anomaly cancellation and gauge coupling unification imply the existence of extra matter multiplets and that several fields participate in U(1)′ symmetry breaking simultaneously. While there are several studies addressing subsets of these requirements, this work uncovers simultaneous solutions to all of them. It is surprising and encouraging that extending the Minimal Supersymmetric Standard Model by a simple U(1) factor solves its major drawbacks with respect to the non-supersymmetric Standard Model, especially as current precision data seem to offer a hint to the existence of its corresponding Z′ boson. It is also remarkable that there are many solutions where the U(1)′ charges of the known quarks and leptons are predicted to be identical to those E6 motivated Z′ bosons which give the best fit to the data. I discuss the solutions to these constraints including some phenomenological implications.
