We discuss the scale and effects of a new neutral gauge boson, Z', in our recently derived superstring standard-like model, which is a combination of B - L and T3R and provides a mechanism to suppress proton decay. We show that the mass and mixing angle of the Z' with the standard model Z depend only on MZ and MW. For the central values of MZ and MW from recent experiments, MZ'~1000 GeV . We discuss the effect of Z-Z' mixing on the width of the Z and investigate the effect on primordial nucleosynthesis calculations, from which we find that the existence of light right-handed neutrinos with a Z' is excluded unless MZ'≥1.5 TeV .

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We present an exact description of the metric on the moduli space of vacua and the spectrum of massive states for four dimensional N = 2 supersymmetric SU(n) gauge theories. The moduli space of quantum vacua is identified with the moduli space of a special set of genus n -1 hyperelliptic Riemann surfaces.

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