TITLE: Astrophysical Limits on Additional U(1) Gauge Couplings

SPEAKER: Jack W. Brockway,

In the standard model the difference between muon and tau lepton numbers (N_m-N_t) is conserved. It may be that an unbroken U(1) symmetry and its associated gauge boson gN is coupled to this quantum number. If that were to be the case, there may be observable effects. In particular, a mixing with photons would be an inevitable consequence. Such a mixing would allow us to search for direct evidence of the gN. In the absence of such evidence, we can limit the strength of the coupling. Consequences of the mixing are investigated in the cases of relative lifetimes of red giant phases in stellar evolution, distortion of the Cosmic Microwave Background radiation, and primordial nucleosynthesis. Improvements are made over existing limits on the coupling.