Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Physics and Astronomy

First Advisor

William Metcalf


The reaction e$\sp+$e$\sp-$ $\to$ $\mu\sp+\mu\sp-$ has been observed by the AMY Detector at 52 GeV $\leq$ $\sqrt{s}$ $\leq$ 57 GeV at the TRISTAN storage ring in Tsukuba, Japan. With an integrated luminosity of 18.6 pb$\sp{-1}$, this presents a new test of the standard model of the electroweak interactions in this previously unexplored energy region. The forward-backward charge asymmetry and the cross-section calculated at the various energies show agreement with the standard model predictions. The products of the vector and the axial-vector coupling constants of the electron and muon extracted from these measurements are also consistent with theory. The data were combined at the average energy of $\sqrt{s}$ = 55.2 GeV. The measured asymmetry and cross-section are $-$34.4 $\pm$ 7.7% and 29.7 $\pm$ 2.1 pb respectively. This is in agreement with the standard model prediction of $-$28.3% for the asymmetry and 29.5 pb for the cross-section. The product of the axial couplings, $g\sbsp{A}{e}g\sbsp{A}{\mu}$ = 0.29 $\pm$ 0.07, and the product of the vector couplings, $g\sbsp{V}{e}g\sbsp{V}{\mu}$ = 0.01 $\pm$ 0.06, agree with the standard model predictions of 0.25 and.002 for these respective constants.