[en] This dissertation describes a portion of the results from experiment SP19 conducted by the Maryland-Pavia-Princeton (MP²) collaboration at the e⁺e^- storage ring SPEAR II at the Stanford Linear Accelerator Center. The inclusive measurements described were obtained in the 6 and 7 GeV center-of-mass energy regions using a small solid angle (ΔΩ/sub MAX/ = 0.085 sr) magnetic spectrometer situated at 90⁰ +- 13⁰ with respect to the beams. The spectrometer and a conjugate detector opposite the spectrometer were used to measure back-to-back Bhabhas and muons, and the latter were used to normalize results. The inclusive muon signal at <√3> = 7.3 GeV with observed multiplicity n/sub CH/ = 2, acoplanarity par. delta/sub A/ > 20⁰ and momentum p > 1.15 GeV/c is found to be in excess of QED and expected backgrounds. The background subtracted inclusive cross section is 10.1 +- 5.4 pb/sr. Both the momentum spectrum and the muon branching ratio of b/sub mu/ = 0.17 +- 0.09 are found to be consistent with the tau. An excess of events above expected backgrounds is also observed in those muons with n/sub CH/ > 2 and p > 1.15 GeV/c. The inclusive background subtracted cross section at <√3> = 7.3 GeV of 19.0 +- 6.3 pb/sr cannot be explained by the tau and may indicate the weak decays of charmed mesons. 5 references