Precision Measurements of Tau Lepton Decays Using Inclusive Spectra.

The tau lepton decays to final states with one, three, or five charged particles. Measurements of the branching fractions of the exclusive single charged particle decay modes do not agree with measurements of the inclusive one prong branching fraction. The sum of the exclusive modes differs from the inclusive mode by 6.4 +/- 2.1%. A satisfactory resolution of the one prong deficit has not yet been obtained. In this analysis, a new method is used to determine these decay rates. A sample of tau events is obtained using the Mark II detector at the PEP storage ring. Charged topology of these decays are determined. The inclusive one and three prong branching fractions are measured to be 86.5 +/- 0.2% and 13.4 +/- 0.2% respectively, in agreement with previous measurements. One prong tau decays are selected from the tau sample. Various inclusive spectra are measured. The best simultaneous fit to several inclusive spectra, using a combination of exclusive tau decay spectra, determines the relative contribution of each decay mode. The sum is constrained to equal the total one prong rate. The results of this analysis indicate that B( tau^{-} to nu _{tau}| {nu} _{e}e^{-}) = 19.2 +/- 0.2_sp{-0.9 }{+0.7}% and B(tau ^{-} to nu_ {tau}a_sp{1}{-} to nu_{tau} pi^{-}pi^0pi^0) = 9.1 +/- 1.2_sp {-0.8}{+1.1}%. Both of these rates are 4.0 standard deviations above the present world averages. Some of the other branching ratios are less significantly higher than the world averages.