Measurement of the Topological Branching Fractions of the tau lepton at LEP

TL;DR

This paper reports precise measurements of tau lepton decay branching fractions into different charged particle multiplicities using LEP data, providing results comparable to the world average.

Contribution

First precise measurement of tau decay branching fractions into 1, 3, and 5 prongs using LEP data from 1992-1995.

Findings

Branching fraction for 1-prong decay: 85.274%

Branching fraction for 3-prong decay: 14.556%

Branching fraction for 5-prong decay: 0.170%

Abstract

Using data collected with the L3 detector at LEP from 1992 to 1995 on the Z peak, we determine the branching fractions of the tau lepton into one, three and five charged particles to be: B(tau->(1-prong)) = 85.274 +- 0.105 +- 0.073 %, B(tau->(3-prong)) = 14.556 +- 0.105 +- 0.076 %, B(tau->(5-prong)) = 0.170 +- 0.022 +- 0.026 %. The first uncertainties are statistical and the second systematic. The accuracy of these measurements alone is similar to that of the current world average.