A Measurement of the Tau Topological Branching Ratios

TL;DR

This paper reports precise measurements of tau lepton decay modes involving different numbers of charged particles, providing detailed branching ratios crucial for understanding tau decay dynamics.

Contribution

It presents new, highly accurate measurements of tau decay branching ratios for modes with one, three, or five charged particles using LEP-1 data.

Findings

Branching ratio for one-prong decays: 85.316%

Branching ratio for three-prong decays: 14.569%

Branching ratio for five-prong decays: 0.115%

Abstract

Using data collected in the DELPHI detector at LEP-1, measurements of the inclusive tau branching ratios for decay modes containing one, three, or five charged particles have been performed, giving the following results: B_1 = B(\tau^- -> (particle)^- \geq 0pi^0 \geq 0K^0 \nu_\tau(\bar{\nu})) = (85.316 +/- 0.093 +/- 0.049)%; B_3 = B(\tau^- -> 2h^-h^+ \geq 0pi^0 \geq 0K^0 \nu_\tau) = (14.569 +/- 0.093 +/- 0.048)%; B_5 = B(\tau^- -> 3h^-2h^+ \geq 0pi^0 \geq 0K^0 \nu_\tau) = (0.115 +/- 0.013 +/- 0.006)%, where h is either a charged pi or K meson. The first quoted uncertainties are statistical and the second systematic.