A study of three-prong tau decays with charged kaons

Abstract

From an analysis of the ionisation energy loss of charged particles selected from a sample of 147926 e+e-→τ+τ- candidates recorded in the OPAL detector at e+e- centre-of-mass energies near the Z° resonance, we determine the branching ratios: Br(τ- → ντ K-π-π+(π0)) = 0.343 ± 0.073 ± 0.031 % Br(τ- → ντK-π-K+(π 0)) = 0.159 ± 0.053 ± 0.020 %, where the (π0) notation refers to decay modes with or without an accompanying π0. The τ- → ντK-π-π+(π 0) final states occurring through τ- → ντK-KS0(π0) are treated as background in this analysis. We also examine the resonant structure of τ- → ντK-π-π+ candidates. Under the assumption that the resonant structure is dominated by the K1 resonances, we determi..