One-prong τ decays with neutral kaons

Abstract We have analyzed one-prong τ decays with neutral kaons using the information from a fine-grained hadron calorimeter. The data sample consists of 43 500 Z → τ + τ − ( γ ) events collected by the L3 detector at LEP in 1991, 1992 and 1993. The following branching fractionsare measured: B(τ − → ν τ π − K 0 ) = 0.0095 ± 0.0015 ( stat) ± 0.0006(syst) ; B(τ − → ν τ π − π 0 K 0 ) = 0.0041 ± 0.0012( stat) ± 0.0003(syst) and B(τ − → ν τ π − K 0 K 0 ) = 0.0031 ± 0.0012( stat) ± 0.0004(syst) .