Measurement of exclusive branching fractions of hadronic one-prong tau decays

Abstract

We have measured the branching fractions for the hadronic τ decays, τ→π/Knπ°v (0 ≤ n ≤ 3), with the L3 detector at LEP. Multiphoton final states are analyzed using the fine-grained, high-resolution electromagnetic calorimeter. The decay channels are identified using a neural network method. The results are: BR(τ→π/Kv) = (11.82 ± 0.26 ± 0.43)%, BR (τ→π/Kπ°v) = (25.05 ± 0.35 ± 0.50)%, BR(τ→π/ K2π°v) = (8.88 ± 0.37 ± 0.42)%, BR(τ→π/K3π°v) = (1.70 ± 0.24 ± 0.38)%, where the first error quoted is statistical, the second systematic.