Measurement of the branching fractions of the decays τ−→ K−nπ0ντ (n = 0, 1, 2, 3) and τ−→ π−nπ0ντ (n = 3, 4) by BABAR

Abstract

We report preliminary measurements of the branching fractions of the decays τ−→ K−nπ0 ντ (n = 0, 1, 2, 3) and τ−→ π−nπ0ντ (n = 3, 4), excluding the contributions that proceed through the decay of intermediate K0 and η mesons. The measurements are based on a data sample of 435 million τ pairs produced in e+e− collisions at and near the γ(4S) peak and collected with the BABAR detector in 1999–2008. The measured branching fractions are B(τ−→ K− ντ) = (7.174±0.033±0.213)×10−3, B(τ−→ K−π0ντ) = (5.054± 0.021 ± 0.148) × 10−3, B(τ−→ K−2π0ντ) = (6.151 ± 0.117 ± 0.338) × 10−4, B(τ−→ K−3π0ντ) = (1.246 ± 0.164 ± 0.238) × 10−4, B(τ−→ π−3π0ντ) = (1.168 ±0.006 ±0.038) ×10−2, B(τ−→ π−4π0ντ) = (9.020 ±0.400 ±0.652) × 10−4, where the ?rst uncertainty is statistical and the second one systematic.