Measurement of the branching fractions of the decays τ⁻→ K⁻nπ⁰ν_τ (n = 0, 1, 2, 3) and τ⁻→ π⁻nπ⁰ντ (n = 3, 4) by BABAR

¹ Scuola Normale Superiore, Pisa, Italy
² INFN sezione di Pisa, Pisa, Italy

^* e-mail: alberto.lusiani@pi.infn.it

Published online: 17 June 2019

Abstract

We report preliminary measurements of the branching fractions of the decays τ⁻→ K⁻nπ⁰ ν_τ (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⁻ ν_τ) = (7.174±0.033±0.213)×10⁻³, B(τ⁻→ K⁻π⁰ν_τ) = (5.054± 0.021 ± 0.148) × 10⁻³, B(τ⁻→ K⁻2π⁰ν_τ) = (6.151 ± 0.117 ± 0.338) × 10⁻⁴, B(τ⁻→ K⁻3π⁰ν_τ) = (1.246 ± 0.164 ± 0.238) × 10⁻⁴, B(τ⁻→ π⁻3π⁰ν_τ) = (1.168 ±0.006 ±0.038) ×10⁻², B(τ⁻→ π⁻4π⁰ν_τ) = (9.020 ±0.400 ±0.652) × 10⁻⁴, where the ?rst uncertainty is statistical and the second one systematic.