Measurement of the branching fractions of the decays τ ?→ K ? nπ 0ν _τ ( n = 0, 1, 2, 3) and τ ?→ π ? nπ 0ντ ( n = 3, 4) by BABAR

摘要

We report preliminary measurements of the branching fractions of the decays τ~(?)→ K ~(?) n π~(0)ν_(τ)( n = 0, 1, 2, 3) and τ~(?)→ π~(?) n π~(0)ντ ( n = 3, 4) , excluding the contributions that proceed through the decay of intermediate K ~(0)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(4 S ) 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 ~(?)π~(0)ν_(τ)) = (5.054± 0.021 ± 0.148) × 10~(?3), B (τ~(?)→ K ~(?)2π~(0)ν_(τ)) = (6.151 ± 0.117 ± 0.338) × 10~(?4), B (τ~(?)→ K ~(?)3π~(0)ν_(τ)) = (1.246 ± 0.164 ± 0.238) × 10~(?4), B (τ~(?)→ π~(?)3π~(0)ν_(τ)) = (1.168 ±0.006 ±0.038) ×10~(?2), B (τ~(?)→ π~(?)4π~(0)ν_(τ)) = (9.020 ±0.400 ±0.652) × 10~(?4) , where the ?rst uncertainty is statistical and the second one systematic.