Measurement of the spectral function for the τ–→K–KSντ decay

The decay τ^− → K^−K_Sν_τ has been studied using 430×10^6 e^+e^− → τ^+τ^− events produced at a center-of-mass energy around 10.6 GeV at the PEP-II collider and studied with the BABAR detector. The mass spectrum of the K^−K_S system has been measured and the spectral function has been obtained. The measured branching fraction B(τ^− → K^−K_Sν_τ) = (0.739 ± 0.011(stat) ± 0.020(syst)) × 10^(-3) is found to be in agreement with earlier measurements.