Study of τ−→KSπ−ντ decay with Belle

We present a study of τ−→KSπ−ντ decay using a data sample corresponding to the integrated luminosity of ≃351fb−1 collected by the Belle detector. Analysis is based on 55017 lepton tagged signal events. The measured branching ratio Br(τ→KSπντ)=(0.391±0.004stat±0.014syst)% is consistent with the PDG value and has much better accuracy. The invariant mass spectrum of KSπ was analyzed. This spectrum is not saturated with the K⋆(892) contribution only, so that other mechanisms are considered.