Latest Belle results on Tau decays

We present preliminary results of a latest measurement at Belle, the branching fraction of rare tau decay, \tau^- \rightarrow \pi^- \nu_{\tau} \ell^+ \ell^-τ−→π−ντℓ+ℓ− (\ell = eℓ=e or \muμ), using a 562 \rm fb^{-1} data set. The branching fraction of \tau^- \rightarrow \pi^- e^+ e^- \nu_\tauτ−→π−e+e−ντ is measured to be \mathbf{ \mathcal{B}(\tau^-\rightarrow \pi^- e^+ e^- \nu_\tau) = (2.11 \pm 0.19 \pm 0.30) \times 10^{-5}}ℬ(𝛕−→𝛑−𝐞+𝐞−𝛎𝛕)=(2.11±0.19±0.30)×10−5, where the first uncertainty is statistical and the second is systematic. An upper limit is set on the branching fraction of \tau^- \rightarrow \pi^- \mu^+ \mu^- \nu_\tauτ−→π−μ+μ−ντ, \mathbf{\mathcal{B}(\tau^-\rightarrow \pi^- \mu^+ \mu^- \nu_\tau) < 1.06 \times 10^{-5}}ℬ(𝛕−→𝛑−𝛍+𝛍−𝛎𝛕)<1.06×10−5, at 90% confidence level.