New precise determination of the τ lepton mass at KEDR detector ⁎

The status of the experiment on the precise τ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the τ+τ− cross section behaviour around the production threshold. The preliminary result based on 6.7 pb−1 of data is . Using 0.8 pb−1 of data collected at the ψ′ peak the preliminary result is also obtained: Γee⋅Bττ(ψ′)=7.2±2.1 eV.