Contributor info: Dr Jianyong Zhang

Jianyong Zhang on behalf of BESIII collaboration

SciPost Phys. Proc. 1, 004 (2019) · published 18 February 2019 | Toggle abstract · pdf

In order to obtain the mass of $\tau$ lepton at BESIII precisely, a beam energy measurement system was built at BEPCII. A scenario for high precision $\tau$ mass measurement was put forth before data taken. More than 130 $pb^{-1}$ $\tau$ mass scan data were collected in April 2018, and the uncertainty of $m_{\tau}$ is expected to be less than 100 keV.