Discussion on upper limit of the precision for τ mass measurement

Abstract

τ lepton is one of three chareged leptons in nature, the measurements of its mass have been performed since its discovery. The present relative accuracy is already at the level of 10 −4 ; more factors are still being studied in order to increase the accuracy. However, the available techniques for analysis and expectable luminosity from e + e − collider indicate that the precision upper limit of τ mass is almost reached, which means that brand new approaches should be looked for if the great improvement is yearned for.

Future Physics Programme of BESIII *

“…Prior to conducting the experiment, a study was carried out using MC simulation and sampling to find the scheme that provides the highest precision of for a specified period of data taking, or equivalently for a giv-en integrated luminosity. The main conclusions of the optimization study can be summarized as follows [193][194][195][196][197]:…”