Tau Lepton Mass Measurements

We present the preliminary results from the precision measurement of the mass of the tau lepton using 423 fb−1 of data collected at BaBar. Using a pseudomass endpoint method, we determine the mass to be 1776.68±0.12 (stat)±0.41 (syst) MeV. We also measure the mass difference between the τ+ and τ−, and obtain . This results in a limit of at 90% CL.