Measurement of the mass of the $\ddot{I}„$-lepton and an upper limit on the mass difference between $\ddot{I}{„}^{+}$ and $\ddot{I}{„}^{-}$

Abstract

The mass of the $\ddot{I}„$-lepton has been measured in the decay modes $\ddot{I}„\to 3\ddot{I}€\hat{I}{½}_{\ddot{I}}„$ and $\ddot{I}„\to 3\ddot{I}€\ddot{I}{€}^0\hat{I}{½}_{\ddot{I}}„$ using a pseudomass technique. The preliminary result is $1776.71\pm 0.25(stat)\pm 0.62(syst)$ MeV. The preliminary value of an upper limit on the relative mass difference between positive and negative $\ddot{I}„$ leptons is $|(M_{\ddot{I}{„}^{+}}-M_{\ddot{I}{„}^{-}})|/M_{\mathrm{average}}$ is $5.0\times 10^{-4}$ at 90% CL.

13 pages, 8 figures, contributed to Lepton Photon and EPS 2005