Journal article

Measurement of the τ lepton mass and an upper limit on the mass difference between τ+ and τ-

Belous, K.; Shapkin, M.; Sokolov, A.; Abe, K.; Abe, K.; Adachi, I.; Aihara, H.; Anipko, D.; Arinstein, K.; Aulchenko, V.

The mass of the τ lepton has been measured in the decay mode τ→3πντ using a pseudomass technique. The result obtained from 414fb-1 of data collected with the Belle detector is Mτ=[1776.61±0. 13(stat)±0.35(sys)]MeV/c2. The upper limit on the relative mass difference between positive and negative τ leptons is |Mτ+-Mτ-|/ Mτ<2.8×10-4 at 90% confidence level. © 2007 The American Physical Society.


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