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

Abstract

The mass of the $\tau$ lepton has been measured in the decay mode $\tau \to 3\pi {\nu }_{\tau }$ using a pseudomass technique. The result obtained from $414{\mathrm{fb}}^{-1}$ of data collected with the Belle detector is $M_{\tau }=(1776.61\pm 0.13(stat.)\pm 0.35(sys.))$ MeV/$c^2$. The upper limit on the relative mass difference between positive and negative $\tau$ leptons is $|M_{{\tau }^{+}}-M_{{\tau }^{-}}|/M_{\tau }<2.8\times 10^{-4}$ at 90% confidence level.

9 pages, 3 figures. Submitted to Phys. Rev. Lett

Cited by in corpus (1)

• Tau Physics: Theory Overview