Observation of τ -Lepton Decay to Five Charged Particles

This is the authors' abstract. We don't add key points for this paper.

The production of τ-lepton pairs in e⁺e^- collisions at 29 GeV has been used to study the inclusive τ decay into five charged particles. Ten events are observed in the high-resolution spectrometer giving a branching ratio of $B({τ}{→}5{{π}}^{±{}}+n{γ}+{{ν}}_{{τ}})=(1.3±{}0.4)×{}{10}^{{-}3}$. Five of the events contain photons which are consistent with coming from a single ${{π}}⁰$. With this interpretation we measure $B({τ}{→}5{{π}}^{±{}}+{{ν}}_{{τ}})$, $B({τ}{→}5{{π}}^{±{}}+{{π}}⁰+{{ν}}_{{τ}})=(6.7±{}3.0)×{}{10}^{{-}4}$. The branching-ratio upper limit for the decay mode ${τ}{→}{K}⁰+3{{π}}^{±{}}+n{γ}+{{ν}}_{{τ}}is found, at 90% confidence level, to be 2.7×{10}^{{-}3}$.