Limit onτdecay to seven charged particles

Abstract

A data sample corresponding to a luminosity of 300 ${\mathrm{pb}}^{\mathrm{-}1}$ from $e^{+}$ $e^{\mathrm{-}}$ collisions at 29 GeV, obtained using the High Resolution Spectrometer at the SLAC $e^{+}$ $e^{\mathrm{-}}$ storage ring PEP, was used to search for τ decay to seven charged particles. No candidates were found and the corresponding upper limit for the branching ratio is B(τ→7${\mathrm{\pi }}^{\pm }$+${\nu }_{\mathrm{\tau }}$+nγ)〈1.9×${10}^{\mathrm{-}4}$〉 at 90% confidence level (n≥0). This data sample was also used to obtain the branching ratios of B(τ→5${\mathrm{\pi }}^{\pm }$+${\nu }_{\mathrm{\tau }}$)=(5.1±2.0)×${10}^{\mathrm{-}4}$ and B(τ→5${\pi }^{\pm }$+${\pi }^0$ ${\nu }_{\tau }$)=(5.1 ±2.2)×${10}^{\mathrm{-}4}$. .AE