Study of high-multiplicity three-prong and five-prong τ decays at BABAR

Abstract

We present measurements of the branching fractions of three-prong and five-prong τ decay modes using a sample of 430million τ lepton pairs, corresponding to an integrated luminosity of 468fb -1, collected with the BABAR detector at the PEP-II asymmetric-energy e +e - storage rings at SLAC National Accelerator Laboratory. The τ -→(3π) -ην τ, τ -→(3π) -ων τ, and τ -→π -f 1(1285)ν τ branching fractions are presented, as well as a new limit on the branching fraction of the second-class current decay τ -→π -η ′(958)ν τ. We search for the decay mode τ -→K -η ′(958) ν τ and for five-prong decay modes with kaons, and place the first upper limits on their branching fractions. © 2012 American Physical Society.