New measurement of the branching fractions of τ− → h− h− h+ ντ and τ− → h− h− h+ π0 ντ

Abstract

Abstract A new measurement of BR(τ− → h− h− h+ ντ) and BR(τ− → h− h− h + π0 ντ) was performed using the detector ARGUS at the e+ e− storage ring DORIS II. Strong emphasis is put on systematic effects due to different event topologies. BR(τ− → h− h− h + ντ) amounts to (7.8 ± 0.6)% compared to (7.2 ± 0.51)% of our old measurement (Albrecht et al., 1993). BR(τ− → h− h− h + π0 ντ) yields (5.2 ± 0.7)% compared to (4.2 ± 1.0)% of our measurement published in 1987 (Albrecht et al., 1987). These results are preliminary.