Study of the five-charged-pion decay of the τ lepton

The branching fractions for the five-charged-particle decays of the [tau] lepton have been measured in [ital e][sup +][ital e][sup [minus]] annihilations using the CLEO II detector at the Cornell Electron Storage Ring. Assuming all charged particles to be pions, the results are [ital B](3[pi][sup [minus]]2[pi][sup +][ge]0 neutrals [nu][sub [tau]])=(0.097[plus minus]0.005[plus minus]0.011)%, [ital B](3[pi][sup [minus]]2[pi][sup +][nu][sub [tau]])=(0.077[plus minus]0.005 [plus minus]0.009)%, [ital B](3[pi][sup [minus]]2[pi][sup +][pi][sup 0][nu][sub [tau]])=(0.019[plus minus]0.004[plus minus]0.004)%, and [ital B](3[pi][sup [minus]]2[pi][sup +]2[pi][sup 0][nu][sub [tau]])[lt]0.011% at the 90% C.L. [ital B](3[pi][sup [minus]]2[pi][sup [minus]][pi][sup 0][nu][sub [tau]]) is measured for the first time by exclusive [pi][sup 0] reconstruction. The results are compared with the predictions from the partially conserved-axial-current and conserved-vector-current hypotheses assuming isospin invariance.