Search for τ-lepton decays to seven or more pions with BABAR

We report the results of searches for several decay modes of the τ-lepton with ≥7 pions in the final state using 207x106τ-pairs collected with the BABAR detector. For the decays with 7 charged pions in the final state we find the following 90% CL upper limits: B(τ-→4π-3π+(π0)ντ)<3.0x10-7, B(τ-→4π-3π+ντ)<4.3x10-7, and B(τ-→4π-3π+π0ντ)<2.5x10-7. We also search for the decay τ-→3π-2π+2π0ντ and report a 90% CL upper limit of <3.4x10-6 for its branching fraction. Finally, we search for the exclusive final state τ-→2ωπ-ντ and find a 90% CL upper limit for its branching fraction of <5.4x10-7