Aubert, B (reprint author), Lab Annecy Le Vieux Phys Particules, F-74941 Annecy Le Vieux, France.
A search for the decay of the tau lepton to seven charged pions and one or zero pi(0) mesons was performed using the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider. The analysis uses 232.2 fb(-1) of data at center-of-mass energies on or near the Upsilon(4S) resonance. We observe 24 events with an expected background of 21.6 +/- 1.3 events. Without evidence for a signal, we calculate an upper limit of B(tau(-)-> 4 pi(-)3 pi(+)(pi(0))nu(tau))< 3.0 x 10(-7) at 90% confidence level. This is an improvement by nearly an order of magnitude over the previously established limit. In addition, we set upper limits for the exclusive decays tau(-)-> 4 pi(-)3 pi(+)nu(tau) and tau(-)-> 4 pi(-)3 pi(+)pi(0)nu(tau).