Miyazaki, Y (reprint author), Nagoya Univ, Nagoya, Aichi 4648601, Japan.
We search for lepton flavor and lepton number violating tau decays into a lepton (l = electron or muon) and two charged mesons (h, h' = pi(+/-) or K(+/-)), tau(-) -> l(-)h(+)h'(-) and tau- -> l(+)h(-)h'(-), using 671 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We obtain 90% C.L. upper limits on the branching fractions in the range (4.4-8.8) x 10(-8) for tau -> ehh', and (3.3-16) x 10(-8) for tau -> mu hh' processes. These results improve upon previously published upper limits by factors between 1.6 to 8.8. (C) 2009 Elsevier B.V. All rights reserved.