Search for the decay B+→τ+ντ

Abstract

We search for the rare leptonic decay B+→τ+ντ in a sample of 232×106 BB̄ pairs collected with the BABAR detector at the SLAC PEP-II B-Factory. Signal events are selected by examining the properties of the B meson recoiling against the semileptonic decay B-→D*0-ν̄. We find no evidence for a signal and set an upper limit on the branching fraction of B(B+→τ+ντ)<2.8×10-4 at the 90% confidence level. We combine this result with a previous, statistically independent BABAR search for B+→τ+ντ to give an upper limit of B(B+→τ+ντ)<2.6×10-4 at the 90% confidence level. © 2006 The American Physical Society.