Search for the Lepton-Flavor-Violating Leptonic B Decays B^0 -> μ^\pm τ^\mp and B^0 -> μ^\pm τ^\mp

Abstract

We have searched a sample of 9.6 million BBbar events for the lepton-flavor-violating leptonic B decays, B^0 -> μ^\pm τ^\mp and B^0 -> e^\pm τ^\mp. The τ-lepton was detected through the decay modes τ-> \ellν\barν, where \ell = e, μ. There is no indication of a signal, and we obtain the 90% confidence level upper limits [Br(B^0 -> μ^\pm τ^\mp)] < 3.8 X 10^-5 and [Br(B^0 -> e^\pm τ^\mp)] < 1.1 X 10^-4.

7 pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2004/, Submitted to PRL