Search for the rare decay B→πl+l-

Abstract

We have performed a search for the flavor-changing neutral-current decays B→π + -, where + - is either e+e- or μ+μ-, using a sample of 230×106 Υ(4S)→BB̄ decays collected with the BABAR detector. We observe no evidence of a signal and measure the upper limit on the isospin-averaged branching fraction to be B(B→π + -)<9.1×10-8 at 90 confidence level. We also search for the lepton-flavor-violating decays B→πe±μ and measure an upper limit on the isospin-averaged branching fraction of B(B→πe±μ )<9.2×10-8 at 90 confidence level. © 2007 The American Physical Society.