Search for Rare b →dℓ ℓ- Transitions at Belle

Abstract

We present the results of a search for the b→dℓ+ ℓ- flavor-changing neutral-current rare decays B+,0→(η,ω,π+,0,ρ+,0)e+e- and B+,0→(η,ω,π0,ρ+)μ+μ- using a 711 fb-1 data sample that contains 772×106 BB¯ events. The data were collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find no evidence for signal and set upper limits on branching fractions at the 90% confidence level in the range (3.8-47)×10-8 depending on the decay channel. The obtained limits are the world's best results. This is the first search for the channels B+,0→(ω,ρ+,0)e+e- and B+,0→(ω,ρ+)μ+μ-.