PS02 Rare Decays
Evidence for K→ K *ℓ+ℓ– and measurement of B→ Kℓ+ℓ–
California Institute of Technology, Pasadena CA 91125,
Accepted: 11 December 2003
Published online: 12 December 2003
We present evidence for the flavor-changing neutral current decay B→ K *ℓ+ℓ– and a measurement of the B→ Kℓ+ℓ– branching fraction, where ℓ+ℓ– is either an e + e – or μ + μ – pair. The data sample analyzed comprises 88.5× 106 decays collected with the BABAR detector at the PEP-II e + e – storage ring. Averaging over K (*) isospin and lepton flavor, we obtain and , where the uncertainties are statistical and systematic. The significance for the B→ K *ℓ+ℓ– signal is 3.0σ and for B→ Kℓ+ℓ– the signal significance is over 7σ.
PACS: 13.25.Hw – 13.20.He
© Società Italiana di Fisica, Springer-Verlag, 2004