Evidence for the Rare Decay B {yields} K*{ell}{sup +}{ell}{sup -} land Measurement of the B {yields} K{ell}{sup +}{ell}{sup -} Branching Fraction
We present evidence for the flavor-changing neutral current decay B {yields} K*{ell}{sup +}{ell}{sup -} and a measurement of the branching fraction for the related process B {yields} K{ell}{sup +}{ell}{sup -}, where {ell}{sup +}{ell}{sup -} is either an e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -} pair. These decays are highly suppressed in the Standard Model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} storage ring. Averaging over K* isospin and lepton flavor, we obtain the branching fractions {Beta}(B {yields} K{ell}{sup +}{ell}{sup -}) = (0.65{sub -0.13}{sup +0.14} {+-} 0.04) x 10{sup -6} {Beta}(B {yields} K*{ell}{sup +}{ell}{sup -}) = (0.88{sub -0.29}{sup +0.33} {+-} 0.10) x 10{sup -6}, where the uncertainties are statistical and systematic, respectively. The significance of the B {yields} K{ell}{sup +}{ell}{sup -} signal is over 8{sigma}, while for B {yields} K*{ell}{sup +}{ell}{sup -} it is 3.3{sigma}.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (US)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 815274
- Report Number(s):
- SLAC-PUB-10132; TRN: US0304570
- Resource Relation:
- Other Information: PBD: 18 Aug 2003
- Country of Publication:
- United States
- Language:
- English
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