Measurement of the Differential Branching Fraction and Forward-Backward Asymmetry for B->K{sup (*)}l{sup +}l{sup -}

Journal Article · Fri Oct 23 04:00:00 EDT 2009 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.103.171801· OSTI ID:21370777

Wei, J -T; Chang, P; Chang, Y -W; Chao, Y; Chen, K -F; Chiang, C -C; Hou, W -S; Shiu, J -G; Wang, C C; Wang, M -Z ^[1]; Adachi, I; Dalseno, J; Hazumi, M; Itoh, R; Iwasaki, Y; Katayama, N; Kichimi, H; Krokovny, P; Nakao, M; Nishida, S ^[2]

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1. Department of Physics, National Taiwan University, Taipei (China)
2. High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)

We study B->K{sup (*)}l{sup +}l{sup -} decays (l=e, mu) based on a data sample of 657x10{sup 6} BB pairs collected with the Belle detector at the KEKB e{sup +}e{sup -} collider. We report the differential branching fraction, isospin asymmetry, K* polarization, and the forward-backward asymmetry (A{sub FB}) as functions of q{sup 2}=M{sub ll}{sup 2}c{sup 2}. The fitted A{sub FB} spectrum exceeds the standard model expectation by 2.7 standard deviations. The measured branching fractions are B(B->K*l{sup +}l{sup -})=(10.7{sub -1.0}{sup +1.1}+-0.9)x10{sup -7} and B(B->Kl{sup +}l{sup -})=(4.8{sub -0.4}{sup +0.5}+-0.3)x10{sup -7}, where the first errors are statistical and the second are systematic, with the muon to electron ratios R{sub K*}=0.83+-0.17+-0.08 and R{sub K}=1.03+-0.19+-0.06.

• OSTI ID: 21370777
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 17 Vol. 103; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
ASYMMETRY
B MESONS
BEAUTY MESONS
BEAUTY PARTICLES
BOSONS
BRANCHING RATIO
DECAY
DIMENSIONLESS NUMBERS
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
FIELD THEORIES
GRAND UNIFIED THEORY
HADRONS
INTERACTIONS
ISOSPIN
KAONS
LEPTONS
MATHEMATICAL MODELS
MATTER
MESONS
MUONS
PAIR PRODUCTION
PARTICLE DECAY
PARTICLE MODELS
PARTICLE PRODUCTION
PARTICLE PROPERTIES
POLARIZATION
POSITRONS
PSEUDOSCALAR MESONS
QUANTUM FIELD THEORY
STANDARD MODEL
STRANGE MESONS
STRANGE PARTICLES
UNIFIED GAUGE MODELS