We measure the total branching fraction of the flavor-changing neutral-current process B→Xℓ+ℓ-, along with partial branching fractions in bins of dilepton and hadronic system (Xs) mass, using a sample of 471×106 (4S)→BB̄ events recorded with the BABAR detector. The admixture of charged and neutral B mesons produced at PEP-II2 are reconstructed by combining a dilepton pair with 10 different Xs final states. Extrapolating from a sum over these exclusive modes, we measure a lepton-flavor-averaged inclusive branching fraction B(B→Xℓ+ℓ-)=[6.73-0.64+0.70(stat)-0. 25+0.34(exp syst)±0.50(model syst)]×10-6 for mℓ+ℓ-2>0. 1GeV2/c4. Restricting our analysis exclusively to final states from which a decaying B meson's flavor can be inferred, we additionally report measurements of the direct CP asymmetry ACP in bins of dilepton mass; over the full dilepton mass range, we find ACP=0.04±0.11±0.01 for a lepton-flavor- averaged sample.
Lees, J., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., et al. (2014). Measurement of the B → Xℓ+ℓ- Branching fraction and search for direct CP violation from a sum of exclusive final states. PHYSICAL REVIEW LETTERS, 112(21), 1-8 [10.1103/PhysRevLett.112.211802].
Measurement of the B → Xℓ+ℓ- Branching fraction and search for direct CP violation from a sum of exclusive final states
CARPINELLI, MassimoMembro del Collaboration Group
;
2014
Abstract
We measure the total branching fraction of the flavor-changing neutral-current process B→Xℓ+ℓ-, along with partial branching fractions in bins of dilepton and hadronic system (Xs) mass, using a sample of 471×106 (4S)→BB̄ events recorded with the BABAR detector. The admixture of charged and neutral B mesons produced at PEP-II2 are reconstructed by combining a dilepton pair with 10 different Xs final states. Extrapolating from a sum over these exclusive modes, we measure a lepton-flavor-averaged inclusive branching fraction B(B→Xℓ+ℓ-)=[6.73-0.64+0.70(stat)-0. 25+0.34(exp syst)±0.50(model syst)]×10-6 for mℓ+ℓ-2>0. 1GeV2/c4. Restricting our analysis exclusively to final states from which a decaying B meson's flavor can be inferred, we additionally report measurements of the direct CP asymmetry ACP in bins of dilepton mass; over the full dilepton mass range, we find ACP=0.04±0.11±0.01 for a lepton-flavor- averaged sample.
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