We measure the total branching fraction of the flavor-changing neutral-current process B → Xslþl−, along with partial branching fractions in bins of dilepton and hadronic system (Xs) mass, using a sample of 471 × 106 ϒð4SÞ → BB¯ 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 BðB → Xslþl−Þ ¼ ½6.73 þ0.70 −0.64 ðstatÞþ0.34 −0.25 ðexp systÞ 0.50ðmodel systÞ × 10−6 for m2 lþl− > 0.1 GeV2=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 ¼ 0.04 0.11 0.01 for a leptonflavor- averaged sample.
Measurement of the B->X(s)l(+)l(-) Branching Fraction and Search for Direct Violation from a Sum of Exclusive Final States
BIANCHI, Fabrizio;DE MORI, FRANCESCA;
2014-01-01
Abstract
We measure the total branching fraction of the flavor-changing neutral-current process B → Xslþl−, along with partial branching fractions in bins of dilepton and hadronic system (Xs) mass, using a sample of 471 × 106 ϒð4SÞ → BB¯ 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 BðB → Xslþl−Þ ¼ ½6.73 þ0.70 −0.64 ðstatÞþ0.34 −0.25 ðexp systÞ 0.50ðmodel systÞ × 10−6 for m2 lþl− > 0.1 GeV2=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 ¼ 0.04 0.11 0.01 for a leptonflavor- averaged sample.File | Dimensione | Formato | |
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PhysRevLett.112.211802.pdf
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