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arXiv · 1501.01702

Measurement of the direct $CP$ asymmetry in $\bar{B}\rightarrow X_{s+d}\gamma$ decays with a lepton tag

L. Pesántez·P. Urquijo·J. Dingfelder·A. Abdesselam·I. Adachi·K. Adamczyk·H. Aihara·S. Al Said·K. Arinstein·D. M. Asner·V. Aulchenko·T. Aushev·R. Ayad·S. Bahinipati·A. M. Bakich·V. Bansal·E. Barberio·V. Bhardwaj·B. Bhuyan·A. Bobrov·A. Bondar·G. Bonvicini·A. Bozek·M. Bračko·T. E. Browder·D. Červenkov·V. Chekelian·A. Chen·B. G. Cheon·K. Chilikin·R. Chistov·K. Cho·V. Chobanova·Y. Choi·D. Cinabro·J. Dalseno·Z. Doležal·Z. Drásal·A. Drutskoy·D. Dutta·S. Eidelman·H. Farhat·J. E. Fast·T. Ferber·O. Frost·V. Gaur·N. Gabyshev·S. Ganguly·A. Garmash·D. Getzkow·R. Gillard·Y. M. Goh·B. Golob·J. Haba·J. Hasenbusch·X. H. He·A. Heller·T. Horiguchi·W. -S. Hou·M. Huschle·T. Iijima·K. Inami·A. Ishikawa·R. Itoh·Y. Iwasaki·I. Jaegle·D. Joffe·T. Julius·K. H. Kang·E. Kato·T. Kawasaki·C. Kiesling·D. Y. Kim·J. B. Kim·J. H. Kim·K. T. Kim·M. J. Kim·S. H. Kim·Y. J. Kim·B. R. Ko·P. Kodyš·S. Korpar·P. Križan·P. Krokovny·B. Kronenbitter·T. Kuhr·T. Kumita·A. Kuzmin·Y. -J. Kwon·J. S. Lange·I. S. Lee·Y. Li·L. Li Gioi·J. Libby·D. Liventsev·P. Lukin·D. Matvienko·K. Miyabayashi·H. Miyata·R. Mizuk
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Abstract

We report the measurement of the direct $CP$ asymmetry in the radiative $\bar{B}\rightarrow X_{s+d}\gamma$ decay using a data sample of $(772 \pm 11)\times 10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. The $CP$ asymmetry is measured as a function of the photon energy threshold. For $E^{\rm{*}}_{\gamma} \geq 2.1~{\rm{GeV}}$, where $E^{\rm{*}}_{\gamma}$ is the photon energy in the center-of-mass frame, we obtain $\mathcal{A}_{CP}(\bar{B}\rightarrow X_{s+d}\gamma)= (2.2 \pm 3.9 \pm 0.9) \%$, consistent with the Standard Model prediction.

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L. Pesántez, P. Urquijo, J. Dingfelder, A. Abdesselam, I. Adachi, K. Adamczyk, H. Aihara, S. Al Said, K. Arinstein, D. M. Asner, V. Aulchenko, T. Aushev, R. Ayad, S. Bahinipati, A. M. Bakich, V. Bansal, E. Barberio, V. Bhardwaj, B. Bhuyan, A. Bobrov, A. Bondar, G. Bonvicini, A. Bozek, M. Bračko, T. E. Browder, D. Červenkov, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, R. Chistov, K. Cho, V. Chobanova, Y. Choi, D. Cinabro, J. Dalseno, Z. Doležal, Z. Drásal, A. Drutskoy, D. Dutta, S. Eidelman, H. Farhat, J. E. Fast, T. Ferber, O. Frost, V. Gaur, N. Gabyshev, S. Ganguly, A. Garmash, D. Getzkow, R. Gillard, Y. M. Goh, B. Golob, J. Haba, J. Hasenbusch, X. H. He, A. Heller, T. Horiguchi, W. -S. Hou, M. Huschle, T. Iijima, K. Inami, A. Ishikawa, R. Itoh, Y. Iwasaki, I. Jaegle, D. Joffe, T. Julius, K. H. Kang, E. Kato, T. Kawasaki, C. Kiesling, D. Y. Kim, J. B. Kim, J. H. Kim, K. T. Kim, M. J. Kim, S. H. Kim, Y. J. Kim, B. R. Ko, P. Kodyš, S. Korpar, P. Križan, P. Krokovny, B. Kronenbitter, T. Kuhr, T. Kumita, A. Kuzmin, Y. -J. Kwon, J. S. Lange, I. S. Lee, Y. Li, L. Li Gioi, J. Libby, D. Liventsev, P. Lukin, D. Matvienko, K. Miyabayashi, H. Miyata, R. Mizuk. 2015-01-08. Measurement of the direct $CP$ asymmetry in $\bar{B}\rightarrow X_{s+d}\gamma$ decays with a lepton tag. https://doi.org/10.1103/physrevlett.114.151601

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