| Thème(s) : |
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Physique/Physique des Hautes Energies - Expérience
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| Titre : |
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Measurement of B(B-->X_s \gamma), the B-->X_s \gamma photon energy spectrum, and the direct CP asymmetry in B-->X_{s+d} \gamma decays |
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| Auteur : |
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J. P. Lees1, V. Poireau1, V. Tisserand1, N. Arnaud2, M. Davier2, D. Derkach2, G. Grosdidier2, F. Le Diberder2, A. M. Lutz2, B. Malaescu2, P. Roudeau2, M. H. Schune2, A. Stocchi2, G. Wormser2, D. Bernard3, M. Verderi3, S. Emery4, G. Hamel de Monchenault4, G. Vasseur4, Ch. Yèche4, S. Akar5, E. Ben-Haim5, M. Bomben5, G.R. Bonneaud5, H. Briand5, G. Calderini5, J. Chauvau5, O. Hamon5, Ph. Leruste5, G. Marchiori5, J. Ocariz5, S. Sitt5 |
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| Laboratoire : |
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| Résumé : |
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The photon spectrum in B --> X_s \gamma decay, where X_s is any strange hadronic state, is studied using a data sample of (382.8\pm 4.2) \times 10^6 e^+ e^- --> Upsilon(4S) --> BBbar events collected by the BABAR experiment at the PEP-II collider. The spectrum is used to measure the branching fraction B(B --> X_s \gamma) = (3.21 \pm 0.15 \pm 0.29 \pm 0.08)\times 10^{-4} and the first, second, and third moments = 2.267 \pm 0.019 \pm 0.032 \pm 0.003 GeV, <(E_\gamma - )^2> = 0.0484 \pm 0.0053 \pm 0.0077 \pm 0.0005 GeV^2, and <(E_\gamma - )^3> = -0.0048 \pm 0.0011 \pm 0.0011 \pm 0.0004 GeV^3, for the range E_\gamma > 1.8 GeV, where E_\gamma is the photon energy in the B-meson rest frame. Results are also presented for narrower E_\gamma ranges. In addition, the direct CP asymmetry A_{CP}(B --> X_{s+d} \gamma) is measured to be 0.057 \pm 0.063. The spectrum itself is also unfolded to the B-meson rest frame; that is the frame in which theoretical predictions for its shape are made. |
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| Collaboration/Projet : |
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BABAR |
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| Type de publication : |
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Articles dans des revues avec comité de lecture |
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Date de publication ou d'écriture : |
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2012 |
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| Nom du périodique : |
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| Physical Review D (Phys. Rev. D) |
| Publisher |
American Physical Society |
| ISSN |
1550-7998 (eISSN : 1550-2368) |
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| Volume : |
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86 |
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| Page/Article : |
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112008 |
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| Identifiant local : |
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BABAR-PUB-12/018; SLAC-PUB-15181 |
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| Commentaire : |
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36 pages, 18 postscript figures, submitted to Phys. Rev. D - See paper for full list of authors |
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