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Physical Review D 86 (2012) 112008
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
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
BABAR Collaboration(s)
(2012)

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.
1 :  LAPP - Laboratoire d'Annecy le Vieux de Physique des Particules
2 :  LAL - Laboratoire de l'Accélérateur Linéaire
3 :  LLR - Laboratoire Leprince-Ringuet
4 :  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
5 :  LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
Physique/Physique des Hautes Energies - Expérience
Lien vers le texte intégral : 
http://fr.arXiv.org/abs/1207.5772