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Physical Review Letters 109 (2012) 191801
Precision Measurement of the B to X_s \gamma Photon Energy Spectrum, Branching Fraction, and Direct CP Asymmetry A_{CP}(B to X_{s+d}\gamma
J. P. Lees1, V. Poireau1, V. Tisserand1, D. Bernard2, M. Verderi2, S. Emery3, G. Hamel de Monchenault3, G. Vasseur3, Ch. Yèche3, N. Arnaud4, M. Davier4, D. Derkach4, G. Grosdidier4, F. Le Diberder4, A. M. Lutz4, B. Malaescu4, P. Roudeau4, M. H. Schune4, A. Stocchi4, G. Wormser4, 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
For the BABAR collaboration(s)
(2012)

The photon spectrum in the inclusive electromagnetic radiative decays of the $B$ meson, $B \to X_{s} \gamma$ plus $B \to X_{d} \gamma$, is studied using a data sample of $(382.8 \pm 4.2) \times 10^6$ $\Upsilon(4S) \to B\overli\ ne{B}$ decays collected by the \babar\ experiment at SLAC. The spectrum is used to extract the branching fraction ${\cal B}(B \to X_{s} \gamma)=(3.21 \pm 0.33)\times 10^{-4}$ for $E_{\gamma}>1.8 \gev$ and the direct CP asymmetry $A_{CP}(B \to X_{s+d} \gamma)=0.057 \pm 0.063$. The effects of detector resolution and Doppler smearing are unfolded to measure the photon energy spectrum in the $B$ meson rest frame.
1:  LAPP - Laboratoire d'Annecy le Vieux de Physique des Particules
2:  LLR - Laboratoire Leprince-Ringuet
3:  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
4:  LAL - Laboratoire de l'Accélérateur Linéaire
5:  LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
Physics/High Energy Physics - Experiment
Fulltext link: 
http://fr.arXiv.org/abs/1207.2690