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 <E_\gamma> = 2.267 \pm 0.019 \pm 0.032 \pm 0.003 GeV,, <(E_\gamma - <E_\gamma>)^2> = 0.0484 \pm 0.0053 \pm 0.0077 \pm 0.0005 GeV^2, and <(E_\gamma - <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.

Measurement of B (B→X_{s}γ), the B→X_{s}γ photon energy spectrum, and the direct CP asymmetry in B→X_{s+d}γ decays

BETTONI, Diego;BOZZI, Concezio;CALABRESE, Roberto;CIBINETTO, Gianluigi;FIORAVANTI, Elisa;GARZIA, Isabella;LUPPI, Eleonora;SANTORO, Valentina;
2012

Abstract

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.
2012
J. P., Lees; V., Poireau; V., Tisserand; J., Garra Tico; E., Grauges; A., Palano; G., Eigen; B., Stugu; D. N., Brown; L. T., Kerth; Kolomensky, Y. u. ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1818304
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