Measurement of B (B→X[subscript sγ]), the B→X[subscript sγ] photon energy spectrum, and the direct CP asymmetry in B→X[subscript s + dγ] decays
Name
Lees-2012-photon energy spectrum.pdf
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1.35 MB
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Author(s)
Dujmic, Denis
Sciolla, Gabriella
Cowan, Ray F
Date Issued
December 2012
Journal
Physical Review D
Publisher
American Physical Society
Citation
Lees, J. P. et al. “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.” Physical Review D 86.11 (2012). © 2012 American Physical Society
Version
Final published version
Abstract
The photon spectrum in B→X[subscript s]γ decay, where X[subscript s] is any strange hadronic state, is studied using a data sample of (382.8±4.2)×10[superscript 6] e[superscript +]e[superscript -]→Υ(4S)→BB̅ events collected by the BABAR experiment at the PEP-II collider. The spectrum is used to measure the branching fraction B(B→Xsγ)=(3.21±0.15±0.29±0.08)×10-4 and the first, second, and third moments (E[subscript γ)=2.267±0.019±0.032±0.003 GeV, ((E [subscript γ-](E[subscript γ]))[superscript 2])=0.0484±0.0053±0.0077±0.0005 GeV[superscript 2], and ((E[subscript γ-](E[subscript γ]))[superscript 3])=0.0048±0.0011±0.0011±0.0004 GeV[superscript 3], for the range E[subscript γ]>1.8 GeV, where E[subscript γ] is the photon energy in the B-meson rest frame. Results are also presented for narrower E[subscript γ] ranges. In addition, the direct CP asymmetry A[subscript CP](B→X[subscript s+dγ]) is measured to be 0.057±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.
MIT Department
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
https://doi.org/10.1103/PhysRevD.86.112008
