Graugés Pous, EugeniBABAR Collaboration2019-09-182019-09-182006-10-240031-9007https://hdl.handle.net/2445/140394The photon spectrum in B → X s γ decay, where X s is any strange hadronic state, is studied using a data sample of 88.5 × 10 6 e + e − → Υ ( 4 S ) → B ¯¯¯ B decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, Δ B ( B → X s γ ) = ( 3.67 ± 0.29 ( stat ) ± 0.34 ( syst ) ± 0.29 ( model ) ) × 10 − 4 , the first moment ⟨ E γ ⟩ = 2.288 ± 0.025 ± 0.017 ± 0.015     GeV , and the second moment ⟨ E 2 γ ⟩ = 0.0328 ± 0.0040 ± 0.0023 ± 0.0036     GeV 2 are measured for the photon energy range 1.9     GeV < E γ < 2.7     GeV . They are also measured for narrower E γ ranges. The moments are then fit to recent theoretical calculations to extract the heavy quark expansion parameters m b and μ 2 π and to extrapolate the partial branching fraction to E γ > 1.6     GeV . In addition, the direct C P asymmetry A C P ( B → X s + d γ ) is measured to be − 0.110 ± 0.115 ( stat ) ± 0.017 ( syst ) .7 p.application/pdfeng(c) American Physical Society, 2006Física de partículesExperimentsParticle physicsExperimentsinfo:eu-repo/semantics/article5516632019-09-18info:eu-repo/semantics/openAccess