Measurement of the Branching Fraction and Photon Energy Moments ofB→XsγandACP(B→Xs+dγ)

2006/07/26 by The BaBar Collaboration, R. Barate, B. Aubert +98 · 70 citations
Physics and Astronomy · #Analytical Chemistry (journal) #Branching (polymer chemistry) #Branching fraction #Electron–positron annihilation #Hadron #High-Energy Particle Collisions Research #Materials science #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Quantum Chromodynamics and Particle Interactions #Quark #hep-ex

paper · pdf · doi:10.1103/physrevlett.97.171803

published in Physical Review Letters 97(17), 171803 (American Physical Society) · 8 pages 1 figure, submitted to PRL

arxiv created 2006/07/26 · openalex publication_date 2006/10/24 · arxiv updated 2010/03/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06

Abstract

The photon spectrum in B\ensuremath→X_s\ensuremathγ decay, where X_s is any strange hadronic state, is studied using a data sample of 88.5\ifmmode×\else\texttimes\fi10⁶ e⁺e^\ensuremath-\ensuremath→\mathit\ensuremathΥ(4S)\ensuremath→BB decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, \ensuremathΔB(B\ensuremath→X_s\ensuremathγ)=(3.67\ifmmode±\else\textpm\fi0.29(stat)\ifmmode±\else\textpm\fi0.34(syst)\ifmmode±\else\textpm\fi0.29(model))\ifmmode×\else\texttimes\fi10^\ensuremath-4, the first moment ⟨E_\ensuremathγ⟩=2.288\ifmmode±\else\textpm\fi0.025\ifmmode±\else\textpm\fi0.017\ifmmode±\else\textpm\fi0.015 GeV, and the second moment ⟨E_\ensuremathγ²⟩=0.0328\ifmmode±\else\textpm\fi0.0040\ifmmode±\else\textpm\fi0.0023\ifmmode±\else\textpm\fi0.0036 GeV² are measured for the photon energy range 1.9 GeV<E_\ensuremathγ<2.7 GeV. They are also measured for narrower E_\ensuremathγ ranges. The moments are then fit to recent theoretical calculations to extract the heavy quark expansion parameters m_b and \ensuremathμ_\ensuremathπ² and to extrapolate the partial branching fraction to E_\ensuremathγ>1.6 GeV. In addition, the direct CP asymmetry A_CP(B\ensuremath→X_s+d\ensuremathγ) is measured to be \ensuremath-0.110\ifmmode±\else\textpm\fi0.115(stat)\ifmmode±\else\textpm\fi0.017(syst).

Citations

• Measurement of the CP Asymmetry in B→X_sγ
• On the photon energy moments and their ‘bias’ corrections in B→Xs+γ
• CP violation and the CKM matrix: assessing the impact of the asymmetric B factories
• Untagged B¯→Xs+dγ CP asymmetry as a probe for new physics
• The BABAR detector
• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)