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Measurements of direct CP asymmetries in B →xsγ decays using sum of exclusive decays
Journal article   Open access   Peer reviewed

Measurements of direct CP asymmetries in B →xsγ decays using sum of exclusive decays

Eugeni Graugés Pous and BaBar Collaboration
Physical review. D, Particles, fields, gravitation, and cosmology, Vol.90(9), 092001
11/05/2014
DOI: 10.1103/PhysRevD.90.092001
url
https://doi.org/10.1103/PhysRevD.90.092001View
Published (Version of record) Open Access

Abstract

We measure the direct C P violation asymmetry, A C P , in B → X s γ and the isospin difference of the asymmetry, Δ A C P , using 429     fb − 1 of data collected at Υ ( 4 S ) resonance with the BABAR detector at the PEP-II asymmetric-energy e + e − storage rings operating at the SLAC National Accelerator Laboratory. B mesons are reconstructed from ten charged B final states and six neutral B final states. We find A C P = + ( 1.7 ± 1.9 ± 1.0 ) % , which is in agreement with the Standard Model prediction and provides an improvement on the world average. Moreover, we report the first measurement of the difference between A C P for charged and neutral decay modes, Δ A C P = + ( 5.0 ± 3.9 ± 1.5 ) % . Using the value of Δ A C P , we also provide 68% and 90% confidence intervals on the imaginary part of the ratio of the Wilson coefficients corresponding to the chromomagnetic dipole and the electromagnetic dipole transitions.
Particle Physics Physics BaBar detector Experiments Fisica Nucleare e Subnucleare Física de partícules Settore FIS

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