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arXiv · hep-ex/0308038

Measurement of the CP Asymmetry in B -> X_s gamma

S. Nishida
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Abstract

Direct CP violation in the b->sgamma process is a sensitive probe of physics beyond the Standard Model. We report a measurement of the CP asymmetry in B -> X_s gamma, where the hadronic recoil system Xs is reconstructed using a pseudo-reconstruction technique. In this approach there is negligible contamination from b->dgamma decays, which are expected to have a much larger CP asymmetry. We find ACP = 0.002 +- 0.050(stat.) +- 0.030(syst.) for B -> Xs gamma events having recoil mass smaller than 2.1 GeV/c^2. The analysis is based on a data sample of 140 /fb recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- storage ring.

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S. Nishida. 2004-07-22. Measurement of the CP Asymmetry in B -> X_s gamma. https://doi.org/10.1103/physrevlett.93.031803

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