Measurement of the CP asymmetry in B → Xsγ

The CP asymmetry in the B → Xsγ, where hadronic recoil system Xs is reconstructed, was investigated using pseudoreconstruction technique. Negligible contamination from b → dγ decays was observed, which were expected to have larger CP asymmetry. The qq̄ and BB̄ distributions were obtained from off-resonance data and Monte Carlo (MC) simulation. The results show that 50% error is assigned to Gaussian width and to ratio of the Gaussian and ARGUS function for rare B decays.