CMS performance for CP Violation measurements

Recent set of structure functions, branching ratios and the current understanding of detector performance lead to a new evaluation of the CP reach of CMS. Compared to previous analysis, expected numbers of fully reconstructed and μ tagged B events are smaller, but are partly recovered thanks to progress on low p _T electron identification based upon the high-resolution and fine granular electromagnetic calorimeter. This allow to use electrons for tagging purpose as well as for J/ ψ - e⁺e^- reconstruction.