Results on direct CP violation in B decays in LHCb

Abstract

I present three studies from the LHCb experiment on the subject of direct CP violation in $B^0$ and $B_s$ decays. First, we measure the CP asymmetry in $B^{\pm }\to \psi K^{\pm }$ decays, with $\psi =J/\psi ,\psi (2S)$, using 0.35 $f{b}^{-1}$ of $pp$ collisions at $\sqrt{s}=7TeV$. We find no evidence for CP violation. Second, using the same data sample, we see the first evidence of CP violation in the decays of $B_s$ mesons to $K^{\pm }{\pi }^{-}{\pi }^{+}$ pairs, $A_{CP}(B_s\to K\pi )=0.27\pm 0.08(\mathrm{stat})\pm 0.02(\mathrm{syst})$ ($3.3\sigma$). Third, using 1.0 $f{b}^{-1}$ of data, measurements of CP sensitive observables of the $B^{\pm }\to D{K}^{\pm }$ system are presented. They include the first observation of the suppressed mode $B^{\pm }\to [{\pi }^{\pm }{K}^{\mp }{]}_D{K}^{\pm }$. Combining several $D$ final states, CP violation in $B^{\pm }\to D{K}^{\pm }$ decays is observed with a significance of $5.8\sigma$.

Contribution to the proceedings of the Rencontres de Moriond EW 2012

References in corpus (4)

• Evidence for CP violation in time-integrated D0 -> h-h+ decay rates
• First evidence of direct CP violation in charmless two-body decays of Bs mesons
• Measurements of the branching fractions and CP asymmetries of B+ to J/psi pi+ and B+ to psi(2S) pi+ decays
• Observation of B^{\pm} \to χ_{c1} π^{\pm} and Search for Direct CP Violation