Results on direct CP violation in B decays in LHCb

• Published in: arXiv.org
• Main Authors: Till Moritz Karbach, the LHCb collaboration
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 30.05.2012
• Subjects: CP violation; Decay; Large Hadron Collider; Matter & antimatter; Mesons
• ISSN: 2331-8422

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 \(fb^{-1}\) of \(pp\) collisions at \(\sqrt{s}=7 TeV\). 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, \(A_{CP}(B_s\to K\pi) = 0.27 \pm 0.08 {\rm (stat)}\pm 0.02 {\rm (syst)}\) (\(3.3\sigma\)). Third, using 1.0 \(fb^{-1}\) 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 \(5.8\sigma\).