First observation of CP violation in the decays of Bs mesons

• Published in: arXiv.org 2013-06
• Main Authors: collaboration, LHCb, Amato, S, Archilli, F, Artamonov, A, Back, J J, Belyaev, I, Blanc, F, Bondar, A, Bressieux, J, Buytaert, J, Cardini, A, Cliff, H V, Corti, G, De Bonis, I, De Bruyn, K, De Silva, W, Deckenhoff, M, Dijkstra, H, Easo, S, Egede, U, Eidelman, S, Eitschberger, U, I El Rifai, Elsasser, Ch, Ferguson, D, Fitzpatrick, C, Francisco, O, Frei, C, A Gallas Torreira, J Garra Tico, Gaspar, C, Göbel, C, Gomes, A, Hall, S, Hoballah, M, Hunt, P, Hutchcroft, D, Hynds, D, Jing, F, Johnson, D, Kaballo, M, Kandybei, S, Keune, A, Kreps, M, Kucharczyk, M, Kvaratskheliya, T, Lai, A, Lambert, R W, Lanfranchi, G, Latham, T, J van Leerdam, Leroy, O, Leverington, B, Linn, C, Longstaff, I, Maciuc, F, Mancinelli, G, Marconi, U, Massafferri, A, Meissner, M, Milanes, D A, Needham, M, Oblakowska-Mucha, A, Obraztsov, V, Pavel-Nicorescu, C, Perazzini, S, Perret, P, Pessina, G, M Plo Casasus, Polycarpo, E, Popov, D, Potterat, C, Redford, S, V Rives Molina, Ruiz, H, Sail, P, Saitta, B, Satriano, C, Schneider, O, Semennikov, A, Shevchenko, O, Soler, F J P, Soomro, F, Sparkes, A, Stagni, F, Szczekowski, M, Szumlak, T, Tisserand, V, Torr, N, Tran, M T, Vecchi, S, Vieira, D, Wallace, R, Websdale, D, Wilson, F F, S Wu, Yuan, X, Zangoli, M, Zhang, Y, Zhokhov, A
• Format: Article
• Language: English
• Subjects: CP violation; Decay; Luminosity; Matter & antimatter; Mesons
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1304.6173

Using pp collision data, corresponding to an integrated luminosity of \(1.0 \mathrm{fb}^{-1}\), collected by LHCb in 2011 at a center-of-mass energy of 7 TeV, we report the measurement of direct CP violation in \(B^0_s \to K^-\pi^+\) decays, \(A_{C/!P}(B^0_s \rightarrow K^- \pi^+)=0.27 \pm 0.04\,\mathrm{(stat)} \pm 0.01\,\mathrm{(syst)}\), with significance exceeding five standard deviations. This is the first observation of CP violation in the decays of \(B^0_s\) mesons. Furthermore, we provide an improved determination of direct CP violation in \(B^0 \to K^+\pi^-\) decays, \(A_{C/!P}(B^0\rightarrow K^+ \pi^-)=-0.080 \pm 0.007\,\mathrm{(stat)} \pm 0.003\,\mathrm{(syst)}\), which is the most precise measurement of this quantity to date.