Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur GraphSearch.
A measurement is presented of decay-time-dependent CP violation in the decays B-0 -> J/psi K-S(0) and B-0 -> psi(2S) K-S(0), where the J/psi is reconstructed from two electrons and the psi(2S) from two muons. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb(-1). The CP-violation observables are measured to be C(B-0 -> J/psi K-S(0)) = 0.12 +/- 0.07 +/- 0.02, S(B-0 -> J/psi K-S(0)) = 0.83 +/- 0.08 +/- 0.01, C(B-0 -> psi(2S) K-S(0)) = -0.05 +/- 0.10 +/- 0.01, S(B-0 -> psi(2S) K-S(0)) = 0.84 +/- 0.10 +/- 0.01, where C describes CP violation in the direct decay, and S describes CP violation in the interference between the amplitudes for the direct decay and for the decay after B-0-(B) over bar (0) oscillation. The first uncertainties are statistical and the second are systematic. The two sets of results are compatible with the previous LHCb measurement using B-0 -> J/psi K-S(0) decays, where the J/psi meson was reconstructed from two muons. The averages of all three sets of LHCb results are C(B-0 -> [c (c) over bar] K-S(0)) = -0.017 +/- 0.029, S(B-0 -> [c (c) over bar] K-S(0)) = 0.760 +/- 0.034, under the assumption that higher-order contributions to the decay amplitudes are negligible. The uncertainties include statistical and systematic contributions.
Olivier Schneider, Aurelio Bay, Yi Zhang, Yi Wang, Guido Haefeli, Frédéric Blanc, Tatsuya Nakada, François Fleuret, Elena Graverini, Renato Quagliani, Federico Betti, Sebastian Schulte, Veronica Sølund Kirsebom, Jian Wang, Mingkui Wang, Zhirui Xu, Zheng Wang, Lei Zhang, Christoph Frei, Jessica Prisciandaro, Mark Tobin, Minh Tâm Tran, Niko Neufeld, Matthew Needham, Marc-Olivier Bettler, Michel De Cian, Greig Alan Cowan, Maurizio Martinelli, Vladislav Balagura, Liang Sun, Pietro Marino, Luca Pescatore, Mirco Dorigo, Xiaoxue Han, Liupan An, Federico Leo Redi, Chitsanu Khurewathanakul, Plamen Hristov Hopchev, Thibaud Humair, Maxime Schubiger, Hang Yin, Guido Andreassi, Violaine Bellée, Maria Vieites Diaz, Olivier Göran Girard, Axel Kuonen, Preema Rennee Pais, Pavol Stefko, Tara Nanut, Maria Elena Stramaglia, Tommaso Colombo, Vladimir Macko, Guillaume Max Pietrzyk, Evgenii Shmanin, Dipanwita Dutta, Yiming Li, Hans Dijkstra, Gerhard Raven, Peter Clarke, Frédéric Teubert, Victor Coco, Adam Davis, Paolo Durante, Yu Zheng, Anton Petrov, Maxim Borisyak, Chunhui Chen, Zhipeng Tang