HAL : in2p3-00653545, version 1
 arXiv : 1112.3183
 Physical Review Letters 108 (2012) 101803
 Measurement of the CP-violating phase $\phi_s$ in the decay $\B^0_s ->\J/psi \phi$
 LHCb Collaboration(s)
 (2012)
 We present a measurement of the time-dependent CP-violating asymmetry in B_s -> J/psi phi decays, using data collected with the LHCb detector at the LHC. The decay time distribution of B_s -> J/psi phi is characterized by the decay widths Gamma_H and Gamma_L of the heavy and light mass eigenstates of the B_s-B_s-bar system and by a CP-violating phase phi_s. In a sample of about 8500 B_s -> J/psi phi events isolated from 0.37 fb^-1 of pp collisions at sqrt(s)=7 TeV we measure phi_s = 0.15 +/- 0.18 (stat) +/- 0.06 (syst) rad. We also find an average B_s decay width Gamma_s == (Gamma_L + Gamma_H)/2 = 0.657 +/- 0.009 (stat) +/- 0.008 (syst) ps^-1 and a decay width difference Delta Gamma_s == Gamma_L - Gamma_H} = 0.123 +/- 0.029 (stat) +/- 0.011 (syst) ps^-1. Our measurement is insensitive to the transformation (phi_s,DeltaGamma_s --> pi - phi_s, - Delta Gamma_s.
 Thème(s) : Physique/Physique des Hautes Energies - Expérience
 Lien vers le texte intégral : http://fr.arXiv.org/abs/1112.3183
 in2p3-00653545, version 1 http://hal.in2p3.fr/in2p3-00653545 oai:hal.in2p3.fr:in2p3-00653545 Contributeur : Nicole Berger <> Soumis le : Lundi 19 Décembre 2011, 16:39:07 Dernière modification le : Lundi 26 Mars 2012, 14:57:48