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تسجيل مستخدم جديدMeasurement of B_s mixing phase at CDF
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Michal Kreps
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We present improved bounds on the CP-violating phase beta_s^{Jpsiphi} and on the decay-width difference DeltaGamma of the neutral B_s^0 meson system obtained by the CDF experiment at the Tevatron collider . We use 6500 B_s^0 --> J/psi phi decays collected by the dimuon trigger and reconstructed in a sample corresponding to integrated luminosity of 5.2 fb-1. Besides exploiting a two-fold increase in statistics with respect to the previous measurement, several improvements have been introduced in the analysis including a fully data-driven flavour-tagging calibration and proper treatment of possible S-wave contributions.
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The latest results for the measurement of the CP violating phase beta_s in B0s -> J/psi phi decays, from 5.2 fb-1 integrated luminosity of CDF data are presented. For the first time, this measurement includes the contribution of B0s -> J/psi K+K- or
B0s -> J/psi f0 events to the signal sample, where the f0 and non-resonant K+K- are S-wave states. Additional improvements to the analysis include more than doubling the signal sample, improved selection and particle ID, and fully calibrated flavour tagging for the full dataset. Additionally, the worlds most precise single measurements of the B0s lifetime, tau_s, and width difference, DeltaGamma_s are given.
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-1}$. Measurements are performed as a function of the photon transverse momentum for photons with $p_{T}>$30 GeV and $|eta|<$1.0. Photons are required to be isolated in the calorimeter. The measurement is corrected to the hadron level and compared to NLO pQCD predictions.
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