Bouhova-Thacker, Evelina Vassileva (2017) Mixing and CPV in the Bd and Bs systems at ATLAS. In: XIII International Conference on Heavy Quarks and Leptons :. Proceedings of Science.
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Abstract
The most recent results on mixing and CP violation in the B0 and B0s systems published by the ATLAS experiment at the LHC are presented. The measurement of the B0s → J/ψφ decay parameters, using data collected in pp collisions at √s = 7 TeV and √s = 8 TeV and corresponding to 4.9 fb−1 and 14.3 fb−1 of integrated luminosity, includes the CP-violating phase φs and the width difference of the mass eigenstates ∆Γs . The combined Run-1 results are φs = −0.098±0.084(stat.)±0.040(syst.) rad and ∆Γs = 0.083±0.011(stat.)±0.007(syst.) ps−1 . The measured values agree with the Standard Model predictions. The second result presented is the measurement of the relative width difference ∆Γd/Γd of the B 0–B¯0 system, using data collected in pp collisions at √s = 7 TeV and √s = 8 TeV, and corresponding to a total integrated luminosity of 25.2 fb−1 . The measured value is ∆Γd/Γd = (−0.1±1.1 (stat.)±0.9 (syst.))×10−2 . Currently, this is the most precise single measurement of ∆Γd/Γd. It agrees with the Standard Model prediction and measurements by other experiments.