Measurements of charm mixing parameters from the decay-time-dependent ratio of D0→K +π - to D0→K -π + rates and the charge-conjugate ratio are reported. The analysis uses data, corresponding to 3 fb -1 of integrated luminosity, from proton-proton collisions at 7 and 8 TeV center-of-mass energies recorded by the LHCb experiment. In the limit of charge-parity (CP) symmetry, the mixing parameters are determined to be x ′2=(5.5±4.9) ×10 -5, y ′=(4.8±1.0)×10 -3, and R D=(3.568±0.066)×10 -3. Allowing for CP violation, the measurement is performed separately for D0 and D ̄0 mesons yielding A D=(-0.7±1.9)%, for the direct CP-violating asymmetry, and 0.75<|q/p|<1.24 at the 68.3% confidence level, for the parameter describing CP violation in mixing. This is the most precise determination of these parameters from a single experiment and shows no evidence for CP violation.
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)