  Measurements of charm mixing parameters from the decay-time-dependent ratio
of D0->K+pi- to D0->K-pi+ 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)x10^{-5}, y'= (4.8 +-
1.0)x10^{-3}, and R_D=(3.568 +- 0.066)x10^{-3}. Allowing for CP violation, the
mixing parameters are determined separately for D0 and D0bar 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, where q and p are parameters that describe
the mass eigenstates of the neutral charm mesons in terms of the flavor
eigenstates. This is the most precise determination of these parameters from a
single experiment and shows no evidence for CP violation.

High Energy Physics - Experiment