PT Journal AU LHCb Collaboration (Aaij, Rea Garcia Martin, LM Henry, L Martinez-Vidal, F Oyanguren, A Remon Alepuz, C Ruiz Vidal, J Sanchez Mayordomo, C TI Measurement of the Charm-Mixing Parameter y(CP) SO Physical Review Letters JI Phys. Rev. Lett. PY 2019 BP 011802 EP 10pp VL 122 IS 1 DI 10.1103/PhysRevLett.122.011802 LA English AB A measurement of the charm-mixing parameter Y-CP using D-0 -> K+K-, D-0 -> pi(+)pi(-), and D-0 -> K-pi(+)decays is reported. The D-0 mesons are required to originate from semimuonic decays of B- and (B) over bar (0)mesons. These decays are partially reconstructed in a data set of proton-proton collisions at center-of-mass energies of 7 and 8 TeV collected with the LHCb experiment and corresponding to an integrated luminosity of 3 fb(-1). The y c p parameter is measured to be (0.57 +/- 0.13(stat) +/- 0.09(syst))%, in agreement with, and as precise as, the current world-average value. ER