Gascón Fora, DavidGraciani Díaz, RicardoGraugés Pous, EugeniMarin Benito, CarlaPicatoste Olloqui, EduardoRives Molina, Vicente JoséGarrido Beltrán, LluísLHCb Collaboration2017-07-212017-07-212016-06-170031-9007https://hdl.handle.net/2445/114163Charm meson oscillations are observed in a time-dependent analysis of the ratio of D0→K+π−π+π− to D0→K−π+π−π+ decay rates, using data corresponding to an integrated luminosity of 3.0  fb−1 recorded by the LHCb experiment. The measurements presented are sensitive to the phase-space averaged ratio of doubly Cabibbo-suppressed to Cabibbo-favored amplitudes rK3πD and the product of the coherence factor RK3πD and a charm mixing parameter y′K3π. The constraints measured are rK3πD=(5.67±0.12)×10−2, which is the most precise determination to date, and RK3πDy′K3π=(0.3±1.8)×10−3, which provides useful input for determinations of the CP-violating phase γ in B±→DK±, D→K∓π±π∓π± decays. The analysis also gives the most precise measurement of the D0→K+π−π+π− branching fraction, and the first observation of D0-¯D0 oscillations in this decay mode, with a significance of 8.2 standard deviations.10 p.application/pdfengcc by (c) CERN, 2016http://creativecommons.org/licenses/by/3.0/HadronsPartícules (Física nuclear)HadronsParticles (Nuclear physics)info:eu-repo/semantics/article6698472017-07-21info:eu-repo/semantics/openAccess27367383