2019/05/14 by F. Betti, Betti, Federico
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1905.05428
openalex publication_date 2019/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A search for charge-parity (CP) violation in D0 → K- K+ and D0 → π-π+ decays is reported, using pp collision data corresponding to an integrated luminosity of 5.9 fb-1 collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the D0 meson is determined from the charge of the pion in D^*(2010)+ → D0 π+ decays or from the charge of the muon in \kern 0.18em\kern -0.18em B → D0 μ- νμX decays. The difference between the CP asymmetries in D0 → K- K+ and D0 → π-π+ decays is measured to be ΔA\rm CP = [ -18.2 ± 3.2 (\rm stat.) ± 0.9 (\rm syst.) ] × 10-4 for π-tagged and ΔA\rm CP = [ -9 ± 8 (\rm stat.) ± 5 (\rm syst.) ] × 10-4 for μ-tagged D0 mesons. The combination with previous LHCb results leads to ΔA\rm CP = ( -15.4 ± 2.9) × 10-4, where the uncertainty includes both statistical and systematic contributions. The measured value differs from zero by more than five standard deviations. This is the first observation of CP violation in the decay of charm hadrons.