2019/03/31 by LHCb collaboration, R. Aaij, C. Abellán Beteta +848 · 1 citation
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1103/physrevlett.122.211803
published as Phys. Rev. Lett. 122, 211803 (2019) · All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2019-006.html
arxiv created 2019/05/31 · arxiv updated 2019/06/03
A search for charge-parity (C P) violation in D0 → K- K+ and D0 → π- π+ decays is reported, using pp collision data corresponding to an integrated luminosity of 6 fb-1 collected at a center-of-mass energy of 13 TeV with the LHCb detector. The flavor of the charm meson is inferred from the charge of the pion in D^*(2010)+ → D0 π+ decays or from the charge of the muon in B → D0 μ-νμX decays. The difference between the C P asymmetries in D0 → K- K+ and D0 → π- π+ decays is measured to be ΔAC P = [ -18.2 ± 3.2 (\rm stat.) ± 0.9 (\rm syst.) ] × 10-4 for π-tagged and ΔAC P = [ -9 ± 8 (\rm stat.) ± 5 (\rm syst.) ] × 10-4 for μ-tagged D0 mesons. Combining these with previous LHCb results leads to ΔAC P = ( -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 C P violation in the decay of charm hadrons.