Observation of C P Violation in Charm Decays
Abstract
A search for charge-parity (C P ) violation in D0→K-K+ and D0→π-π+ decays is reported, using p p 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 charm meson is inferred from the charge of the pion in D*(2010 )+ →D0π+ decays or from the charge of the muon in B ¯ →D0μ-ν¯ μX decays. The difference between the C P asymmetries in D0→K-K+ and D0→π-π+ decays is measured to be Δ AC P=[-18.2 ±3.2 (stat )±0.9 (syst )]×10-4 for π -tagged and Δ AC P=[-9 ±8 (stat )±5 (syst )]×10-4 for μ -tagged D0 mesons. Combining these with previous LHCb results leads to Δ AC 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 5 standard deviations. This is the first observation of C P violation in the decay of charm hadrons.
- Publication:
-
Physical Review Letters
- Pub Date:
- May 2019
- DOI:
- 10.1103/PhysRevLett.122.211803
- Bibcode:
- 2019PhRvL.122u1803A