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Observation of CP Violation in Charm Decays

  • LHCb Collaboration

Research output: Contribution to Journal › Article › Academic › peer-review

Abstract

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 charm meson is inferred from the charge of the pion in D∗(2010)+→D0π+ decays or from the charge of the muon in B̄→D0μ-ν̄μX decays. The difference between the CP asymmetries in D0→K-K+ and D0→π-π+ decays is measured to be ΔACP=[-18.2±3.2(stat)±0.9(syst)]×10-4 for π-tagged and ΔACP=[-9±8(stat)±5(syst)]×10-4 for μ-tagged D0 mesons. Combining these with previous LHCb results leads to ΔACP=(-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 CP violation in the decay of charm hadrons.

Original languageEnglish
Article number211803
Pages (from-to)1-12
Number of pages12
JournalPhysical Review Letters
Volume122
Issue number21
Early online date29 May 2019
DOIs
Publication statusPublished - 2019

Funding

We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ, and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG, and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MEN/IFA (Romania); MSHE (Russia); MinECo (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); NSF (USA). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT, and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), RRCKI and Yandex LLC (Russia), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), PL-GRID (Poland), and OSC (USA). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from AvH Foundation (Germany); EPLANET, Marie Sk\u0142odowska-Curie Actions and ERC (European Union); ANR, Labex P2IO and OCEVU, and R\u00E9gion Auvergne-Rh\u00F4ne-Alpes (France); Key Research Program of Frontier Sciences of CAS, CAS PIFI, and the Thousand Talents Program (China); RFBR, RSF and Yandex LLC (Russia); GVA, XuntaGal and GENCAT (Spain); the Royal Society and the Leverhulme Trust (United Kingdom); Laboratory Directed Research and Development program of LANL (USA).

FundersFunder number
Agence Nationale de la Recherche
National Academy of Sciences of Ukraine
Narodowe Centrum Nauki
OCEVU
National Science Foundation
Institut national de physique nucléaire et de physique des particules
H2020 Marie Skłodowska-Curie Actions
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Ministry of Science and Technology, Taiwan
Leverhulme Trust
MSHE
Instituto Nazionale di Fisica Nucleare
Los Alamos National Laboratory
Financiadora de Estudos e Projetos
Centre National de la Recherche Scientifique
Bundesministerium für Bildung und Forschung
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Deutsche Forschungsgemeinschaft
Région Auvergne-Rhône-Alpes
Russian Foundation for Basic Research
Yandex LLC
Russian Science Foundation
Laboratory Directed Research and Development
Chinese Academy of Sciences
Recruitment Program of Global Experts
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
XuntaGal
Key Research Program of Frontier Sciences of CAS
Royal Society
Sociedad Española de Reumatología
European Research Council
EPLANET
Ministerstwo Nauki i Szkolnictwa Wyższego
Generalitat Valenciana
CERN
Alexander von Humboldt-Stiftung
National Natural Science Foundation of China
Horizon 2020 Framework Programme792684
Science and Technology Facilities CouncilST/N000250/1, ST/J004332/1, ST/K003410/1, 1796908, ST/G005974/1, ST/N000331/1, ST/N000234/1, GRIDPP, ST/L003163/1, ST/N000242/1

    UN SDGs

    This output contributes to the following UN Sustainable Development Goals (SDGs)

    1. SDG 7 - Affordable and Clean Energy
      SDG 7 Affordable and Clean Energy

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