Measurement of the CP-violating phase ϕs from Bs 0→J/ψπ+π decays in 13 TeV pp collisions

LHCb Collaboration

Research output: Contribution to JournalArticleAcademicpeer-review


Decays of Bs 0 and B‾0 s mesons into J/ψπ+π final states are studied in a data sample corresponding to 1.9 fb−1 of integrated luminosity collected with the LHCb detector in 13 TeV pp collisions. A time-dependent amplitude analysis is used to determine the final-state resonance contributions, the CP-violating phase ϕs=−0.057±0.060±0.011 rad, the decay-width difference between the heavier mass Bs 0 eigenstate and the B0 meson of −0.050±0.004±0.004 ps−1, and the CP-violating parameter |λ|=1.01−0.06 +0.08±0.03, where the first uncertainty is statistical and the second systematic. These results are combined with previous LHCb measurements in the same decay channel using 7 TeV and 8 TeV pp collisions obtaining ϕs=0.002±0.044±0.012 rad, and |λ|=0.949±0.036±0.019.

Original languageEnglish
Article number134789
Pages (from-to)1-12
Number of pages12
JournalPhysics Letters. Section B : Nuclear, Elementary Particle and High-Energy Physics
Early online date18 Jul 2019
Publication statusPublished - 10 Oct 2019


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 Skłodowska-Curie Actions and ERC (European Union); ANR , Labex P2IO and OCEVU , and Région Auvergne-Rhône-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
Not addedST/J004332/1, ST/N000250/1, ST/K003410/1, 1796908, ST/N000331/1, ST/L003163/1, ST/N000242/1
Key Research Program of Frontier Sciences of CAS
Yandex LLC
National Science Foundation
Alexander von Humboldt-Stiftung
Laboratory Directed Research and Development
Los Alamos National Laboratory
Karlsruhe Institute of Technology
Horizon 2020 Framework Programme792684
H2020 Marie Skłodowska-Curie Actions
Institutul National de Cercetare-Dezvoltare pentru Fizica si Inginerie Nucleara 'Horia Hulubei'
Science and Technology Facilities CouncilST/N000234/1
Leverhulme Trust
Royal Society
European Research Council
Deutsches Elektronen-Synchrotron
Deutsche Forschungsgemeinschaft
Agence Nationale de la Recherche
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
National Natural Science Foundation of China
Russian Foundation for Basic Research
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Bundesministerium für Bildung und Forschung
Chinese Academy of Sciences
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Ministerio de Economía y Competitividad
Generalitat Valenciana
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Instituto Nazionale di Fisica Nucleare
Narodowe Centrum Nauki
Ministerstwo Edukacji i Nauki
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
Ministry of Science and Technology, Taiwan
National Academy of Sciences of Ukraine
Centre National de la Recherche Scientifique
Financiadora de Estudos e Projetos
Russian Science Foundation
Région Auvergne-Rhône-Alpes
Recruitment Program of Global Experts
Institut national de physique nucléaire et de physique des particules
Sociedad Española de Reumatología


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