Measurement of the branching ratio Γ(Λb 0→ψ(2S)Λ0)/Γ(Λb 0→J/ψΛ0) with the ATLAS detector

G Aad; B Abbott; J Abdallah; O Abdinov; R Aben; M Abolins; OS AbouZeid; H Abramowicz; H Abreu; R Abreu; Y Abulaiti; BS Acharya; L Adamczyk; DL Adams; J Adelman; S Adomeit; T Adye; AA Affolder; T Agatonovic-Jovin; J Agricola; JA Aguilar-Saavedra; SP Ahlen; F Ahmadov; G Aielli; H Akerstedt; TPA Åkesson; AV Akimov; GL Alberghi; J Albert; S Albrand; MJ Alconada Verzini; M Aleksa; IN Aleksandrov; C Alexa; G Alexander; T Alexopoulos; M Alhroob; G Alimonti; L Alio; J Alison; SP Alkire; BMM Allbrooke; PP Allport; A Aloisio; A Alonso; F Alonso; C Alpigiani; A Altheimer; B Alvarez Gonzalez; D Álvarez Piqueras; MG Alviggi; BT Amadio; K Amako; Y Amaral Coutinho; C Amelung; D Amidei; SP Amor Dos Santos; A Amorim; S Amoroso; N Amram; G Amundsen; C Anastopoulos; LS Ancu; N Andari; T Andeen; CF Anders; G Anders; JK Anders; KJ Anderson; A Andreazza; V Andrei; S Angelidakis; I Angelozzi; P Anger; A Angerami; F Anghinolfi; AV Anisenkov; N Anjos; A Annovi; M Antonelli; A Antonov; J Antos; F Anulli; M Aoki; L Aperio Bella; G Arabidze; Y Arai; JP Araque; ATH Arce; FA Arduh; JF Arguin; S Argyropoulos; M Arik; AJ Armbruster; O Arnaez; V Arnal; H Arnold; M Arratia; O Arslan; A Artamonov

Journal article

Measurement of the branching ratio Γ(Λb 0→ψ(2S)Λ0)/Γ(Λb 0→J/ψΛ0) with the ATLAS detector

G Aad, B Abbott, J Abdallah, O Abdinov, R Aben, M Abolins, OS AbouZeid, H Abramowicz, H Abreu, R Abreu, Y Abulaiti, BS Acharya, L Adamczyk, DL Adams, J Adelman, S Adomeit, T Adye, AA Affolder, T Agatonovic-Jovin, J Agricola Show all

Physics Letters Section B Nuclear Elementary Particle and High Energy Physics | Published : 2015

DOI: 10.1016/j.physletb.2015.10.009

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Abstract

An observation of the Λb 0→ψ(2S)Λ0 decay and a comparison of its branching fraction with that of the Λb 0→J/ψΛ0 decay has been made with the ATLAS detector in proton–proton collisions at s=8 TeV at the LHC using an integrated luminosity of 20.6 fb−1. The J/ψ and ψ(2S) mesons are reconstructed in their decays to a muon pair, while the Λ0→pπ− decay is exploited for the Λ0 baryon reconstruction. The Λb 0 baryons are reconstructed with transverse momentum pT>10 GeV and pseudorapidity |η|<2.1. The measured branching ratio of the Λb 0→ψ(2S)Λ0 and Λb 0→J/ψΛ0 decays is Γ(Λb 0→ψ(2S)Λ0)/Γ(Λb 0→J/ψΛ0)=0.501±0.033(stat)±0.019(syst), lower than the expectation from the covariant quark model.

University of Melbourne Researchers

Federico Scutti Author

Elisabetta Barberio Author

Matteo Volpi Author

G. N. Taylor Author

Grants

Awarded by Departamento Administrativo de Ciencia, Tecnología e Innovación

Funding Acknowledgements

We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; RGC, Hong Kong SAR, China; ISF, MINERVA, GIF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW and NCN, Poland; GRICES and FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MIZS, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, United Kingdom; DOE and NSF, United States of America.