Measurement of the prompt-production cross-section ratio σ(χc2)/σ(χc1) in pPb collisions at √sNN = 8.16 TeV

Research output: Contribution to journalArticlepeer-review

Authors

  • LHCb Collaboration

Colleges, School and Institutes

External organisations

  • Nikhef National Institute for Subatomic Physics
  • University of Zurich
  • University of Liverpool
  • Universidad de Santiago de Compostela
  • University of Bristol
  • Université Clermont Auvergne
  • University of Michigan
  • Istituto Nazionale di Fisica Nucleare, Sezione di Milano
  • University of Cincinnati
  • TU Dortmund University, Germany
  • CERN
  • University of Glasgow
  • Universitat de Barcelona
  • University of Manchester
  • Petersburg Nuclear Physics Institute (PNPI)
  • University of Cambridge
  • Universidade Federal Do Rio de Janeiro
  • Paris-Saclay University
  • Sezione INFN di Firenze
  • Sezione INFN di Ferrara
  • Ruprecht-Karls-Universität Heidelberg
  • Institute for High Energy Physics (IHEP)
  • Syracuse University
  • Yandex School of Data Analysis
  • IN2P3
  • Ecole Polytechnique Federale de Lausanne
  • University of Warwick
  • Imperial College London
  • Sezione di Perugia
  • University of Ferrara
  • Chinese Academy of Sciences
  • Sezione di Genova

Abstract

This article reports the first measurement of prompt χc1 and χc2 charmonium production in nuclear collisions at Large Hadron Collider energies. The cross-section ratio σ(χc2)/σ(χc1) is measured in pPb collisions at √sNN = 8.16 TeV, collected with the LHCb experiment. The χc1,2 states are reconstructed via their decay to a J/ψ meson, subsequently decaying into a pair of oppositely charged muons, and a photon, which is reconstructed in the calorimeter or via its conversion in the detector material. The cross-section ratio is consistent with unity in the two considered rapidity regions. Comparison with a corresponding cross-section ratio previously measured by the LHCb Collaboration in pp collisions suggests that χc1 and χc2 states are similarly affected by nuclear effects occurring in pPb collisions.

Bibliographic note

Funding Information: 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); MICINN (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); DOE NP and 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 NERSC (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 ARC and ARDC (Australia); AvH Foundation (Germany); EPLANET, Marie Skłodowska-Curie Actions, and ERC (European Union); A*MIDEX, ANR, Labex P2IO and OCEVU, and Région Auvergne-Rhône-Alpes (France); Key Research Program of Frontier Sciences of CAS, CAS PIFI, CAS CCEPP, Fundamental Research Funds for the Central Universities, and Sci. & Tech. Program of Guangzhou (China); RFBR, RSF, and Yandex LLC (Russia); GVA, XuntaGal, and GENCAT (Spain); the Leverhulme Trust, the Royal Society, and UKRI (United Kingdom). Publisher Copyright: © 2021 CERN.

Details

Original languageEnglish
Article number064905
Number of pages10
JournalPhysical Review C
Volume103
Issue number6
Publication statusPublished - 9 Jun 2021

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