Measurement of the prompt-production cross-section ratio σ ( χ c 2 ) / σ ( χ c 1 ) in p Pb collisions at √ s N N = 8.16 TeV

K. De Bruyn, C. J. G. Onderwater, M. van Veghel, LHCb Collaboration

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This article reports the first measurement of prompt chi(c1) and chi(c2) charmonium production in nuclear collisions at Large Hadron Collider energies. The cross-section ratio sigma(chi(c2))/sigma(chi(c1)) is measured in pPb collisions at root s(NN) = 8.16 TeV, collected with the LHCb experiment. The chi(c1,2) states are reconstructed via their decay to a J/psi 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 chi(c1) and chi(c2) states are similarly affected by nuclear effects occurring in pPb collisions.
Original languageEnglish
Article number064905
Number of pages10
JournalPhysical Review C
Issue number6
Publication statusPublished - 9-Jun-2021


  • J/PSI
  • LEAD

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