Prompt and non-prompt J/ψ and ψ(2S) suppression at high transverse momentum in 5.02 TeV Pb+Pb collisions with the ATLAS experiment

Abstract

Ajuts: We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of MINECO, Spain and EPLANET, ERC, ERDF, FP7, Horizon 2020 and Marie Skłodowska-Curie Actions, European Union and CERCA Programme Generalitat de Catalunya. ; A measurement of and production is presented. It is based on a data sample from Pb+Pb collisions at and pp collisions at recorded by the ATLAS detector at the LHC in 2015, corresponding to an integrated luminosity of and in Pb+Pb and pp, respectively. The measurements of per-event yields, nuclear modification factors, and non-prompt fractions are performed in the dimuon decay channel for GeV in dimuon transverse momentum, and in rapidity. Strong suppression is found in Pb+Pb collisions for both prompt and non-prompt , increasing with event centrality. The suppression of prompt is observed to be stronger than that of , while the suppression of non-prompt is equal to that of the non-prompt within uncertainties, consistent with the expectation that both arise from b -quarks propagating through the medium. Despite prompt and non-prompt arising from different mechanisms, the dependence of their nuclear modification factors on centrality is found to be quite similar.