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Charged-particle nuclear modification factors in PbPb and pPb collisions at $\sqrt{s_{\mathrm{NN}}}= $ 5.02 TeV

The CMS collaboration
JHEP, 2016

Abstract
The spectra of charged particles produced within the pseudorapidity window $| \eta | < $ 1 at $\sqrt{s_{\mathrm{NN}}}= $ 5.02 TeV are measured using 404 $ \mu $b$^{-1}$ of PbPb and 27.4 pb$^{-1}$ of pp data collected by the CMS detector at the LHC in 2015. The spectra are presented over the transverse momentum ranges spanning 0.5 $ < p_{\mathrm{T}} < $ 400 GeV in pp and 0.7 $ < p_{\mathrm{T}} < $ 400 GeV in PbPb collisions. The corresponding nuclear modification factor, ${R_\mathrm{AA}} $, is measured in bins of collision centrality. The ${R_\mathrm{AA}} $ in the 5% most central collisions shows a maximal suppression by a factor of 7-8 in the $p_{\mathrm{T}}$ region of 6-9 GeV. This dip is followed by an increase, which continues up to the highest $ p_{\mathrm{T}}$ measured, and approaches unity in the vicinity of $p_{\mathrm{T}}= $ 200 GeV. The ${R_\mathrm{AA}} $ is compared to theoretical predictions and earlier experimental results at lower collision energies. The newly measured pp spectrum is combined with the pPb spectrum previously published by the CMS Collaboration to construct the pPb nuclear modification factor, ${R_{\mathrm{ p }\mathrm{A}}} $, up to 120 GeV. For $ p_{\mathrm{T}} > $ 20 GeV, ${R_{\mathrm{ p }\mathrm{A}}} $ exhibits weak momentum dependence and shows a moderate enhancement above unity.

  • Table 1

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t1

    Charged-particle per-event yields measured in 0-5% PbPb centrality class.

  • Table 2

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t2

    Charged-particle per-event yields measured in 5-10% PbPb centrality class.

  • Table 3

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t3

    Charged-particle per-event yields measured in 10-30% PbPb centrality class.

  • Table 4

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t4

    Charged-particle per-event yields measured in 30-50% PbPb centrality class.

  • Table 5

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t5

    Charged-particle per-event yields measured in 50-70% PbPb centrality class.

  • Table 6

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t6

    Charged-particle per-event yields measured in 70-90% PbPb centrality class.

  • Table 7

    Data from Fig. 2

    10.17182/hepdata.77101.v2/t7

    Charged-particle per-event yields measured in pp collisions. A factor of 70 mb is used to scale the pp spectrum from...

  • Table 8

    Data from Fig. 3 Top Left Panel

    10.17182/hepdata.77101.v2/t8

    PbPb nuclear modification factor measured in 0-5% PbPb centrality class.

  • Table 9

    Data from Fig. 3 Top Right Panel

    10.17182/hepdata.77101.v2/t9

    PbPb nuclear modification factor measured in 5-10% PbPb centrality class.

  • Table 10

    Data from Fig. 3 Middle Left Panel

    10.17182/hepdata.77101.v2/t10

    PbPb nuclear modification factor measured in 10-30% PbPb centrality class.

  • Table 11

    Data from Fig. 3 Middle Right Panel & Fig. 4 Right Panel

    10.17182/hepdata.77101.v2/t11

    PbPb nuclear modification factor measured in 30-50% PbPb centrality class.

  • Table 12

    Data from Fig. 3 Bottom Left Panel

    10.17182/hepdata.77101.v2/t12

    PbPb nuclear modification factor measured in 50-70% PbPb centrality class.

  • Table 13

    Data from Fig. 3 Bottom Right Panel

    10.17182/hepdata.77101.v2/t13

    PbPb nuclear modification factor measured in 70-90% PbPb centrality class.

  • Table 14

    Data from Fig. 4 Left Panel

    10.17182/hepdata.77101.v2/t14

    PbPb nuclear modification factor measured in 0-10% PbPb centrality class.

  • Table 15

    Data from Fig. 6

    10.17182/hepdata.77101.v2/t15

    PbPb nuclear modification factor measured in 0-100% PbPb centrality class.

  • Table 16

    Data from Fig. 6

    10.17182/hepdata.77101.v2/t16

    pPb nuclear modification factor.

Version 2 modifications: Table 3, the entry for pT 73.6-86.4 GeV, a missing 'e' for the scientific notation was added.

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