The jet fragmentation function of inclusive jets with transverse momentum $p_{\mathrm{T}}$ above $100\text{GeV}/c$ in PbPb collisions has been measured using reconstructed charged particles with $p_{\mathrm{T}}$ above $1\text{GeV}/c$ in a cone of radius 0.3 around the jet axis. A data sample of PbPb collisions collected in 2011 at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{{}_{\mathit{NN}}}}=2.76\text{TeV}$ corresponding to an integrated luminosity of $150\mu {\mathrm{b}}^{-1}$ is used. The results for PbPb collisions as a function of collision centrality and jet transverse momentum are compared to reference distributions based on $\mathit{pp}$ data collected at the same center-of-mass energy in 2013, with an integrated luminosity of $5.3{\text{pb}}^{-\text{1}}$. A centrality-dependent modification of the fragmentation function is found. For the most central collisions, a significant enhancement is observed in the PbPb/$\mathit{pp}$ fragmentation function ratio for charged particles with $p_{\mathrm{T}}$ less than $3\text{GeV}/c$. This enhancement is observed for all jet $p_{\mathrm{T}}$ bins studied.

• Received 3 June 2014

DOI:https://doi.org/10.1103/PhysRevC.90.024908

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©2014 CERN, for the CMS Collaboration