Jet fragmentation in two-particle correlations in pp, p–Pb and Pb–Pb collisions

The per-trigger normalized associated particle yield as a function of the pseudorapidity difference ($\Delta\eta{}$) was measured in Pb-Pb and pp collisions at $\sqrt{s_{\rm NN}}$~=~2.76 TeV. For the transverse momentum of the trigger hadron $8<p_{\rm T,trig}<15$ GeV/$c$ and the associated hadron $6<p_{\rm T,assoc}<8$ GeV/$c$ it is observed that the near side peak is narrower in central Pb-Pb collisions relative to the pp results. In peripheral Pb-Pb collisions, the near side peak width is comparable with pp.Furthermore, a detailed study is presented on the jet fragmentation transverse momentum distribution in p-Pb and pp collisions at $\sqrt{s_{\rm NN}}$~=~5.02 TeV and $\sqrt{s}$~=~7 TeV, respectively. The distribution exhibits two components, narrow and wide, that can be associated with hadronization and QCD radiation components in the jet fragmentation process, respectively. The shapes of these components measured in pp and p-Pb collisions agree within the experimental uncertainties.