Particle Production as a Function of Underlying-event Activity and Search for Jet-like Modifications in \(pp\), \(p\)–Pb, and Pb–Pb Collisions at \(\sqrt {s_{NN}}=5.02\)\thinspace TeV with ALICE

The charged-particle multiplicity in the transverse region, \(N^{\mathrm {T}}_{\mathrm {ch}}\), which is sensitive to the underlying event, is studied. Measurements of charged-particle production as a function of \(N^{\mathrm {T}}_{\mathrm {ch}}\) in \(pp\), \(p\)–Pb, and Pb–Pb collisions at \(\sqrt {s_{NN}}=5.02\) TeV in the toward, away, and transverse regions are discussed. These regions are defined relative to the track with the largest transverse momentum in the event (\(p_{\mathrm {T}}^{\mathrm {trig}}\)). The activity in the transverse region is subtracted from the activity in the toward and away regions to search for jet-like modifications in small collision systems. The jet-like signals are studied both as a function of \(N^{\mathrm {T}}_{\mathrm {ch}}\) and \(p_{\mathrm {T}}^{\mathrm {trig}}\). Results are compared with two general-purpose Monte Carlo event generators: PYTHIA 8 and EPOS LHC.