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Multiplicity dependence of the average transverse momentum in pp, p–Pb, and Pb–Pb collisions at the LHC

The average transverse momentum 〈pT〉 versus the charged-particle multiplicity Nch was measured in p–Pb collisions at a collision energy per nucleon–nucleon pair View the MathML source and in pp collisions at collision energies of View the MathML source in the kinematic range 0.15<pT<10.0 GeV/c and |η|<0.3 with the ALICE apparatus at the LHC. These data are compared to results in Pb–Pb collisions at View the MathML source at similar charged-particle multiplicities. In pp and p–Pb collisions, a strong increase of 〈pT〉 with Nch is observed, which is much stronger than that measured in Pb–Pb collisions. For pp collisions, this could be attributed, within a model of hadronizing strings, to multiple-parton interactions and to a final-state color reconnection mechanism. The data in p–Pb and Pb–Pb collisions cannot be described by an incoherent superposition of nucleon–nucleon collisions and pose a challenge to most of the event generators.

multiplicity; transverse momentum; pp; p-Pb; Pb-Pb; heavy ion; ALICE

The ALICE Collaboration