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

Submission Date: 
08/07/2013
Article Information
Submission Form
System: 
p-p
System: 
Pb-Pb
System: 
p-Pb
Energy: 
900 GeV
Energy: 
2.76 TeV
Energy: 
5.02 TeV
Energy: 
7 TeV
Abstract Plain Text: 

The average transverse momentum <p_T> versus the charged-particle multiplicity Nch was measured in p-Pb collisions at a collision energy per nucleon-nucleon pair sqrt(s_NN) = 5.02 TeV and in pp collisions at collision energies of sqrt(s) = 0.9, 2.76,  and 7 TeV in the kinematic range 0.15<p_T<10.0 GeV/c and  |eta|<0.3 with the ALICE apparatus at the LHC.  These data are compared to results in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV at similar charged-particle multiplicities. In pp and p-Pb collisions, a strong increase of <p_T> 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.