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

B. Abelev , Laurent Aphecetche (1) , Y.W. Baek (2) , A. Baldisseri (3) , V. Barret (2) , N. Bastid (2) , Guillaume Batigne (1) , H. Borel (3) , M. Bregant (1) , J.L. Charvet (3) , B. Cheynis (4) , C. Cheshkov (4) , P. Crochet (2) , H. Delagrange (1) , L. Ducroux (4) , B. Erazmus (1) , Magali Estienne (1) , Marie Germain (1) , J.-Y. Grossiord (4) , Maxime Guilbaud (4) , B. Hippolyte (2) , R. Ichou (2) , C. Kuhn (2) , A. Lardeux (1) , S. Li (2) , X. Lopez (2) , F. Manso (2) , M. Marchisone (2) , J. Martin Blanco (1) , Gines Martinez Garcia (1) , A. Mas (1) , L. Massacrier (1) , L. Molnar (5) , H. Pereira da Costa (3) , Philippe Pillot (1) , S. Porteboeuf-Houssais (2) , A. Rakotozafindrabe (1) , P. Rosnet (2) , C. Roy (5) , X. Sanchez Castro (5) , Y. Schutz (1) , S. Senyukov (5) , Alexandre Shabetai (1) , Diego Stocco (1) , R. Tieulent (4) , A. Uras (4) , R. Vernet (6) , B. Vulpescu (2) , X. Zhang (2) , Y. Zoccarato (4) , N. Arbor (7) , G. Conesa Balbastre (7) , J. Faivre (7) , C. Furget (7) , R. Guernane (7) , S. Kox (7) , J.S. Real (7) , C. Silvestre (7) , Z. Conesa Del Valle (8) , I. Das (8) , B. Espagnon (8) , C. Hadjidakis (8) , I. Lakomov (8) , C. Suire (8) , J. D. Tapia Takaki (8) , L. Valencia Palomo (8)

1 SUBATECH - Laboratoire SUBATECH Nantes
2 LPC - Laboratoire de Physique Corpusculaire - Clermont-Ferrand
3 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
4 IPNL - Institut de Physique Nucléaire de Lyon
5 IPHC - Institut Pluridisciplinaire Hubert Curien
6 CC-IN2P3 - Centre de Calcul de l'IN2P3
7 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
8 IPNO - Institut de Physique Nucléaire d'Orsay

The average transverse momentum versus the charged-particle multiplicity N_ch 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 with N_ch 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.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]; Physique Nucléaire Expérimentale [nucl-ex]

B. Abelev, Laurent Aphecetche, Y.W. Baek, A. Baldisseri, V. Barret, et al.. Multiplicity dependence of the average transverse momentum in pp, p-Pb, and Pb-Pb collisions at the LHC. Physics Letters B, 2013, 727, pp.371-380. ⟨10.1016/j.physletb.2013.10.054⟩. ⟨in2p3-00841162⟩