Event-by-event mean $p_{\rm T}$ fluctuations in pp and Pb-Pb collisions at the LHC

B. Abelev , Laurent Aphecetche (1) , Guillaume Batigne (1) , I. Belikov (2) , C. Cheshkov (3) , B. Cheynis (3) , H. Delagrange (1) , L. Ducroux (3) , B. Erazmus (1) , Magali Estienne (1) , J.-Y. Grossiord (3) , Maxime Guilbaud (3) , A. Lardeux (1) , A. Maire (2) , Gines Martinez Garcia (1) , J. Martin Blanco (1) , A. Mas (1) , L. Massacrier (1) , L. Molnar (2) , A. Morreale (1) , Philippe Pillot (1) , L. Ronflette (1) , C. Roy (2) , Y. Schutz (1) , Alexandre Shabetai (1) , Diego Stocco (1) , R. Tieulent (3) , A. Uras (3) , R. Vernet (4) , M. Wang (1) , Y. Zoccarato (3) , G. Conesa Balbastre (5) , J. Faivre (5) , C. Furget (5) , R. Guernane (5) , S. Kox (5) , J.S. Real (5) , C. Silvestre (5) , Y.W. Baek (6) , V. Barret (6) , N. Bastid (6) , A. Batista Camejo (6) , P. Crochet (6) , P. Dupieux (6) , Marie Germain (1) , S. Li (6) , X. Lopez (6) , F. Manso (6) , M. Marchisone (6) , S. Porteboeuf-Houssais (6) , P. Rosnet (6) , L. Valencia Palomo (6) , B. Vulpescu (6) , Z. Conesa Del Valle (7) , I. Das (7) , B. Espagnon (7) , C. Hadjidakis (7) , I. Lakomov (7) , C. Suire (7) , J. D. Tapia Takaki (7) , L. Valencia Palomo (7) , Alberto Baldisseri (8) , Herve Borel (8) , Javier Castillo Castellanos (8) , Jean-Luc Charvet (8) , Hugo Pereira da Costa (8) , A Rakotozafindrabe (9, 8)

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

Event-by-event fluctuations of the mean transverse momentum of charged particles produced in pp collisions at $\sqrt{s}$ = 0.9, 2.76 and 7 TeV, and Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV are studied as a function of the charged-particle multiplicity using the ALICE detector at the LHC. Non-statistical fluctuations are observed in all systems. The results in pp collisions show little dependence on collision energy. The Monte Carlo event generators PYTHIA and PHOJET are in qualitative agreement with the data. Peripheral Pb-Pb data exhibit a similar multiplicity dependence as that observed in pp. In central Pb-Pb, the results deviate from this trend, featuring a significant reduction of the fluctuation strength. The results in Pb-Pb are in qualitative agreement with previous measurements in Au-Au at lower collision energies and with expectations from models that incorporate collective phenomena.

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

B. Abelev, Laurent Aphecetche, Guillaume Batigne, I. Belikov, C. Cheshkov, et al.. Event-by-event mean $p_{\rm T}$ fluctuations in pp and Pb-Pb collisions at the LHC. European Physical Journal C: Particles and Fields, 2014, 74, pp.3077. ⟨10.1140/epjc/s10052-014-3077-y⟩. ⟨in2p3-01030781⟩