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Issue Eur. Phys. J. C Volume 61, Number 4, June 2009 Hard Probes 2008 Page(s) 575 - 582 Section Regular Article - Experimental Physics DOI 10.1140/epjc/s10052-009-0911-8 Published online 10 February 2009

Eur. Phys. J. C 61, 575-582 (2009)
DOI: 10.1140/epjc/s10052-009-0911-8

Recent results from PHOBOS on particle production at high p _T

PHOBOS Collaboration, B. Alver¹, B. B. Back², M. D. Baker³, M. Ballintijn¹, D. S. Barton³, R. R. Betts⁴, A. A. Bickley⁵, R. Bindel⁵, W. Busza¹, A. Carroll³, Z. Chai³, V. Chetluru⁴, M. P. Decowski¹, E. García⁴, T. Gburek⁶, N. George³, K. Gulbrandsen¹, C. Halliwell⁴, J. Hamblen⁷, I. Harnarine⁴, M. Hauer³, C. Henderson¹, D. J. Hofman⁴, R. S. Hollis⁴, R. Holyński⁶, B. Holzman³, A. Iordanova⁴, E. Johnson⁷, J. L. Kane¹, N. Khan⁷, P. Kulinich¹, C. M. Kuo⁸, W. Li¹, W. T. Lin⁸, C. Loizides¹, S. Manly⁷, A. C. Mignerey⁵, R. Nouicer³, A. Olszewski⁶, R. Pak³, C. Reed¹, E. Richardson⁵, C. Roland¹, G. Roland¹, J. Sagerer⁴, H. Seals³, I. Sedykh³, C. E. Smith⁴, M. A. Stankiewicz³, P. Steinberg³, G. S. F. Stephans¹, A. Sukhanov³, A. Szostak³, M. B. Tonjes⁵, A. Trzupek⁶, C. Vale¹, G. J. van Nieuwenhuizen¹, S. S. Vaurynovich¹, R. Verdier¹, G. I. Veres¹, P. Walters⁷, E. Wenger¹, D. Willhelm⁵, F. L. H. Wolfs⁷, B. Wosiek⁶, K. Woźniak⁶, S. Wyngaardt³ and B. Wysłouch<sup>1

1</sup>  Massachusetts Institute of Technology, Cambridge, MA, 02139-4307, USA
²  Argonne National Laboratory, Argonne, IL, 60439-4843, USA
³  Brookhaven National Laboratory, Upton, NY, 11973-5000, USA
⁴  University of Illinois at Chicago, Chicago, IL, 60607-7059, USA
⁵  University of Maryland, College Park, MD, 20742, USA
⁶  Institute of Nuclear Physics PAN, Kraków, Poland
⁷  University of Rochester, Rochester, NY, 14627, USA
⁸  National Central University, Chung-Li, Taiwan

gabor.veres@cern.ch

Received 15 September 2008 / Revised version 6 January 2009 / Published online 10 February 2009

Abstract

A selection of experimental results from the PHOBOS Collaboration relevant for probing high-energy nuclear collisions with high transverse momentum particles is presented. The inclusive yields of charged particles and comparisons between nuclear and elementary collisions already reveal a large amount of parton energy loss in the hot and dense medium created in heavy ion collisions. Remarkable scaling and factorization features are observed, unifying the data taken at various collision energies, centralities and nuclear sizes. To further analyze the nature of the energy loss, a measurement of pseudorapidity (Δη) and azimuthal angle (Δφ) correlations between high transverse momentum charged hadrons (p _T >2.5 GeV/c) and all associated charged particles is presented at both short-range (small Δη) and long-range (large Δη) over a continuous detector acceptance covering −4<Δη<2. Various near- and away-side features of the correlation structure are discussed as a function of centrality in Au + Au collisions at  GeV. The results provide new information about the longitudinal (Δη) extent of the near-side ‘ridge’ structure, first observed by the STAR Collaboration over a narrower η range. In central Au + Au collisions the ridge structure extends to at least Δη=4, and its strength completely diminishes as collisions become more peripheral.

Presenter of the paper on the 3rd International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, 8–14 June 2008, Illa da Toxa (Galicia-Spain).

Correspondence: gabor.veres@cern.ch


© Società Italiana di Fisica, Springer-Verlag 2009

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