APH N.S., Heavy Ion Physics 16/1–4 (2002) 153–161 HEAVY ION PHYSICS c Akad´ emiai Kiad´ o The PHOBOS Experiment at RHIC Edmundo Garcia 6 for the PHOBOS Collaboration B.B. Back, 1 M.D. Baker, 2 D.S. Barton, 2 R.R. Betts, 1,6 R. Bindel, 7 A. Budzanowski, 3 W. Busza, 4 A. Carroll, 2 M.P. Decowski, 4 N. George, 1 K. Gulbrandsen, 4 S. Gushue, 2 C. Halliwell, 6 G.A. Heintzelman, 2 C. Henderson, 4 D.J. Hofman, 6 R. Holy´ nski, 3 B. Holzman, 2,6 E. Johnson, 8 J.L. Kane, 4 J. Katzy, 4,6 N. Khan, 8 W. Kucewicz, 6 P. Kulinich, 4 W.T. Lin, 5 S. Manly, 8 D. McLeod, 6 J. Michalowski, 3 A.C. Mignerey, 7 J. M¨ ulmenst¨ adt, 4 R. Nouicer, 6 A. Olszewski, 2,3 R. Pak, 2 I.C. Park, 8 H. Pernegger, 4 C. Reed, 4 L.P. Remsberg, 2 M. Reuter, 6 C. Roland, 4 G. Roland, 4 L. Rosenberg, 4 P. Sarin, 4 P. Sawicki, 3 W. Skulski, 8 S.G. Steadman, 4 P. Steinberg, 2 G.S.F. Stephans, 4 M. Stodulski, 3 A. Sukhanov, 2 J.-L. Tang, 5 R. Teng, 8 A. Trzupek, 3 C. Vale, 4 G.J. van Nieuwenhuizen, 4 R. Verdier, 4 B. Wadsworth, 4 F.L.H. Wolfs, 8 B. Wosiek, 3 K. Wo´ zniak, 3 A.H. Wuosmaa 1 and B. Wys louch 4 1 Argonne National Laboratory, Argonne, IL 60439, USA 2 Brookhaven National Laboratory, Upton, NY 11973, USA 3 Institute of Nuclear Physics, Krak´ ow, Poland 4 Massachusetts Institute of Technology, Cambridge, MA 02139, USA 5 National Central University, Chung-Li, Taiwan 6 University of Illinois at Chicago, IL 60607, USA 7 University of Maryland, College Park, MD 20742, USA 8 University of Rochester, Rochester, NY 14627, USA Received 21 November 2001 Abstract. Since June 2000, the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory has delivered the first collisions be- tween Au nuclei at the highest center of mass energies achieved in the laboratory to date. PHOBOS is one of four experiments studying the Au + Au interactions at RHIC. In this paper we will describe the PHO- BOS experiment, and discuss some of the current physics results ob- tained for Au + Au collisions at √ s NN = 56 and 130 and 200 GeV. They include the study of the charged particle multiplicity as a func- tion of pseudo-rapidity and centrality, and the measurements of the anti- 1219-7580/02/ $ 5.00 c  2002 Akad´ emiai Kiad´ o, Budapest