1. Charged-particle pseudorapidity densities in d-Au collisions at  s=200GeV/A Hironori Ito Brookhaven National Laboratory BRAHMS Collaboration

2. I.G. Bearden 7, D. Beavis 1, C. Besliu 10, Y. Blyakhman 6, J. Bondorf 7, J.Brzychczyk 4, B. Budick 6, H. Bøggild 7, C. Chasman 1, C. H. Christensen 7, P. Christiansen 7, J.Cibor 4, R.Debbe 1, J. J. Gaardhøje 7, K. Grotowski 4, K. Hagel 8, O. Hansen 7, H. Heiselberg 7, A. Holm 7, A.K. Holme 12, H. Ito 11, E. Jacobsen 7, A. Jipa 10, J. I. Jordre 10, F. Jundt 2, C. E. Jørgensen 7, T. Keutgen 9, E. J. Kim 5, T. Kozik 3, T.M.Larsen 12, J. H. Lee 1, Y. K.Lee 5, G. Løvhøjden 2, Z. Majka 3, A. Makeev 8, B. McBreen 1, M. Murray 8, J. Natowitz 8, B.S.Nielsen 7, K. Olchanski 1, D. Ouerdane 7, R.Planeta 4, F. Rami 2, D. Roehrich 9, B. H. Samset 12, S. J. Sanders 11, I. S. Sgura 10, R.A.Sheetz 1, Z.Sosin 3, P. Staszel 7, T.S. Tveter 12, F.Videbæk 1, R. Wada 8 and A.Wieloch 3. 1Brookhaven National Laboratory, USA 2IreS and Université Louis Pasteur, Strasbourg, France 3Jagiellonian Univeristy, Cracow, Poland 4Institute of Nuclear Physics, Cracow, Poland 5Johns Hopkins University, Baltimore, USA 6New York University, USA 7Niels Bohr Institude, University of Copenhagen, Denmark 8Texas A&M University, College Station, USA 9University of Bergen, Norway 10University of Bucharest, Romania 11University of Kansas, Lawrence, USA 12University of Oslo, Norway Member of the BRAHMS Collaboration

3. Beam-Beam Counter Arrays Right Array Left Array Two Arrays located at 219 cm from the nominal collision vertex along the beam axis on either size of the vertex Two sizes of Cherenkov radiator --- Diameter of ¾ in and 2 in Pseudorapidity coverage at nominal vertex location: --- 3 <  < 4.2

4. Multiplicity Arrays Two Layers of Multiplicity Arrays 1. Silicon Strip Multiplicity Array (SiMA) --- 175 detector channels --- Si strip dimension.86 cm x 4 cm x.3 mm 2. Scintillation Tile Multiplicity Array (TMA) --- 38 tiles --- Tile dimension 12 cm x 12 cm x.5 cm TMA SiMA At nominal vertex location, two arrays cover  <2.2

5. Centrality determination 0-30% central 30-60% central Average charged-particle multiplicities from silicon and scintilator tile detectors determine event centralities. Forward energy in Zero-degree calorimeter is used to exclude peripheral collisions. Preliminary

6. Pseudorapidity density Square box --- Beam-beam counter Circle --- Multiplicity detector Blue marker --- Systematic errors 0-30% Central Events 30-60% Central Events Preliminary

7. Model comparison 0-30% Central Events 30-60% Central Events Red line: Saturation model(hep-ph/0212316), Green line: Hijing model (centrality selection by impact parameter) Pink line: Hijing model (centrality selection by numbers of charged particles) Preliminary

8. Pseudorapididty dependence (deuteron fragmentation region) Circle --- η = 0 Square --- η = 1 Up triangle --- η = 2 Down triangle --- η = 3 Saturation model Hijing model 0-30% Central 30-60% Central 0-30% Central 30-60% Central Preliminary

9. Pseudorapididty dependence (Au fragmentation region) Circle --- η = 0 Square --- η = 1 Up triangle --- η = 2 Down triangle --- η = 3 Saturation model Hijing model 30-60% Central 0-30% Central 30-60% Central Preliminary

10. Summary Charged-particle pseudorapidty densities in d-Au collisions have been measured at  s=200 GeV/A. Centrality-dependent charged-particle productions are compared with two different models. Experimental results are largely in line with Hijing model prediction.