Transverse-momentum spectra in Au+Au and d+Au collisions at sqrt[s(NN)]=200 GeV and the pseudorapidity dependence of high-p(T) suppression.

Journal: Physical Review Letters
Published:
Abstract

We present spectra of charged hadrons from Au+Au and d+Au collisions at sqrt[s(NN)]=200 GeV measured with the BRAHMS experiment at RHIC. The spectra for different collision centralities are compared to spectra from p+(-)p collisions at the same energy scaled by the number of binary collisions. The resulting ratios (nuclear modification factors) for central Au+Au collisions at eta=0 and eta=2.2 evidence a strong suppression in the high p(T) region (>2 GeV/c). In contrast, the d+Au nuclear modification factor (at eta=0) exhibits an enhancement of the high p(T) yields. These measurements indicate a high energy loss of the high p(T) particles in the medium created in the central Au+Au collisions. The lack of suppression in d+Au collisions makes it unlikely that initial state effects can explain the suppression in the central Au+Au collisions.

Authors
I Arsene, I Bearden, D Beavis, C Besliu, B Budick, H Bøggild, C Chasman, C Christensen, P Christiansen, J Cibor, R Debbe, E Enger, J Gaardhøje, M Germinario, K Hagel, O Hansen, A Holm, H Ito, A Jipa, F Jundt, J Jørdre, C Jørgensen, R Karabowicz, E Kim, T Kozik, T Larsen, J Lee, Y Lee, S Lindal, G Lystad, G Løvhøiden, Z Majka, A Makeev, B Mcbreen, M Mikelsen, M Murray, J Natowitz, B Neumann, B Nielsen, J Norris, D Ouerdane, R Płaneta, F Rami, C Ristea, O Ristea, D Röhrich, B Samset, D Sandberg, S Sanders, R Scheetz, P Staszel, T Tveter, F Videbaek, R Wada, Z Yin, I Zgura