1. Nuclear modification factor for identified hadrons at forward rapidity in Au+Au reactions at 200GeV
Radoslaw Karabowicz
for the BRAHMS Collaboration
Marian Smoluchowski Institute of Physics,
Jagiellonian University, Kraków, Poland

2. BRAHMS experiment 2 Tracking Detectors Magnets Data analyzed:
Au+Au, p+p at sqrt(s_NN)=200GeV 2

3. RICH Pid RICH Pid – 3 sigma cut.
r [cm]
m2 [GeV2/c4]
RICH Pid – 3 sigma cut.
In the overlapping regions Pid based on statistical weighting of Gaussian distibution
in r.
p [GeV/c] 3

4. y-pT map coverage 4 Different colors – different angle and
field settings
trigger normalization
acceptance
tracking efficiency
Pid efficiency
Au+Au 200 AGeV pions 4

5. pT spectra 7

6. RCP in Au+Au @ 200 AGeV RCP = 6 [(d2NAu+Au/dpTdy)/<Ncoll>]0-10%

7. RAA in Au+Au @ 200 AGeV RAA = 6 7 1 d2NAu+Au/dpTdy
<Ncoll> d2Nppinel/dpTdy 6 7
Increase of ratios with decreasing centrality
Pions and kaons ratios flat
Protons show Cronin peak at pt=2

8. RAA comparison with RCP
RCP and RAA are consistent for pions and kaons
For protons RCP shows suppression, while RAA shows enhancement 8

9. RAA for pions at forward rapidities agrees with RAA at midrapidity
RAA at y=0 and y=3.1
RAA for pions at forward rapidities agrees with RAA at midrapidity 9

10. RCP at y=0 and y=3.1
RCP for pions at forward rapidities copies the behaviour of RCP at midrapidity 10

11. RCP at y=0 and y=3.0
For protons however data at forward rapidity show significant suppression in RCP 11

12. RdAu compared with RAA 12

13. SUMMARY
identified particle yields has been measured by BRAHMS at forward rapidity for Au+Au and p+p collisions
RAA shows significant suppression for pions and kaons, but for protons it shows enhancement
RCP and RAA are consistent for pions and kaons, but deviate for protons
no difference in pion RAA between midrapidity (PHENIX p0) and forward rapidity (BRAHMS p++p-/2) consistent with surface jet-emission
baryons’ RCP shows suppression at forward rapidities in contrast with midrapidity
pions RAA shows stronger suppression as compared to RdAu 13

14. The BRAHMS Collaboration
I.Arsene11, I.G. Bearden6, D. Beavis1, S.Bekele10, C. Besliu9, B. Budick5, H. Bøggild6 ,
C. Chasman1, C. H. Christensen6, P. Christiansen6, R.Clarke9, R.Debbe1,
J. J. Gaardhøje6, K. Hagel7, H. Ito1, A. Jipa9, J. I. Jordre9, F. Jundt2, E.B.Johnson10,
J.I.Jordre8, C.Jørgensen6, R. Karabowicz3, E. J. Kim10, T.M.Larsen6, J. H. Lee1,
Y. K.Lee4, S.Lindal11, G. Løvhøjden2, Z. Majka3, M. Murray10, J. Natowitz7, B.S.Nielsen6,
D.Ouerdane6, R.Planeta3, F. Rami2, C.Ristea6, O.Ristea9,
D. Röhrich8, B. H. Samset11, S. J. Sanders10, R.A.Sheetz1, P. Staszel3, T.S. Tveter11,
F.Videbæk1, R. Wada7, H.Yang8, Z. Yin8, and I. S. Zgura9
1Brookhaven National Laboratory, USA, 2IReS and Université Louis Pasteur, Strasbourg, France
3Jagiellonian University, Cracow, Poland,
4Johns Hopkins University, Baltimore, USA, 5New York University, USA
6Niels Bohr Institute, University of Copenhagen, Denmark
7Texas A&M University, College Station. USA, 8University of Bergen, Norway
9University of Bucharest, Romania, 10University of Kansas, Lawrence,USA
11 University of Oslo Norway
48 physicists from 11 institutions 14