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Measurements with BRAHMS

Measurements with BRAHMS. I.G. Bearden, Niels Bohr Institute For The BRAHMS collaboration. The BRAHMS Collaboration. - 12 institutions-. I.Arsene 10 ,I.G. Bearden 7 , D. Beavis 1 , C. Besliu 10 , Y. Blyakhman 6 , J.Brzychczyk 4 ,

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Measurements with BRAHMS

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  1. Measurements with BRAHMS I.G. Bearden, Niels Bohr Institute For The BRAHMS collaboration Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  2. The BRAHMS Collaboration - 12 institutions- I.Arsene10,I.G. Bearden7, D. Beavis1, C. Besliu10, Y. Blyakhman6, J.Brzychczyk4, B. Budick6,H. Bøggild7 ,C. Chasman1, C. H. Christensen7, P. Christiansen7, J.Cibor4,R.Debbe1,J. J. Gaardhøje7,M. Germinario7, K. Hagel8, O. Hansen7, H. Ito11, E. Jacobsen7, A. Jipa10, J. I. Jordre10, F. Jundt2, C.E.Jørgensen7, E. J. Kim5, T. Kozik3, T.M.Larsen12, J. H. Lee1, Y. K.Lee5, G. Løvhøjden2, Z. Majka3, A. Makeev8, B. McBreen1, M. Murray8, J. Natowitz8, B. Neuman11,B.S.Nielsen7, K. Olchanski1, D. Ouerdane7, R.Planeta4, F. Rami2, D. Roehrich9, B. H. Samset12, S. J. Sanders11, I. S. Sgura10, R.A.Sheetz1, Z.Sosin3, P. Staszel7, T.S. Tveter12, F.Videbæk1, R. Wada8 ,A.Wieloch3,Z. Yin9 1Brookhaven National Laboratory, USA, 2IReS and Université Louis Pasteur, Strasbourg, France 3Jagiellonian University, Cracow, Poland, 4Institute of Nuclear Physics, Cracow, Poland 5Johns Hopkins University, Baltimore, USA, 6New York University, USA 7Niels Bohr Institute, Blegdamsvej 17, University of Copenhagen, Denmark 8Texas A&M University, College Station. USA, 9University of Bergen, Norway 10University of Bucharest, Romania,11University of Kansas, Lawrence,USA 12 University of Oslo Norway Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  3. The BRAHMS Experiment Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  4. Sys. Error : 8% 10% 0-5% 5-10% 10-20 Charged Particle MultiplicitydN/dh According to Bjorken, e>5GeV/fm3 Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  5. AMPT High density QCD gluon saturation Kharzeev and Levin, PLB523(2001)79 h=0 h=1 h=4 Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  6. Particle Spectra After appropriate corrections, we combinine all data sets to obtain final invariant yields over a broad range of rapidity and pT p K p Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  7. Pions: power law Kaons: exponential Protons: Gaussian Particle Spectra Top 5% central collisions Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  8. Rapidity Densities At y ~ 0, dN/dy is ~ 300 (300) for + (-) ~ 47 (44) for K+ (K) ~ 27 (20) for p (pbar) N() >> N(K) > N(p) N(+) = N() N(K+) > N(K) and N(p) > N(pbar) systematically Integrated multiplicities (Gaussian fit) N() ~ 1780 N(+) ~1760 N(K+) ~ 290 N(K) ~ 240 N(pbar) ~ 85 Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  9. Net-proton measured up to y = 3 AGS : high stopping RHIC: more transparent Nuclear Stopping Net-proton rapidity densities (top 5% central collisions) BRAHMS, submitted to PRL, nucl-ex/0312023 P. Christiansen Ph.D. Thesis Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  10. Rapidity loss: Gaussians in pz: Gaussians in pz: 2.03  0.16 empirical scaling 2.00  0.10 6 order polynomial scaling broken Total E=25.72.1TeV Nuclear Stopping Net-baryon after feed-down & neutron corrections Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  11. Energy (in GeV) p : 3108 p : 428 K+ : 1628 K- : 1093 + : 5888 - : 6117 • 0 : 6004 • n : 3729 • n : 513 • K0 : 1628 • K0 : 1093 •  : 1879 • : 342 sum: 33.4 TeV produced: 24.8TeV • 35 TeV (EbeamNpart) • of which 25 TeV are • carried by produced • particles. NB: the method is very sensitive to the tails of the dN/dy dist. (10-15%) Energy Balance • Fit , K and p distributions (dN/dy and mT vs y) •  total energy of , K and p • Assume reasonable distribution • for particles we don’t detect (0,n,…) • Calculate the total energy… Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  12. Increasing y Y < 1 : consistent with Hadron Gas Stat. Model K+/+ : 15.6  0.1 % (stat) K/ : 14.7  0.1 % (stat) [Phys. Lett. B 518 (2001) 41] Divergence at higher y : Associated K+ production No single source with unique T and B BRAHMS, PRL90 (2003) 102301 T~constant, Bvaries with y 63 GeV Strangeness with Kaons RAPIDITY DEPENDENCE Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  13. no change for + Over the full phase space: K+/+ = 16.6  1.5 % (syst) K/ = 13.7  2.0 % (syst) Why this behavior ? Net-Kaon distribution evolves like net-proton ENERGY DEPENDENCE At y = 0, ratios converge to ~ 15 % Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  14. Transverse Flow… p p Points: BRAHMS Data Curves: 3D Hydro (Hirano) Histos: AMPT Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  15. Spectra with BW Fits at y~0,1,2,3(T,bs,ain the fit Rmax=13fm) BRAHMS Preliminary Fix a,T y~0 y~1 Fix a,b y~2 y~3 Riken BNL Workshop I.G.Bearden, Niels Bohr Institute pT (GeV/c)

  16. jet parton nucleon nucleon Jets at RHIC Find this……….in this And, in BRAHMS, we only “see” this much… p+p jet+jet (STAR@RHIC) Au+Au ??? (STAR@RHIC) Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  17. Characterize “high” pT by single particle spectra h=0 h=2.2 Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  18. Arsene et al.PRL2003 To look at ‘only’ data, form ratioRh=Rcp(h=2.2)/Rcp(h=0) Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  19. d+Au Nuclear Modification h =0 High pT enhancement observed in d+Au collisions at sNN=200 GeV. • Comparing Au+Au to d+Au • strong effect of dense medium Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  20. Predictions from theory D. Kharzeev et al. Phys.Rev.D68:094013,2003 I. Vitev nucl-th/0302002 v2 CGC at y=0 Y=0 As y grows Y=3 Y=-3 Very high energy Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  21. RdAu Croninlike enhancement at =0. Clear suppression as  changes up to 3.2 Same ratio made with dn/d follows the low pT RdAu 1 d2Nd+Au/dpTdh RdA= <Ncoll> d2Nppinel/dpTdh where < Ncoll> = 7.2±0.3 Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  22. Preliminary central h~3 Periph. pbar/- ratio probes extent of new medium in y p+p d+Au Au+Au Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  23. Preliminary results from 63GeV Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  24. Preliminary results from 63GeV Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  25. High energy density Gluon saturation describes data, though not uniquely 70% of energy available for particle production Source (nearly) same over >1 unit rapidity High pT suppression persists to high y in Au+Au Grows vs y in d+Au Lots left to do… Conclusions Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

  26. Reference Spectrum ISR DATA h=1 Fit to ISR (R203) DATA Global Parameterization Of ISR DATA Riken BNL Workshop I.G.Bearden, Niels Bohr Institute

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