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BRAHMS at RHIC Au+Au, d+Au @ s nn =200 GeV

BRAHMS at RHIC Au+Au, d+Au @ s nn =200 GeV. 100 AGeV + 100 AGeV Au+Au Ecm = s  40 TeV THE LITTLE BIG BANG and search for Quark Gluon Plasma.  5000 charged hadrons produced per central Au + Au collision. Nuclear Transparency, Bjorken boost invariant plateau?

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BRAHMS at RHIC Au+Au, d+Au @ s nn =200 GeV

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  1. BRAHMS at RHICAu+Au, d+Au @ snn=200 GeV • 100 AGeV + 100 AGeV Au+Au Ecm = s  40 TeV THE LITTLE BIG BANG and search for Quark Gluon Plasma. •  5000 charged hadrons produced per central Au + Au collision. • Nuclear Transparency, Bjorken boost invariant plateau? • Towards nuclear ’stuff’ with matter-antimatter balance • Equilibrated matter ? • High pt suppression, the smoking gun of QGP? NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  2. NIM, A499 (2003) 437 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  3. Global: || < 5 BRAHMS:The forward experiment FS:TPC, TOF, Cherenkov 2.5 - 30 deg.  = 1.5 - 4 MRS:TPC, TOF 30 - 90 deg. = 0 - 1.5 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  4. BRAHMS Intl. collaboration I.G. Bearden7, D. Beavis1, C. Besliu10, Y. Blyakhman6, J. Bondorf7, J.Brzychczyk4, B. Budick6, H. Bøggild7, C. Chasman1, C. H. Christensen7, P. Christiansen7, J.Cibor4, R.Debbe1, J. J. Gaardhøje7, M. Germinario7, K. Grotowski4, K. Hagel8, O. Hansen7, A. Holm7, A.K. Holme12, H. Ito11, E. Jacobsen7, A. Jipa10, J. I. Jordre10, F. Jundt2,C. E. Jørgensen7,T. Keutgen9, 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.S.Nielsen7, K. Olchanski1, D. Ouerdane7, R.Planeta4, F. Rami2, D. Roehrich9, B. H. Samset12, S. J. Sanders11, D. Sandberg7,I. S. Sgura10, R.A.Sheetz1, Z.Sosin3, P. Staszel7, T.S. Tveter12, F.Videbæk1, R. Wada8 and A.Wieloch3. 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, Denmark8Texas A&M University, College Station. USA 9University of Bergen, Norway 10University of Bucharest, Romania 11University of Kansas, Lawrence,USA 12 University of Oslo Norway NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  5. m2=p2( t2 / L2 -1) Excellent Hadron ID by TOF and RICH p D D K  NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  6. BRAHMS acceptanceMany fields and angles … NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  7. Hadron spectra vs. Pt, rapidity and centrality a sample of Djamels spectra vs y f. eks pions. NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  8. dN/dy 0 y dN/dy dN/dy 0 y y 0 Stopping, transparency, & boost invariance NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  9. Stopping or transparency at RHIC ? NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  10. Net Proton yield for Au+Au at snn=200 GeV Net protons = N(p)-N(anti-p) A measure of the baryon transport BRAHMS Preliminary Observed protons: only part of the story. Corrections needed for other hadrons (n, , , etc…) Central (Bjorken) Plateau ? NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  11. Transparency at RHIC Relative rapidity loss : 32% < y/yb < 48% Transparency but still a large transfer of kinetic energy to excitations (of the color field) Peter Christiansen Ph. D. thesis, NBI, June 2003 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  12. Do models describe reaction mechanism at RHIC? Hijing: (Partonic, Strings, no rescattering) UrQMD: Hadronic, Transport calc., resonance excitat. rescattering Data corrected for p feed down from hyperons NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  13. Boost Invariant Plateau ?! Antiparticle/particle ratios @ 200AGeV p-/p = p-(pair) / [p+p(pair)] K-/K+ = K-(pair) / [K+(pair)+K+(dir)] (p+p  p++K+) +- pair prod (& ch. exch). Midrapidity: near matter-antimatter balance ’+’  ’-’ + + BRAHMS130 PRL 87 (2001) 202301 BRAHMS200 PRL 90 (2003) 112305. NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  14. Quark chemistryChemical equilibrium? • Grand Canonical Ensemble with Strangeness and charge conservation (p-)/(p+)= exp(-6u,d/T) (K-)/(K+)= exp(-2[u,d -s]/T) = exp(2s/T) [(p-)/(p+)]1/3 • Universal relationship between u,d & s • Chemical equilibration for different rapidity slices? BRAHMS200 PRL 90 (2003) 112305. NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  15. Phase diagram of nuclear matter Lowest baryo- chemical potential yet measured in NN collisions HG NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  16. 4630 charged particles produced for 0-5% central 14% increase over 130GeV 50% increase over p+p scaled by particip. => significant medium effects pp Charged particle multiplicity@ 200 AGeV Brahms 200 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  17. Deuteron coalescence Average Transverse Momentum B21/V Multiplicity, <pt>, V(R)  energy density Bjorken energy density = 1/(R20) dEt/d dEt=dN • <mt> mt2=pt2+m2 =>  5 GeV/fm3 cf: QGPcritical  1 GeV/fm3 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  18. 4 yields of charged mesons. NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  19. Strangeness Production vs. CM energy K+/ =(us) / (ud) K-/- =(u s) /(u d) p + pp +  + K+ NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  20. Universal correlation of Charged kaon vs pion? Djamel Ouerdane, Ph. D. thesis, NBI, 2003. NPA715 (2003) 478 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  21. q q q q SPS (snn=17 GeV) High p_t enhancement when compared to p+p scaled by N_binary: flow and quark mult scattering High pt suppression& Jet quenching at RHIC? NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  22. Jet Quenching?High pt yield suppression. NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  23. Jet quenching Does it persist at fwd. rapidity? BRAHMS preliminary y=2.2 Analysis by Claus E. Jørgensen, NBI QM2002: NPA715 (2003) See parallel session talk this afternoon NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  24. Au D q D+Au, snn=200GeV BRAHMS preliminary q NO ! y=0 See Claus Jørgensen’s talk! Is there also high pt suppression for d+Au ? NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  25. Summary • Central region near baryon-free. • Evidence for boost invariant and central plateau (|y|<2) • Near matter-antimatter balance • Largest energy density yet seen • Consistency with thermal models over |y|=2 • High pt suppression, seen at y=0,2, not seen in d+Au (y=0) • www.nbi.dk/~gardhoje/JJG-NN2003-june2003.ppt NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

  26. Saturation of excitations in fragmentation region Shift data to beam frame of reference BRAHMS PRL 88 (2002) 202301 NN2003, Moscow, Jens Jørgen Gaardhøje, Niels Bohr Institute

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