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BRAHMS Y2000 + Y2001 @ RHIC: s nn =130 GeV, and s nn =200 GeV. First physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions Ecm= s 40 TeV 4000-5000 charged particles produced per collision Transparency or Stopping ?
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BRAHMS Y2000 + Y2001 @ RHIC: snn=130 GeV, and snn=200 GeV • First physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions • Ecm= s 40 TeV • 4000-5000 charged particles produced per collision • Transparency or Stopping ? • Towards nuclear ’stuff’ with matter-antimatter balance BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
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, H. Heiselberg7, 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 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
RHIC physicsAugust 2000 & August 2001 BRAHMS: Lpeak = 3.3 1025 cm-2 s-1 Lave = 1.7 1025 cm-2 s-1 Rcoll= 350 Hz 2:00 o’clock PHOBOS 10:00 o’clock RHIC PHENIX 8:00 o’clock 4:00 o’clock STAR 6:00 o’clock 6 b-1 9 GeV/u Q = +79 U-line BAF (NASA) m g-2 LINAC BOOSTER 2 wks HEP/NP AGS 1 MeV/u Q = +32 TANDEMS August 2000 and 2001 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
QGP Freeze out Hadron gas HG Mixed phase QGP Pre-equil. quark Quark Gluon PlasmaHot and dense matter 2.1012K BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
URQMD simulation of Au+Au at snn=200 GeV • Rapidity y = ½ ln (E+pz / E- pz) = ½ ln(1+cos / 1-cos) y(lab) = y + y(cm) • Pseudorapidity = ln (cot [/2]) • Transverse momentum pt= p sin BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Central Au+AU collision event in STAR BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
BRAHMS in the 2’ hall … in 1998 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Forward & Midrapidity spectrometers in 2001 MRS:2 TPC, 1 Dipole, 1TOF 30 - 90 deg. = 0 - 1.5 FS:2 TPC, 2 TOF, C1-threshold,3 Drift Ch.Mod.,RICH, 4 Dipoles 2.5 - 30 deg. = 1.5 - 4 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
First BRAHMS collision at 100 AGeV+100AGeV T2 FS: 6 deg 0.8 msr T1 MRS: 90 deg 6.5 msr MTPC1 MTPC2 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
BRAHMS acceptance Y2000 & Y2001 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Centrality determinationVertex distribution 1m BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
TPC tracks, Vertex reconstruction, Charged particle track density y z MTPC1 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
dNch/d @ snn= 130 GeVSiMA, TMA, BB, TPC BRAHMS Phys. Lett. B 523 (2001) 227; nucl-ex 0108015 • N=dE /<dE> • P(0)/P(n1) • Background corr.due to secondaries (37-50%) • Consistency between 4 independent detector systems • 65 AGeV+ 65 AGeV: • N(ch)d= 3860±300 • Central 0-5% dN(ch)/d (=0) =550 • FWHM of distribution = 7.6 0.7 600 0-5% 5-10% 10-20% 20-30% 30-40% 40-50% BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
RHIC: 200 AGeVWill this happen? BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
5630 charged particles produced for 0-5% central 14% increase over 130GeV 50% increase over p +p (UA5) => significant medium effects pp Pseudorapidity densities@ 200 AGeV Brahms 200 Bjorken energy density BJ = (1/R20) dEt/d 5 GeV/fm3 dEt=dN • <pt> cf: QGPcritical 1 GeV/fm3 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Gluon saturation ? Hard and Soft vs.High Density QCD @ 200 AGeV • Kharzeev and Levin (nucl-th/0108006) • HIGH DENSITY QCD MODEL • Soft-Hard: dN/d=(1-X) npp <Npart>/2 + X npp <Ncoll> <Ncoll>=1049, <Npart>=339, npp=2.43=>dN/d=668 (with X=0.9) • High Density QCD-saturation: dN/dy = f( Npart, Qs2, ,QCD,s,y) with =0.3 from HERA data => dN/d=620 (using dN/d=549 at s=130GeV) =0 =3.0 =4.5 BRAHMS Submitted to PRL dec. 2001 Nucl-ex. 00112001 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Saturation of excitations in fragmentation region Shift data to beam frame of reference BRAHMS subm. to PRL- n-ex. 00112001 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Hadron identification MRS (90 - 40 deg). TOF m2=p2( t2 / L2 -1) BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
p 4 deg K+ + Hadron IdentificationFS (4-20deg @200AGeV) C1,H1,T2 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
C1 Threshold CherenkovPID Cos=1/n => th=1/n BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Ring Imaging Cherenkovfor high momentum PID R BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
ISR R803 s=63 s=23 Bjorken limit reached for Au+Au snn= 130GeV? BRAHMS PRL87(2001)112305 BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Antiparticle/particle ratios @ 200AgeV BRAHMS Preliminary p-/p = p-(pair) / [p+p(pair)] K-/K+ = K-(pair) / [K+(pair)+K+(ap)] (p+p p++K+) +- pair prod (& ch. exch). Midrapidity: near matter-antimatter balance ’+’ ’-’ + + BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
How consistent are the models @ snn= 130GeV? BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Highest particle multiplicity in nuclear collisions ( 4600 ch. part) ever seen Large energy density > 5 crit High reaction transparency Decoupling of central and ’fragmentation’ regions Partonic (color) description appears necessary Central region dominated by matter-antimatter balance: Qualitatively new physics regime To come: Strangeness net baryon density jet quenching, …. Summary: First Au+Au snn=130 & 200 GeV 2006: ALICE @ LHC -CERN snn=6000 GeV, Pb+Pb BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
A few Extra’s BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute
Pbar/p ratio systematics BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute