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Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute1 nFirst physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions.

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Presentation on theme: "Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute1 nFirst physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions."— Presentation transcript:

1 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute1 nFirst physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions nEcm=  s  40 TeV n4000-5000 charged particles produced per collision nTransparency or Stopping ? nTowards nuclear ’stuff’ with matter-antimatter balance BRAHMS Y2000 + Y2001 @ RHIC:  s nn =130 GeV, and  s nn =200 GeV

2 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute2 I.G. Bearden 7, D. Beavis 1, C. Besliu 10, Y. Blyakhman 6, J. Bondorf 7, J.Brzychczyk 4, B. Budick 6, H. Bøggild 7, C. Chasman 1, C. H. Christensen 7, P. Christiansen 7, J.Cibor 4, R.Debbe 1, J. J. Gaardhøje 7, M. Germinario 7, K. Grotowski 4, K. Hagel 8, O. Hansen 7, H. Heiselberg 7, A. Holm 7, A.K. Holme 12, H. Ito 11, E. Jacobsen 7, A. Jipa 10, J. I. Jordre 10, F. Jundt 2, C. E. Jørgensen 7, T. Keutgen 9, E. J. Kim 5, T. Kozik 3, T.M.Larsen 12, J. H. Lee 1, Y. K.Lee 5, G. Løvhøjden 2, Z. Majka 3, A. Makeev 8, B. McBreen 1, M. Murray 8, J. Natowitz 8, B.S.Nielsen 7, K. Olchanski 1, D. Ouerdane 7, R.Planeta 4, F. Rami 2, D. Roehrich 9, B. H. Samset 12, S. J. Sanders 11, D. Sandberg 7,I. S. Sgura 10, R.A.Sheetz 1, Z.Sosin 3, P. Staszel 7, T.S. Tveter 12, F.Videbæk 1, R. Wada 8 and A.Wieloch 3. 1 Brookhaven National Laboratory, USA 2 IReS and Université Louis Pasteur, Strasbourg, France 3 Jagiellonian University, Cracow, Poland 4 Institute of Nuclear Physics, Cracow, Poland 5 Johns Hopkins University, Baltimore, USA 6 New York University, USA 7 Niels Bohr Institute, Blegdamsvej 17, University of Copenhagen, Denmark 8 Texas A&M University, College Station. USA 9 University of Bergen, Norway 10 University of Bucharest, Romania 11 University of Kansas, Lawrence,USA 12 University of Oslo Norway BRAHMS Intl. collaboration

3 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute3 RHIC physics August 2000 & August 2001 2:00 o’clock 4:00 o’clock 6:00 o’clock 8:00 o’clock 10:00 o’clock STAR PHENIX RHIC AGS LINAC BOOSTER TANDEMS 9 GeV/u Q = +79 1 MeV/u Q = +32 HEP/NP  g-2 U-line BAF (NASA) BRAHMS: L peak = 3.3  10 25 cm -2 s -1 L ave = 1.7  10 25 cm -2 s -1 Rcoll= 350 Hz PHOBOS 6  b -1 2 wks August 2000 and 2001

4 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute4 Quark Gluon Plasma Hot and dense matter QGP HG Freeze out Hadron gas Mixed phase QGP Pre-equil. quark 2.10 12 K

5 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute5 URQMD simulation of Au+Au at  s nn =200 GeV nRapidity y = ½ ln (E+pz / E- pz) = ½ ln(1+  cos  / 1-  cos  ) y(lab) = y + y(cm) nPseudorapidity  = ln (cot [  /2]) nTransverse momentum p t = p sin 

6 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute6 Central Au+AU collision event in STAR

7 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute7 BRAHMS in the 2’ hall … in 1998

8 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute8 Forward & Midrapidity spectrometers in 2001 FS: 2 TPC, 2 TOF, C1-threshold, 3 Drift Ch. Mod., RICH, 4 Dipoles 2.5 - 30 deg.  = 1.5 - 4 MRS: 2 TPC, 1 Dipole, 1TOF 30 - 90 deg.  = 0 - 1.5

9 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute9 First BRAHMS collision at 100 AGeV+100AGeV T1 MTPC1 T2 MTPC2 MRS: 90 deg 6.5 msr FS: 6 deg 0.8 msr

10 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute10 BRAHMS acceptance Y2000 & Y2001

11 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute11 Centrality determination Vertex distribution 1m

12 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute12 TPC tracks, Vertex reconstruction, Charged particle track density MTPC1 z y

13 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute13 dN ch /d  @  s nn = 130 GeV SiMA, TMA, BB, TPC nN=  dE / nP(0)/P(n  1) nBackground corr.due to secondaries (37-50%) nConsistency between 4 independent detector systems n65 AGeV+ 65 AGeV: n  N(ch)d  = 3860±300 nCentral 0-5% dN(ch)/d  (  =0) =550 nFWHM of distribution  = 7.6  0.7 0-5% 10-20% 20-30% 30-40% 40-50% 5-10% 600 BRAHMS Phys. Lett. B 523 (2001) 227; nucl-ex 0108015

14 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute14 RHIC: 200 AGeV Will this happen?

15 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute15 Pseudorapidity densities @ 200 AGeV n5630 charged particles produced for 0- 5% central n14% increase over 130GeV n50% increase over p +  p (UA5) => significant medium effects Bjorken energy density  BJ = (1/  R 2  0 ) dE t /d   5 GeV/fm 3 dE t =dN cf:  QGP critical  1 GeV/fm 3 Brahms 200 pppp

16 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute16 Hard and Soft vs. High Density QCD @ 200 AGeV nKharzeev and Levin (nucl- th/0108006) nHIGH DENSITY QCD MODEL nSoft-Hard: dN/d  =(1-X) n pp /2 + X n pp =1049, =339, npp=2.43 =>dN/d  =668 (with X=0.9) nHigh Density QCD-saturation: dN/dy = f( Npart, Q s 2,,  QCD,  s,y) with =0.3 from HERA data => dN/d  =620 (using dN/d  =549 at  s=130GeV) BRAHMS Submitted to PRL dec. 2001 Nucl-ex. 00112001  =4.5  =3.0  =0 Gluon saturation ?

17 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute17 Saturation of excitations in fragmentation region Shift data to beam frame of reference BRAHMS subm. to PRL- n-ex. 00112001

18 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute18 Hadron identification MRS (90 - 40 deg). TOF m 2 =p 2 ( t 2 / L 2 -1)

19 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute19 Hadron Identification FS (4-20deg @200AGeV) C1,H1,T2 ++ p K+ 4 deg

20 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute20 C1 Threshold Cherenkov PID Cos  =1/n  =>  th =1/n

21 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute21 Ring Imaging Cherenkov for high momentum PID   R 

22 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute22 Bjorken limit reached for Au+Au  s nn = 130GeV? ISR R803  s=23  s=63 BRAHMS PRL87(2001)112305

23 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute23 Antiparticle/particle ratios @ 200AgeV ’+’  ’-’ 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 ++ BRAHMS Preliminary

24 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute24 How consistent are the models @  s nn = 130GeV?

25 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute25 Summary: First Au+Au  s nn =130 & 200 GeV nHighest particle multiplicity in nuclear collisions ( 4600 ch. part) ever seen nLarge energy density > 5  crit nHigh reaction transparency nDecoupling of central and ’fragmentation’ regions nPartonic (color) description appears necessary nCentral region dominated by matter-antimatter balance:  Qualitatively new physics regime To come: Strangeness net baryon density jet quenching, …. 2006: ALICE @ LHC -CERN  s nn =6000 GeV, Pb+Pb

26 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute26 A few Extra’s

27 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute27 Pbar/p ratio systematics

28 Dec 6, 2001BH-symposium, Jens Jørgen Gaardhøje, Niels Bohr Institute28


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