Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Ins titute 1 First physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions: THE LITTLE BIG BANG Ecm= s 40 TeV 4000-5000 charged particles produced per collision Transparency or Stopping ? Towards nuclear ’stuff’ with matter-antimatter balance BRAHMS Y2000 + Y2001 @ RHIC: s nn =130 GeV, and s nn =200 GeV
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Dec 18, 2001Odense Uni., 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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Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
1
First physics at RHIC with 65 AGeV + 65 AGeV and 100 AGeV + 100 AGeV Au+Au collisions: THE LITTLE BIG BANG
Ecm= s 40 TeV
4000-5000 charged particles produced per collision
Transparency or Stopping ?
Towards nuclear ’stuff’ with matter-antimatter balance
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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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, 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
BRAHMS Intl. collaboration
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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First BRAHMS collision at 100 AGeV+100AGeV
T1
MTPC1
T2
MTPC2
MRS: 90 deg
6.5 msr
FS: 6 deg
0.8 msr
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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BRAHMS acceptance Y2000 & Y2001
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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Centrality determinationVertex distribution
1m
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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TPC tracks, Vertex reconstruction, Charged particle track density
MTPC1
z
y
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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dNch/d @ snn= 130 GeVSiMA, TMA, BB, TPC
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
0-5%
10-20%
20-30%
30-40%
40-50%
5-10%
600
BRAHMS Phys. Lett. B 523 (2001) 227; nucl-ex 0108015
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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Background…A slight complication
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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RHIC: 200 AGeVWill this happen?
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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Whirlpool Galaxy. M51, Hubble space telescope
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute
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Pseudorapidity densities@ 200 AGeV
5630 charged particles produced for 0-5% central
14% increase over 130GeV 50% increase over p +p (UA5) => significant medium effects
Bjorken energy density
BJ = (1/R20) dEt/d 5 GeV/fm3
dEt=dN • <pt>
cf: QGPcritical 1 GeV/fm3
Brahms 200
pp
Dec 18, 2001 Odense Uni., Jens Jørgen Gaardhøje, Niels Bohr Institute