Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]H H ot ot M M atter atter P P hysics hysics D D ivision ivision Kielce Physics Workshops, October 15-17, 2004 Zbigniew Majka Hot Matter Physics Division M.Smoluchowski Institute of Physics Jagiellonian University
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Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
Kielce Physics Workshops, October 15-17, 2004
Zbigniew Majka Hot Matter Physics Division
M.Smoluchowski Institute of PhysicsJagiellonian University
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
The BRAHMS CollaborationI.Arsene10, I. G. Bearden7, D. Beavis1, C. Besliu10, B. Budick6, H. Bøggild7, C. Chasman1, C.H.Christensen7,
P. Christiansen7, J. Cibor3, R. Debbe1, E. Enger12, J. J. Gaardhøje7, M. Germinario7, K. Hagel8, H. Ito1, A.Jipa10, F. Jundt2, J. I. Jørdre9, C. E. Jørgensen7, R. Karabowicz4, E. J. Kim1,11, T. Kozik4 ,
T. M. Larsen12, J. H. Lee1, Y. K. Lee5, S. Lindal12, R. Lystad9, G. Løvhøiden12, Z. Majka4, A. Makeev8, M. Mikelsen12, M. Murray8, 11, J. Natowitz8, B. Neumann11, B. S. Nielsen7, D. Ouerdane7, R. Planeta4,
F. Rami2, C. Ristea10, O. Ristea10, D. Röhrich9, B. H. Samset12, D. Sandberg7, S. J. Sanders11, R. A. Scheetz1, P. Staszel7, T. S. Tveter12, F. Videbæk1, R. Wada8, Z. Yin9, I. S. Zgura10
1Brookhaven National Laboratory, Upton, New York, USA2IReS and Université Louis Pasteur, Strasbourg, France
3Institute of Nuclear Physics, Krakow, Poland4 M. Smoluchkowski Inst. of Physics, Jagiellonian University, Krakow, Poland
5Johns Hopkins University, Baltimore, USA6New York University, New York, USA
7 Niels Bohr Institute, University of Copenhagen, Denmark8Texas A&M University, College Station, Texas, USA
9 University of Bergen, Bergen, Norway 10 University of Bucharest, Romania
11University of Kansas, Lawrence, Kansas, USA 12University of Oslo, Oslo, Norway
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
Review of the BRAHMS experiment results
Overall goal:
Concise review of the BRAHMS experiment abilities.
Presentation of a representative experimental results from BRAHMS.
(Also data from other experiments will be recall for comparison.)
Conclusions.
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
BNL/RHIC/BRAHMS/DC-pictures
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
Summary of RHIC runs
RHICrun
Collidingsystem
√sNN
[GeV]Dates of BRAHMSdata taking
I Au+AuAu+Au
56130
2000 (June 15)
2000 (summer)
II Au+AuAu+AuAu+Aup+p
13020019.6
200
2002 (winter)
2001 (fall)
2001 (winter)
2001/02 (winter)
III d+Aup+p
200
200
2002/03 (winter)
2003 (spring)
IV Au+AuAu+Aup+p
20062.4
200
2003/04 (winter)
2004 (spring)
2004 (spring)
Au +Au 56 bunches
of ~ 109 ionsin each ring
To control:• Time of interaction• z-distribution of the
interaction
Currently analyzedA few results available
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
Designed to measure charged hadrons: p, K, πIdentification of particles over a broad range of:angles – 2.3o – 95o momenta (up to 30 GeV/u, σ(dp/p) ~ 1%)
0 < |y| < 4 0.2 < pt < ~ 3GeV/c
• Small solid angles:MRS = 6.5 msrFS = 0.8 mrs
• Rotation around the nominal IP
Drawback:A small region of thePhase-space per settingGlobal detectors:
non-perturbative QCD mechanisms,involve the longer length scales
** “Hard” partonic processes –and the interactions of these partonsin a high energy environment.
(Two Component Parameterization)
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
The charged particle multiplicity(comparison to 130 GeV and p+p )
[GeV]NNs10 210 310
>)pa
rt /(
1/2<
N0≈ηη
dN/d
0
1
2
3
4
5
BRAHMSRHIC combinedE866 (AGS)NA49 (SPS)PHOBOS
)pUA5/CDF (p
dNch
/dη/
(0.5
Npa
rt)
The particle production in the Au+Au central collisionsexceeds by 40-50 % particle production in p+p collisions
14% increase over 130GeV
=> nucleus–nucleus collisions far from being the simple superposition of elementary collisions
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
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The charged particle production per participant pair
Fragmentation:
Particle production stays constant for differentcollision geometry, different energies at rapidity0.5 – 1.5 units below beam rapidity.
Energy available for the particle production saturates below top SPS energy.(Limiting Fragmentation Pictures)
Midrapidity
Significant increase of the particle productionwith the increasing collision energy=> the dissipated energy is transported into
central rapidity regionMidrapidity Fragmentation
dNch/dη/(0.5Npart) vs. η - ybeam
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
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Rapidity dependence of charged antihadron to hadron ratio.Observation• No significant dependence on pT or centrality
in two selected rapidity intervals (y = 0, 2)=> yields integrated over centrality (0 – 20) %
and over pT within acceptance
# π--/ π+ K-/ K+ p/p ~ 1 0.95 – 0.67 0.75 – 0.23
# p/p and K-/ K+ ratios are essentially constantin the rapidity interval 0 – 1.
# particle production in central regionpredominantly from pair creation
# correlation of p/p and K-/ K+ ratios welldescribed by the statistical approach => an indication that the system is in
chemical equilibrium
PRL, 87 (2001) 112305
PRL, 90 (2003) 102301
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
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Net protons rapidity density
12
7(highest rapidity measurementsnot yet completed)
Net protons rapidity density comparison
• With increasing energy the nucleus – nucleus collisons re more and more transparent(a depletion of the net-proton density at central rapidities)
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]
HHototMMatteratterPPhysicshysicsDDivisionivision
• Charged particle density, dN ch/dη = 625 around η = 0 (integrated: ≈ 4600)• Particle production in central region predominantly from pair creation• the nucleus – nucleus collisions are quite transparent
Bjorken energy density(Au+Au at √SNN = 200 GeV, central collision for y = 0)
εBJ = 3/2 (1/πR2τ0) d<ET >/dη
(R = 6 fm, τ 0 =1 fm/c, d<E T > = dN ch<p T >,
dN ch/dη =625, <p T > 0.5 GeV/c,)
εQGPcritical ≈ 1 GeV/fm3≈ 4 GeV /fm3
≈ 30 • ρnormal nuclear matter
≈ 4 • density of baryon
Zbigniew Majka, M.Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland, [email protected]