BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle...
-
Upload
amice-chandler -
Category
Documents
-
view
217 -
download
1
Transcript of BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle...
![Page 1: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/1.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
1
BRAHMS
Particle Production at Forward Rapiditieswith BRAHMSBRAHMS
I.G. Bearden,
Niels Bohr Institute For
The BRAHMS collaboration
![Page 2: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/2.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
2
BRAHMSCharged Particle Multiplicity
dN/d According to Bjorken,
>5GeV/fm3
170MeV
T
B
![Page 3: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/3.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
3
BRAHMS
Integrated multiplicities (Gaussian fit)
N() ~ 1780 N(+) ~1760N(K+) ~ 290 N(K) ~ 240N(pbar) ~ 85
Rapidity DensitiesAt y ~ 0, dN/dy is ~ 300 (300) for + (-) ~ 47 (44) for K+ (K) ~ 27 (20) for p (pbar) N() >> N(K) > N(p)N(+) = N()N(K+) > N(K) and N(p) > N(pbar) systematically
![Page 4: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/4.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
4
BRAHMS
BRAHMS, submittedto PRL, 31/12/03nucl-ex/0312023P. Christiansen Ph.D. Thesis, København’s Universitet
protons
antiprotons
Proton & antiproton dN/dy (5% central)
![Page 5: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/5.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
5
BRAHMS
BRAHMS, submittedto PRL, 31/12/03nucl-ex/0312023P. Christiansen Ph.D. Thesis, København’s Universitet
“Net” Proton= proton - antiproton dN/dy (5% central)
protons
antiprotons
net-proton
![Page 6: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/6.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
6
BRAHMS
BRAHMS, submittedto PRL, nucl-ex/0312023P. Christiansen Ph.D. Thesis
AGS : high stoppingRHIC: more transparent
RHIC vs. AGS,SPS:
![Page 7: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/7.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
7
BRAHMS
Calculate net-baryon distribution from net-protons (and y=0 yields of
, and Hijing…)
Net Baryon dN/dy
![Page 8: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/8.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
8
BRAHMS
Gaussians in pz:
∑± ⎥
⎥⎦
⎤
⎢⎢⎣
⎡ ±− 2
2
2
))sinh((exp
pz
zN pym
σ =yδ 2.03 0.16
Rapidity loss: gaussian in pz
Rapidity loss:
∫ −−=−= py BB
partpp dy
dy
dNy
Nyyyy
0
)(2δ
![Page 9: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/9.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
9
BRAHMS
=yδ 2.03 0.16
Rapidity loss: 6th order polynomial
Rapidity loss:
∫ −−=−= py BB
partpp dy
dy
dNy
Nyyyy
0
)(2δ
6 order polynomial
Gaussians in pz:
∑± ⎥
⎥⎦
⎤
⎢⎢⎣
⎡ ±− 2
2
2
))sinh((exp
pz
zN pym
σ
=yδ 2.00 0.10
∫−−p
p
y
y
BB
yT dyydy
dNm cosh)(
Total E=25.72.1TeV
![Page 10: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/10.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
10
BRAHMS
y vs. ybeam
Even (unphysically) extreme approximations don’t change conclusions: scaling broken,large energy available
∫−−p
p
y
y
BB
yT dyydy
dNm cosh)(
Total E=25.72.1TeV
![Page 11: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/11.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
11
BRAHMS
• Fit , K and p distributions (dN/dy and mT vs y) total energy of , K and p • Assume reasonable distribution for particles we don’t detect (0,n,…)• Calculate the total energy…
∑ ∫ ⎥⎦
⎤⎢⎣
⎡=
specieTtotal dy cosh(y)m
dydN E
NB: the method is verysensitive to the tails of the dN/dy dist. (10-15%) k+k-
pi+
pi-
pi0
lbar
k0bar
p
pbar
l
nbark0
n
?
35 TeV (EbeamNpart)of which 25 TeV are carried by produced particles.
p : 3108 p : 428K+ : 1628K- : 1093+: 5888- : 6117
0 : 6004n : 3729n : 513K0 : 1628K0 : 1093 : 1879 : 342
Energy (in GeV)
sum: 33.4 TeVproduced: 24.8TeV
Energy Balance…
![Page 12: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/12.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
12
BRAHMS
Where is the energy?
≈9TeV in produced particlesin the covered y range-3<y<3
![Page 13: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/13.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
13
BRAHMS
Strange to non-strange meson ratios
K-/-≈K+/+ at midrapidity
Depend strongly on baryochemical potential
![Page 14: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/14.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
14
BRAHMS
Y < 1 : consistent with Hadron Gas Stat. ModelK+/+ : 15.6 0.1 % (stat)K/ : 14.7 0.1 % (stat) [Phys. Lett. B 518 (2001) 41]
Divergence at higher y :Associated K+ productionNo single source with
unique T and B
Strangeness with Kaons
RAPIDITY DEPENDENCE
BRAHMS, PRL90 (2003) 102301
T~constant, B varies with y
Increasing y
63 GeV
![Page 15: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/15.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
15
BRAHMS
Jets at RHIC
p+p jet+jet (STAR@RHIC)
Au+Au ??? (STAR@RHIC)
nucleon nucleonparton
jet
Find this……….in this
And, in BRAHMS, we only “see” this much…
![Page 16: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/16.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
16
BRAHMS
Characterize “high” pT by single particle spectra
![Page 17: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/17.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
17
BRAHMS
Nuclear Modification
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
Jet-quenchingenergy loss of high momentum particles in the dense medium due to- gluon brehmstralung in the colored medium- hadronic multiple scattering
suppression of leading hadrons- Au+Au at sNN = 130GeV and 200GeV- next: energy+rapidity dependence
![Page 18: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/18.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
18
BRAHMS
Arsene et al.PRL2003
To look at ‘only’ data, form ratio
R=Rcp(=2.2)/Rcp(=0)
![Page 19: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/19.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
19
BRAHMS
d+Au Nuclear Modification =0
High pT enhancement observed in d+Au collisionsat sNN=200 GeV.
Comparing Au+Au to d+Au strong effect of dense medium
![Page 20: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/20.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
20
BRAHMS
submitted to PRLCronin enhancement at =0- the “null” experiment that ruled out initial state effect as explanation for Au+Au suppressionIncreasing suppression for 3
- window to the low-x partons in the Au nuclei (QS~A1/3e-y)- consistent with CGC prediction
RdAu at sNN = 200 GeV
![Page 21: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/21.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
21
BRAHMS
one week of 62.4 GeV running…
New BRAHMS resultsNo RHIC p+p running at this energy:- what should we use as reference?
![Page 22: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/22.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
22
BRAHMS
Nuclear modification factor RAuAu
- different centrality classesEnergy dependence (SPSRHIC) pT=3-4GeV/c
pT=3-4GeV/c40-60%20-40%10-20%0-10%
RAuAu at sNN = 62.4 GeV
![Page 23: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/23.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
23
BRAHMS
Conclusions
High energy density 70% of energy
available for particle production
Source (nearly) same over >1 unit rapidity
63 GeV data: climb
the K/ “matterhorn”?
High pT suppression persists to high y in Au+Au
More saturation as y increases in d+Au
Gluon saturation describes data, though not uniquely
Lots left to do…
![Page 24: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/24.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
24
BRAHMS
The BRAHMS Collaboration
I.Arsene10,I.G. Bearden7, D. Beavis1, C. Besliu10, Y. Blyakhman6, J.Brzychczyk4, B. Budick6,H. Bøggild7 ,C. Chasman1, C. H. Christensen7, P. Christiansen7,
J.Cibor4,R.Debbe1,J. J. Gaardhøje7,M. Germinario7, K. Hagel8, O. Hansen7, H. Ito11, E. Jacobsen7, A. Jipa10, J. I. Jordre10, F. Jundt2,
C.E.Jørgensen7, 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. Neuman11,B.S.Nielsen7, K. Olchanski1, D. Ouerdane7, R.Planeta4, F. Rami2,
D. Roehrich9, B. H. Samset12, S. J. Sanders11, I. S. Sgura10, R.A.Sheetz1, Z.Sosin3, P. Staszel7, T.S. Tveter12, F.Videbæk1, R. Wada8 ,A.Wieloch3,Z. Yin9
1Brookhaven National Laboratory, USA, 2IReS and Université Louis Pasteur, Strasbourg, France3Jagiellonian University, Cracow, Poland, 4Institute of Nuclear Physics, Cracow, Poland
5Johns Hopkins University, Baltimore, USA, 6New York University, USA7Niels 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
- 12 institutions-
![Page 25: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/25.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
25
BRAHMS
In ’BT’ (Danish morning tabloid)Feb. 2004
…….as plastic slippers with acrylic lining
?
That you can recreate the Big Bang in a particle accelerator
is simply a fantastic and earth shattering….
…discovery!
At the same level .....
![Page 26: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/26.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
26
BRAHMS
Random Back-up slides…
![Page 27: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/27.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
27
BRAHMS
After appropriate corrections, we combinine all data sets to obtainfinal invariant yields over a broad range of rapidity and pT
Particle Spectra
K
p
![Page 28: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/28.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
28
BRAHMS
Particle Spectra
n
T
p
pA
−
⎟⎟⎠
⎞⎜⎜⎝
⎛+
1
Pions: power law Kaons: exponential
⎟⎠
⎞⎜⎝
⎛ −−
T
mmA Texp
Protons: Gaussian
⎥⎦
⎤⎢⎣
⎡−
2
2
2exp
σTpA
Top 5% central collisions
![Page 29: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/29.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
29
BRAHMS
BRAHMS at RHIC
The three first years:Au+Au at sNN = 130GeVAu+Au at sNN = 200GeVd+Au at sNN = 200GeVp+p at sNN = 200GeVAu+Au at sNN = 62.4GeV
![Page 30: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/30.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
30
BRAHMS
Broad RAnge Hadron Magnetic spectrometerS
Two small solid anglespectrometers (FS and MRS)
2.3°30°
that can rotate from 2.3° to 30°
90°
30°
and 30° to 90° (MRS)
provide excellent PID over broad range in y-pT
The BRAHMS Experiment
![Page 31: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/31.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
31
BRAHMS
ENERGY DEPENDENCE
At y = 0, ratios convergeto ~ 15 %
Over the full phase space:K+/+ = 16.6 1.5 % (syst)K/ = 13.7 2.0 % (syst)
no change for +
Why this behavior ?Net-Kaon distributionevolves like net-proton
![Page 32: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/32.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
32
BRAHMS
y~0
y~3y~2
y~1
pT (GeV/c)
Spectra with BW Fits at y~0,1,2,3 (T,s, in the fit
Rmax=13fm)
BR
AH
MS
Pre
limin
ary Fix ,T
Fix ,
![Page 33: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/33.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
33
BRAHMS
Transverse Flow…
Points: BRAHMS DataCurves: 3D Hydro (Hirano)Histos: AMPT
p
Transverse flow roughly constant over ≈2 units ofrapidity.“blast-wave” fitparameters confirm this.
![Page 34: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/34.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
34
BRAHMS
The BRAHMS Experiment
![Page 35: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/35.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
35
BRAHMS
Preliminary results from 63GeV
![Page 36: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/36.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
36
BRAHMSHigh pt suppression, jet
quenching in Au+AuThe smoking gun of
deconfinement?
Large high pt suppression also at forward rapidity.
Longitudinally extended medium, boost invariance, CGC or …?
Not quantitatively understood.
![Page 37: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/37.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
37
BRAHMS
BRAHMS: PRL 91 (2003) 072305
Absence of suppression in d+Au at midrapidity
1/5
QCD predicts large energy loss from gluon bremsstrahlung in
deconfined medium:
<E> ∫g ln(1/L) dz
<L2>
![Page 38: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/38.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
38
BRAHMS
High pt suppression in d+Au
at forward rapidity.Color Glass
Condensate ?
BRAHMS: Submitted to PRL, March 2004
![Page 39: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/39.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
39
BRAHMS
Nuclear Modification
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
![Page 40: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/40.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
40
BRAHMS
Nuclear Modification
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
“Cronin effect”Initial state multiple scattering leading to Cronin enhancement (RAA>1)- heavy ions at lower energy - d+Au collisions at RHIC
![Page 41: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/41.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
41
BRAHMS
Nuclear Modification
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
Shadowing/saturationdepletion of low-x partons due to:- coherent multiple scattering- saturation
leading to suppression below the saturation scale. QS?? The Color Glass Condensate (CGC)
gives theoretical framework
![Page 42: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/42.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
42
BRAHMS
Global ParameterizationOf ISR DATA
Fit toISR (R203) DATA
ISR DATA=1
Reference Spectrum
![Page 43: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/43.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
43
BRAHMS
Nuclear Modification
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
“Cronin effect”Initial state multiple scattering leading to Cronin enhancement (RAA>1)- heavy ions at lower energy - d+Au collisions at RHIC
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
![Page 44: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/44.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
44
BRAHMS
Nuclear Modification
Shadowing/saturationdepletion of low-x partons due to:- coherent multiple scattering- saturation
leading to suppression below the saturation scale. QS?? The Color Glass Condensate (CGC)
gives a solid theroretical framework
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
![Page 45: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/45.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
45
BRAHMS
Nuclear Modification
Jet-quenchingenergy loss of high momentum particles in the dense medium due to- gluon brehmstralung in the colored medium- hadronic multiple scattering
suppression of leading hadrons- Au+Au at sNN = 130GeV and 200GeV- next: energy dependence
Quantified by:
ddpNdN
ddpNdR
TNN
bin
TAB
AB /
/2
2
=
• Cronin Enhancement• Shadowing/Saturation• Jet-quenching
- yield relative to that fromN+N collisions, scaled forthe nuclear geometry (Nbin)
![Page 46: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/46.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
46
BRAHMS
Gaussians in pz:
∑± ⎥
⎥⎦
⎤
⎢⎢⎣
⎡ ±− 2
2
2
))sinh((exp
pz
zN pym
σ
=yδ 2.03 0.16
Nuclear Stopping
Net-baryon after feed-down & neutron corrections
=yδ 2.00 0.106 order polynomial
Gaussians in pz:
∫−−p
p
y
y
BB
yT dyydy
dNm cosh)(
Total E=25.72.1TeV
∑± ⎥
⎥⎦
⎤
⎢⎢⎣
⎡ ±− 2
2
2
))sinh((exp
pz
zN pym
σ
Rapidity loss:
∫ −−=−= py BB
partpp dy
dy
dNy
Nyyyy
0
)(2δ
![Page 47: BRAHMS 16. August 2004 ICHEP04 Beijing, Kina I.G.Bearden, Niels Bohr Institute 1 BRAHMS Particle Production at Forward Rapidities with BRAHMS I.G. Bearden,](https://reader036.fdocuments.us/reader036/viewer/2022062422/56649ec75503460f94bd36da/html5/thumbnails/47.jpg)
16. August 2004 ICHEP04 Beijing, KinaI.G.Bearden, Niels Bohr Institute
47
BRAHMS
Predictions from theory
I. Vitev nucl-th/0302002 v2D. Kharzeev et al. Phys.Rev.D68:094013,2003
CGC at y=0Y=0
Y=3
Y=-3
Very high energy
As y grows