Centrality and Energy Dependence
of Meson, Proton and Hyperon
Production
Christoph Blume
for the
Collaboration
The NA49 Collaboration
C. Alt, T. Anticic, B. Baatar, D. Barna, J. Bartke, L. Betev, H. Białkowska,
C. Blume, B. Boimska, M. Botje, J. Bracinik, R. Bramm, P. Bunčić, V. Cerny,
P. Christakoglou, P. Chung, O. Chvala, J.G. Cramer, P. Csató, P. Dinkelaker,
V. Eckhardt, D. Flierl, Z. Fodor, P. Foka, V. Friese, J. Gál, M. Gaździcki,
V. Genchev, G. Georgopoulos, E. Gładysz, K. Grebieszkow, S. Hegyi,
C. Höhne, K. Kadija, A. Karev, D. Kikola, M. Kliemant, S. Kniege,
V.I. Kolesnikov, E. Kornas, R. Korus, M. Kowalski, I. Kraus, M. Kreps,
A. Laszlo, R. Lacey, M. van Leeuwen, P. Lévai, L. Litov, B. Lungwitz,
M. Makariev, A.I. Malakhov, M. Mateev, G.L. Melkumov, A. Mischke,
M. Mitrovski, J. Molnár, S. Mrówczyński, V. Nicolic, G. Pálla, A.D. Panagiotou,
D. Panayotov, A. Petridis, W. Peryt, M. Pikna, J. Pluta, D. Prindle, F. Pühlhofer,
R. Renfordt, C. Roland, G. Roland, M. Rybczyński, A. Rybicki, A. Sandoval,
N. Schmitz, T. Schuster, P. Seyboth, F. Siklér, B. Sitar, E. Skrzypczak,
M. Slodkowski, G. Stefanek, R. Stock, C. Strabel, H. Ströbele, T. Susa,
I. Szentpétery, J. Sziklai, M. Szuba, P. Szymanski, V. Trubnikov, D. Varga,
M. Vassiliou, G.I. Veres, G. Vesztergombi, D. Vranić, A. Wetzler,
Z. Włodarczyk, A. Wojtaszek, I.K. Yoo, and J. Zimányi
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
2
Outline
Protons
Energy dependence of stopping
Light fragments (t, 3He)
Coalescence  production at chemical freeze-out
Hyperons
System size dependence at 40 and 158A GeV
Elliptic Flow
Scaling properties at SPS (quark number, KEt)
High-pt
Baryon-meson ratios
Nuclear suppression relative to p+A
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
3
Protons
(Anti-)Proton y-Spectra in Central Pb+Pb
Mid-rapidity
(TOF analysis)
Phys. Rev. C 73
(2006), 044910
NA49 preliminary
p
NA49 preliminary
p
Forward rapidities
(dE/dx analysis)
E. Kornas
Central Pb+Pb (7 %)
Feed-down corrected
Syst. error  10%
New data points at forward rapidities
dE/dx-Analysis
Clear evolution of shape for protons
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
4
Protons
Net-Baryon Distributions in Central Pb+Pb
20A GeV
30A GeV
40A GeV
80A GeV
Construction of total net-baryon distributions



n B  B  Sn p  p   S       S 0    
Scaling factors S
X

taken from statistical model fits
(F. Becattini et al., Phys. Rev. C 73 (2006), 044905.)
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
5
Protons
Energy-Dependence of Net-Baryons
158A GeV
Phys. Rev. Lett. 82
(1999), 2471
E802
Phys. Rev. C 60
(1999), 064901
BRAHMS
Phys. Rev. Lett. 93
(2004), 102301
NA49 preliminary
Central Pb+Pb/Au+Au
Change of shape most
pronounced at SPS energies
Peak  dip structure
Mid-rapidity net-baryon
density decreases rapidly
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
6
Protons
Energy-Dependence of Stopping
y /yp  0.6
at AGS+SPS
NA49 preliminary
Central Pb+Pb/Au+Au
Drops towards
RHIC energies
Good agreement
with UrQMD
UrQMD values
correspond to
almost energy
independent
xF ( 0.38)
Averaged rapidity shift y :
UrQMD
M. Bleicher,
Florence Workshop on
Critical Point an Onset
of Deconfinement, 2006
Christoph Blume
y  y p  y
 yp 
Quark Matter, Nov. 14.-20. 2006
2
N part

yp
0
y
dN ( B  B )
dy
dy
7
Protons
Energy-Dependence of Inelasticity
NA49 preliminary
Energy of single net-baryon:
E B B 
1
yp
N B B  y p
mT
dN ( B B )
y
dy
Central data
cosh y dy
Total inel. energy per net-baryon:
E inel 
s NN
 E B B
2
Central data
Inelasticity:
K
2 E inel
s NN  2mp
NA49 preliminary
Inelasticity in central A+A around K  0.7-0.8
Indications for weak energy dependence at SPS ?
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
NA35
Phys. Rev. Lett. 72
(1994), 1419
8
Light Fragments
Rapidity Distributions of 3He
3He
identification (dE/dx + TOF):
3He
d
t
3He
Concave shape is energy
independent
Central Pb+Pb
NA49 preliminary
Contrast to protons
Coalescence picture ?
Christoph Blume
NA49 data
V. Kolesnikov
Quark Matter, Nov. 14.-20. 2006
9
Light Fragments
mt-m0 Spectra of t and 3He
NA49 preliminary
NA49 preliminary
Central Pb+Pb
|y | < 1.0
Central Pb+Pb
|y | < 1.0
t
3He
Provides constraints to coalescence models
 Extraction of mt-m0 from data
(+2 exp. fit for extrapolation)
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
10
Light Fragments
Energy-Dependence of 3He Yields
Agrees with statistical
hadron gas prediction
NA49 preliminary
4 extrapolation ?
Clusters produced at
chemical freeze-out?
How about coalescence at
thermal freeze-out?
3He
Do both coincide?
4 yields
Central Pb+Pb
Statistical hadron gas model (SHM):
F. Becattini et al.,
Phys. Rev. C 73 (2006), 044905,
and private communication
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
11
Hyperons
System Size Dependence of Yields
Data at 158A GeV
M. Mitrovski et al.,
arXiv:nucl-ex/0606004
NA49 preliminary
NA49 preliminary
Mid-rapidity:
|y| < 0.4 (, )
|y| < 0.5 (-)
Open symbols: Central
Filled symbols: Min. bias
New data on  ,, - production in
minimum bias Pb+Pb at 40A GeV
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
12
Hyperons
Hyperon Enhancement at 158A GeV
NA49 preliminary
Enhancement factor:
 1 dn Pb  Pb  

E 
 Nw

dy
y 0 

Mid-rapidity: |y| < 0.4
 1 dn p  p  


2

dy
y 0 

158A GeV
p+p baseline!
Enhancement increases with
system size for No significant size dependence
observed for  and 
Open symbols: Central
Filled symbols: Min. bias
NA49 data
M. Mitrovski et al.,
arXiv:nucl-ex/0606004
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
13
Elliptic Flow
Scaling Properties of v2 (Pb+Pb at 158A GeV)
Quark number scaling ?
Quark coalescence picture
pt-reach at SPS too small ?
Scaling with KEt/n ?
Ok for , p, 
K0s below others
NA49 preliminary
NA49 poster
Definition of KEt :
G. Stefanek
NA49 data
G. Stefanek et al.,
arXiv:nucl-ex/0611003
Christoph Blume
KEt Scaling
M. Issah and A. Taranenko,
arXiv:nucl-ex/0604011
R. Lacey and A. Taranenko,
arXiv:nucl-ex/0610029
Quark Matter, Nov. 14.-20. 2006
KE t  mt  m0
m0  m , mK 0 , mp , m
14
High-pt
Energy Dependence of Baryon/Meson-Ratios
NA49 preliminary
p/+ NA49 preliminary
p/-
Central Pb+Pb (sNN = 17.3 GeV)
Central Au+Au (sNN = 200 GeV)
pt-dependence of baryon/meson ratio
appears to be energy independent
Christoph Blume
/K0s
NA49 preliminary
Quark Matter, Nov. 14.-20. 2006
NA49
T. Schuster et al.,
arXiv: nucl-ex/0606005
STAR
arXiv: nucl-ex/0601042
PHENIX
Phys. Rev. C 69
(2004), 034909
15
High-pt
Nuclear Suppression Factor
Nuclear suppression factor
relative to p+A baseline
RAA pt  
N coll pA  d N AA dp t dy 
N coll AA  d 2 N pA dp t dy 
2
Central Pb+Pb/Au+Au
(+ + -)/2 -0.3 < y < 0.7
NA49 preliminary
SPS
Larger pt-reach than p+p at SPS
Divides out Cronin effect
PHENIX
Small suppression relative
to p+A observed at SPS
for pt < 2.5 GeV/c
Christoph Blume
NA49 poster
Z. Fodor, A. Laszlo, G. Vesztergombi
Quark Matter, Nov. 14.-20. 2006
16
Summary
(Anti-)proton rapidity spectra
Stopping: y /yp  0.6 at AGS+SPS
Inelasticity approx. energy independent in A+A (K  0.7-0.8)
3He
and t production
Concave 3He rapidity distribution, shape independent of energy
Remarkable agreement of 3He yields with statistical model
Hyperons
New data on system size dependence of -, ,  production
Elliptic flow
KEt scaling at the SPS?
High-pt
Same pt-dependence of baryon/meson ratio at SPS and RHIC
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
17
The End
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
18
Light Fragments
Mass Dependence of mt-m0
Linear dependence of
mt-m0 on cluster mass
NA49 preliminary
Same at all energies (20 – 80A GeV)
Coalescence with blast wave:
(A. Polleri et al., Phys. Lett. B419 (1998) 19 )
Box + lin. velocity profile:
20A GeV
mt-m0 ~ A
Gaussian + v(r) = vf (r/R):
Central Pb+Pb
|y | < 1.0
mt-m0 ~ A1-
Described by box shaped
density profile
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
19
Light Fragments
Energy-Dependence of BA
Coalescence parameter BA
from p, d, and 3He
distributions:
 d 3N p
d 3N d

Ed

B
2  Ep
dPd3
dPp3

E 3 He
d 3N 3 He
dP 33He
 d 3N p
 B3  E p

dPp3

2

 , Pd  2Pp


3

 , P3  3Pp
He


Strong but smooth
energy dependence
of B2 and B3
Christoph Blume
NA49 preliminary
Quark Matter, Nov. 14.-20. 2006
20
Light Fragments
A-Dependence of Yields
NA49 preliminary
Penalty factor p :
dn A 
~ const p A- 1
dy
mid-rapidity yields
Agrees with statistical
hadron gas prediction
Central Pb+Pb
Statistical hadron gas model (SHM):
F. Becattini,
private communication
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
21
Hyperons
System Size Dependence of Slope Parameters
NA49 preliminary
NA49 preliminary
Fit-range:
0.1GeV < mt-m0 < 0.8 GeV
0.3GeV < mt-m0 (, 158A GeV)
Mid-rapidity: |y| < 0.4
Open symbols: Central
Filled symbols: Min. bias
No system size dependence of T for Slight dependence for  and 
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
22
Protons
Energy-Dependence of Stopping (UrQMD)
UrQMD values correspond
to almost energy
independent xF ( 0.38)
UrQMD
M. Bleicher,
Florence Workshop on
Critical Point an Onset
of Deconfinement, 2006
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
23
Elliptic Flow
pt-Dependence of v2
New results on
K0s flow
Hydro with
Tf = 120MeV
overpredicts data
(P. Huovinen, priv. comm.)
NA49 data
G. Stefanek et al.,
arXiv:nucl-ex/0611003
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
24
High-pt
Baryon/Meson-Ratios
Baryon/meson ratio
increases with pt
Similar to RHIC
Coalescence models
applicable at SPS?
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
25
The NA49 Experiment
Setup
13m
Particle identification:
Pions, charged Kaons:
dEdx in TPCs + TOF (mid-rapidity)
K0s, , , :
Decay topology + invariant mass
:
Invariant mass of identified Kaons
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
26
The NA49 Experiment
Particle Identification
dE/dx measured in TPCs
Large acceptance
Resolution 3-4%
Time-of-flight
Mid-rapidity
Resolution 60 ps
Example:
Pb+Pb @ 40 AGeV
Christoph Blume
Quark Matter, Nov. 14.-20. 2006
27