Transcript Energy Dependence of Hadronic Observables

Recent Results from the
NA49 Experiment
Christoph Blume
for the
Collaboration
Strange Quark Matter 2007
Levoča, Slovakia
Outline
Protons
Energy dependence of stopping
Hyperons
System size dependence at 40 and 158A GeV
Global  polarisation
Quark coupling to QGP global angular momentum
Elliptic Flow
Scaling properties at SPS (quark number, KEt)
High-pt
Baryon-meson ratios
Nuclear suppression factors
Christoph Blume
SQM07 Levoča 24-29 June 2007
2
Protons
(Anti-)Proton y-Spectra in Central Pb+Pb
Mid-rapidity data
Phys. Rev. C 73
(2006), 044910
NA49 preliminary
p
NA49 preliminary
p
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
SQM07 Levoča 24-29 June 2007
3
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
Christoph Blume
X

taken from statistical model fits
SQM07 Levoča 24-29 June 2007
Statistical Model
F. Becattini et al.,
Phys. Rev. C73
(2006), 044905.
4
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
SQM07 Levoča 24-29 June 2007
5
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 and Onset
of Deconfinement, 2006
Christoph Blume
y  y p  y
 yp 
SQM07 Levoča 24-29 June 2007
2
N part

yp
0
y
dN ( B  B )
dy
dy
6
Protons
Energy-Dependence of Inelasticity
NA49 preliminary
Energy of single net-baryon:
1
yp
N B B  y p
E B B 
mT
dN ( B  B )
y
dy
Central data
cosh y dy
Total inel. energy per net-baryon:
E inel 
sN N
 E B B
2
Central data
Inelasticity:
K
2 Einel
s N N  2mp
NA49 preliminary
Inelasticity in central A+A around K  0.7-0.8
Indications for weak energy dependence at SPS ?
Christoph Blume
SQM07 Levoča 24-29 June 2007
NA35
Phys. Rev. Lett. 72
(1994), 1419
7
Hyperons
System Size Dependence of Yields
Data at 158A GeV
M. Mitrovski et al.,
J. Phys. G32 (2006) 543.
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
SQM07 Levoča 24-29 June 2007
8
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
SQM07 Levoča 24-29 June 2007
9
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 Weak dependence for 
No significant Nw dependence for 
Christoph Blume
Open symbols: Central
Filled symbols: Min. bias
SQM07 Levoča 24-29 June 2007
10
Hyperons
Comparison of Enhancements
NA49 preliminary
Mid-rapidity: |y| < 0.4
158A GeV
Open symbols: Central
Filled symbols: Min. bias
Stronger Enhancement
observed at SPS energies
Different size dependence for 
Christoph Blume
STAR (sNN = 200GeV): Filled symbols
arXiv:nucl-ex/0705.3371
NA57 (sNN = 17.3GeV): Open symbols
Nucl. Phys. A698 (2002), 118c.
SQM07 Levoča 24-29 June 2007
11
Global  Polarization
Idea
Polarization of quarks
L
Coupling of system orbital
momentum L to spins of
(anti-)quarks in QGP
(for non-central A+A collisions)
Might survive hadronization
as a polarization of hadrons
 polarization PH relative
to the reaction plane
H = Hyperon decay parameter
* = Angle between momentum
of daughter baryon relative to L
Standard technique for
event plane determination
EP(1)
REP (1)
p*
= Event plane angle
= Event plane resolution
= Azimuthal angle rel. to EP
Christoph Blume
Globally polarized QGP
Z. Liang and X.N. Wang,
Phys. Rev. Lett. 94 (2005), 102301.
dN
 1   H PH cos  *
*
d cos 
PH 
8
 H
SQM07 Levoča 24-29 June 2007

1
sin p*  EP

1
REP
12
Global  Polarization
Results
Pb+Pb at 158A GeV
minimum bias (12.5–43.5%)
No significant polarization
P observed
Similar to RHIC measurements
NA49 preliminary
stat. errors only
Au+Au @ 200GeV (20-70%)
Au+Au @ 62GeV (0-80%)
P
STAR
STAR Preliminary
J. Chen, QM06
arXiv:nucl-ex/0705.1691
Christoph Blume
pT (GeV/c)
NA49 preliminary
stat. errors only
SQM07 Levoča 24-29 June 2007
13
Elliptic Flow
pt-Dependence of v2
New results on K0s flow
Mass hierarchy
v2() > v2(K0s)  v2 (p) > v2()
Hydro withTf = 120MeV
overpredicts data
Good description by
blast wave fit
Tf = 90 MeV,  = 0.5
NA49 data
G. Stefanek et al.,
arXiv:nucl-ex/0611003
Hydro model Blast wave model
P. Huovinen,
priv. comm.
Christoph Blume
SQM07 Levoča 24-29 June 2007
F. Retiere and M. Lisa,
Phys. Rev. C70 (2004), 044907.
14
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
Definition of KEt :
KEt Scaling
KEt  mt  m0
M. Issah and A. Taranenko,
arXiv:nucl-ex/0604011
R. Lacey and A. Taranenko,
arXiv:nucl-ex/0610029
Christoph Blume
m0  m , mK 0 , mp , m
SQM07 Levoča 24-29 June 2007
15
High-pt
Baryon/Meson-Ratios
Baryon/meson ratio
increases with pt
Similar to RHIC
Coalescence models
applicable at SPS?
Christoph Blume
SQM07 Levoča 24-29 June 2007
16
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
SQM07 Levoča 24-29 June 2007
NA49
T. Schuster et al.,
J. Phys. G32 (2006), s479.
STAR
arXiv: nucl-ex/0601042
PHENIX
Phys. Rev. C 69
(2004), 034909
17
High-pt
Nuclear Suppression Factor RAA
Unsatisfactory exp.
situation for RAA
N coll pp d 2 N AA dpt dy 
RAA pt  
N coll AA  d 2 N pp dpt dy 
p+W @ s = 19.4GeV
A+A measurements up
to pt = 4.2GeV/c, but no
equivalent p+p spectra
Consistent with energy loss
scenario with constructed
p+p baseline (?)
Prediction with energy loss
dNg/dy = 400-600
Compilation
C. Blume,
Nucl. Phys. A783 (2007), 65c.
p+p baseline
Energy loss calc.
Phys. Rev. D62
(2000), 094030.
Phys. Rev. Lett. 89
(2002), 252301.
S. Blattnig et al.,
D. d’Enterria,
I. Vitev and M. Gyulassy,
Phys. Lett. B596 (2004), 32.
Christoph Blume
SQM07 Levoča 24-29 June 2007
18
High-pt
Nuclear Suppression Factor: RCP
NA49
PHENIX
NA49 preliminary
NA49 preliminary
-0.3 < y < 0.7
NA49 preliminary
Measured baseline
Peripheral A+A
Feed down corrected
RCP() < 1
RCP(p)  1
RCP pt  
PHENIX
N coll per. d N AA cen. dpt dy 
N coll cen. d 2 N AA per. dpt dy 
Christoph Blume
2
SQM07 Levoča 24-29 June 2007
Phys. Rev. C69 (2004), 034909.
Phys. Rev. C74 (2006), 024904.
19
High-pt
Nuclear Suppression Factor rel. to p+A
Measured baseline
p+A spectra
Larger pt-reach than p+p at SPS
Divides out Cronin effect
(+ + -)/2
-0.3 < y < 0.7
NA49 preliminary
NA49
N coll pA d 2 N AA dpt dy 
RAA pt  
N coll AA  d 2 N pA dpt dy 
Small suppression relative
to p+A observed at SPS
PHENIX
PHENIX
Phys. Rev. C69 (2004), 034909.
Phys. Rev. C74 (2006), 024904.
Christoph Blume
SQM07 Levoča 24-29 June 2007
20
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)
Hyperons
New data on system size dependence of -, ,  production
Global  polarization
No significant polarization observed
Elliptic flow
KEt scaling at the SPS?
High-pt
Same pt-dependence of baryon/meson ratio at SPS and RHIC
Weak high-pt suppression (pt < 3.5 GeV/c )
Christoph Blume
SQM07 Levoča 24-29 June 2007
21
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
SQM07 Levoča 24-29 June 2007
22
The End
Christoph Blume
SQM07 Levoča 24-29 June 2007
23
Hyperons
Comparison of Enhancements
STAR (sNN = 200GeV)
Stronger Enhancement
observed at SPS energies
Christoph Blume
arXiv:nucl-ex/0705.3371
NA57 (sNN = 17.3GeV): Open symbols
Nucl. Phys. A698 (2002), 118c.
SQM07 Levoča 24-29 June 2007
24