HighpT 0,, Identified and Inclusive Charged Hadron Spectra from PHENIX

1
High-pT ?0,?, Identified and Inclusive Charged
Hadron Spectra from PHENIX

• Maya SHIMOMURA
• University of Tsukuba
• for the PHENIX Collaboration

2
Physics motivation

• What we have studied.

Comparison between AuAu and dAu collision with
high energy.

• ltPossible explanationgt
• Cronin effect in nuclear. (Initial)
• Gluon interaction in hot dense matter. (final)

PRL 91 072303 (2003)
The suppression at high pT is due to the final
state interaction. ltQuestiongt Dependence on the
System size ? Dependence on the particles
species ?
3
PHENIX Detectors
EMCAL --- measure energy deposit of electron and
gamma DC --- obtain momentum of charged particles
PC --- measure hit position of charged particles
?

• Tracking and Matching (DC, PC)
• ?charged hadron

?
?
?,?0
?0
h
?
Ks
EMCAL (PbSc PbGl) ??,?0,Ks
?
?0
h-
?
4
Spectra
5
Spectra in different systems

• 200GeV

• ltAu Au _at_ 200GeVgt
• ?0 spectra
• ? spectra
• charged hadron spectra
• ltCu Cu _at_ 200GeVgt
• ?0 spectra
• charged hadron spectra
• ltd Augt
• Ks spectra
• ? spectra
• ltppgt
• Ks spectra
• ? spectra

Au Au
See poster by T.Isobe
6
Spectra in AuAu

• 200GeV

Charged Hadron
PRC69,034910 (2004)
7
Spectra in CuCu

• 200GeV

Charged Hadron
See poster by C. M. Vale
8
Spectra in d Au

• 200GeV

See talk and poster by V.G. Ryabov
9
Spectra in p p

• 200GeV

10
RAA

• Comparison to pp collision data

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RAA for ?0 and Charged Hadron
ltMinimum biasgt
ltAu Augt

• factor 3 suppression.
• Constant out to 20GeV/c.
• Clear difference between ?0 and charged hadron
  for pt lt 5GeV/c.

(Ref talk by D.L.Winter for reaction plane
dependence)
The data is consistent with energy loss models.
(XN-Wang, GLV).
Phys.Lett.B595165-170,2004
12
Centrality evolution of RAA
ltPeripheral to Central AuAu Collisiongt

• Stronger Suppression for more central collision.
• ?0 RAA is flat for all centrality for pTgt5 GeV/c.
  
• Difference between ?0 and charged increases for
  pT lt 5 GeV/c.

13
RAA of ?
In Au Au

• Suppression is similar to ?0

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and Charged Hadron RAA in Cu Cu

• RAA is 1 within error for peripheral collision.
• RAA 0.5 for most central collision.
• Charged Hadron RAA is higher in more central
  collision.

15
Comparison between AuAu and CuCu
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High pT Particle Ratio
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200GeV
dAu
AuAu

• pp

0.4 - 0.5. in all systems and for all
centralies.
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200GeV
pp
dAu

• Ks/?0 ratio becomes flat at high pT.

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Summary

• High pT ?0 suppression is flat out to 20 GeV/c in
  Au Au.
• Consistent with Energy loss models.
• ? has a similar suppression pattern as ?0.
• Suppression is flat as function of pT.
• ?0 and charged hadron are also suppressed in
  central CuCu collision.
• RAA is 0.5 for ?0
• RAA comparison between AuAu and CuCu
• Suppression is similar for similar Npart
• ?/?0 ratio 0.4 0.5,
• The ratio is independent of centralities and
  system size.
• The ratio is similar to pp/dAu, consistent with
  Jet fragmentation.

20
Thanks To Many Effort

• PHENIX

I am proud of our colleagues!
21
13 Countries 62 Institutions 550
Participants
as of March 2005
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Related talk and poster

• ltTalkgt
• 1a M.Konno Systematic study of identified
  particle production in PHENIX
• 3a D.L.Winter PHENIX measurement of particle
  yields at high pT with respect to reaction plane
  in AuAu collision at ?sNN 200GeV
• 6b V.G.Ryabov First measurement of the ?-meson
  production at RHIC by PHENIX
• ltPostergt
• 32 C.M.Vale Charged hadron transverse momentum
  spectra in CuCu collisions from PHENIX
• 74 T.Isobe Measurement of neutral pions in ?sNN
  200GeV and 62.4GeV AuAu collisions at
  RHIC-PHENIX
• 192 K.Miki Measurement of inclusive photon and
  direct photon v2 in ?sNN 200GeV Au-Au collision
  with the PHENIX experiment at RHIC
• 200 M.L. Purschek Measurement of eta pT
  distribution in ?sNN 200GeV Au-Au collision at
  RHIC-PHENIX
• 203 Y.G. Riabov Measurement of multiparticle
  hadron decays of light mesons at PHENIX

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Back up slides
24
Npart(x,y)
60-80
50-60
30-40
80-92.2
AuAu
6.3
19.5
45.5
114
ltNpartgt
6.4
25.4
53.0
98.2
CuCu
40-50
20-30
0-10
60-94
Distribution of Npart density versus x and y (in
fermi) for similar ltNpartgt in AuAu,
CuCu Ellipticity is very different v2 should
be quite different for same ltNpartgt
25
Npart(x,y0), Npart(y,x0)
blue CuCu red AuAu
x (fm)
y (fm)
Projection of Npart density in x and y Shows that
Npart density in AuAu and CuCu are similar (for
same ltNpartgt)
26
Collision Geometry
r
y
z
y
z

• One can calculate at what impact parameter b(2y)
  in AuAu that one gets the same Nnucleon as a
  central CuCu collision (where Nnucleon(0) 10)
• For AuAu, b10 fm corresponds to 40
  centrality...

27
AuAu ?0 RAA
Phys. Rev. Lett. 89, 252301,2002 nucl-th/0404052
Phys.Lett.B595165-170,2004
28
Integrated RAB
200GeV
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Comparison of ?0 RAA in CuCu collision to ?0 RAA
in AuAu collision as the function of Npart

• Peripheral (Au Au) Mid central (Cu Cu)

30
RdA of ?