Transcript Have we seen a QGP at RHIC?
Azimuthal Anisotropy and the QGP
Yasuo MIAKE, Univ. of Tsukuba
i) Why I Iike azimuthal anisotropy ii) Tsukuba strategy for RHIC-PHENIX iii) What is found at RHIC
Reasons why I love azimuthal anisotropy
Reaction Plane
ecc
x
2
x
2
y
2
y
2
v
2
p x
2
p
2
x
p y
2
p y
2 λ>>Ｒ b ; Im pact param Almond shape λ<<Ｒ J .Y. Ollitra ult, P .R.D48('93)1132 Info. on mean free path vs. R Clear origin of the signal !
Geometry is clear observable Conversion of eccentricity to v 2 Anisotropy of the coordinate space converted to that of the momentum space.
Centrailty dependence/different collision(AuAu vs CuCu) gives good tests Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 2
Sensitivity to the early stage
RQMD Kolb et.al., PRC62(2000)054909
Time
Anisotropy in coordinate space disappears quickly Ratio of eccentricity after a time delay Disappears quickly
v 2
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
senses early stage of collision
3
Key1; reliable R.P. determination
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0-5% 5-10% 10-20% beam BBC
north
Central arm BBC
south Free from other source of corr such as HBT, decays, jets & auto-corr.
→R.P. determination from whole event wide
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 4
Key2; PID with TOF & Aerogel
n
index 1.012
n
pe 20 TOF 100ps
200cm
385cm 200cm e +
p
+ K +
Proton
TIFFÅià• QuickTimeý Dz èkǻǵÅj êLí£ÉvÉçÉOÉâÉÄ ÅB
p
e -
p
K -
High resolution TOF and low index of 1.01 Aerogel Cherenkov Both Tsukuba contribution Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 5
What we expected before RHIC
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 There is a tendency of saturation!? Hadron cascade predicts a few %.
6
Surprise !
SPS AGS Early compilation Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 RHIC 7
Large azimuthal anisotropy
N
N
0 1 2
v
1 cos 0 2
v
2 cos 2( 0 ) PHOBOS; nucl-ex/0406021
Phenix; P.R.L. 94, 232302(2005)
QuickTimeý Dz TIFFÅià• ÅB Central Peripheral Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 Larger in higher energies.
Increase with pt and saturate 8
Failure of hadronic scenarios
M. Bleicher, H. Stocker Phys. Lett. B526 (2003) 309 Hadronic cascade calculation found to underestimate v 2 at RHIC.
v 2 ~ 1 - 2 % Mean free path is shorter than that from hadronic rescatternings.
System thermalized early with the mechanism other than hadronic rescatterings.
9 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
v
2
vs. Eccentricity
Phenix; PRL 89(2002)212301
v
2
v
2 At low pt region, the ratio stays ~constant Eccentricity scaling observed in comparison of Au+Au, Cu+Cu Scaling with eccentricity shows v 2 builds up at early stage 10 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
v
2
with particle identification
PHENIX : P.R.L. 91, 182301 (2003)
PHENIX Preliminary
: Masui@QM05
Extended PID
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 Low pt region; v2( p ) > v2(K) > v2(p)
Mass Ordering
Good agreement with hydrodynamics Very early thermalization (0.6 fm/c) & high energy density (~20 GeV/fm 3 ) required !
More from Hirano’s talk Perfect fluid (low viscous) What brings the system thermalization in such a short time!
Partonic degree of freedom Deviations at high pt region (> 1.5 GeV/c); v2( p ,K) < v2(p) Other mechanism?
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Mass Ordering in single spectra
Au+Au at 200 GeV/n
PHENIX, PRC69,034909(2004)
E d
3
dp
3
e
m t T
m t
p t
2
m
2 m t -m QuickTimeý Dz TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄ Ç™Ç±ÇÃÉsÉNÉ`ÉÉǾå©ÇÈǞǽDžÇÕïKóvÇÇ• QuickTimeý Dz TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄ Ç™Ç±ÇÃÉsÉNÉ`ÉÉǾå©ÇÈǞǽDžÇÕïKóvÇÇ•
T
T
0 1 2
m v r
2 Collective Known from AGS & SPS era
Mass ordering
of slope parameters Proof of hydrodynamical collective flow Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 12
Other surprise; baryon dominance
Phenix; P.R.L. 91(2003)172301
We had many reasons to consider > 2GeV/c is the jet region.
In peripheral, p/ p ratio similar to those in ee/pp suggesting fragmentaton process.
Fragmentation process should show in ee/pp.
n p < n p as seen In central Au+Au, p/ p ratio increases with centrality, suggesting other mechanism.
High resolution Time-of flight detector
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
Quark Recombination Model (Quark Coalescence Model)
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Quark coalescence model (RECO)
Hadron Quarks, anti-quarks combine to form mesons and baryons from universal quark distribution, w(pt) .
Mom. distr. of meson (2q) ；
W
M
C
M
w
2 (
p t
2 ) Mom. distr. of baryon (3q) ；
W
B
C B
w
3 (
p t
3 ) w(pt) ； distr. of quarks ｛
steep in p t
｝ QGP Because of the steep distr. of
w(pt), RECO
wins at high pt even w. small
Cx
.
Characteristic scaling features expected.
Quark number scaling 14 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
Proton dominance by RECO
Recombination model explains the proton dominance.
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 15
V
2
from RECO
Characteristic scaling behavior Hadron Azimutal distr. of meson (2q) ；
dN M d
w
2 (1 2
v
2,
q
cos2 ) 2 (1 4
v
2,
q
cos2 ) Azimuthal distr. of baryon (3q) ；
dN B d
w
3 (1 2
v
2,
q
cos2 ) 3 (1 6
v
2,
q
cos2 ) QGP Azimuthal distr of quark; w
w
(1 2
v
2,
q
cos2 ) Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 16
Quark number scaling observed!
Presented by M. Lamont (QM04)
Meson Baryon
Quark number scaling clearly observed in v 2 .
Distinct difference between Baryon Meson also seen in R CP , yield ratio of central and peripheral coll.
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 17
Mass ordering of quarks?
WWND 2006, M. Issah KE T = m T – m
Kinetic energy of constituent quarks
Accidental OR ordering in mass of quarks?
Existence of hypersurface where QGP converted to hadrons?
18 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
Study of electron for charm
g
conversion
p
0
g
ee
h g
ee, 3
p
0
w
ee,
p
0 ee
ee,
h
ee
r
ee
h
’
g
ee
Origins of electrons “photonic” Dalitz decays of phrw Photon conversions “non-photonic” Semi-leptonic decays of heavy flavored mesons Electron yields are consistent with those photonic + charm decays.
19 Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
Charm v
2
from electrons
S.Esumi & S. Sakai@SQM2006 photonic e v 2 inclusive e v 2 (w.o. converter) Measure v 2 electrons of inclusive Evaluate contribution of photonic electron Cocktail Method Converter Method Then, subtract !
N e
[1 2
v
2
e
cos2 ]
N e
g [1 2
v
g 2
e
cos2 ]
N e
non g [1 2
v
non g 2
e
cos2 ] (
N e
g
N e
non g )[1 2 measured evaluated known Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006
N e
g g
v
2
e N e
g
N e
non g
N e
non g non g
v
2
e
cos2 ] obtained!
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Charm seems to flow!
S.Esumi & S. Sakai@SQM2006
V.Greco, C.M.Ko, R.Rapp,PLB595(2004)202.
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 V 2 of the non photonic electron, mostly charm contribution at low pt Data seem to favor the flow of the charm.
If so, thermalized & flowing charm supports quark coalescence & formation of QGP.
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2 v 0.2
Study of direct photon
PHENIX, PRL 96,032302(2006) 2 v 0.2
0.1
0.1
0.0
0.0
Measure v 2 of inclusive photon and p 0 ’s.
Subtract hadronic decays ( p , h , etc) from the inclusive v2 , direct photon!
R; direct photon excess ratio Direct photons are from compton-like “prompt” process?
Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 22
Summary of my talk
New text book for graduate students
v 2 is fun!
Establishment of R.P. is great !
v 2 is even useful !
Thermalization as early as 0.6 fm/c QuickTimeý Dz TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄ Large azimuthal anisotropy cannot be generated with hadronic process.
ǙDZÇÃÉsÉNÉ`ÉÉǾå©ÇÈǞǽDžÇÕïKóvÇÇ• Support the quark recombination model Collectivity at parton level Phenomenological, but universal quark distribution function!
statistical description of quarks QGP Y.Miake, 6th China-Japan Joint Nuclear Physics Symposium, Shanghai, May 16-20, 2006 Much fun to come Charm & photon !
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