identified particle elliptic anisotropy in 200 gev au+au collision at rhic-phenix
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Identified particle elliptic anisotropy in 200 GeV Au+Au collision
at RHIC-PHENIX
Shingo Sakai
Univ. of Tsukuba
for the PHENIX Collaboration
Introduction
x
y
p
x
p y
Initial spatial anisotropyMomentum space anisotropy
of particle emission
) ) 2( cos 2 ) cos( 2 1(2 1 0... φ v φ v Ndφ
dN
The azimuthal anisotropy of particle emission is sensitive
to the early stages of system evolution
Motivation
pK vvv 222 ・ at low pT
(<1.5GeV/c)pvv 22
How about heavier particle ?
Measure of deuteron + anti-deuteron in 200 GeV Au+Au collision at RHIC-PHENIX
2v
・ at pT >2.5GeV/c
Coalescence model
deuteron and anti-deuteron produce the coalescence of the individual nucleons
-Coalescence model-
2
23
3
23
3
)
p
pp
d
dd dp
NdEB
dp
NdE
pn
d
)2( pd pp
Quark Matter 2002
Anuj K. Purwar and Rickard du Rietz
Au+Au collision at sqrt(SNN)=200GeV
)2/(2)( 22 tp
td pvpv
Method
/22obsvv
)]) ( 2 cos[ 2 1() (
2 0obs obs
obsv Nd
dN
σ=<cos(2(m-real))> = {<cos(2(A-B))>}1/2
particle emission
2)2cos(
)2sin(tan 1
iii
iii
w
w
-Reaction plane method-Measure azimuthal angle of each particle respect to the reaction plane
Reaction
Plane
X
Y
Less non-flow contribution
HBT 、 jet 、 resonance decay
64 pmts in each BBC
PHENIX detector
Beam Beam Counter (BBC)||=3-4
3 units of rapidity away
from the mid-rapidity
DCPC1
PC3
TOF
Tracking
DC+PC1+PC3p,φ
PID ・・・ TOF
m2 = p2 {(TOF/L)2 -1}
BBC
Reaction plane distribution
BB
CN
[rad]
[rad]
2obs
20
BBCS [rad]
obs+
0 = (Ancos(2nobs) + Bnsin(2nobs)) An = -2/n*<sin(2nobs)> Bn = 2/n*<cos(2nobs)>
PID
π
K
mass^2 [(GeV/c^2)^2] mass^2 [(GeV/c^2)^2]
Momentum [GeV/C]d
P
Including background
dN/dφ distribution
dn/dφ of
background
(normalize N )
dn/dφ of
subtracted
background
2d+dbar v
Φ-Ψ
32 2 m 54 2 m
b
)))(2cos(21(: 20 fitvNfit
2.0<p<3.0 dn/dφ
Compare with theory
P(PHENIX preliminary)
d-coalescence model
d+dbar
systematic error
)(
)(0
22
2
lowvv
upvprotonb
b
assuming
2vPHENIX Preliminary
PID v 2v
dpK vvvv 2222 ・
at low momentum
(<1.5GeV/c)
deuteron (estimate)
p pi
PHENIX Preliminary2
(*) P.Huovinen, P.F.Kolb, U.W.Heinz, P.V.Ruuskanen and S.A.Voloshin, Phys. Lett. B503, 58 (2001)
Summary
・ deuteron + anti-deuteron (d+dbar)elliptic anisotropy are measured respect to the reaction plane
・ of d+dbar is estimated taking into account background
・ at low momentum (<1.5 GeV/c) ・ Coalescence model & hydro model is comparable within error bar (sys.+stat.)
2v
dv2
dpK vvvv 2222
Coalescence model(2)
))cos()2(21(
))cos(21())cos(21(
)()(
2
2
nv
nvnv
d
dN
d
dN
pn
pn
dn
pd
)2/(2)( 22 tproton
tdeuteron pvpv
(1.0<p(GeV/c)<2.0) (2.0<p(GeV/c)<3.0)
(3.0<p(GeV/c)<4.0)
d+dbar
Gaussian+exp fit
< selection>
Quality 31 || 63
TOF-Track matching cut < 2 σ
PC3-Track matching cut < 2 σ
TOF E loss > 0.0014Β^(-5/3)
|Mass^2|<1.5σ(p)
32 2 m 54 2 m
dn/dφ of
background
(normalize N )
dn/dφ of
subtracted
background
2d,dbar v
dn/dφ
Φ-Ψ
b
)))(2cos(21(: 20 fitvNfit
1.0<p<2.0
dN/dφ distribution(1)
dn/dφ of
background
(normalize N )
dn/dφ of
subtracted
background
2d+dbar v
Φ-Ψ
dn/dφ
32 2 m 54 2 m
b)))(2cos(21(: 20 fitvNfit
3.0<p<4.0
dN/dφ distribution(2)
0-5%
5-10%
10-20%
BBC
Central arm
beam
Resolution
))(cos( truemeasurednCan’t measure
2))(cos(
))(cos())(cos(
))()((cos
))(cos(
trueA
trueBtrueA
trueBtrueA
BA
n
nn
n
n
Reaction plane resolutionReaction plane sub-event
(divide one event)
B2
Quark Matter 2002
Anuj K. Purwar and Rickard du Rietz
PID v2
Lambda
dpK vvvvv 22222 )( ・
at low momentum
(<1.5GeV/c)
dv2・ doesn’t saturate
(p<3.0 GeV/c)
π+&K+ (PHENIX preliminary)
p (PHENIX preliminary)
d+dbar
PHENIX Preliminary
(C. Adler et al. Phys. Rev. Lett. 89, 132301 (2002))
PID v 2
dpK vvvv 2222 ・
at low momentum
(<1.5GeV/c)
dv2・ doesn’t saturate
(p<3.0 GeV/c)
2v
PHENIX Preliminary
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