1. Quarkonia and vector mesons in d+Au collision at forward rapidity in PHENIX
Kwangbok Lee
Korea University
for PHENIX collaboration
21 April DIS 2010, Florence, Italy
Kwangbok Lee

2. MotivationⅠ- Quarkonia in A+A
state
J/y cc
U1S
U2S
U3S
mass [GeV]
3.10
3.53
9.46
10.02
10.36
DE [GeV]
0.64
0.20
1.10
0.54
radius [fm]
0.25
0.36
0.14
0.28
0.39
- Each quarkonium has different
binding radius.
hep-ph/ v1 H. Satz
Binding of a pair is subject to
color screening in QGP.
Melting temperatures depend on their
binding radius.
Temperature of QGP can be estimated
or another models like regeneration
can be tested.
arXiv:
21 April DIS 2010, Florence, Italy
Kwangbok Lee

3. MotivationⅡ- Quarkonia in d+A
RGPb
Q2 = 1.69 GeV2
EPS08
EPS09
nDS
EKS98
HKN07
1. Cold nuclear matter effect
antishadowing
- Shadowing model
<- Gluon densities in nucleus with
different parton distribution
functions(PDF)
Color Glass Condensate(CGC)/Gluon saturation.
Nuclear absorption
(Now we are comparing shadowing models
to J/y signal)
- Initial state parton energy loss
- Cronin effect
2. Essential information to understand QGP.
shadowing
arXiv:
Gluon density in different x
low x
high x
21 April DIS 2010, Florence, Italy
Kwangbok Lee

4. PHENIX Muon Arm d Au + South North <y> ~ -1.7, x2 ~ 0.11- Au
South
North
<y> ~ -1.7, x2 ~ 0.11
Gold going direction
<y> ~ 1.7, x2 ~
deuteron going direction
thought to be in shadowing region
South
North
The average value of the momentum fraction x2
in the gold nucleus vs. rapidity for √sNN = 200 GeV
South
North
21 April DIS 2010, Florence, Italy
Kwangbok Lee

5. Nuclear modification factorspp
dAu
(all centralities)
(0-20%)
(60-88%)
Ncoll 1
7.6 ± 0.4
15.1 ± 1.0
3.2 ± 0.2
Ncoll : number of binary collisions, 1 in p+p collision.
If there is no nuclear matter effect, RdAu = Rcp = 1
If there is suppression, RdAu , Rcp < 1
21 April DIS 2010, Florence, Italy
Kwangbok Lee

6. 21 April DIS 2010, Florence, Italy
J/y RdAu
Run2003 dAu/Run2005 pp, PRC 79, (E) (2009)
arXiv: (Erratum)
Shadowing model comparison to
RdAu values with EKS PDF and
fixed breakup cross sections
With NDSG and fixed breakup
cross sections
PDF
EKS(mb)
NDSG(mb)
breakup
Published RdAu vs. rapidity result
21 April DIS 2010, Florence, Italy
Kwangbok Lee

7. 21 April DIS 2010, Florence, Italy
J/y Rcp
EKS
σ = 0 mb
σ = 4 mb
Preliminary result with 2008 d+Au data
which has ~30 times statistics than
2003 d+Au data.
Can’t fit the data with fixed breakup
cross sections.
Need to understand the suppression of
shadowing region.
PHENIX PRELIMINARY
NDSG
σ = 0 mb
σ = 4 mb
PHENIX PRELIMINARY
Rcp vs. rapidity
21 April DIS 2010, Florence, Italy
Kwangbok Lee

8. High mass distribution
p+p
d+Au
Gold(Au) going, y<0
Deuteron(d) going, y>0
Physical background of Drell Yan, and is estimated (pythia)
21 April DIS 2010, Florence, Italy
Kwangbok Lee

9. Upsilon cross sections
BR*dσ/dy = 28.2±9.4(stat.)±4.8(syst.)pb, y [-2.2, -1.2]
BR*dσ/dy = 9.6±2.1(stat.)±1.5(syst.)nb, y [-2.2, -1.2]
BR*dσ/dy = 31.1±8.7(stat.)±6.2(syst.)pb, y [1.2, 2.2]
BR*dσ/dy = 6.7±1.7(stat.)±1.5(syst.)nb, y [1.2, 2.2]
pp cross section is reference to comparison to d+Au collision.
pp cross section vs. rapidity is following the shape of
Color Evaporation Model-CTEQ6M(PDF)(scaled down by ~2).
Cross section vs. rapidity of d+Au collision is asymmetric.
21 April DIS 2010, Florence, Italy
Kwangbok Lee

10. 21 April DIS 2010, Florence, Italy
Upsilon RdAu
RdAu = 0.84±0.34(stat.)±0.20(sys.), y [-2.2, -1.2]
RdAu = 0.53±0.20(stat.)±0.16(sys.), y [1.2, 2.2]
First Upsilon RdAu measurement at forward rapidity.
Showing suppression at small x region.
Waiting for theoretical comparison.
21 April DIS 2010, Florence, Italy
Kwangbok Lee

11. Light Vector Mesons Rcp
Gold(Au) going, y<0
Deuteron(d) going, y>0
First nuclear modification factor measurement for low mass vector mesons
in forward rapidity.
Significant suppression at deuteron going direction.
Stronger suppression for r/w than f and J/Y.
21 April DIS 2010, Florence, Italy
Kwangbok Lee

12. 21 April DIS 2010, Florence, Italy
Prospect for cc
cc is a very important particle
to calculate the actual feed-down
contributions to J/y,
to decouple the cold nuclear matter
effect.
Muon Arm
1.2<|y|<2.2
MPC
3.1<|y|<3.8
Foreground event
Scaled mixed event
Signal(Foreground – Mixed)
Signal fitting with
Gaussian and polynomial
2008 dAu North arm
21 April DIS 2010, Florence, Italy
Kwangbok Lee

13. 21 April DIS 2010, Florence, Italy
Summary
Nuclear modification factors of Upsilon, J/y and light vector mesons are shown.
They show suppression at low x region but, not clearly understood yet.
Recent J/y Rcp result is not explained well with shadowing model and fixed breakup cross sections.
New Upsilon RdAu shows suppression in low x region and need to have theoretical comparison.
Low mass vector meson need to understand its production mechanisms.
feed down to J/y measurement is underway and important to decouple the cold nuclear matter effect and QGP state.
In future, PHENIX FVTX/VTX upgrade will reduce more background and make the y’ and even Drell-Yan measurement possible.
21 April DIS 2010, Florence, Italy
Kwangbok Lee