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Quarkonia and vector mesons in d+Au collision at forward rapidity in PHENIX. Kwangbok Lee Korea University for PHENIX collaboration. Kwangbok Lee. Motivation Ⅰ - Quarkonia in A+A. - Each quarkonium has different binding radius. hep -ph/0609197v1 H. Satz. - PowerPoint PPT Presentation
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Quarkonia and vector mesons in d+Au collision at forward rapidity in PHENIX
Kwangbok Lee
Korea Universityfor PHENIX collaboration
121 April DIS 2010, Florence, ItalyKwangbok Lee
MotivationⅠ- Quarkonia in A+A
hep-ph/0609197v1 H. Satz
Kwangbok Lee
- 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.
- Each quarkonium has different binding radius.
state J/y cc U1S U2S U3S
mass [GeV] 3.10 3.53 9.46 10.02 10.36DE [GeV] 0.64 0.20 1.10 0.54 0.20radius [fm] 0.25 0.36 0.14 0.28 0.39
Perturbative Vacuum
cc
Color Screening
cc
arXiv:0911.4806
221 April DIS 2010, Florence, Italy
MotivationⅡ- Quarkonia in d+A
R GPb
Q2 = 1.69 GeV2
EPS08
EPS09
nDS
EKS98
HKN07
- 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.
1. Cold nuclear matter effect
low x high x
shadowing
antishadowing
Gluon density in different x
321 April DIS 2010, Florence, ItalyKwangbok Lee
arXiv:0902.4154
4
South North
d Au + -
PHENIX Muon Arm
Kwangbok Lee
The average value of the momentum fraction x2
in the gold nucleus vs. rapidity for √sNN = 200 GeV
<y> ~ -1.7, x2 ~ 0.11Gold going direction
<y> ~ 1.7, x2 ~ 0.0035deuteron going direction
thought to be in shadowing region
21 April DIS 2010, Florence, ItalySouth
Sout
hNorth
Nor
th
Nuclear modification factors
Ncoll : number of binary collisions, 1 in p+p collision.
If there is no nuclear matter effect, RdAu = Rcp = 1If there is suppression, RdAu , Rcp < 1
pp dAu(all centralities)
dAu(0-20%)
dAu(60-88%)
Ncoll 1 7.6 ± 0.4 15.1 ± 1.0 3.2 ± 0.2
521 April DIS 2010, Florence, ItalyKwangbok Lee
J/y RdAu
Shadowing model comparison toRdAu values with EKS PDF and fixed breakup cross sections
With NDSG and fixed breakupcross sections
arXiv:0903.4845(Erratum)
Published RdAu vs. rapidity result
PDF EKS(mb) NDSG(mb)
breakup 2.8 +2.3 -2.1 2.6 +2.2 -2.6621 April DIS 2010, Florence, ItalyKwangbok Lee
Run2003 dAu/Run2005 pp, PRC 79, 059901(E) (2009)
EKSσ = 0 mb
σ = 4 mb
NDSGσ = 0 mb
σ = 4 mb
PHENIX PRELIMINARY
PHENIX PRELIMINARY
J/y Rcp
• 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.
Rcp vs. rapidity721 April DIS 2010, Florence, ItalyKwangbok Lee
p+p
d+Au
8Kwangbok Lee 21 April DIS 2010, Florence, Italy
High mass distribution
Physical background of Drell Yan, and is estimated (pythia)
Deuteron(d) going, y>0Gold(Au) going, y<0
BR*dσ/dy = 9.6±2.1(stat.)±1.5(syst.)nb, y [-2.2, -1.2]
Upsilon cross sections
9Kwangbok Lee
BR*dσ/dy = 31.1±8.7(stat.)±6.2(syst.)pb, y [1.2, 2.2]
BR*dσ/dy = 28.2±9.4(stat.)±4.8(syst.)pb, y [-2.2, -1.2]
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
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.
Upsilon RdAu
1021 April DIS 2010, Florence, ItalyKwangbok Lee
Light Vector Mesons Rcp
• 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.
Gold(Au) going, y<0 Deuteron(d) going, y>0
1121 April DIS 2010, Florence, ItalyKwangbok Lee
Prospect for cc
12
cc is a very important particle to calculate the actual feed-down contributions to J/y, to decouple the cold nuclear matter effect.
2008 dAu North arm
Muon Arm1.2<|y|<2.2
Kwangbok Lee 21 April DIS 2010, Florence, Italy
Foreground eventScaled mixed eventSignal(Foreground – Mixed)
Signal fitting with Gaussian and polynomial
MPC3.1<|y|<3.8
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.
1321 April DIS 2010, Florence, ItalyKwangbok Lee