Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
Quarkonium production in CMS
Hyunchul Kim 김현철 (Korea University)
For the CMS collaboration
Content • CMS detector@LHC
• Quarkonia physics motivation
• Result from CMS – Charmonia : J/ψ – Bottomonia : ϒ
• Summary
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 2
LHC (Large Hadron Collider)
3 HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
ATLAS
CMS
ALICE
LHCb FRANCE
SWITZERLAND
ATLAS
CMS
ALICE
LHCb
Accelerate proton : 99.9999991% of speed of light From surface ~100m
LHC (Large Hadron Collider)
4 HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
ATLAS
CMS
ALICE
LHCb FRANCE
SWITZERLAND
27 km in circumference
28.7m
15.0m
Total weight : 14000 t
CMS (Compact Muon Solenoid) detector
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 5
Superconducting Solenoid B=3.8T, 6m internal diameter
Inner tracker Silicon pixel(100×150 µm2, ~66M channels) Microstrips(80~180 µm, ~9.6M channels) pT resolution at barrel
≤ 1.5%, pT<100GeV/c
Muon system Tracking
Barrel : Drift Tube (DT) Endcap : Cathode Strip Chamber (CSC)
Trigger (Barrel, Endcap) Resistive Plate Chamber (RPC)
Muon reconstruction mechanism in CMS
• With information from inner tracker and muon stations, global muons reconstructed
• Because of the magnetic field and energy loss(2~3 GeV) in the iron yoke, Global muons need p ≥ 3~5 GeV to reach the muon stations, (depending on eta)
• Further muon ID based on track quality (χ2, # of hits,…)
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 6
Dimuon mass plot by the CMS experiment
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
• Cover from low mass to high mass region • Good dimuon resolution thanks to the tracking • pT > 4.0 GeV/c : to remove background around the upsilon mass region
• At 2010, the integrated luminosity used in the HI analysis corresponds to 7.28 µb-1 for 2.76 TeV PbPb and 225 nb-1 for 2.76 TeV pp collisions
7
5
Different variables to select good quality global muons have been studied in Monte-Carlo gen-erated PbPb events. Prior to these studies, checks were made to ensure that the MC distribu-tions of the J/ψ decay muons are in good agreement with those from data. The agreement wasfound to be better than 2%, which is within the systematic uncertainty that was estimated onthe data/MC efficiency comparison (see Sec. 5.2). In order to resolve ambiguities when twomuons share the same segment in the muon stations, a requirement on the arbitration of eachmuon is made. The transverse (longitudinal) impact parameter from the measured vertex isrequired to be less than 3 (15) cm. Tracks are only kept if they have 11 hits or more in the sil-icon tracker and the χ2 per degree of freedom of the global (tracker) track fit is required to belower than 20 (4). The probability of the two tracks to belong to a common vertex is requestedto be better than 1%, removing background arising from B-meson semileptonic decays. Theseselection criteria result in a 6.6%, 5.1% 3.9% loss of the prompt J/ψ, non-prompt J/ψ and Υ(1S)MC signals respectively.
Fig. 3 shows the dimuon spectrum in PbPb collisions at 2.76 TeV, between 2 and 200 GeV/c2
with a single muon pT cut at 4 GeV/c, after applying all of the above mentioned event filtersand single-muon selection criteria.
)2 (GeV/cµµm10 210
)2E
vent
s/(G
eV/c
1
10
210
310CMS Preliminary
= 2.76 TeVNNsPbPb -1bµ = 7.28 intL
!J/(1,2,3S)"
Z
> 4.0 GeV/cµ
Tp
Figure 3: Invariant mass spectrum of µ+µ− pairs over the mass range 2.0 ≤ mµµ < 200 GeV/c2
for single muons with pT > 4.0 GeV/c. Visible are the J/ψ, Υ and Z peaks.
4 Signal Extraction4.1 J/ψ Analysis
4.1.1 Inclusive J/ψ
The J/ψ analysis follows closely the pp analysis published in Ref. [21]. The invariant mass spec-trum of µ+µ− pairs with pT < 30 GeV/c, in the region 2 ≤ mµµ < 4 GeV/c, after applying thesingle muon quality cuts, is shown in Fig. 4 as black circles for all µ+µ− pairs in |y| < 2.4. Thesame sign muon pair spectrum (µ+µ− − µ−µ−) is overlaid as red squares for the same selec-tion. The curve is an unbinned maximum log-likelihood fit with a “Crystal Ball” function [22]
Quarkonia candidate in PbPb at CMS
8 HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
ϒ candidate in PbPb at √sNN = 2.76 TeV
4
µ+µ! pair:mass:" 9.46 GeV/c2
pT:" " 0.06 GeV/crapidity:"!0.33
µ+:pT" =" 4.74 GeV/c2
η" =" !0.39
µ!:pT" =" 4.70 GeV/c2
η" =" !0.28
Physics motivation of quarkonia study (1) • Quarkonium : flavorless meson whose constituents are a
quark and its own antiquark – Charmonium(c-cbar), Bottomonium(b-bbar)
• Suppression of quarkonium states : Good candidates to probe the QGP in Heavy-Ion collisions – Because of their large mass (mc~1.27 GeV, mb~4.19 GeV), heavy
quarks are produced in parton-parton collisions with large momentum transfer Q2, at the initial stage of the reaction.
– T<Td, heavy quark pair make strongly bound resonance. – T>Td, by Debye screening of the heavy quark binding potential no
resonance can be formed. – Td is depend on the binding energy and radius of the resonance. – Sequential suppression of the resonances thermometer for the
temperature reached in the HI collisions.
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 9
State Υ (1S) J/Ψ (1S) Χb’ (2P) Χc (1P) Υ (3S) Ψ’ (2S) ΔE (GeV/c2) 9.46 3.10 10.26 3.53 10.36 3.68 R0 (fm) 0.28 0.50 0.68 0.72 0.78 0.90
Physics motivation of quarkonia study (2)
• Owing to the long lifetime of the b hadrons, compared to the QGP lifetime, non-prompt J/ψ should not suffer from color screening, but instead may reflect the b-quark energy loss in the medium.
• Energy loss would lead to a reduction of the b-hadron yield at high pT in PbPb collisions compared to the binary-collision-scaled pp yield.
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 10
Inclusive J/ψ
Prompt J/ψ Non-Prompt J/ψ from B decays
Direct J/ψ Feed-down from ψ’ and χc
• Prompt J/ψincludes the information of the initial state of hot-dense matter.
J/ψ in pp at √s = 7 TeV
EPIC@LHC
J/ in pp at = 7 TeV
Reconstruct µ+µ vertex Simultaneous fit of µ+µ mass and pseudo-proper decay length
Mihee Jo (Korea Univ.) 8
B Lxy
J/ µ µ+
Inclusive J/
Prompt J/
Direct J/ Feed-down from c
Non-Prompt J/ from B decays
EPJC 71:1515 (2011)
Inclusive J/ψ
Prompt J/ψ Non-Prompt J/ψ
from B decays
Direct J/ψ
Feed-down from ψ’ and χc
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 11
)2 invariant mass (GeV/c-µ +µ2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
)2Ev
ents
/ ( 0.
02 G
eV/c
200
400
600
800
1000
)2 invariant mass (GeV/c-µ +µ2.5 2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
)2Ev
ents
/ ( 0.
02 G
eV/c
200
400
600
800
1000 = 7 TeVsCMS - -1L = 37 pb
< 15 GeV/cT
12 < p0.9 < |y| < 1.2
datatotal fitbackground
= 45.5/44DoF/n2χ
-0.5 0 0.5 1 1.5 2
Even
ts / (0
.06 m
m)
-110
1
10
210
-0.5 0 0.5 1 1.5 2
Even
ts / (0
.06 m
m)
-110
1
10
210
= 7 TeVsCMS - -1L = 37 pb
datatotal fitpromptnon-promptbackground
< 15 GeV/cT
12 < p
1.6 < |y| < 2.4
(mm)(2S)ψl-0.5 0 0.5 1 1.5 2
Fit pu
ll
-4-3-2-101234
(mm)(2S)ψl-0.5 0 0.5 1 1.5 2
Fit pu
ll
-4-3-2-101234
• Reconstruct µ+µ- vertex • Simultaneous 2D unbinned maximum
likelihood fit of µ+µ- mass and pseudo-proper decay length (lJ/ψ)
J/ψ in pp at √s = 7 TeV
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 12
(GeV/c)T
p6 7 8 910 20 30 40 50
dy (n
b/(G
eV/c
))T
/dp
ψJ/σ2
d×B
-110
1
10
210
(GeV/c)T
p6 7 8 910 20 30 40 50
dy (n
b/(G
eV/c
))T
/dp
ψJ/σ2
d×B
-110
1
10
210
-1 = 7 TeV L = 37 pbsCMS
Luminosityuncertainty not shown
, corrected for acceptance-µ +µ →ψnon-prompt J/
625)×0.0 < |y| < 0.9 (125)×0.9 < |y| < 1.2 (25)×1.2 < |y| < 1.6 (5)×1.6 < |y| < 2.1 (1)×2.1 < |y| < 2.4 (
FONLL
(GeV/c)T
p6 7 8 910 20 30 40 50
dy (n
b/(G
eV/c
))T
/dp
ψJ/σ2
d×B
-210
-110
1
10
210
310
(GeV/c)T
p6 7 8 910 20 30 40 50
dy (n
b/(G
eV/c
))T
/dp
ψJ/σ2
d×B
-210
-110
1
10
210
310-1 = 7 TeV L = 37 pbsCMS
Luminosity and polarizationuncertainties not shown
, corrected for acceptance-µ +µ →ψprompt J/
625)×0.0 < |y| < 0.9 (125)×0.9 < |y| < 1.2 (25)×1.2 < |y| < 1.6 (5)×1.6 < |y| < 2.1 (1)×2.1 < |y| < 2.4 (
prompt NLO NRQCD
• Prompt J/ψ well described by NRQCD • Non-prompt J/ψ fall faster at high pT than expected from
FONLL
arXiv : 1111.1557 (accepted by JHEP)
ψ(2S) in pp at √s = 7 TeV
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 13
• Prompt ψ(2S) well described by NRQCD • Non-prompt ψ(2S) overestimated by FONLL
(however, large uncertainty on BR(B→ψ(2S)X) • falls faster with pT than expected from FONLL
(GeV/c)T
p6 7 8 9 10 20 30
dy (n
b/(G
eV/c
))T
/dp
(2S)
ψσ2
d×B
-310
-210
-110
1
(GeV/c)T
p6 7 8 9 10 20 30
dy (n
b/(G
eV/c
))T
/dp
(2S)
ψσ2
d×B
-310
-210
-110
1
-1 = 7 TeV L = 37 pbsCMS
Luminosityuncertainty not shown
, corrected for acceptance-µ +µ →(2S)ψnon-prompt
25)×0.0 < |y| < 1.2 (5)×1.2 < |y| < 1.6 (1)×1.6 < |y| < 2.4 (
FONLL
(GeV/c)T
p6 7 8 9 10 20 30
dy (n
b/(G
eV/c
))T
/dp
(2S)
ψσ2
d×B
-310
-210
-110
1
10
(GeV/c)T
p6 7 8 9 10 20 30
dy (n
b/(G
eV/c
))T
/dp
(2S)
ψσ2
d×B
-310
-210
-110
1
10 -1 = 7 TeV L = 37 pbsCMS
Luminosity and polarizationuncertainties not shown
, corrected for acceptance-µ +µ →(2S)ψprompt
25)×0.0 < |y| < 1.2 (5)×1.2 < |y| < 1.6 (1)×1.6 < |y| < 2.4 (
prompt NLO NRQCD
arXiv : 1111.1557 (accepted by JHEP)
J/ψ in PbPb at √sNN = 2.76 TeV
• Same mechanism used as in pp • For the first time, prompt and non-prompt J/ψ have been separated
in heavy-ion collisions
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 14
8 4 Signal Extraction
point back to the primary vertex within six times the primary vertex resolution. This reducesthe reconstruction efficiency for J/ψ with large values of �J/ψ, i.e. it causes a difference in theprompt and non-prompt J/ψ reconstruction efficiencies that increases with the J/ψ meson pT.
The prompt J/ψ result is presented (in Section 7.1) in the centrality bins 0–10%, 10–20%, 20–30%,30–40%, 40–50%, and 50–100%, while the non-prompt J/ψ result, given the smaller sample,is presented (in Section 7.2) in only two centrality bins, 0–20% and 20–100%. Examples ofmµ+µ− and �J/ψ distributions are shown in Fig. 4. The two-dimensional fit results are shownas projections onto the mass and �J/ψ axes. Integrated over centrality, the numbers of promptand non-prompt J/ψ mesons with |y| < 2.4 and 6.5 < pT < 30 GeV/c are 307 ± 22 and 90 ± 13,respectively.
)2 (GeV/cµµm2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
)2Ev
ents
/ ( 0
.02
GeV
/c
0
20
40
60
80
100
120 = 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL
Cent. 0-100%, |y| < 2.4 < 30 GeV/c
T6.5 < p 2 = 34 MeV/c!
datatotal fitbkgd + non-promptbackground
(mm)!J/l-1 -0.5 0 0.5 1 1.5 2
Even
ts /
(0.0
88 m
m)
1
10
210
310
= 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL Cent. 0-100%, |y| < 2.4
< 30 GeV/cT
6.5 < p
datatotal fitbkgd + non-promptbackground
)2 (GeV/cµµm2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
)2Ev
ents
/ ( 0
.02
GeV
/c
0
5
10
15
20
25
30
35
40 = 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL
Cent. 0-10%, |y| < 2.4 < 30 GeV/c
T6.5 < p 2 = 34 MeV/c!
datatotal fitbkgd + non-promptbackground
(mm)!J/l-1 -0.5 0 0.5 1 1.5 2
Even
ts /
(0.0
88 m
m)
1
10
210
310 = 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL Cent. 0-10%, |y| < 2.4
< 30 GeV/cT
6.5 < p
datatotal fitbkgd + non-promptbackground
Figure 4: Invariant-mass spectra (left) and pseudo-proper decay length distributions (right) ofµ+µ− pairs integrated over centrality (top) and for the 0–10% centrality bin (bottom). The spec-tra are integrated over the rapidity range |y| < 2.4 and the pT range 6.5 < pT < 30 GeV/c. Theprojections of the two-dimensional fit onto the respective axes are overlaid as solid black lines.The dashed red lines show the fitted contribution of non-prompt J/ψ. The fitted backgroundcontributions are shown as dotted blue lines.
In order to determine the systematic uncertainty on the yield extraction, the signal and back-
8 4 Signal Extraction
point back to the primary vertex within six times the primary vertex resolution. This reducesthe reconstruction efficiency for J/ψ with large values of �J/ψ, i.e. it causes a difference in theprompt and non-prompt J/ψ reconstruction efficiencies that increases with the J/ψ meson pT.
The prompt J/ψ result is presented (in Section 7.1) in the centrality bins 0–10%, 10–20%, 20–30%,30–40%, 40–50%, and 50–100%, while the non-prompt J/ψ result, given the smaller sample,is presented (in Section 7.2) in only two centrality bins, 0–20% and 20–100%. Examples ofmµ+µ− and �J/ψ distributions are shown in Fig. 4. The two-dimensional fit results are shownas projections onto the mass and �J/ψ axes. Integrated over centrality, the numbers of promptand non-prompt J/ψ mesons with |y| < 2.4 and 6.5 < pT < 30 GeV/c are 307 ± 22 and 90 ± 13,respectively.
)2 (GeV/cµµm2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
)2Ev
ents
/ ( 0
.02
GeV
/c
0
20
40
60
80
100
120 = 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL
Cent. 0-100%, |y| < 2.4 < 30 GeV/c
T6.5 < p 2 = 34 MeV/c!
datatotal fitbkgd + non-promptbackground
(mm)!J/l-1 -0.5 0 0.5 1 1.5 2
Even
ts /
(0.0
88 m
m)
1
10
210
310
= 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL Cent. 0-100%, |y| < 2.4
< 30 GeV/cT
6.5 < p
datatotal fitbkgd + non-promptbackground
)2 (GeV/cµµm2.6 2.7 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5
)2Ev
ents
/ ( 0
.02
GeV
/c
0
5
10
15
20
25
30
35
40 = 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL
Cent. 0-10%, |y| < 2.4 < 30 GeV/c
T6.5 < p 2 = 34 MeV/c!
datatotal fitbkgd + non-promptbackground
(mm)!J/l-1 -0.5 0 0.5 1 1.5 2
Even
ts /
(0.0
88 m
m)
1
10
210
310 = 2.76 TeVNNsCMS PbPb -1bµ = 7.28 intL Cent. 0-10%, |y| < 2.4
< 30 GeV/cT
6.5 < p
datatotal fitbkgd + non-promptbackground
Figure 4: Invariant-mass spectra (left) and pseudo-proper decay length distributions (right) ofµ+µ− pairs integrated over centrality (top) and for the 0–10% centrality bin (bottom). The spec-tra are integrated over the rapidity range |y| < 2.4 and the pT range 6.5 < pT < 30 GeV/c. Theprojections of the two-dimensional fit onto the respective axes are overlaid as solid black lines.The dashed red lines show the fitted contribution of non-prompt J/ψ. The fitted backgroundcontributions are shown as dotted blue lines.
In order to determine the systematic uncertainty on the yield extraction, the signal and back-
arXiv : 1201.5069 (submitted by JHEP)
Prompt J/ψ RAA vs pT, y
EPIC@LHC
Prompt J/ RAA vs. pT and y : Comparison
CMS pTJ/ > 6.5 GeV/c
STAR pTJ/ < 8 GeV/c , PHENIX lower pT
Mihee Jo (Korea Univ.) 13
High pT J/RHIC (and SPS) is not seen at the LHC CMS shows opposite trend than PHENIX but different pT
Increasing RAA going towards ALICE y range
Watch out for anti-shadowing
ALICE low pTJ/
RAA = 0.49±0.03±0.11 pT=0 up to x1~0.06(x2~2.10-5)
CMS pT > 3 GeV/c RAA = 0.39±0.06±0.03 pT=10 up to x1~0.02(x2~5.10-4)
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
• RHIC : lower pT, but RAA increase with pT
• CMS : factor 3 suppression for pT > 6.5 GeV/c almost no pT dependence
(do not seem to be observed by RHIC)
• PHENIX : stronger suppression in forward range
• CMS : less suppression in forward range
• Increasing RAA going towards ALICE y range
15
Prompt J/ψ RAA vs. pT and y
• CMS: pT > 6.5 GeV/c
‣ Factor 3 suppression for pT > 6.5 GeV/c and at y = 0
‣ Trend to less suppression at forward rapidity
• STAR: no suppression at high pT
• PHENIX: lower pT
‣ opposite rapidity dependence
• ALICE: inclusive J/!, pT > 0 GeV/c, 0–80%
‣ RAA = 0.49 ± 0.03 ± 0.11 (Pillot, QM2011)
• Careful when comparing RAA of prompt J/! (CMS) and inclusive J/! (ALICE)
‣ In pp at low pT: !10% b-fraction
‣ From RHIC we know that open charm cross section is unmodified(can assume the same for open bottom)
‣ non-prompt J/! could shift RAA by 10% 14
RAA =Lpp
TAANMB
NPbPb(J/ψ)Npp(J/ψ)
εpp
εPbPb(cent)
y-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
!Prompt J/
= 200 GeVNNsAuAu PHENIX: |y|<0.35PHENIX: 1.2<|y|<2.2(both PRL 98, 232301 (2007))
CMS Preliminary = 2.76 TeVNNsPbPb
0-100% < 30.0 GeV/c
T6.5 < p
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)
y-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4 = 2.76 TeVNNsPbPb !CMS: prompt J/
Cent. 0-100% < 30 GeV/c
T6.5 < p
= 200 GeVNNsAuAu (|y|<0.35)!PHENIX: J/ (1.2<|y|<2.2)!PHENIX: J/
(both PRL 98 (2007) 232301)
(GeV/c)T
p0 5 10 15 20 25 30
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
= 200 GeVNNsAuAu (|y|<0.35)!PHENIX: J/ (1.2<|y|<2.2)!PHENIX: J/
(both PRL 98 (2007) 232301) (preliminary)!STAR: J/
Cent. 0-60%, |y|<1.0
= 2.76 TeVNNsPbPb !CMS: prompt J/
Cent. 0-100%, |y| < 2.4
Prompt J/ψ RAA vs. pT and y
• CMS: pT > 6.5 GeV/c
‣ Factor 3 suppression for pT > 6.5 GeV/c and at y = 0
‣ Trend to less suppression at forward rapidity
• STAR: no suppression at high pT
• PHENIX: lower pT
‣ opposite rapidity dependence
• ALICE: inclusive J/!, pT > 0 GeV/c, 0–80%
‣ RAA = 0.49 ± 0.03 ± 0.11 (Pillot, QM2011)
• Careful when comparing RAA of prompt J/! (CMS) and inclusive J/! (ALICE)
‣ In pp at low pT: !10% b-fraction
‣ From RHIC we know that open charm cross section is unmodified(can assume the same for open bottom)
‣ non-prompt J/! could shift RAA by 10% 14
RAA =Lpp
TAANMB
NPbPb(J/ψ)Npp(J/ψ)
εpp
εPbPb(cent)
y-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
!Prompt J/
= 200 GeVNNsAuAu PHENIX: |y|<0.35PHENIX: 1.2<|y|<2.2(both PRL 98, 232301 (2007))
CMS Preliminary = 2.76 TeVNNsPbPb
0-100% < 30.0 GeV/c
T6.5 < p
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)
y-2 -1.5 -1 -0.5 0 0.5 1 1.5 2
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4 = 2.76 TeVNNsPbPb !CMS: prompt J/
Cent. 0-100% < 30 GeV/c
T6.5 < p
= 200 GeVNNsAuAu (|y|<0.35)!PHENIX: J/ (1.2<|y|<2.2)!PHENIX: J/
(both PRL 98 (2007) 232301)
(GeV/c)T
p0 5 10 15 20 25 30
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
= 200 GeVNNsAuAu (|y|<0.35)!PHENIX: J/ (1.2<|y|<2.2)!PHENIX: J/
(both PRL 98 (2007) 232301) (preliminary)!STAR: J/
Cent. 0-60%, |y|<1.0
= 2.76 TeVNNsPbPb !CMS: prompt J/
Cent. 0-100%, |y| < 2.4
arXiv : 1201.5069 (submitted by JHEP)
Prompt J/ψ RAA vs Npart
• 0~10% : suppressed by factor 5 with respect to pp
• 50~100% : suppressed by factor 1.6 remains
• Similar suppression seen at PHENIX though CMS is high pT while PHENIX is low pT
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) EPIC@LHC
Prompt J/ RAA vs. pT and y : Comparison
CMS pTJ/ > 6.5 GeV/c
STAR pTJ/ < 8 GeV/c , PHENIX lower pT
Mihee Jo (Korea Univ.) 13
High pT J/RHIC (and SPS) is not seen at the LHC CMS shows opposite trend than PHENIX but different pT
Increasing RAA going towards ALICE y range
Watch out for anti-shadowing
ALICE low pTJ/
RAA = 0.49±0.03±0.11 pT=0 up to x1~0.06(x2~2.10-5)
CMS pT > 3 GeV/c RAA = 0.39±0.06±0.03 pT=10 up to x1~0.02(x2~5.10-4)
16
Prompt J/ψ RAA vs. centrality
• Prompt J/!:
‣ 0-10% suppressed by factor 5with respect to pp
‣ 50-100% suppressed by factor ~1.6
• Similar suppression seen by PHENIX
‣ though at lower pT
15
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
= 200 GeVNNsAuAu (|y|<0.35)!PHENIX: J/ (1.2<|y|<2.2)!PHENIX: J/
(both PRC 84 (2011) 054912)
= 2.76 TeVNNsPbPb !CMS: prompt J/
|y| < 2.4 < 30 GeV/c
T6.5 < p
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)
arXiv : 1201.5069 (submitted by JHEP)
Prompt J/ψ RAA vs. centrality
• Prompt J/!:
‣ 0-10% suppressed by factor 5with respect to pp
‣ 50-100% suppressed by factor ~1.6
• Similar suppression seen by PHENIX
‣ though at lower pT
• STAR measures less suppression at high pT
16
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
= 200 GeVNNsAuAu (preliminary)!STAR: J/
> 5 GeV/c, |y|<1.0T
p
= 2.76 TeVNNsPbPb !CMS: prompt J/
|y| < 2.4 < 30 GeV/c
T6.5 < p
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)
Prompt J/ψ RAA vs Npart
• 0~10% : suppressed by factor 5 with respect to pp
• 50~100% : suppressed by factor 1.6 remains
• Similar suppression seen at PHENIX though CMS is high pT while PHENIX is low pT
• STAR measured less suppression at high pT
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) EPIC@LHC
Prompt J/ RAA vs. pT and y : Comparison
CMS pTJ/ > 6.5 GeV/c
STAR pTJ/ < 8 GeV/c , PHENIX lower pT
Mihee Jo (Korea Univ.) 13
High pT J/RHIC (and SPS) is not seen at the LHC CMS shows opposite trend than PHENIX but different pT
Increasing RAA going towards ALICE y range
Watch out for anti-shadowing
ALICE low pTJ/
RAA = 0.49±0.03±0.11 pT=0 up to x1~0.06(x2~2.10-5)
CMS pT > 3 GeV/c RAA = 0.39±0.06±0.03 pT=10 up to x1~0.02(x2~5.10-4)
17 arXiv : 1201.5069 (submitted by JHEP)
Non-prompt J/ψ RAA
• Suppression of non-prompt J/ψ observed in minimum bias and central PbPb collisions, no centrality dependence
• First indications of high-pT b-quark quenching like light quarks
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 18
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
!Prompt J/!Non-prompt J/
= 2.76 TeVNNsCMS PbPb
|y| < 2.4 < 30 GeV/c
T6.5 < p
0-20%20-100%
Open heavy-flavour: Non-Prompt J/ψ RAA
• Suppression of non-prompt J/! observed in min. bias and central PbPb collisions
‣ First indications of high-pT b-quark quenching!
19
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
!Prompt J/!Non-prompt J/
= 2.76 TeVNNsCMS PbPb
|y| < 2.4 < 30 GeV/c
T6.5 < p
0-20%20-100%
Open heavy-flavour: Non-Prompt J/ψ RAA
• Suppression of non-prompt J/! observed in min. bias and central PbPb collisions
‣ First indications of high-pT b-quark quenching!
19
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)arXiv : 1201.5069 (submitted by JHEP)
b fraction compared with earlier results
19 HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
20 7 Results
(GeV/c)T
p0 5 10 15 20 25 30
b fra
ctio
n
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1 = 2.76 TeV (|y|<2.4)NNsCMS PbPb = 2.76 TeV (1.6<|y|<2.4)NNsCMS PbPb
= 2.76 TeV (|y|<2.4)sCMS pp = 2.76 TeV (1.6<|y|<2.4)sCMS pp = 7 TeV (1.6 < |y| < 2.4)sCMS pp = 7 TeV (1.2 < |y| < 1.6)sCMS pp = 7 TeV (|y| < 1.2)sCMS pp = 1.96 TeV (|y|<0.6)s pCDF p
Figure 13: b fraction of J/ψ production in pp and PbPb collisions at √sNN = 2.76 TeV as afunction of pT for the rapidity bins |y| < 2.4 and 1.6 < |y| < 2.4, compared to b fractionsmeasured by CDF in pp collisions at
√s = 1.96 TeV [41] and by CMS in pp collisions at
√s =
7 TeV [26]. Points are plotted at their measured average pT. Statistical (systematic) uncertaintiesare shown as bars (boxes).
partN0 50 100 150 200 250 300 350 400
/dy
(nb)
! d
N/d
y o
r d
AA1/
T
0
0.5
1
1.5
2
2.5 (PbPb)"Non-prompt J/ (pp)
= 2.76 TeVNNsCMS pp & PbPb
|y| < 2.4 < 30 GeV/c
T6.5 < p
0-20%20-100%
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
!Non-prompt J/
= 2.76 TeVNNsCMS PbPb
|y| < 2.4 < 30 GeV/c
T6.5 < p
0-20%20-100%
Figure 14: Left: non-prompt J/ψ yield divided by TAA (orange stars) as a function of Npartcompared to the non-prompt J/ψ cross section measured in pp (black cross). Right: nuclearmodification factor RAA of non-prompt J/ψ as a function of Npart. A global uncertainty of 6%,from the integrated luminosity of the pp data sample, is shown as a grey box at RAA = 1.Statistical (systematic) uncertainties are shown as bars (boxes).
• Good agreement within uncertainties, between the earlier results at other collision energies and the present measurements.
arXiv : 1201.5069 (submitted by JHEP)
ϒ(nS) in pp at √s = 7 TeV ϒ(nS) in pp at √s = 7 TeV
• Separation of the 3 ! states with good mass resolution
• PYTHIA agrees in shape, but not in normalization
‣ Total cross section overestimated by about a factor 2
)2 mass (GeV/c-µ+µ8 8.5 9 9.5 10 10.5 11 11.5 12
)2Ev
ents
/ ( 0
.07
GeV
/c
0
2000
4000
6000
8000
10000
)2 mass (GeV/c-µ+µ8 8.5 9 9.5 10 10.5 11 11.5 12
)2Ev
ents
/ ( 0
.07
GeV
/c
0
2000
4000
6000
8000
10000 = 7 TeVsCMS Preliminary, -1 = 40 pbintL
| < 1µ!|2 = 67 MeV/c"
17
(GeV/c)YT
p0 5 10 15 20 25 30
) (n
b/(G
eV/c
))µµ
BR
(!
dy
T/d
p"2 d
-310
-210
-110
1
CMS data
PYTHIA (normalized)
|<2#|y
(1S)#
-1 = 7 TeV, L = 3 pbs
Phys. Rev. D 83 (2011) 112004
ϒ(nS) in pp at √s = 7 TeV
• Separation of the 3 ! states with good mass resolution
• PYTHIA agrees in shape, but not in normalization
‣ Total cross section overestimated by about a factor 2
)2 mass (GeV/c-µ+µ8 8.5 9 9.5 10 10.5 11 11.5 12
)2Ev
ents
/ ( 0
.07
GeV
/c
0
2000
4000
6000
8000
10000
)2 mass (GeV/c-µ+µ8 8.5 9 9.5 10 10.5 11 11.5 12
)2Ev
ents
/ ( 0
.07
GeV
/c
0
2000
4000
6000
8000
10000 = 7 TeVsCMS Preliminary, -1 = 40 pbintL
| < 1µ!|2 = 67 MeV/c"
17
(GeV/c)YT
p0 5 10 15 20 25 30
) (n
b/(G
eV/c
))µµ
BR
(!
dy
T/d
p"2 d
-310
-210
-110
1
CMS data
PYTHIA (normalized)
|<2#|y
(1S)#
-1 = 7 TeV, L = 3 pbs
Phys. Rev. D 83 (2011) 112004
1S
2S
3S
• Separation of the 3 ϒ states with good mass resolution • The normalized pT-spectrum prediction from PYTHIA is consistent with
the measurements
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 20
ϒ(nS) in PbPb at √sNN = 2.76 TeV ϒ(nS) in PbPb at √sNN = 2.76 TeV• Signal extraction
‣ Resolution fixed from MC
‣ Peak separation fixed to PDG
• Efficiencies from Monte Carlo
‣ Same method and validation process as J/!
• Acceptance to pT = 0 GeV/c
)2 (GeV/cµµm7 8 9 10 11 12 13 14
)2Ev
ents
/ ( 0
.14
GeV
/c
0
10
20
30
40
50
60CMS Preliminary
= 2.76 TeVNNsPbPb 0-100%, 0.0 < |y| < 2.4
< 20 GeV/cT
0 < p-1bµ = 7.28 intL
> 4 GeV/cµ
Tp
(fixed to MC)2 = 92 MeV/c!
datafit
25 (GeV/c)T
p0 5 10 15 20 25 30
Effic
ienc
y
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
(1S)!
CMS Simulation = 2.76 TeVNNsPbPb
PYTHIA+EvtGen+HYDJET(Bass)
• Extended unbinned maximum likelihood fit
• Signal • Resolution fixed from MC
simulation • Peak separation fixed to
PDG • Background
• Second order polynomial • Obvious Upsilon(1S)
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 21
arXiv : 1201.5069 (submitted by JHEP)
ϒ(2S+3S) Suppression
• Measure !(2S+3S) production relative to !(1S) production
• Simultaneous fit to pp and PbPb data at 2.76 TeV
• Probability to obtain measured value, or lower, if the real double ratio is unity, has been calculated to be less than 1% 20
PRL 107 (2011) 052302Υ (2S + 3S)/Υ (1S)|PbPb
Υ (2S + 3S)/Υ (1S)|pp= 0.31+0.19
−0.15 ± 0.03
)2 (GeV/cµµm7 8 9 10 11 12 13 14
)2Ev
ents
/ ( 0
.14
GeV
/c
0
10
20
30
40
50
60
70
80 = 2.76 TeVsCMS pp |y| < 2.4
< 20 GeV/cT
0 < p-1 = 231 nbintL > 4 GeV/cµ
Tp
(fixed to MC)2 = 92 MeV/c!
datafit
NΥ (1S) = 101± 12
Υ (2S + 3S)/Υ (1S)|pp = 0.78+0.16−0.14 ± 0.02 Υ (2S + 3S)/Υ (1S)|PbPb = 0.24+0.13
−0.12 ± 0.02
)2 (GeV/cµµm7 8 9 10 11 12 13 14
)2Ev
ents
/ ( 0
.14
GeV
/c
0
10
20
30
40
50
60 = 2.76 TeVNNsCMS PbPb
Cent. 0-100%, |y| < 2.4 < 20 GeV/c
T0 < p
-1bµ = 7.28 intL > 4 GeV/cµ
Tp
(fixed to MC)2 = 92 MeV/c!
dataPbPb fitpp shape
NΥ (1S) = 86± 12
ϒ(2S+3S) Suppression
• Measure !(2S+3S) production relative to !(1S) production
• Simultaneous fit to pp and PbPb data at 2.76 TeV
• Probability to obtain measured value, or lower, if the real double ratio is unity, has been calculated to be less than 1% 20
PRL 107 (2011) 052302Υ (2S + 3S)/Υ (1S)|PbPb
Υ (2S + 3S)/Υ (1S)|pp= 0.31+0.19
−0.15 ± 0.03
)2 (GeV/cµµm7 8 9 10 11 12 13 14
)2Ev
ents
/ ( 0
.14
GeV
/c
0
10
20
30
40
50
60
70
80 = 2.76 TeVsCMS pp |y| < 2.4
< 20 GeV/cT
0 < p-1 = 231 nbintL > 4 GeV/cµ
Tp
(fixed to MC)2 = 92 MeV/c!
datafit
NΥ (1S) = 101± 12
Υ (2S + 3S)/Υ (1S)|pp = 0.78+0.16−0.14 ± 0.02 Υ (2S + 3S)/Υ (1S)|PbPb = 0.24+0.13
−0.12 ± 0.02
)2 (GeV/cµµm7 8 9 10 11 12 13 14
)2Ev
ents
/ ( 0
.14
GeV
/c
0
10
20
30
40
50
60 = 2.76 TeVNNsCMS PbPb
Cent. 0-100%, |y| < 2.4 < 20 GeV/c
T0 < p
-1bµ = 7.28 intL > 4 GeV/cµ
Tp
(fixed to MC)2 = 92 MeV/c!
dataPbPb fitpp shape
NΥ (1S) = 86± 12
ϒ(2S+3S)/ϒ(1S) suppression
• Measure ϒ(2S+3S) production relative to ϒ(1S) production • Simultaneous fit to pp and PbPb data at 2.76 TeV
EPIC@LHC
(2S+3S) suppression (2S+3S) production relative to (1S) in pp and PbPb
Simultaneous fit to PbPb and pp data at 2.76 TeV
Mihee Jo (Korea Univ.) 18
arXiv: 1105.4894 Accepted by PRL
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)
arXiv : 1105.4894 PRL 107 (2011) 052302
22
21
conclusions on any pT or rapidity dependence. The Υ(1S) yield in PbPb collisions divided
by TAA and the Υ(1S) RAA are presented as a function of Npart in the left and right panels of
Fig. 17, respectively. Within uncertainties, no centrality dependence of the Υ(1S) suppression
is observed.
(GeV/c)T
p0 2 4 6 8 10 12 14 16 18 20
(nb
c/G
eV)
T/d
ydp
!2 o
r d
TN
/dyd
p2
dAA
1/T
-210
-110
(1S) (PbPb)" (pp)
= 2.76 TeVNNsCMS pp & PbPb
Cent. 0-100%|y| < 2.4Cent. 0-100%|y| < 2.4
(GeV/c)T
p0 2 4 6 8 10 12 14 16 18 20
AAR
0
0.5
1
1.5
2
2.5
(1S)!
= 2.76 TeVNNsCMS PbPb
Cent. 0-100%|y| < 2.4
Figure 15: Left: Υ(1S) yield divided by TAA in PbPb collisions (green diamonds) as a function
of pT. The result is compared to the cross section measured in pp collisions (black crosses). The
global scale uncertainties on the PbPb data due to TAA (5.7%) and the pp integrated luminosity
(6.0%) are not shown. Right: nuclear modification factor RAA of Υ(1S) as a function of pT. A
global uncertainty of 8.3%, from TAA and the integrated luminosity of the pp data sample, is
shown as a grey box at RAA = 1. Points are plotted at their measured average pT. Statistical
(systematic) uncertainties are shown as bars (boxes). Horizontal bars indicate the bin width.
8 DiscussionThis paper has presented the first measurements of the prompt and non-prompt J/ψ, as well
as the Υ(1S) mesons, via their decays into µ+µ−pairs in PbPb and pp collisions at
√sNN
=
2.76 TeV. The results are based on data recorded with the CMS detector from the first LHC
PbPb run in 2010, and from a pp run during March 2011 at√
s = 2.76 TeV.
The prompt J/ψ cross section shows a factor of two suppression in central PbPb collisions with
respect to peripheral collisions for J/ψ with 6.5 < pT < 30 GeV/c. With respect to pp, a nuclear
modification factor of RAA = 0.20 ± 0.03 (stat.) ± 0.01 (syst.) has been measured in the 10%
most central collisions. Prompt J/ψ produced in peripheral collisions are already suppressed
with respect to pp: RAA = 0.61 ± 0.12 (stat.)± 0.10 (syst.) in the 50–100% centrality bin. While
no pT dependence is observed in the measured pT range, within uncertainties, less suppression
is observed at forward rapidity (RAA = 0.43 ± 0.06 (stat.)± 0.01 (syst.)) than at mid-rapidity
(RAA = 0.29 ± 0.04 (stat.)± 0.02 (syst.)).
A comparison of the RAA centrality dependence to results measured for pT < 5 GeV/c by
PHENIX [21] in AuAu collisions at√s
NN= 200 GeV shows a similar suppression, despite the
different collision energies and kinematic ranges. Integrated over centrality, CMS has mea-
sured an inclusive J/ψ nuclear modification factor of RAA = 0.41 ± 0.05 (stat.)± 0.02 (syst.) in
the most forward rapidity bin (1.6 < |y| < 2.4) in the pT range 3 < pT < 30 GeV/c.
22 8 Discussion
|y|0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
/dy
(nb)
! d
N/d
y o
r d
AA1/
T
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
(1S) (PbPb)" (pp)
= 2.76 TeVNNsCMS pp & PbPb
Cent. 0-100% < 20 GeV/cT
0 < p
|y|0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
(1S)!
= 2.76 TeVNNsCMS PbPb
Cent. 0-100% < 20 GeV/c
T0 < p
Figure 16: Left: Υ(1S) yield divided by TAA in PbPb collisions (green diamonds) as a function
of rapidity. The result is compared to the cross section measured in pp collisions (black crosses).
The global scale uncertainties on the PbPb data due to TAA (5.7%) and the pp integrated lumi-
nosity (6.0%) are not shown. Right: nuclear modification factor RAA of Υ(1S) as a function of
rapidity. A global uncertainty of 8.3%, from TAA and the integrated luminosity of the pp data
sample, is shown as a grey box at RAA = 1. Points are plotted at their measured average |y|.Statistical (systematic) uncertainties are shown as bars (boxes). Horizontal bars indicate the bin
width.
partN0 50 100 150 200 250 300 350 400
/dy
(pb)
! d
N/d
y o
r d
AA1/
T
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
(1S) (PbPb)" (pp)
= 2.76 TeVNNsCMS pp & PbPb
|y| < 2.4 < 20 GeV/c
T0 < p
0-10%10-20%20-100%
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
(1S)!
= 2.76 TeVNNsCMS PbPb
|y| < 2.4 < 20 GeV/c
T0 < p
0-10%
10-20%
20-100%
Figure 17: Left: Υ(1S) yield divided by TAA (green diamonds) as a function of Npart compared
to the Υ(1S) cross section measured in pp (black cross). Right: nuclear modification factor RAAof Υ(1S) as a function of Npart. A global uncertainty of 6%, from the integrated luminosity of
the pp data sample, is shown as a grey box at RAA = 1. Statistical (systematic) uncertainties
are shown as bars (boxes).
ϒ(1S) RAA vs pT, y and Npart
• Are ϒ(1S) suppressed at high pT? • No obvious rapidity dependence within the large statistical uncertainties
• In CMS, ϒ(1S) suppressed by factor ~2.3 in 0~10%
• STAR measures RAA of ϒ(1S+2S+3S) = 0.56 • for CMS (0~100%) calculated RAA of ϒ(1S+2S+3S) = 0.43
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 23
(GeV/c)T
p0 2 4 6 8 10 12 14 16 18 20
AAR
0
0.5
1
1.5
2
2.5
(1S)!
= 2.76 TeVNNsCMS PbPb
Cent. 0-100%|y| < 2.4
|y|0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
(1S)!
= 2.76 TeVNNsCMS PbPb
Cent. 0-100% < 20 GeV/c
T0 < p
partN0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4 = 2.76 TeVNNsPbPb (1S)!CMS:
|y|<2.4 < 20 GeV/c
T0.0 < p
= 200 GeVNNsAuAu (1S+2S+3S)!STAR:
|y|<0.5 (preliminary)
ϒ(1S) RAA
• !(1S) suppressed at low pT
• No obvious rapidity dependence
• CMS: !(1S)
‣ suppressed by factor ~2.2 in 0–10%
• STAR measures
‣ for CMS (0–100%):
22
RAA(Υ (1S + 2S + 3S)) = RAA(Υ (1S))×1 + Υ (2S + 3S)/Υ (1S)|PbPb
1 + Υ (2S + 3S)/Υ (1S)|pp
= 0.62× 1 + 0.24
1 + 0.78≈ 0.43
(arXiv:1109.3891)RAA(Υ (1S + 2S + 3S)) = 0.56± 0.21+0.08−0.16
CMS-HIN-10-006arXiv:1201.5069
(submitted to JHEP)
arXiv : 1201.5069 (submitted by JHEP)
Summary of the results
• prompt J/ψ and J/ψ from B decays suppressed
• ϒ(1S) and ϒ(2S+3S) with respect to ϒ(1S) are suppressed
HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University) 24 partN
0 50 100 150 200 250 300 350 400
AAR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
!Prompt J/!Non-prompt J/
(1S)"
= 2.76 TeVNNsCMS PbPb
|y| < 2.4 < 30 GeV/c!J/
T6.5 < p < 20 GeV/c"
T0 < p
0-20%20-100%
SummaryIn PbPb collisions at !sNN = 2.76 TeV
• Prompt J/! suppressed
• !(2S+3S) suppressed relative to !(1S)
‣ Observed !(1S) suppression consistent with melting of excited states only
• J/! from B decays suppressed
In pp collisions at !s = 7 TeV
• Differential cross sections described by models within theoretical and experimental uncertainties
24
In pp collisions at √s = 7 TeV,
In PbPb collisions at √sNN = 2.76 TeV,
• prompt J/ψ and ϒ(1S) is well described by models within uncertainties
• J/ψ from B decays is overestimated by FONLL model
arXiv : 1201.5069 (submitted by JHEP)
CMS HI group is analyzing with 2011 HI data now !
Expect new excited result !
25 HIM@Pyeongchang, Korea, 2012/02/21 Hyunchul Kim (Korea University)