Sunrise in Grand Teton National Park
INT Workshop on Heavy Flavor and
Electromagnetic Probes in Heavy-Ion Collisions
University of Washington
19/Sep/2014
Heavy Quarkonium

ϒ production


pp, p(d)A collisions

RHIC & LHC

Comparison to models

Questions from trends
in data
AA collisions

Ditto...
Two beautiful and massive objects
that roam freely a colorful field.
3/7/13
Manuel Calderón de la Barca Sánchez
2
States are massive, produced early

pQCD can estimate production
Sensitive to temperature and deconfined
color fields: input from Lattice QCD

Debye screening, Landau damping


Re and Im V(r, T)
Different states have different
sizes/binding energy

Sequential suppression
Cold-nuclear matter


Initial state effects: e.g. nPDF
Final state: energy loss, absorption
Regeneration

Uncorrelated heavy-quarks can pair up
Bottomonium: a cleaner probe than
charmonium...



3/7/13
3 states are accessible experimentally
expect small CNM effects
expect small regeneration effects
From A. Mocsy
Manuel Calderón de la Barca Sánchez
3
Counts
STAR p+p
N+ ++N - - N+ -
CMS:
Comb. Background (CB)

CB + Drell-Yan + bb
PHENIX: PRC 87,
044909 (2013)
CB + DY + bb + ¡ (1S+2S+3S)

11
STAR: PLB 735 (2014)
127
10

12
13
mee (GeV/c2)
Experimental Results:
s = 200 GeV
9
CMS, PHENIX, ALICE:
dimuon channel
70
8
60 |yee|<0.5
50
40
30
20
10
0
STAR: electron channel
 PRL 109 222301
(2012)
 JHEP 04 103 (2014)

ALICE:
 arXiv:1405.4493
3/7/13
Manuel Calderón de la Barca Sánchez
4
Results on cross sections
120 STAR
p+p, s = 200 GeV
¡ (1S+2S+3S) ® l + l
-
STAR
PHENIX
NLO pQCD CEM
Color Singlet Model
1.5
¡
CEM: R. Vogt
CSM: Lansberg & Brodsky
2 2.5
y

100
1
Calculations:

80
Less inner material
0.5

60
20 pb-1, all from pp run
2009.
Improvement over 2006:
0

-1 -0.5
STAR data:

40
-1.5

20

STAR: PLB 735 (2014) 127
PHENIX: PRC 87, 044909
(2013)
0
-2.5 -2

¡ (1S+2S+3S), Bl +l - ´ ds /dy (pb)
Data ~ in between CEM
and CSM predictions.
3/7/13
Manuel Calderón de la Barca Sánchez
5
¡ (1S+2S+3S), Bl +l - ´ ds /dy (pb)
pp
STAR
pp
PHENIX
dAu / 1000
pp
200
STAR
180 s = 200 GeV
NN
¡ (1S+2S+3S) ® l + l
160
140
dAu / 1000
0.5
R. Vogt
1.5
(a)
NLO pQCD CEM
1
3/7/13
¡

2 2.5
y
pp data is also lower than
prediction,
dAu / 1000
Calculation includes
shadowing
Does not include estimate of
nuclear absorption
0

-1 -0.5

120
-1.5
Midrapidity point is lower
than expectations from CEM.
100
80
60
40
Note: Scaled by 103.
20

0
-2.5 -2
STAR dAu cross section
compare RdAu, where many
theoretical and experimental
uncertainties cancel.
Manuel Calderón de la Barca Sánchez
6
Counts
35 STAR d+Au
N+ ++N - N+ (b)
2
1.8
1.6
¡ (1S+2S+3S) RdAu
1.4
STAR RdAu (1S+2S+3S)
STAR p+p Syst. Uncertainty
PHENIX
Shadowing, EPS09 (Vogt)
Energy Loss (Arleo, Peigne)
Energy Loss + EPS09
0.5
1
1.5
2.5
y
¡
Manuel Calderón de la Barca Sánchez
(b)
2
3/7/13
1.2
1
0.8
0.6
0

y~0 is right in the middle of the
antishadowing region
Expect RdAu > 1 (small effect)
Observe RdAu < 1
Absorption seems to be important
-1 -0.5

-2 -1.5

Arleo & Peigné
0.4
Energy loss
Energy loss + shadowing


R. Vogt
-2.5

Comb. Background (CB)

sNN = 200 GeV

30
|y |<0.5
Shadowing, EPS09
CB + Drell-Yan + bb

CB + DY + bb + ¡(1S+2S+3S)
p+p´<Ncoll>
11
Model comparison:
ee
10

12
13
mee (GeV/c2)
RdAu vs. y
25
20
15
10
9
Scaled pp reference fit shown for
comparison
8

5
0
Invariant mass distribution in dAu
at |y|<0.5
7
Shadowing/Antishadowing of gluon nPDF: green band

Note: STAR data on plot were preliminary.
EMC effect (right panel)

Also expects slight enhancement at mid-rapidity.
A. Rakotozafindrabe,
E. Ferreiro,
F. Fleuret,
J.P. Lansberg,
N. Matagne,
arXiv:1207.3193
Must include additional absorption (red lines)

3/7/13
Why does absorption still give RdAu>1? : Heard that absorption in this calculation needed
updating/revisiting.
Manuel Calderón de la Barca Sánchez
8
Ratio of nuclear targets
normalized to deuterium
Suppression seen with
increasing A.
a
s
=
A
s pp
A dependence: pA
a1S = 0.962 ± 0.006
a 2S+3S = 0.948 ± 0.012
STAR result is in the
same range:

for sdAu = (2 A)aspp :


a =ln(sdAu /spp )/ln (2A)
a ~ 0.9
Suppression is the same for 1S and 2S+3S (within errors).


3/7/13
Drell-Yan is not suppressed, follows A scaling.
Suppression is not as large as for J/y (a=0.92±0.008)
Manuel Calderón de la Barca Sánchez
9
1.1
1
1.2
sdA/2
Aspp
,
A
0.96
scaling
C
Ca Fe
W (a)
Au
1.3
a
1.2
1.1
E772 1S (pA), sNN = 40 GeV
E772 2S+3S (pA), sNN = 40 GeV
STAR 1S+2S+3S (dAu), sNN = 200 GeV
STAR 1S (dAu), sNN = 200 GeV
(b)
0.6
0.7
Manuel Calderón de la Barca Sánchez
1
0.1 0.2 0.3 0.4 0.5
Note: dAu 2008 run was first attempt
at measuring bottomonium in cold
nuclear matter, can revisit with higher
statistics
xF
3/7/13
0.9
0
A higher-statistics d+Au run would
help.
0.9
0.8
-0.2 -0.1
Effect goes away in the forward y bins.

0.8
0.7
0.7
Shadowing, or shadowing+E. Loss
cannot explain suppression at y=0.
A(spd/2)
E772 1S (pA), sNN = 40 GeV, 0<y<1.05
Same as STAR |y|<0.5 points.
E772 2S+3S (pA), sNN = 40 GeV, 0<y<1.05

102
Large suppression seen near xF~0 by
E772, a~0.9.
Mass Number (A)
STAR result: consistent with A trend
from E772.
10

STAR 1S (dAu), sNN = 200 GeV, |y|<1.0

Increases the statistical uncertainty
compared to sum ϒ(1S+2S+3S)
Use|y|< 1, check A dependence.
Also compare y or xF dependence.
0.6

0.5
2
For a similar comparison, separate
ϒ(1S) stat
spA
10
Not trivial either.


Suppression largest at ~1 GeV
Gives way to large enhancement
above 3 GeV
Might follow up later in STAR:
but again, need more statistics.
3/7/13
Manuel Calderón de la Barca Sánchez
11
Expectations From Ramona’s calculations for LHC
Left: fixed PDF, varying sabs : absorption has little effect
Right: fixed sabs, vary the PDF : effect on pPb nPDF is large
At LHC, kinematics of initial gluons different than at RHIC

Lower-x gluons: stronger shadowing.


3/7/13
Expect suppression at midrapidity at LHC from shadowing alone.
Larger uncertainty from gluon PDF than from absorption at LHC
Manuel Calderón de la Barca Sánchez
12
CMS Upsilon dataset for
pPb

31 nb-1 @ √sNN=5.02 TeV

From two datasets:



Pb+p, ~18 nb-1
p+Pb, ~12 nb-1
Energy of p beam: 4 TeV
 Pb beam: 4 x Z/A =
1.58 eV
Observables:



Double ratio, single ratio
“Self-normalized” yields
Study as a function of
event activity

Look at activity close to or
far from ϒ meson.


3/7/13
ϒ
(-1.93, 1.93)
Close: Ntracks
Far: ET
h
ET
(-5.2, -4)
Ntracks
(-2.4, 2.4)
Manuel Calderón de la Barca Sánchez
ET
(4, 5.2)
13
¡¡(nS) ¡
¡
¡
¡¡(1S) ¡pPb RpPb ( ¡(nS))
=
¡¡(nS) ¡
RpPb ( ¡(1S))
¡
¡
¡¡(1S) ¡pp
pp reference for single ratio:


No pp data at the same energy
Solution: use results from 1.9, 2.76, and 7 TeV

No significant dependence is observed vs. √s
Key feature of double ratio:

All initial-state effects should cancel

e.g. shadowing affects excited and ground
state in the same way
Observation:



Double ratio < 1 in pPb
Double ratio in pPb higher than in PbPb
Similar for 2S than for 3S
Implication: possible presence of final state
effects in pPb which affect excited states more
than ground state


3/7/13
Note: double ratio = 1 does not imply
absence of final-state effects
They could modify excited and ground state
equally
Expect small ϒ absorption in hadronic matter
Lin & Ko, PLB 503 (2001) 104
Note: depends on radius.
Hence, larger absorption for 2S and 3S
Manuel Calderón de la Barca Sánchez
14
ET|h|>4, Far activity:

Single ratios vary very little as the activity increases
Ntrack|h|<2.4, Near activity:


Single ratios decrease significantly with increasing activity
Interplay between produced and surrounding event, both in pp and pPb


3/7/13
Additional multiplicity produced with the ground state?
Final-state interactions breaking up the excited states?
Manuel Calderón de la Barca Sánchez
15
Span large range in event activity variables, pp, pPb, PbPb
Overlap is limited between pPb and PbPb

3/7/13
Need additional data to investigate the dependence in the three
systems.
Manuel Calderón de la Barca Sánchez
16



Allows us to look at scaling of cross section with activity
In PbPb, activity connected to Ncoll via Glauber model
A simple binary-nucleon-nucleon collision ansatz:





3/7/13
In a given event, the yield of scales with binary collisions
In the same event, the activity of the event also scales with binary collisions
Leads to linear scaling of yields with activity, assuming no other effects
Similar connection for pPb is also common paradigm: still deal with nucleon-nucleon collisons
For pp, does this hold?
Manuel Calderón de la Barca Sánchez
17
ET, Far activity
Note: x-axis is also self-normalized.
Close to linear scaling is observed for all systems, all states.

Suppression in PbPb for high ET: central events.
pPb, pp follow very closely line with slope 1 (dashed line)


3/7/13
Fit gives slope consistent with 1 within errors.
All systems, all ϒ states.
Manuel Calderón de la Barca Sánchez
18
Ntracks, Near activity
Significant differences among systems and among states!


ϒ(1S) production scaling: stronger than linear in pp.
pp: indications that slope is smaller for 2S and for 3S.
All states, even in pp, regardless of whether activity is far or near, show
increase relative yield in higher activity events.

3/7/13
Number of parton-parton collision scaling? Multi-parton interactions in pp?
Manuel Calderón de la Barca Sánchez
19
arXiv:1405.5152
Signal seen in LHCb
3/7/13
Signal yield
Forward (pPb)
Backward
(Pbp)
ϒ(1S)
189±16
72±14
ϒ(2S)
41±9
17±10
ϒ(3S)
13±7
4±8
Manuel Calderón de la Barca Sánchez
20
Used interpolated pp reference
Slight enhancement at negative rapidity, indication of antishadowing
Slight suppression at forward rapidity
Different theoretical models are consistent with data, within uncertainties


3/7/13
EPS09 NLO: IJMP E22 (2013) 1330007
E. loss : JHEP 03 (2013) 122
Manuel Calderón de la Barca Sánchez
21
ALICE sees no enhancement at backward rapidity, slight suppression.

EPS09 NLO expects antishadowing. ELoss + EPS09 also expects enhancement.
Forward rapidity data:


EPS09 NLO expects only modest suppression
Including E. Loss lowers RpPb, data near lower end of prediction
Note: ALICE data in both cases lower than LHCb data.
3/7/13
Manuel Calderón de la Barca Sánchez
22
Cold Nuclear Matter effects are
important
STAR dAu results show suppression at
y=0



Not expected from shadowing
Absorption seems to be needed
Similar effect seen in E772
CMS pPb results:

Evidence for final state effects in pPb:
suppress excited states relative to
ground state
CMS event activity study:

single ratios affected by nearby
activity


self-normalized yields increase vs.
activity

3/7/13
final-state breakup of excited state?
multi-parton interactions in pp?
Manuel Calderón de la Barca Sánchez
23
“Morning glory” pool: a hot spring with a
balmy temperature of 70 C.
3/7/13
Manuel Calderón de la Barca Sánchez
24
9
9.5
9.5
N+ ++N - -
N+ -
Comb. Background (CB)
CB + Drell-Yan + b b
(c)
CB + DY + bb + ¡ (1S+2S+3S)
p+p´<Ncoll>
10 10.5 11 11.5 12
(a)
mee (GeV/c2)
N+ -
10 10.5 11 11.5 12
p+p´<Ncoll>
CB + DY + bb + ¡ (1S+2S+3S)
CB + Drell-Yan + b b
Comb. Background (CB)
N+ ++N - -
10 10.5 11 11.5 12
p+p´<Ncoll>
CB + DY + bb + ¡ (1S+2S+3S)
(b)
mee (GeV/c2)
N+ ++N - -
N+ -
STAR Au+Au
9
9.5
CB + Drell-Yan + b b
Comb. Background (CB)
8.5
10-30% centrality
sNN = 200 GeV, |yee|<1.0
8.5
0-10% centrality
sNN = 200 GeV, |yee|<1.0
140 STAR Au+Au
120
100
80
60
40
20
0
8
140
120
100
80
60
40
20
0
8
sNN = 200 GeV, |yee|<1.0
60 STAR Au+Au
50
40
30
9
30-60% centrality
8.5
25
Manuel Calderón de la Barca Sánchez
3/7/13
20
10
0
8
mee (GeV/c2)

Clear suppression of excited states.
Suppression of ground state in most central bin.

Counts
Counts
Counts
Invariant mass distributions in 3 centrality bins
Possible to separate ground state.
Comparison to Ncoll-scaled pp reference:
¡ (1S+2S+3S) R
AA,dA
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0
1.8
2
1.6
1.4
1.2
1
0.8
0.6
0.4
0
0.2
0
0.4
AA,dA
0.2
¡ (1S+2S+3S) R
STAR Au+Au
STAR Au+Au, Centrality Integrated
350
|y¡|<0.5
300
Emerick-Zhao-Rapp Model
250
Emerick-Zhao-Rapp Model
400
400
Npart
(a)
(b)
350
|y¡|<1.0
300
Strickland-Bazow Model
200
200
250
STAR d+Au
p+p Stat.+Fit Uncertainty
150
STAR Au+Au, Centrality Integrated
100
STAR Au+Au
Strickland-Bazow Model
Common Normalization Syst.
50
STAR d+Au
p+p Stat.+Fit Uncertainty
150
Common Normalization Syst.
100
STAR ¡(1S+2S+3S)
sNN = 200 GeV
50
STAR ¡(1S+2S+3S)
sNN = 200 GeV
0
Npart
Right panel: all data in STAR acceptance |y|<1


dAu, and two most peripheral bins: consistent with no suppression
Suppression most central Au+Au: Consistent with expectations for hot & cold nuclear matter, however...
Left panel: bin closest to midrapidity, |y|<0.5

dAu suppression is of the same magnitude as central AuAu: Important to understand dAu system
Calculations:
 Strickland & Bazow: Includes estimate of heavy quarkonium potential, Re and Im. Models
evolution through anisotropic hydro. (Nucl. Phys. A 879 (2012) 25 )
 Emerick, Zhao & Rapp: attempt to include both Hot & Cold nuclear effects
3/7/13
Manuel Calderón de la Barca Sánchez
26
Strong
Weak
Binding
Weak vs. Strong Binding



Binding energy changes (or not) with T.
Narrower spectral functions for “Strong” case
Ratios of correlators compared to Lattice: favor
“Strong” binding case
Emerick, Zhao & Rapp.
EPJ A (2012) 48:72
Kinetic Theory Model


Rate Equation: dissociation + regeneration
Fireball model: T evolution.


3/7/13
T ~ 300 MeV @ RHIC
T ~ 600 MeV @ LHC
Manuel Calderón de la Barca Sánchez
27
Comparison to data:



Mostly consistent with
data
Little regeneration:
Final result ~
Primordial suppression
Large uncertainty in
nuclear absorption.
Need dAu, pPb.


3/7/13
Based on our
preliminary result
RdAu=0.78
sabs ~ 1 – 3.1 mb
H
o
t
Emerick, Zhao & Rapp.
EPJ A (2012) 48:72
Suppression due to
nuclear matter:
can bring RAA down to ~0.6
(most central, lower edge of green band).
Additional suppression needed to bring
RAA down to ~0.4 :
nuclear effects
Manuel Calderón de la Barca Sánchez
28
¡ (1S) R
AA,dA
2.5
2
1.5
1
0.5
0
0
STAR d+Au
STAR Au+Au
Liu-Chen Model
Strickland-Bazow Model
STAR Au+Au, Centrality Integrated
200
p+p Stat.+Fit Uncertainty
150
Common Normalization Syst.
100
STAR ¡(1S)
sNN = 200 GeV
50
250
350
|y¡|<1.0
300
(c)
400
Npart
Consistent with no suppression in dAu and peripheral AuAu
Suppression in most central collisions


R AA(1S) = 0.66 ± 0.13(Au + Au stat.) ± 0.10(p + p stat.)+0.02 −0.05(Au + Au syst.) ± 0.08(p + p syst.).
Models from Strickland et al., and Liu et al. consistent with central suppression

3/7/13
However, neither model includes any CNM effects.
Manuel Calderón de la Barca Sánchez
29
Measurements: vertical line


8
6
4
2
STAR dAu ¡ (1S+2S+3S)
No Suppression
a
A -scaling
1.2
(a)
(b)
RAA
1.4
QGP+Aa scaling: consistent with
AuAu data
Probability Density
|y¡|<1.0
QGP Effects only
1
QGP effects + Aa scaling
STAR AuAu 0-10%
No Suppression
Based on Strickland et al.
Aa scaling: consistent with dAu
data
Other scenarios are disfavored.
3/7/13
12
10
8
A2a and QGP Effects
QGP effects only


A2a for AuAu
0.8

2a

A -scaling

No suppression: RAA=1
Aa scaling for dAu (CNM effect)
0.6

6
Run pseudoexperiments for
various scenarios
Stat. unc.: width of distributions
0.4

4

0.2
Hypothesis test:
2
pink band: syst. unc.
0
0

Probability Density
10
RdAu
RAA, 0-10% most central
Manuel Calderón de la Barca Sánchez
30
Hypothesis tests:
Probability Density
10
8
6
4
2
12
10
8
STAR dAu ¡ (1S+2S+3S)
No Suppression
a
A -scaling
|y¡|<0.5
QGP Effects only
STAR AuAu 0-10%
No Suppression
1.2
(c)
(d)
1.4
3/7/13
1

A2a and QGP Effects
2a
0.8
Comparable to central AuAu
No particular scenario is
favored.
RAA

A -scaling
QGP effects + Aa scaling
Clear that |y|<0.5 shows
large suppression in dAu.

6
0.6

Based on Strickland et al.
4
QGP effects only

2

A2a for AuAu
0.4

0.2

No suppression: RAA=1
Aa scaling for dAu (CNM
effect)
0
0

Probability Density
Additional statistics in dAu
would be beneficial.
Manuel Calderón de la Barca Sánchez
31
1200
1000
800
600
400
200
0
7
50
40
30
20
10
0
7
8
8
CMS PbPb sNN = 2.76 TeV
Cent. 0-100%, |y| < 2.4
m
Lint = 150 mb-1
T
11
12
|y| < 2.4
m
T
p > 4 GeV/c
12
13
data
total fit
background
Lint = 230 nb-1
11
14
13
(RAA scaled)
pp shape
background
total PbPb fit
data
p > 4 GeV/c
10
10
CMS pp s = 2.76 TeV
Mass(m+m-) [GeV/c2]
9
9
Mass(m+m-) [GeV/c2]
14
32
Manuel Calderón de la Barca Sánchez
3/7/13
Events / ( 0.1 GeV/c2 )
Events / ( 0.1 GeV/c2 )
Clear suppression of all states in PbPb.
Centrality integrated:



(1S) : 0.56 ± 0.08 ± 0.07
(2S) : 0.12 ± 0.04 ± 0.02
(3S) : < 0.10 @ 95% CL
Observation of sequential
suppression.
Comparison to STAR RAA
(1S), |y|<1 :


0.88±0.09±0.13+0.03−0.07 ±0.11
More suppression at LHC
compared to RHIC
If directly produced fraction
is ~51%: result consistent
with suppression of excited
states only.
3/7/13
Manuel Calderón de la Barca Sánchez
33
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
1.4
1.2
1
0.8
0.6
0.4
CMS PbPb
100
150
¡ (1S)
CMS data
Primordial
Regenerated
Total
50
300
sNN = 2.76 TeV
¡ (2S)
CMS data
Primordial
Regenerated
Total
250
Nuc. Abs.
200
Npart
Lint = 150 mb-1
350
¡ (1S)
|y| < 2.4
200
250
300
350
M. Strickland
¡ (1S), 4ph/s = 3
¡ (1S), 4ph/s = 2
¡ (1S), 4ph/s = 1
¡ (2S), 4ph/s = 3
¡ (2S), 4ph/s = 2
¡ (2S), 4ph/s = 1
¡ (2S)
100
150
CMS PbPb sNN = 2.76 TeV
50
400
400
34
Manuel Calderón de la Barca Sánchez
3/7/13
0.2
0
0
Npart

Suppression level is similar in both models
EZR model: Regeneration component is small for ϒ.

RAA
RAA
Models from Strickland et al. and Emerick et al. consistent with
data.
CMS showed sequential suppression

Models are consistent with this
picture
LHCb shows results consistent with
shadowing, can also have some E.
loss, but both ok within uncertainties
The beauty peaks were painting a
compelling picture.
... but then things got murky...
Beauty
Pool
Mud
Volcano
3/7/13
Manuel Calderón de la Barca Sánchez
35
arXiv:1405.4493
ALICE Measures ϒ in
PbPb

Forward rapidity region


2.5 < y < 4
Note: CMS, |y|<2.4
Fit to 1S to extract yield in
PbPb
Uses LHCb pp for reference
3/7/13
Manuel Calderón de la Barca Sánchez
36
Comparison between CMS and ALICE
 ϒ RAA: more suppression at forward rapidities!

3/7/13
Energy density, T should be smaller at forward y. What gives?
Manuel Calderón de la Barca Sánchez
37
Model from Strickland et al.


Expect largest
suppression “dip” at y=0.
Changing model
parameters does not
change this feature.

Change in T profile




Change in shear viscosity
(and therefore initial T)


Increases/Decreases RAA
scale, but dip remains
Most (all?) models on the
market have this
behavior.

3/7/13
Gaussian profile
Boost invariant profile
Widens/narrows dip, but
dip remains
Note: this model does not
have regeneration...
Manuel Calderón de la Barca Sánchez
38
Model from Emerick et
al.



3/7/13
Includes a
regeneration
component, albeit
small
Includes absorption
component
Yet, model cannot
account for stronger
suppression at
forward rapidity
Manuel Calderón de la Barca Sánchez
39
RAA
RAA
1.4
1.2
1
0.8
0.6
0.4
0.2
¡ (1S)
|y|
10
12
16
18
Cent. 0-100%
|y| < 2.4
14
CMS PbPb sNN = 2.76 TeV
T
8
CMS PbPb sNN = 2.76 TeV
6
¡ (1S)
4
Cent. 0-100%
0 < p < 20 GeV/c
2
0
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
2.5
2
1.5
1
0.5
0
0
T
p (GeV/c)
ALICE
20
CMS results on RAA vs. pT and y with first PbPb run, limited statistics


JHEP 1205 (2012) 063
No indication of smaller RAA at higher y.
In progress, pT and y dependence with higher statistics and finer bins.

3/7/13
150 mb-1, compared to 7.3 mb-1
Manuel Calderón de la Barca Sánchez
40
RAA
RAA
1.4
1.2
1
CMS Preliminary
PbPb sNN = 2.76 TeV
T
0-100%
Inclusive y (2S) (6.5 < p < 30 GeV/c, |y| < 1.6)
¡ (3S) (|y| < 2.4), 95% upper limit
0.8
U (1S)
1
1.2
¡(1S)
0-10%
Centrality
Manuel Calderón de la Barca Sánchez
0.8
T
J/ y
0.8
¡(2S+3S), 95% limit
0-60% Centrality
0.6
3/7/13
¡ (2S) (|y| < 2.4)
prompt J/ y (6.5 < p < 30 GeV/c, |y| < 2.4)
¡ (1S) (|y| < 2.4)
0.4
But there are important details that do not fit.
41

0.6
0.4
U (2S)
0.6
Binding energy [GeV]
0.4
U (3S)
0.2
0.2 y(2S)
0
0
0.2
J/y, p >5 GeV/c
T
0-10% Centrality
1.2 STAR Inclusive Quarkonium Measurements
Au+Au, sNN = 200 GeV, |y|<1
1
0.8
0.6
0.4
0.2
0
0
1.4
1.2
1
Binding Energy (GeV)
Overall pattern of sequential suppression is observed.
ϒ: an observable that is throwing surprises!
dAu, pPb data are now showing intriguing features


Possible large suppression at y=0 at RHIC
Final state modifications of excited state compared to ground state

Double ratio < 1 in pPb
pp data vs. event activity:

single ratios decrease when activity is near ϒ:


breakup of excited states? higher multiplicity when ground state is
produced?
Increase of self-normalized yield: multi-parton interactions?
AuAu data: The first results from STAR and CMS looked very
consistent with sequential suppression picture.

3/7/13
But forward rapidity data challenges our closely held beliefs!
Manuel Calderón de la Barca Sánchez
42
Here’s to the continued exploration of beautiful peaks, and that
we find a crisp, clear vista of the QCD landscape
Manuel Calderón de la Barca Sánchez
3/7/13
43
3/7/13
Manuel Calderón de la Barca Sánchez
44
Study A dependence of ϒ family in pA.
Fixed nuclear targets: liquid deuterium, C, Ca, Fe, W.
proton beam @ 800 GeV.

Equivalent √s=√((800+1)2-(800)2)=√1601 ~ 40 GeV
Measured Drell-Yan, ϒ(1S) and ϒ(2S+3S)

xF, x2 and pT dependence.
Reminder about xF and rapidity:

Definition: xF = pZ/pZ(max) (in CM Frame), y=1/2 ln((E+pZ)/(E-pZ))



xF = 0 is equivalent to y = 0. (pZ=0 gives 0 for both)
For other values, need E, which means we need pT. Assuming pT~1 GeV:



3/7/13
For two protons at √s=40 GeV, pZ(max)=19.98 ~20 GeV
xF = 0.1, pZ=2 GeV, E=10.247, y=0.198 ~ 0.2
xF = 0.2, pZ=4 GeV, E=10.817, y=0.388 ~ 0.4
xF = 0.3, pZ=6 GeV, E=11.704, y=0.566 ~ 0.6
Manuel Calderón de la Barca Sánchez
45