    QGP 1

2

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7

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of:
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J. CMSThomasPbPb s = 2.76 TeV

pair amplitude modulation avn u vnb"

J. Thomas

1 dNpair
CMS Preliminary
n.b. picture shows expansionof !
~ 1+2(v 2 )2 cos(2!! )ultracold atoms released from trap!
sNN = 2.76 TeV
Ntrig d!PbPb!
35-40%

pair

1 d2N
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elliptic flow

4

elliptic 2flow4

Dh 0-24"2#"!

29Long (Rapidity) Range Correlation

4QGP0-4

40-4

"2#

1.8
1.6
1.4
1.22"#

4

elliptic flowpair

CMS Preliminary
PbPb sNN = 2.76 TeV

1 d2N
Ntrigd"! d"#cnNNn.b. picture shows expansion oultracold atoms released from t
1.8
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1.4
1.2pair

1 d2N
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200-2"!

-4 8

system like a liquid-state eccentricity:

Ridge()

Large pressure gradien

1 dNpair~ 1+ 2(v 2 )2 cos(2!! )Ntrig d!!
J. Thomas

Time%picture shows expansion oelliptic n.b.
flow
ultracold
atoms released from t

1 dN~ 1+ 2(v 2 )2 cos(2!! )Ntrig d!!
elliptic flow

pairpair

1 d2N
Ntrigd"! d"#

CMS Preliminary
PbPb sNN = 2.76 TeV

35-40%

1.8
1.6
1.4
1.2
4

4"2#

200-2-4"!
9QGP?


10

p+p@7TeVVery highmultiplicity
pp collisionsVerypp events arerare
in naturehigh-multiplicity
Very exotic
pp events

10-5 – 10-6 prob.

<Noffline>~15 for MB pp
trkRaw counts of tracks!

LHCCMS7TeV

911

The “ridge” in pp collisions





Two-particle Δη-Δϕ correlation

pp N>110, 1<pT<3 GeV/c

pp <N>~15, 1<pT<3 GeV/c









Very high multiplicity pp collisions
Very high-multiplicity pp events are rare in nature

No ridge observed in minimum bias
I pp or any pp MC generators
Very exoticpp events

Ridge QGP!?610-5 – 10-6 prob.

<Noffline>~15 for MB pptrk

12Raw counts of tracks!

Ridge p+pPb+Pb

p+Pb

p+pPb+Pb

p+P= 13 TeV
TeV√s√s= 5.02
NN NN

√sNN = 5.02 TeV= 13TeV√sNN√s= NN
5.02
TeV

√sNN

• Common understanding of•A
• Nearly ideal fluid with low•vi
Reaction • Multi-particle correlations
Reaction •aplaneplanefrom a common source.
f• In dihadron correlations, •Fo I
attributed to hydrodynamic f
impact parameter (b)impact parameter(b)• Nonflow: Non-collectiveorig•particle decays, EP decorrel
Figure 2Pbpp (55). In
Two-particle correlation results in (a) Pb+Pb, (b) p+Pb, and (c) p + p collisions at the LHC
Pb+Pb collisions there is a large cos(2) correlation with peaks at= 0, ⇡ that extend long-range
in pseudorapidity ⌘ (magenta curve). A similar feature is observed in p+Pb and p + p collisions,thought it does not dominate the overall correlations to the same degree.
 

Initial state Pre-equilibrium Thermal
Initial state Pre-equilibriHadronizat
equilibrium

Timee

ATLAS (57), and CMS (58)]. Here the experimental signatures were much stronger than inp + p collisions, and the race was on to repeat as many of the A + A measurements related tocollectivity as possible to determine whether the signals persisted in p+Pb. Experimenters atp
13
RHIC immediately reexamined p+p,d+Aup+PbPb+Pbcollision data at sN N = 200 GeV from 2008 and foundTimeehpp 14p



Pbp



Pb

CMS: Phys.35-40%
Lett. B 7198(2013)

CMS Preliminary
PbPb 2.76 TeV
PbPb sNN = 2.76 TeV

pair

1 d2N
Ntrigd"! d"#pp 7 TeV, N>110

LHC

1.8
1.6
1.4
1.2
4

Elliptic flow: 2"#arXiv:1201.3158!
cos(2Δϕ)JHEP%09%(2010)%091%

4200

JHEP 07 (2011) 076!
EPJC 72 (2012) 2012 ! -4

Physical origin of pp ridge
is not completely clear-2"!

PHENIX datasets

U+U

Au+Au

510
200RHIC“Smoking gun” of a strongly

Cu+Au

3He+Au
Cu+Cu
d+Au
interacting
QGP liquid!

p+Au

13

Nature Physics 15, 214-220 (2019)62.4



39

19.6





§ In small collision systems, can we findsome similar features of the heavy ion
collisions case?







p+p






PRL 120, 062302 (2018)
PRC 96, 064905 (2017)



p+Au,Al(2015) d+Au(2008) 3He+Au(2014)15)√sNN [GeV]

Initial-state geometry+
collective expansion

ppp

deutronn v2 …
16

Ridge (PHENIX)
2(PHENIX)17

d+Au at 200 GeV: ridge evolution with Δη  

Central Arms|h| < 0.35

FVTX-South-3 < h < -1BBC-South-3.9 < h < -3.1

dFVTX-North1<h<3Au

3.1 < h < 3.9BBC-North

A clear ridge is seen with all detector combinations, even for 𝚫h > 6.2
1218

Nonflow
based on pp data estimationPRC 95 (2017) 034910

Central p+Au
33%
25%

10%5%

he “ridge” in pp collisions

V/c

The “ridge” in pp collisions

Two-particle Δη-Δϕ correlation

Two-particle Δη-Δϕ correlation• Correlations in pp minbias data scaled by multiplicity• Not subtracted - cited as a systematic uncertainty
pp N>110, 1<pT<3 GeV/c 

pp <N>~15, 1<pT<3 GeV/c

pp N>110, 1<pT<3 GeV/c16
No ridge observed in minimum bias pp or any pp MC generators

19

Eccentricity

20

T

0.5

1

1.5

2+Au

Au

Au

2.5
3p (GeV/c)

He+A
u

2d+

1.5

31

Au

0.5

p+

0.02

p+

v pT (GeV/c)
0.0

He

0.1

d+

0.04
0.02

30.2

Au

0.04

arXiv:1805.02973
2.5
33pT (GeV/c)

v2p+ Au < v2d+ Au ≈ v2He+ Au

J.Velkovska, Vanderbilt

Nagoya, Feb 16, 201921Parton transport

6Hydrodynamic

4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 -6 4x[fm]x [fm]
x [fm]

t
Initial conditions

MC Glauber

MC GlauberParticle production

N/A

String melting

Expansion

Viscous hydrodynamics Parton scattering

Hadronization

Cooper-FryeSpatial coalescence/quark
recombination

Final stage

Hadron cascade

Hadron cascade

Macroscopice+Au

AMPT+Au

SONIC+Au

t = 3.2 fm/c

t = 1.7 fm/c

= 1.0 fm/c

Two 
model formalisms

HIJING

Microscopic22

"!$Hydrodynamic description (SONIC)√sNN = 200 GeV, central collisions

6420-2-4-6d+Au

6420-2-4-630.30

convolution

0.25

0.20

0.15

0.10

He+Au

0.05

6arXiv:1805.02973-6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6 -6 -4 -2 0 2 4 6
4x [fm]x [fm]
x [fm]
x [fm]x (fm)

x (fm)x (fm)•  •   • #%# (CGC)

0−2−4

0.25

x (fm)

2 Nagoya, Feb 16, 2019

J.Velkovska, Vanderbilt

0.00

0.3• • 

0.2

Temperature [GeV]p+Au

4.5 fm/c

t = 4.5 fm/c

Temperature [GeV]
Temperature (GeV)642
0-2-4-6y [fm]y (fm)
y [fm]y (fm)
y [fm]y (fm)
y [fm]

t = 3.2fm/c
fm/c= 1.0fm/c
fm/c
t = 1.7fm/c
fm/c
1.7
3.2
t = t1.0

0.15

0.123

Norbert Novitzky, sQM

Geometricalcontrol

Geometry control works:
v2(He+Au) ~ v2(d+Au) > v2(p+Au)• •

• TheoreOcal
AMPT1GeV
descripOon:

• Hydrodynamics with small η/s works!
• AMPT: weakly coupled partonic cascade + quark coalescence + hadronic 248 Elliptic flow

Trian

v2 is driven by the participant
eccentricity ε2 defined by∑ r2 cos(2φ)/∑ r2 =-ε2 cos(2ψ∑ r2 sin(2φ) /∑ r2 =-ε2 sin(2ψIntrinsic Component

Outgoing particle
Outgoing particles correlated with ψ2 :<exp(3iφ)> = v3 e<exp(2iφ)>=v
exp(2iψ)22dmeasured
via theHe
measuredvia
thetwo-particle
correlation
AuAu
1-φ2))><exp(2i(φ1-φ2))> = (v2)2 ∝ (ε2<exp(3i(φ)2325

Figure 5LHC#Elliptic flow coefficient v2 as a function of pT for di↵erent hadron species as measured in di↵erent smallsystems: (a) p + p at the LHC, (b) d+Au at RHIC, and (c) p+Pb at the LHC. Theory calculations
utilizing the hydrodynamic standard model are from Reference (80).

arXiv:1801.03477v2

+superSONIC• "$ # )(
Experimental data for momentum anisotropies v , v , and v as a function of p in (a) p + p, (b) p+Pb,•  #$#%'* ! and (c) Pb+Pb collisions at the LHC. Also shown are hydrodynamic standard model (superSONIC)
calculations
that incorporate constituent quark Monte Carlo Glauber initial conditions, pre-equilibrium"&)(Figure 62

3

4

Tdynamics, viscous hydrodynamics with ⌘/s = 1/4⇡, and hadronic scattering (81).
26

measurements in p + p collisions at higher energies of up to 13.1 TeV revealed an even stronger

RHIC

2728

B=C• +KLS@# <$7H8QGP@F0?)3, U, -, U @F0?7/# "<D$7H8.
• =ORT@@PNQ%!<3(<4G2'.
• RHIC<Ap+Au,Al, d+Au, 3He+Au= J 1;@&*J'.
• 6HB<@=6I-PNQ<F5:;/GF09.
• MQTLSECGC?>@D'7H;
/G.

29

30

BACKUP

31

Long Range Two Particle Correlation- Event Mixing-3

15/09/29

Central((Arm(South&&FVTX&North&BBC
FVTX&0BBC

Central((Arm(φ coverage 2π• Two Particle Correlation

PHENIX&Acceptance

Quark Matter 2015, Kobe, Japan-2-10η

12332

Rp/d/3He+Au – centralities
22π0, |η|<0.35, sNN = 200 GeV

0π , |η|<0.35, sNN = 200 GeV
PH ENIX

preliminary

1p+Au, 0-20%, prelim.

0.5PH ENIX

1p+Au, 20-40%, prelim.

0.5

d+Au, 0-20%, PRL98, 172302
3He+Au, 0-20%, prelim.
0051015p [GeV/c]

d+Au, 20-40%, PRL98, 172302
3He+Au, 20-40%, prelim.
02005T15PH ENIXπ0, |η|<0.35, sNN = 200 GeV

Global uncertainty 9.7%

preliminary

1p+Au, 40-60%, prelim.

0.5•51015p+Au, 60-84%, prelim.

0.5

p [GeV/c]T

20d+Au, 60-88%, PRL98, 172302
3He+Au, 60-88%, prelim.
03He+Au results agreewith p+Au and d+Au athigh-pT

1d+Au, 40-60%, PRL98, 172302
3He+Au, 40-60%, prelim.
0Global uncertainty 9.7%

• d+Au results agree withp+Au at high-pT

preliminary

1.5

Rp/d/3He+Au

1.5

PH ENIX• p+Au results show large
centrality dependence

202π0, |η|<0.35, sNN = 200 GeV

Rp/d/3He+Au

10p [GeV/c]
T20Global uncertainty 9.7%

preliminary

1.5

Rp/d/3He+Au

1.5

Rp/d/3He+Au

Global uncertainty 9.7%

Nuclear modiﬁcaOon incentraliOes:• Centrality determined
similarly as for large
systems (PRC90,034902)

05

1015

p [GeV/c]
T20• At moderate pT anordering is seen in mostcentral collisions
soon in PRC

332

v2 at Eixed charged multiplicity

STAR study the correlaOon for ﬁxed mulOplicity rather thancentrality:• v2 show similar trends for all systems.
• v2 is system dependent (shape).
• v2/ε2 (pT) in all systems scales into single curve – iniOal
geometry maoers

934