13 experimental papers: alice (7), atlas (2), cms (3...
Post on 19-May-2020
1 Views
Preview:
TRANSCRIPT
p–Pb Collisions at the LHC: a brief overview
Anton Andronic – GSI Darmstadt
13 experimental papers: ALICE (7), ATLAS (2), CMS (3), LHCb (1)
(...and “innumerable” theoretical ones :)
• Initial state (shadowing/saturation) ...reference measurementsIS2013, http://indico.cern.ch/conferenceTimeTable.py?confId=239958
• Final state? (to flow or not to flow?)
Rencontres QGP-France 2013 - Etretat, Sep. 9-11
Reference measurements
2 A.Andronic@GSI.de
ALICE, PRL 110 (2013) 032301 PRL 110 (2013) 08230230 citations 32 citations
(GeV)NNs210 310
⟩pa
rtN⟨
)/η/d
chN
(d
0
1
2
3
4
5) NSDppp (p
ALICE
CMS
CDF
UA5
UA1
STAR
Central AA
ALICE
ATLAS
CMS
NA50
BRAHMS
PHENIX
STAR
PHOBOS
0.10NN
s ∝
0.11NN
s ∝
0.15NN
s ∝
pPb ALICE
dAu PHOBOSpAu NA35
) INELppp (p
ISR
UA5
PHOBOS
ALICE
(GeV/c)T
p0 2 4 6 8 10 12 14 16 18 20
PbP
b ,
RpP
bR
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8 ALICE, charged particles
| < 0.3cms
η = 5.02 TeV, NSD, | NN
sp-Pb
| < 0.8η = 2.76 TeV, 0-5% central, | NNsPb-Pb
| < 0.8η = 2.76 TeV, 70-80% central, | NNsPb-Pb
p-Pb data exhibit generic features of (gluon) saturation (NB: Ncoll (p-Pb) = 8)
Reference measurements + theory
3 A.Andronic@GSI.de
ALICE, PRL 110 (2013) 032301 PRL 110 (2013) 082302
labη
-2 0 2
lab
η/d
chNd
0
5
10
15
20
25
DPMJET [32]
Sat. Models:IP-Sat [5]KLN [3]rcBK [7]
HIJING:2.1 no shad. [6]
=0.28 [6]g2.1 s2.0 no shad. [4]BB2.0 with shad. [4]BB
ALICE NSD
= 5.02 TeVNNsp-Pb,
0 2 4 6 8 10 12 14 16 18 200.4
0.6
0.8
1
1.2
1.4
1.6
1.8 = 5.02 TeVNNsp-Pb
| < 0.3cms
ηALICE, NSD, charged particles, |
Saturation (CGC), rcBK-MCSaturation (CGC), rcBKSaturation (CGC), IP-Sat
0 2 4 6 8 10 12 14 16 18 20
pPb
R
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8 )0πShadowing, EPS09s (
LO pQCD + cold nuclear matter
(GeV/c)T
p0 2 4 6 8 10 12 14 16 18 20
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8 HIJING 2.1=0.28gs
=0.28gDHC, s
DHC, no shad.
DHC, no shad., indep. frag.
Binary collision scaling: “cold” matter / EW observables
4 A.Andronic@GSI.de
)2 (GeV), or mass (GeV/cT
(GeV/c), ET
p0 10 20 30 40 50 60 70 80 90 100
pPb
, R
PbP
bR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2 = 5.02 TeV, NSD (ALICE)
NNs, p-Pb chN
= 2.76 TeV, 0-10% (CMS)NN
s, Pb-Pb γ
= 2.76 TeV, 0-10% (CMS)NNs, Pb-Pb ±W
= 2.76 TeV, 0-10% (CMS)NN
s, Pb-Pb 0Z
“cold” nuclei (p–Pb):shadowing / saturation(gluon distr. func.) ...at low-x
binary coll. scaling, pT > 2 GeV/c
exhibited by various observables
ALICE, PRL 110 (2013) 082302
CMSγ, PLB 710 (2012) 256W±, PLB 715 (2012) 66Z0, PRL 106 (2011) 212301
ATLAS: PRL 110 (2013) 002301
...and relevance to jet quenching at the LHC
4 A.Andronic@GSI.de
)2 (GeV), or mass (GeV/cT
(GeV/c), ET
p0 10 20 30 40 50 60 70 80 90 100
pPb
, R
PbP
bR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2 = 5.02 TeV, NSD (ALICE)
NNs, p-Pb chN
= 2.76 TeV, 0-10% (CMS)NN
s, Pb-Pb γ
= 2.76 TeV, 0-10% (CMS)NNs, Pb-Pb ±W
= 2.76 TeV, 0-10% (CMS)NN
s, Pb-Pb 0Z
, Pb-Pb (ALICE)chN, Pb-Pb (CMS)chN
= 2.76 TeV, 0-5% NNs
reaches a factor of about 7 aroundpT=7 GeV/c
(stronger than previously measuredat RHIC,
√sNN=200 GeV)
remains substantial even at 50-100GeV/c
ALICE, PLB 720 (2013) 52
CMS, EPJC (2012) 72
seen also with jets
ATLAS, PLB 719 (2013) 220
CMS, PLB 712 (2012) 176PLB 718 (2013) 773 (γ-jet)
ALICE preliminary
Long-range correlations
5 A.Andronic@GSI.de
pp p-Pb
η∆4
20
24
φ∆0
2
4
)φ
∆,η
∆R
( 2101
<3.0GeV/cT
110, 1.0GeV/c<p≥(d) CMS N
η∆-4
-20
24
φ∆0
2
4φ∆
dη∆d
pair
N2 d
trig
N1 1.6
1.7
1.8
110≥ trk
offline = 5.02 TeV, NNNsCMS pPb
< 3 GeV/cT
1 < p
(b)
long range in η
CMS, JHEP 1009 (2010) 091, PLB 718 (2013) 795, ALICE, PLB 719 (2013) 29
Interpretations (long range in η): flow (EPOS MC), initial state (CGC/Glasma)Werner et al., PRL 106 (2011) 122004; Dusling, Venugopalan, PRL 108 (2012) 262001
aligned flux tubes connecting valence quarks (pp), Bjorken, Brodsky, Goldhaber, arXiv:1308.1435
Long-range correlations
5 A.Andronic@GSI.de
pp p-Pb p–Pb
η∆4
20
24
φ∆0
2
4
)φ
∆,η
∆R
( 2101
<3.0GeV/cT
110, 1.0GeV/c<p≥(d) CMS N
η∆-4
-20
24
φ∆0
2
4φ∆
dη∆d
pair
N2 d
trig
N1 1.6
1.7
1.8
110≥ trk
offline = 5.02 TeV, NNNsCMS pPb
< 3 GeV/cT
1 < p
(b)
long range in η ...and in φ (jet-subtracted distr.)
CMS, JHEP 1009 (2010) 091, PLB 718 (2013) 795, ALICE, PLB 719 (2013) 29
Interpretations (long range in η): flow (EPOS MC), initial state (CGC/Glasma)Werner et al., PRL 106 (2011) 122004; Dusling, Venugopalan, PRL 108 (2012) 262001
aligned flux tubes connecting valence quarks (pp), Bjorken, Brodsky, Goldhaber, arXiv:1308.1435
Initial state model (CGC) vs. data
6 A.Andronic@GSI.de
near side (CMS) near and away side (ALICE)
0
0.02
0.04
0 1 2 3 4 5 6
pTtrig=pT
asc [GeV]
Associated Yield
p+Pb: CMS data
p+p: CMS data
0
0.02
0.04
0.06
0.08
0.1
0-20% 20-40% 40-60%
Away-Side, Symmetric Near-Side, Symmetric
Away-Side, Off-DiagonalNear-Side, Off-Diagonal
Dusling, Venugopalan, PRD 87 (2013) 094034
the saturation model (CGC) is successful
Collective flow in p–Pb collisions?
7 A.Andronic@GSI.de
ALICE, PLB 719 (2013) 29
[GeV]⟩T
PbEΣ⟨20 40 60 80 100 120
2v
0
0.05
0.1
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
xxxxxxxxxxxx
{2}2v{4}2v{2PC}2v
hydro{2}2v
ATLAS -1bµ= 1
int = 5.02 TeV, LNNsp+Pb,
< 5 GeVT
0.3 < p| < 2.5η|
{2}2v{4}2v{2PC}2v
hydro{2}2v
ATLAS, PLB 725 (2013) 60
ATLAS, PRL 110 (2013) 182302; CMS, arXiv:1305.0609
also hydrodynamics can explain data...a heated saturation/hydrodynamics debate (and pursuit with data and models)
Flow in p–Pb (d–Au) collisions?
8 A.Andronic@GSI.de
P.Bozek, PRC 85 (2012) 014911 (hydrodynamics)ε2, initial eccentricity, from MC Glauber
PHENIX, arXiv:1303.1794
Pushing the frontiers of deconfined matter?
9 A.Andronic@GSI.de
Au–Au, b=4 fm d–Au
-8-6
-4-2
0 2
4 6
8 -8-6
-4-2
0 2
4 6
8
MC-Glauber
x [fm]
y [fm]
-8-6
-4-2
0 2
4 6
8 -8-6
-4-2
0 2
4 6
8
IP-Glasmao=0.2 fm/c
x [fm]
y [fm]
MC-Glauber
-4 -2 0 2 4
x [fm]
-4
-2
0
2
4
y [fm
]-4 -2 0 2 4
x [fm]
-4
-2
0
2
4
y [fm
]
IP-Glasma
(a)
(b)
Gale, Jeon, Schenke, arXiv: 1301.5893; Bzdak et al., arXiv:1304.3403
Collective flow in p–Pb collisions?
10 A.Andronic@GSI.de
hydrodynamics makes large strides...
0 1 2 3p
T (GeV/c)
0
0.05
0.1
0.15
0.2
0.25
ATLAS pPb 0-2% v2
CMS pPb 0-2% v3
0-1% v2
0-2% v2
0-5% v2
0-1% v3
0-2% v3
0-5% v3
0 1 2 3p
T (GeV/c)
0
0.05
0.1
0.15
0.2
0.25
ALICE pPb 0-20% v2
ALICE pPb 0-20% v3
0-20% v2
0-20% v3
Qin, Muller, arXiv:1306.3439
0 1 2 3 40
0.05
0.1
0.15
0.2p-Pb 5.02TeV CMS Data 0-2%nv
[GeV/c]T
p
2v
3v
Bozek, Broniowski, Torrieri, arXiv:1307.5060
...after it trully predicted collective flow (v2, v3)Bozek, Broniowski, arXiv:1211.0845, PLB 718 (2013) 1557
Collective flow in p–Pb collisions?
11 A.Andronic@GSI.de
(rad)ϕ∆-1
0 1 23 4
η∆
-2
-1
01
2
)-1
(ra
dϕ
∆dη∆d
asso
cN2 d
trig
N1
1.0
1.2
1.4
c < 4 GeV/T,trig
p2 <
c < 2 GeV/T,assoc
p 1 < = 5.02 TeVNNsp-Pb
0-20%
AL
I−P
UB
−4
62
28
AL
I−P
UB
−4
62
28
AL
I−P
UB
−4
62
28
-2-1.5
-1-0.5
00.5
11.5
2 -10
12
34
1.1
1.2
1.3
1.4
2.0-4.0 GeV/ctrigg
Tp 1.0-2.0 GeV/cassoc
Tp
η∆φ∆
R
EPOS3.074
(rad)
ϕ∆-1
01
23
4
η∆
-2
-1
0
1
2
)-1
(ra
dϕ
∆dη∆d
asso
cN2 d
trig
N1
0.75
0.80
0.85
c < 4 GeV/T,trig
p2 <
c < 2 GeV/T,assoc
p 1 < = 5.02 TeVNNsp-Pb
(0-20%) - (60-100%)
AL
I−P
UB
−4
62
46
AL
I−P
UB
−4
62
46
AL
I−P
UB
−4
62
46
-2-1.5
-1-0.5
00.5
11.5
2 -10
12
34
0.72
0.74
0.76
0.78
2.0-4.0 GeV/ctrigg
Tp 1.0-2.0 GeV/cassoc
Tp
η∆φ∆
R
EPOS3.074
Collective flow in p–Pb collisions?
12 A.Andronic@GSI.de
experiment makes strides ...and theory great claims
)c (GeV/T
p0.5 1 1.5 2 2.5 3 3.5 4
{2P
C, s
ub}
2v
0
0.05
0.1
0.15
0.2
0.25ALICE
= 5.02 TeVNNsp-Pb
(0-20%) - (60-100%)
h π
K p
AL
I−P
UB
−5
10
16
AL
I−P
UB
−5
10
16
AL
I−P
UB
−5
10
16
ALICE, 1307.3237
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.5 1 1.5 2 2.5 pt
v2
EPOS3.074πKp
ALICEπKp
Werner et al., arXiv:1307.4379
EPOS 3.074: full hydrodynamical treatment (+Pomerons:)
Collective flow in p–Pb collisions?
13 A.Andronic@GSI.de
more points to hydrodynamics ...
0 0.5 1 1.5 20
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18 p-Pb 5.02TeV ALICE Data 0-20%
πKp
2v
[GeV/c]T
p
(ALICE, 1307.3237)20 40
0
0.5
1
1.5
>
[GeV
]<
p
a) 3+1D Hydro
p-Pb 5.02 TeV
ALICE Data (preliminary)
ηdN/d
20 40
0
0.5
1
1.5 b) HIJING
-π+π
-K+K
pp
ηdN/d
Bozek, Broniowski, Torrieri, arXiv:1307.5060
p–Pb in perspective
14 A.Andronic@GSI.de
chN0 20 40 60 80 100
)c (
GeV
/⟩
Tp⟨
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9 ALICE, charged particlesc<10.0 GeV/
Tp|<0.3, 0.15< η|
= 7 TeVspp = 5.02 TeVNNsp-Pb
= 2.76 TeVNNsPb-Pb
ALICE, 1307.1094
p–Pb exhibits features of both pp andPb–Pb
system√sNN (TeV) 〈Nch〉 〈pT〉 (GeV/c)
pp 7 4.42±0.22 0.622±0.021
p–Pb 5.02 11.9±0.5 0.696±0.024
Pb–Pb 2.76 259.9±5.9 0.678±0.007
NB:
Nch > 14 corresp. to 10%, 50%, 82% upper cross
section for pp, p–Pb, Pb–Pb
Nch > 40 corresp. to upper 1% (70%) of the cross
section p–Pb (Pb–Pb)
p–Pb in perspective
15 A.Andronic@GSI.de
0 20 40 60 80 100
)c (
GeV
/⟩
Tp⟨
0.5
0.6
0.7
0.8
0.9
1Data
PYTHIA 8, tune 4C
without CR
with CR
ALICE, charged particles
c<10.0 GeV/T
p|<0.3, 0.15<η|
= 7 TeVspp
0 20 40 60 80 100
)c (
GeV
/⟩
Tp⟨
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
Data
EPOSDPMJETHIJINGAMPTGlauber MC
= 5.02 TeVNNsp-Pb
chN0 20 40 60 80 100
)c (
GeV
/⟩
Tp⟨
0.45
0.5
0.55
0.6
0.65
0.7
= 2.76 TeVNNsPb-Pb
Data
ALICE, 1307.1094
CR: color reconnection - a “collective”effect of hadronizing strings(a probability parameter)
EPOS LHC: parametrized flow(pp, p–Pb, Pb–Pb)Pierog et al., arXiv:1306.0121
CGC strikes back
16 A.Andronic@GSI.de
0 20 40 60 80 100 120 140N
ch
0.6
0.75
0.9
1.05
1.2
< p
T >
[G
eV]
ALICE, Pb+Pb 2.76 TeVALICE, p+p 7 TeVALICE, p+Pb 5.02 TeVb-CGC (Saturation)
| η| < 0.3, 0.15< pT [GeV]<10
Rezaeian, 1308.4736 (3 parameters)
CGC strikes back
16 A.Andronic@GSI.de
...or does it?
0 20 40 60 80 100 120 140N
ch
0.6
0.75
0.9
1.05
1.2
< p
T >
[G
eV]
ALICE, Pb+Pb 2.76 TeVALICE, p+p 7 TeVALICE, p+Pb 5.02 TeVb-CGC (Saturation)
| η| < 0.3, 0.15< pT [GeV]<10
Rezaeian, 1308.4736 (3 parameters)
)-1 (fm1/2)TS /chN(0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
)c (
GeV
/⟩
Tp⟨
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9 ALICE, charged particlesc<10.0 GeV/
Tp|<0.3, 0.15<η|
= 5.02 TeVNN
sp-Pb
= 7 TeVspp
= 2.76 TeVspp
ALICE, 1307.1094
geometric scaling (ST = πR2), McLerran et al., arXiv:1306.2350;
R ∼ (dNg/dy)1/3 ≃ (1.5 · dNch/dη)
1/3, sat. at 1.54 (2.39) fm for pp (p–Pb)
claim of success based on CMS data, arXiv:1307.3442 ...in a smaller Nch range
p–Pb in perspective
17 A.Andronic@GSI.de
)c (GeV/T
p
S0 /
KΛ
00.20.40.60.8
11.21.41.61.8
22.22.4
0 2 4 6 8
0-5%
60-80%
= 5.02 TeVNNsALICE, p-Pb,
0 2 4 6 8
0-5%
80-90%
= 2.76 TeVNNsALICE, Pb-Pb,
0-5% central p–Pb collisions look like 60-70% central Pb–Pb(dNch/dη ∼1.7 lower)
ALICE, arXiv:1307.6796
η/dchNd10 210 310
)- π +
+ π
) / (
- +
K+
(K
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
= 2.76 TeVNNsALICE, Pb-Pb,
= 200 GeVNNsSTAR, Au-Au,
= 200 GeVNNsPHENIX, Au-Au,
= 200 GeVNNsBRAHMS, Au-Au,
= 5.02 TeVNNsALICE, p-Pb,
= 200 GeVNNsSTAR, d-Au,
η/dchNd10 210 310
)- π +
+ π
) / (
p(p
+
0.02
0.03
0.04
0.05
0.06
0.07
0.08
= 2.76 TeVNNsALICE, Pb-Pb,
= 200 GeVNNsPHENIX, Au-Au,
= 200 GeVNNsBRAHMS, Au-Au, = 5.02 TeVNNsALICE, p-Pb,
More flow arguments
18 A.Andronic@GSI.de
η/dchNd10 210
)c (
GeV
/⟩
Tp⟨
0.4
0.6
0.8
1
1.2
1.4
Λ + Λpp +
0SK
- + K+K
-π + +π
⟩T
β⟨0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7
(G
eV)
kin
T
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
= 5.02 TeVNNsALICE, p-Pb,
= 2.76 TeVNNsALICE, Pb-Pb,
= 7 TeV (with Color Reconnection)sPYTHIA8,
= 7 TeV (without Color Reconnection)sPYTHIA8,
0 2 4 6 8 10
]-2 )c
) [(
GeV
/yd
Tp
/(d
N2 d
Tpπ
1/2
evN
1/
-810
-710
-610
-510
-410
-310
-210
-110
1
10
210
310
410
(100x)-π + +π
(10x)- + K+K
(1x)pp +
(0.1x)0SK
(0.01x)Λ + Λevent class 5-10%
Blast-Wave
EPOS LHC
Krakow
DPMJET
)c (GeV/T
p0 2 4 6 8 10
data
/ m
odel
0.51
1.5 -π + +π
0 2 4 6 8 10
0.51
1.5 - + K+K
0 2 4 6 8 10
0.51
1.5 pp +
0 2 4 6 8 10
0.51
1.5 0SK
0 2 4 6 8 10
0.51
1.5 Λ + Λ
ALICE, 1307.6796
Flow or Cronin effect or saturation?
19 A.Andronic@GSI.de
(GeV/c)T
p0 2 4 6 8 10 12 14 16 18 20
dAu
, R
pPb
R
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8charged particles
| < 0.3cms
η = 5.02 TeV, NSD, | NN
sALICE, p-Pb
| < 0.5η = 0.2 TeV, | NNsSTAR, d-Au
| < 0.18η = 0.2 TeV, | NNsPHENIX, d-Au
LHC vs. RHIC data
ALICE, PRL 110 (2013) 082302
• flow: blue-shift of spectralarger at LHC
• Cronin effect: “re-distribution” oflow-pT hadrons at higher pT dueto multiple (parton) scattering
larger at RHIC
• saturation: depletion of spectra atlow pTlarger at LHC
still need some strategy to distinguish...a challenge: reduce (dominant) systematic uncertainties (?)
Charmonium in p–Pb
20 A.Andronic@GSI.de
ALICE, arXiv:1308.6726; LHCb, arXiv:1308.6729
cmsy
-4 -3 -2 -1 0 1 2 3 4
pPb
R
0
0.2
0.4
0.6
0.8
1
1.2
1.4 c<15 GeV/T
p, 0<-µ+µ→ψ= 5.02 TeV, inclusive J/NNs p-Pb
-1<3.53)= 5.0 nbcms
y (2.03<int
, L-1<-2.96)= 5.8 nbcms
y (-4.46<intL
EPS09 NLO (Vogt)
CGC (Fujii et al.)
/fm (Arleo et al.)2=0.075 GeV0
ELoss, q
/fm (Arleo et al.)2=0.055 GeV0
EPS09 NLO + ELoss, q
(GeV/c)T
p0 2 4 6 8 10 12 14
FB
R
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
EPS09 NLO (Vogt)
/fm (Arleo et al.)2=0.075 GeV0
ELoss, q
/fm (Arleo et al.)2=0.055 GeV0
EPS09 NLO + Eloss, q
< 3.53cms
y, 2.96 < -µ+µ→ψ= 5.02 TeV, inclusive J/NNsp-Pb
theory (nobody’s perfect:) shadowing and Eloss ∼ OK ...CGC seems ruled out
tantalizing implication for Pb–Pb: RAA > 1 (at low pT) if-no-shadowing...cannot turn off shadowing, but means we may see this at the top LHC energy
Summary
• interesting / puzzling features in p–Pb collisions
• both initial state and final state (collective flow?) play a role
... would we be able to disentangle them?
...(if so) is CGC the correct description of the initial state?
• what are the implications for Pb–Pb?...normalize Pb–Pb to p–Pb(min.B)?
• would p–Pb (and pp) help elucidating thermalization and hadronization?
Extra slides
x
Elliptic flow (non-central collisions)
x1 A.Andronic@GSI.de
density of binary collisionsU.Heinz, arXiv:0901.4355
−10 −5 0 5 10
−10
−5
0
5
10
x (fm)
y (f
m)
...arising from different initial gradi-ents along x and y
“self-quenching” (develops early)
determined by the spatial eccentricity
ε(b) = <y2−x2><y2+x2>
with energy dens. as weight
...transformed into momentumanisotropy in φ (wrt reaction plane)
Fourier coef. v2 = 〈cos(2(φ−ΨRP ))〉quantifies collective (elliptic) flow
Higher order harmonics (central collisions)
x2 A.Andronic@GSI.de
Sorensen, JPG 37 (2010) 094011; Alver, Roland, PRC 81 (2010) 054905 ...collision geometry fluctuations
0 2 4
)φ∆C
(
0.99
0.995
1
1.005
1.01
1.015
Pb-Pb 2.76 TeV, 0-2% central
< 2.5 GeV/ctT
2 < p < 2 GeV/ca
T1.5 < p
| < 1.8η∆0.8 < |
/ndf = 33.3 / 352χ
[rad]φ∆0 2 4
ratio
0.998
1
1.002
n1 2 3 4 5 6 7 8
]-2
[10
∆nV
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35 Centrality
0-2%
< 2.5 GeV/ct
T2 < p
< 2 GeV/ca
T1.5 < p
ALICE, PLB 708 (2012) 032301; PRL 107 (2011) 032301ATLAS, PRC 86 (2012) 014907 ; PHENIX, PRL 107 (2011) 252301event-by-event distributions: ATLAS, arXiv:1305.2942constrain initial state and η/s (small) in hydrodynamic models
Identified hadrons at the LHC
x3 A.Andronic@GSI.de
)c (GeV/T
p
)- π +
+ π
) / (
- +
K+
(K
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 1 2 3
0-5%
60-80%
= 5.02 TeVNNsALICE, p-Pb,
0 1 2 3
0-5%
80-90%
= 2.76 TeVNNsALICE, Pb-Pb,
)c (GeV/T
p
)- π +
+ π
) / (
p(p
+
0
0.2
0.4
0.6
0.8
1
0 1 2 3
0-5%
60-80%
= 5.02 TeVNNsALICE, p-Pb,
0 1 2 3
0-5%
80-90%
= 2.76 TeVNNsALICE, Pb-Pb,
ALICE, 1307.6796 ...
0-5% central p–Pb collisions look like 60-70% central Pb–Pb
Identified hadrons at the LHC
x4 A.Andronic@GSI.de
)c (GeV/T
p
S0 /
KΛ
00.20.40.60.8
11.21.41.61.8
22.22.4
0 2 4 6 8
0-5%
60-80%
= 5.02 TeVNNsALICE, p-Pb,
0 2 4 6 8
0-5%
80-90%
= 2.76 TeVNNsALICE, Pb-Pb,
η/dchNd10 210 310
)- π +
+ π
/ (
Λ2
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
= 2.76 TeVNNsALICE, Pb-Pb,
= 200 GeVNNsSTAR, Au-Au,
)-π + +π) / (Λ + ΛSTAR, ( = 5.02 TeVNNsALICE, p-Pb,
ALICE, 1307.6796 ...
0-5% central p–Pb collisions look like 60-70% central Pb–Pb(dNch/dη ∼1.7 lower)
Identified hadrons at RHIC (d–Au collisions)
x5 A.Andronic@GSI.de
-π/p 0-10%10-20%20-40%40-60%60-92%p+p
+πp/ = 200 GeVNNsAu+Au
πR
atio
p/
0
0.2
0.4
0.6
0.8
πR
atio
p/
0
0.2
0.4
0.6
0.8
1
(GeV/c)T
p0 1 2 3 4 5 6
-π/p 0-20%20-40%0-100%40-60%60-88%p+p
+πp/ = 200 GeVNNsd+Au
πR
atio
p/
0
0.1
0.2
0.3
0.4
πR
atio
p/
0
0.1
0.2
0.3
0.4
0.5
(GeV/c)T
p0 1 2 3 4 5 6
PHENIX, arXiv:1304.3410
... 0-20% central d–Au collisions look like 60-92% central Au–Au
top related