Quark Gluon Plasma; in AA, pA and pp collisions? what can we learn - - PowerPoint PPT Presentation
Quark Gluon Plasma; in AA, pA and pp collisions? what can we learn from that? Raimond Snellings Nikhef colloquium 2016 1 What happens when you heat and compress matter to very high temperatures and densities? Do we understand what QCD tells
what can we learn from that?
Raimond Snellings Nikhef colloquium 2016
1
2 Electroweak phase transition QCD phase transition 100,000 x Tcore sun Quark Gluon Plasma (QGP)
What happens when you heat and compress matter to very high temperatures and densities? Do we understand what QCD tells us?
T
4 reaches about 70% of the non-interacting limit, not so different from lattice QCD!
3
Critical Point ?
Early Universe
tions tions, t finite μB
3p/T4 ε/T4 3s/4T3 4 8 12 16 130 170 210 250 290 330 370 T [MeV]
HRG non-int. limit Tc
hotQCD collab: arXiv:1407.6387
which thermodynamics/hydrodynamics can be applied
possible
4
5
hadron cascade? pre-equilibrium flow? AdS/CFT? CGC?
impossible to measure directly from the observed particle distributions
different phases, hadronization, ….
parameters
6
7
pp pA AA
8
(GeV/c)
T
p
2 4 6 8 10 12 14 16 18 20
PbPb
, R
pPb
R
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
ALICE, charged particles
| < 0.3
cms
η = 5.02 TeV, NSD, |
NN
s p-Pb | < 0.8 η = 2.76 TeV, 0-5% central, |
NN
s Pb-Pb | < 0.8 η = 2.76 TeV, 70-80% central, |
NN
s Pb-Pb
ALI−PUB−44351
The Jack fruit is much heavier than a comparable amount of grapes or mixed fruit
impossible to measure directly from the observed particle distributions
hadronization, ….
parameters
9
10
spectators participants
b
UrQMD
11 Howard Wieman
1) superposition of independent p+p:
momenta pointed at random relative to reaction plane Animation: Mike Lisa
b
12
1) superposition of independent p+p: 2) evolution as a bulk system
momenta pointed at random relative to reaction plane high density / pressure at center “zero” pressure in surrounding vacuum pressure gradients (larger in-plane) push bulk “out” à “flow” more, faster particles seen in-plane
b
13
1) superposition of independent p+p: 2) evolution as a bulk system
momenta pointed at random relative to reaction plane pressure gradients (larger in-plane) push bulk “out” à “flow” more, faster particles seen in-plane
N φ-ΨRP (rad)
π/2 π π/4 3π/4
v2 = ⇥cos 2(φ ΨR)⇤
v2 = ⇥cos 2(φ ΨR)⇤ = 0
(rad)
plane
Ψ
φ
0.5 1 1.5 2 2.5 3
Normalized Counts
0.4 0.6 0.8 1 1.2 1.4 1.6
b ≈ 4 fm b ≈ 6.5 fm
14
15
We do not know the reaction plane ψR or in more general ψn
We can calculate these observables only using correlations
vn ⌘ hein(ϕ−Ψn)i hhein(ϕ1−ϕ2)ii = hhein(ϕ1)iihhein(ϕ2)ii + hhein(ϕ1−ϕ2)ici
zero for symmetric detector when averaged over many events
hhein(ϕ1−ϕ2)ii = hhein(ϕ1−Ψn−(ϕ2−Ψn))ii = hhein(ϕ1−Ψn)ihe−in(ϕ2−Ψn)ii = hv2
ni when only ψn correlations are present
16
η ∆
2 4 φ ∆ 2 4 ) φ ∆ , η ∆ R(
1
<3.0GeV/c
T
(b) CMS MinBias, 1.0GeV/c<p
η ∆
2 4
( r a d i a n s ) φ ∆
2 4
φ ∆ d η ∆ d
pair
N
2
d
trig
N 1
2.4 2.6 2.8
< 260
trk
N ≤ = 2.76 TeV, 220
NN
s (a) CMS PbPb < 3 GeV/c
trig T
1 < p < 3 GeV/c
assoc T
1 < p
In minimum bias pp collisions clear jet near and away side peak In PbPb long ridge structures on near and away side Signatures of correlations due to the initial stage (geometry) and in PbPb final state interactions (which translate spatial geometry into momentum space)
17 η ∆
2 4
( r a d i a n s ) φ ∆
2 4
φ ∆ d η ∆ d
pair
N
2
d
trig
N 1
2.4 2.6 2.8
< 260
trk
N ≤ = 2.76 TeV, 220
NN
s (a) CMS PbPb < 3 GeV/c
trig T
1 < p < 3 GeV/c
assoc T
1 < p
The long range correlations can be characterised by the flow Fourier harmonics such as v2, which is the most dominant
1 Ntrig dNpair d∆φ = Nassoc 2π [1 + X
n
2Vn∆ cos(n∆φ)]
18
particle 1 coming from the resonance. Out of remaining M-1 particles there is only one which is coming from the same resonance, particle 2. Hence a probability that out of M particles we will select two coming from the same resonance is ~ 1/(M-1). From this we can draw a conclusion that for large multiplicity:
p1 p2
19
cumulants allow us to see if there are multi-particle correlations in the system (cumulants nonzero only mathematical proof)
20
Build cumulants with multi-particle correlations (Ollitrault and Borghini, 2000) got rid of 2-particle correlations not related to collective flow however now we measure higher moment moments of the distribution
mathematical framework to calculate these analytically developed at Nikhef and used by all RHIC and LHC experiments
21
if the fluctuations are small or for a special pdf we can say for any distributions that the various flow estimates follow:
22
centrality percentile
10 20 30 40 50 60 70 80
2
v
0.02 0.04 0.06 0.08 0.1 0.12
{2}
2
v (same charge) {2}
2
v {4}
2
v (same charge) {4}
2
v {q-dist}
2
v {LYZ}
2
v STAR {EP}
2
v STAR {LYZ}
2
v
23
) c (GeV/
T
p
1 2 3 4 5
{4}
2
v
0.05 0.1 0.15 0.2 0.25
ALICE Phys. Rev. Lett. 105, 252302 (2010) STAR Phys. Rev. C. 86, 054908 (2012) charged particles, centrality 20-30% ALICE 2.76 TeV STAR 200 GeV STAR 62.4 GeV STAR 39 GeV STAR 27 GeV STAR 19.6 GeV STAR 11.5 GeV STAR 7.7 GeV
24
In a hydro picture particles have a common temperature and flow velocity at freeze-out. The difference in pT-differential elliptic flow depends mainly on one parameter: the mass of the particle
) c (GeV/
T
p
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
2
v
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
VISH2+1 Phys. Rev. C84, 044903 (2011) centrality 10-20% π K p φ Λ Ξ VISH2+1
25
hydro picture particles have a common temperature and flow velocity larger radial flow increases mass splitting
) c (GeV/
T
p
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
2
v
0.02 0.04 0.06 0.08
Chun Shen, private communication centrality 0-10% /s = 0.08 η MC Glauber, = 2.76 TeV
NN
s Hydro, π p = 62.4 GeV
NN
s Hydro, π p
26
mass hierarchy follows hydrodynamic picture at low pT!
ALICE arXiv:1405.4632 STAR QM2014
) c (GeV/
T
p
1 2 3 4 5
2
v
0.05 0.1 0.15 0.2 0.25 0.3 0.35
= 62.4 GeV (STAR Preliminary)
NN
s Au-Au centrality 10-40%
+
π
+
K p Λ
+
Ξ
) c (GeV/
T
p
1 2 3 4 5
2
v
0.05 0.1 0.15 0.2 0.25 0.3 0.35
= 2.76 TeV (ALICE Preliminary)
NN
s Pb-Pb centrality 20-30%
±
π + K
±
K p p + Λ + Λ
+
Ξ +
27
while the pT-differential charged particle v2 changes very little over two
the larger collective flow at higher collision energies
ALICE arXiv:1405.4632 STAR QM2014
) c (GeV/
T
p
1 2 3 4 5
2
v
0.05 0.1 0.15 0.2 0.25 0.3
= 2.76 TeV (ALICE Preliminary)
NN
s Pb-Pb = 62.4 GeV (STAR Preliminary)
NN
s Au-Au centrality 10-40% ALICE
±
π STAR
+
π STAR
ALICE p p + p STAR STAR p
) c (GeV/
T
p
0.5 1 1.5 2 2.5 3 3.5 4
2
v
0.02 0.04 0.06 0.08 0.1 0.12 0.14
= 2.76 TeV (ALICE Preliminary)
NN
s Pb-Pb = 62.4 GeV (STAR Preliminary)
NN
s Au-Au centrality 0-10% ALICE
±
π STAR
+
π STAR
ALICE p p + p STAR STAR p
ALICE arXiv:1405.4632 STAR QM2014
28
pure viscous hydrodynamics VISH2+1, status at QM2011
ALICE arXiv:1405.4632 ALICE arXiv:1405.4632
Viscous hydrodynamics predictions worked reasonably well for more peripheral collisions 40-50% For more central collisions, 10-20%, the radial flow seems to be under-predicted as the protons deviate a lot and this was part of the proton puzzle
) c (GeV/
T
p
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
2
v
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16
= 2.76 TeV (ALICE preliminary)
NN
s Pb-Pb VISH2+1 Phys. Rev. C84, 044903 (2011) centrality 10-20%
±
π + K
±
K p p + Λ + Λ
+
Ξ +
VISH2+1
) c (GeV/
T
p
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
2
v
0.05 0.1 0.15 0.2 0.25 0.3
= 2.76 TeV (ALICE preliminary)
NN
s Pb-Pb VISH2+1 Phys. Rev. C84, 044903 (2011) centrality 40-50%
±
π + K
±
K p p + Λ + Λ
+
Ξ +
VISH2+1
29
centrality percentile
10 20 30 40 50 60 70 80
2
v
0.05 0.1
= 2.76 TeV
NN
s ALICE Preliminary, Pb-Pb events at in 1% and 2% centrality bins
2
v > 0) η ∆ ( {2}
2
v > 1) η ∆ ( {2}
2
v {4}
2
v {6}
2
v {8}
2
v
for small fluctuations or specific pdf
30
Frozen PDF fluctuation Frozen PDF fluctuation
How many sources, their sizes & transverse distribution?
! vn ∝εn ∝ 1 nsources
flow fluctuations scale with the number of sources good tool to constrain initial conditions!
31
centrality percentile
5 10 15 20 25 30 35 40 45 50
2
ε /
2
ε
σ
2
v /
2
v
σ
0.2 0.4 0.6 0.8 1
= 2.76 TeV
NN
s ALICE Preliminary, Pb-Pb events at
2 1
))
2
{4}
2
+ v
2
{2}
2
)/(v
2
{4}
2
2
{2}
2
ALICE ((v
2 1
))
2
{4}
2
ε +
2
{2}
2
ε )/(
2
{4}
2
ε
{2}
2
ε MC-KLN ((
2 1
))
2
{4}
2
ε +
2
{2}
2
ε )/(
2
{4}
2
ε
{2}
2
ε MC-Glauber ((
2
ε /
2ε
σ MC-KLN (2.76 TeV)
2
ε /
2ε
σ MC-Glauber (64 mb)
Various initial state models do capture the trend but fail on the details
32
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20 x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
33
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
Spectators
RMS x 7.362 RMS y 3.318
Spectators
RMS x 7.362 RMS y 3.318
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
Wounded Nucleons
RMS x 2.42 RMS y 2.76
Wounded Nucleons
RMS x 2.42 RMS y 2.76
34
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
Spectators
RMS x 7.362 RMS y 3.318
Spectators
RMS x 7.362 RMS y 3.318
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
Wounded NucleonsRMS x 2.42 RMS y 2.76
Wounded NucleonsRMS x 2.42 RMS y 2.76
35
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20 x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
2
Φ
Using the particles produced we (experimentalists) determine, due to the fluctuations, a symmetry plane which is different than the Reaction Plane
vn ∝ εn
36
x (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10 y (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10
RP
Φ
Mean x 07 − 5.81e Mean y 07 − 2.938e − RMS x 2.42 RMS y 2.761 RP
Φ
Mean x 07 − 5.81e Mean y 07 − 2.938e − RMS x 2.42 RMS y 2.761
x (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10 y (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10
2
Φ
Mean x 07 − 8.299e Mean y 07 − 1.672e − RMS x 2.342 RMS y 2.828 2
Φ
Mean x 07 − 8.299e Mean y 07 − 1.672e − RMS x 2.342 RMS y 2.828
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20 2 ΦThe asymmetry of the system is larger versus this symmetry plane
vn ∝ εn
37
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
2
Φ
3
Φ
4
Φ
x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20
There are many more symmetry planes
vn ∝ εn
38
x (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10 y (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10
3Φ
Mean x 06 − 1.355e Mean y 07 − 9.891e − RMS x 2.631 RMS y 2.561 3Φ
Mean x 06 − 1.355e Mean y 07 − 9.891e − RMS x 2.631 RMS y 2.561x (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10 y (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10
4Φ
Mean x 07 − 6.416e − Mean y 07 − 1.869e − RMS x 2.596 RMS y 2.596 4Φ
Mean x 07 − 6.416e − Mean y 07 − 1.869e − RMS x 2.596 RMS y 2.596x (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10 y (fm) 10 − 8 − 6 − 4 − 2 − 2 4 6 8 10
2Φ
Mean x 07 − 8.299e Mean y 07 − 1.672e − RMS x 2.342 RMS y 2.828 2Φ
Mean x 07 − 8.299e Mean y 07 − 1.672e − RMS x 2.342 RMS y 2.828rotated to the planes of symmetry we clearly see the different harmonics
vn ∝ εn
39
b (fm) 2 4 6 8 10 12 14 16 18 20
2∈ 0.2 0.4 0.6 0.8 b (fm) 2 4 6 8 10 12 14 16 18 20
3∈ 0.2 0.4 0.6 0.8 b (fm) 2 4 6 8 10 12 14 16 18 20
4∈ 0.2 0.4 0.6 0.8 x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20 2
Φ
3
Φ
4
Φ
vn ∝ εn
for n=2 and 3
40
centrality percentile
10 20 30 40 50 60 70 80
n
v
0.05 0.1
ALICE > 1} η ∆ {2,
2
v > 1} η ∆ {2,
3
v > 1} η ∆ {2,
4
v {4}
3
v
RPΨ 3/
v
2
2Ψ 3/
v × 100
Alver, Gombeaud, Luzum & Ollitrault, Phys. Rev. C82 034813 (2010) /s=0.08 η Glauber
3
v /s=0.16 η CGC
3
v
higher harmonics very sensitive to fluctuations and transport parameters such as viscosity
41
Higher harmonics clearly seen by eye in correlation function
42
the mass ordering is also observed for higher harmonics
) c (GeV/
T
p
1 2 3 4 5
MC
δ
η ∆ {SP,|
3
v
0.05 0.1 0.15 ALICE Preliminary = 2.76 TeV 20-30%
NN
s Pb-Pb
±
π
±
K p p+
ALI-PREL-102603
) c (GeV/
T
p
1 2 3 4 5
MC
δ
η ∆ {SP,|
4
v
0.05 0.1 ALICE Preliminary = 2.76 TeV 20-30%
NN
s Pb-Pb
±
π
±
K p p+
ALI-PREL-102607
Naghmeh Mohammadi
43
b (fm) 2 4 6 8 10 12 14 16 18 20
2∈ 0.2 0.4 0.6 0.8 b (fm) 2 4 6 8 10 12 14 16 18 20
3∈ 0.2 0.4 0.6 0.8 b (fm) 2 4 6 8 10 12 14 16 18 20
4∈ 0.2 0.4 0.6 0.8 x (fm) 20 − 15 − 10 − 5 − 5 10 15 20 y (fm) 20 − 15 − 10 − 5 − 5 10 15 20 2
Φ
3
Φ
4
Φ
information
lot of information about the initial stage of the collision and the evolution of the system
44
45
p(εn) = εn σ2 I0 ⇣εnεn σ2 ⌘ exp ✓ −ε2
0 + ε2 n
2σ2 ◆ p(εn) = 2α εn
n
α−1
p(εn) = α εn π
α+ 1
2
Z 2π
n
α−1 dφ (1 − ε0 εn cos φ)2α+1
Bessel-Gaussian ε0 is the anisotropy versus the reaction plane and σ the fluctuations. Works for mid-central collisions, not expected to work for peripheral collisions because not constraint to 1 this distribution predict that v3{4}=0 Power-law distribution α quantifies the fluctuations, this function has no ε0 therefore only describes the response due to fluctuations Elliptic Power distribution α and ε0 are the ingredients with same definition as in previous distributions
46
2
ε 0.2 0.4 0.6 0.8 1 )
2
ε P(
10
10 1
2
10
3
10
, 0-5%
2
ε , 30-40%
2
ε , 60-70%
2
ε Elliptic-Power Power-Law Bessel-Gaussian
In 0-5% all three functions work rather
is large. Elliptic Power turns into a Bessel Gaussian and with ε0 small the anisotropy versus the reaction plane and power law also works. For more peripheral collisions the Elliptic Power is the only distributions which works well
47
3
ε 0.2 0.4 0.6 0.8 1 )
3
ε P(
10
10 1
2
10
3
10
, 0-5%
3
ε , 30-40%
3
ε , 60-70%
3
ε Elliptic-Power Power-Law Bessel-Gaussian
ε3, v3 dominated by fluctuations. For more central collisions all three functions work rather well. Again this is understood Bessel Gaussian fails for more peripheral due to lack of constraint < 1. The fact that ε3{4} and v3{4} are non-zero completely excluded the Bessel Gaussian
48
0.02 0.04 0.06 0.08 0.1 0.12 0.14 10 20 30 40 50 〈vn
2〉1/2
centrality percentile η/s = 0.2 ALICE data vn{2}, pT>0.2 GeV v2 v3 v4 v5
0.01 0.1 1 10 100 0.5 1 1.5 2 2.5 3 P(v2/〈v2〉), P(ε2/〈ε2〉) v2/〈v2〉, ε2/〈ε2〉 pT > 0.5 GeV |η| < 2.5 20-25% ε2 IP-Glasma v2 IP-Glasma+MUSIC v2 ATLAS 0.01 0.1 1 10 100 0.5 1 1.5 2 2.5 3 P(v3/〈v3〉), P(ε3/〈ε3〉) v3/〈v3〉, ε3/〈ε3〉 pT > 0.5 GeV |η| < 2.5 20-25% ε3 IP-Glasma v3 IP-Glasma+MUSIC v3 ATLAS 0.01 0.1 1 10 100 0.5 1 1.5 2 2.5 3 P(v4/〈v4〉), P(ε4/〈ε4〉) v4/〈v4〉, ε4/〈ε4〉 pT > 0.5 GeV |η| < 2.5 20-25% ε4 IP-Glasma v4 IP-Glasma+MUSIC v4 ATLAS
49
Constraints from RHIC and LHC data We start to answer the question how well we can constrain the EoS
50
lead to increasingly precise determination of η/s
0.5 1 1.5
ideal hydro viscous hydro AdS/CFT limit
0.5 1 1.5
LO pQCD
2
AdS/CFT limit lattice QCD kinetic theory viscous hydro + flow data
2
/s near T
c
2000 2002 2004 2006 2008 2010 2012 2014 2022
51
2 𝑤𝑜 2
𝑤𝑜 𝑤𝑛
magnitude of the harmonics is correlated
52
clear correlations and anti-correlations between the harmonics, some which are non-trivial from initial conditions, generated during expansion of the system
effects)
distributions (e.g. CGC) if there are no final state effects
53
54
η ∆
2 4 φ ∆ 2 4 ) φ ∆ , η ∆ R(
2
>0.1GeV/c
T(a) CMS MinBias, p
η ∆
2 4 φ ∆ 2 4 ) φ ∆ , η ∆ R(
1
<3.0GeV/c
T
(b) CMS MinBias, 1.0GeV/c<p
η ∆
2 4 φ ∆ 2 4 ) φ ∆ , η ∆ R(
2
>0.1GeV/c
T
110, p ≥ (c) CMS N
η ∆
2 4 φ ∆ 2 4 ) φ ∆ , η ∆ R(
1
<3.0GeV/c
T
110, 1.0GeV/c<p ≥ (d) CMS N
2010 CMS observed near side ridge in pp!
55
pA collisions near and away-side ridge observed by all LHC experiments
2 4
(a)
φ Δ
2 4
η Δ ) η Δ , φ Δ C(
1 1.04
2 4
(b)
=5.02 TeV
NNs p+Pb
b 1 <4 GeV
a,b T0.5<p
>80 GeV
Pb T
E Σ
η Δ
2 4 φ Δ 2 4
φ Δ d η Δ d
pair
N
2
d
trig
N 1
1.6 1.7 1.8
110 ≥
trk= 5.02 TeV, N
NNs CMS pPb < 3 GeV/c
T1 < p (b)
CMS! ALICE! ATLAS! LHCb !
56
pA collisions near and away-side ridge observed by all LHC experiments and characterised by significant flow Fourier harmonics
2 4
(a)
φ Δ
2 4
η Δ ) η Δ , φ Δ C(
1 1.04
2 4
(b)
=5.02 TeV
NNs p+Pb
b 1 <4 GeV
a,b T0.5<p
>80 GeV
Pb TE Σ
η Δ
2 4 φ Δ 2 4
φ Δ d η Δ d
pairN
2d
trigN 1
1.6 1.7 1.8
110 ≥
trk= 5.02 TeV, N
NNs CMS pPb < 3 GeV/c
T1 < p (b)
CMS! ALICE! ATLAS! LHCb !
[GeV]
a T
p
5 10 n
v
0.05 0.1 0.15
<260
trk
N ≤ CMS, 220
<20 sub.
trk
, N
2
v
<20 sub.
trk
, N
3
v
< 260
rec ch
N ≤ 220
|>2 η Δ < 3 GeV, |
b T
1 < p
n=2 n=3 n=4 n=5
ATLAS
p+Pb = 5.02 TeV
NN
s
28 nb ≈
int
L
PRC 90, 044906 (2014)!
57
also multi-particle correlations using cumulants show clear evidence for collectivity in small systems
trk
N
100 200 300
2
v
0.05 0.10 |>2} η Δ {2, |
2
v {4}
2
v {6}
2
v {8}
2
v {LYZ}
2
v
| < 2.4 η < 3.0 GeV/c; |
T
0.3 < p = 2.76 TeV
NN
s CMS PbPb
trk
N
100 200 300 0.05 0.10 | < 2.4 η < 3.0 GeV/c; |
T
0.3 < p = 5.02 TeV
NN
s CMS pPb PRL 115, 012301 (2015)!
58
mass scaling observed in AA also observed in pA and at similar event multiplicity even stronger in pA
(GeV)
T
p
2 4
0.0 0.1 0.2 0.3
CMS = 5.02 TeV
NN
s pPb
< 220
trk
N ≤ 185 (0.006-0.06%)
(GeV)
T
p
2 4
|>2} η Δ {2, |
2
v
0.0 0.1 0.2 0.3 S
K Λ / Λ
±
h
CMS
= 2.76 TeV
NN
s PbPb < 220
trk
N ≤ 185 2%) ± (62
PLB 742 (2015) 200!
PLB 742 (2015) 200
) c (GeV/
T
p
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4
2
v
0.05 0.1 0.15 0.2 0.25 0.3
= 2.76 TeV (ALICE preliminary)
NNs Pb-Pb VISH2+1 Phys. Rev. C84, 044903 (2011) centrality 40-50%
±π + K
±K p p + Λ + Λ
+Ξ +
VISH2+1
behaviour) in small systems for high multiplicity events as in AA collisions?
(EoS, transport parameters), viscous corrections are larger though
“shape”)
59
60
(GeV/c)
T
p
1 2 3
|>2} η Δ {2, |
2
v
0.0 0.1 0.2
/s=0.18 (Very preliminary) η IP-glasma, b=0, Eccentric proton Round proton < 220
trk
N ≤ data, 185
2
CMS v
= 5.02 TeV
NN
s pPb
Initial energy density! (IP-glasma)! Eccentric! Round!
61
Ns!
vn{4} vn{2} = ✏n{4} ✏n{2} = 2 1 + Ns/2
Yan, Ollitrault, PRL 112, 082301 (2014) Mantysaasri, Schenke, arXiv:1603.04349
gory details) in all the correlations
translate them in an almost perfect liquid to momentum space
final state interactions)
far) for a system very similar to the QGP in AA
pA and pp and the geometrical structure of the proton
62