Constraining QCD transport coeﬃcients in hadron colliders€¦ · Constraining QCD transport coeﬃcients in hadron colliders Akihiko Monnai (KEK, Japan) with Gabriel Denicol (UFF,

Constraining QCD transport coefficients in hadron colliders

Akihiko Monnai (KEK, Japan)

with Gabriel Denicol (UFF, Brasil) and Björn Schenke (BNL, USA)

20th InternaLonal Symposium on Very High Energy Cosmic Ray InteracLons May 24, 2018, Nagoya, Japan

G. Denicol, AM, B. Schenke, Phys. Rev. LeY. 116, 212301 (2016)

Akihiko Monnai (KEK), ISVHECRI 2018, May 24th 2018

IntroducLonn  Cosmic ray and nuclear collisions

Transverse momentum spectra

UHECR Nuclear collisions

h

Energy scale:

AIRES by COSMOS, U. Chicago

h

CMS, CERN

√sNN = 300 TeV √sNN = 13 TeV (pp)

UHECR is higher in energy; nuclear colliders allow detailed analyses in a controlled environment

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IntroducLonn  High-energy nuclear colliders momentum spectra

RelaLvisLc Heavy Ion Collider (RHIC)@BNL (2000-)

√sNN = 7.7-200 GeV

AA collisions: Cu-Cu, Cu-Au, Au-Au, U-U

pA, dA, hA collisions: √s = 20-200 GeV

pp collisions: √s = 200, 510 GeV

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IntroducLonn  High-energy nuclear colliders momentum spectra

RelaLvisLc Heavy Ion Collider (RHIC)@BNL (2000-)

√sNN = 7.7-200 GeV

AA collisions: Cu-Cu, Cu-Au, Au-Au, U-U

pA, dA, hA collisions: √s = 20-200 GeV

Large Hadron Collider (LHC)@CERN (2009-)

AA collisions: Xe-Xe, Pb-Pb

√sNN = 2.76-5.44 TeV

pp collisions: √s = 200, 510 GeV

pA collisions: √s = 5.02, 8.16 TeV

pp collisions: √s = 0.9-13 TeV

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IntroducLonn  AA collisions: creaLon of a thermal QCD medium called quark-gluon plasma (QGP) above √sNN ~ 20-200 GeV


p/n (in A)

π+ pK+

π-Δ++

γ

γ

Low-momentum hadrons are produced from the medium

γ

γ

K+

π+

p

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IntroducLonn  AA collisions: creaLon of a thermal QCD medium called quark-gluon plasma (QGP) above √sNN ~ 20-200 GeV


p/n (in A)

π+ pK+

π-Δ++

γ

γ

Low-momentum hadrons are produced from the medium

γ

γ

K+

π+

p

QGP: a high T phase of QCD where quarks are deconfined from hadrons (T > 2×1012 K)

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IntroducLonn  How would the QGP affect collider physics?

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SpaLal anisotropy

y

x

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SpaLal anisotropy

y

x

In-medium InteracLon

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Momentum anisotropySpaLal anisotropy

py

px

y

x


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Momentum anisotropySpaLal anisotropy

py

px

y

x


Characterized by Fourier harmonics of azimuthal distribuLon

: ellipLc flow

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IntroducLonn  Experimental data

Kolb et al., PLB 500, 232 (2001)

Consistent with the nearly-perfect liquid picture up to pT ~ 2 [GeV]

GasGasGas

Liquid: strong-coupling limit

Gas: weak-coupling limit

✓

✗

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IntroducLonn  Experimental data

Kolb et al., PLB 500, 232 (2001)

Consistent with the nearly-perfect liquid picture up to pT ~ 2 [GeV]

GasGasGas

Liquid: strong-coupling limit

Gas: weak-coupling limit

✓

- The QGP is strongly-coupled near the quark-hadron transiLon

- We may use hydrodynamics for an effecLve theory of QGP

✗

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Collider physics has its roots in cosmic ray physics and the study of mulL-parLcle producLon

Fermi, Prog. Theor. Phys. 5, 570 (1950)

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Collider physics has its roots in cosmic ray physics and the study of mulL-parLcle producLon

Fermi, Prog. Theor. Phys. 5, 570 (1950)

Landau model Landau and Belenkii, Uspekhi Fiz. Nauk 56, 309 (1955)

First introducLon of hydrodynamics to nuclear collisions (*in the context of pp collisions)

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IntroducLonn  A modern view of relaLvisLc nuclear collisions

Nuclei (saturated gluons)

Local equilibraLon

Collision

Color glass condensate

Hadronic transport

Freeze-out

Hydrodynamic evoluLon

Glasmaτ < 1 fm

τ = 1-10 fm

τ > 10 fm

τ < 0 fm

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Nuclei (saturated gluons)

Local equilibraLon


Hadronic transport

Freeze-out


Glasmaτ < 1 fm

τ = 1-10 fm

τ > 10 fm

τ < 0 fm

Collision

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Glasma(Longitudinal color magneLc & electric fields)

Local equilibraLon

Collision


Hadronic transport

Freeze-out


Glasmaτ < 1 fm

τ = 1-10 fm

τ > 10 fm

τ < 0 fm

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Local equilibraLon

Collision


Hadronic transport

Freeze-out


Glasma

QGP fluid(Aer local thermalizaLon)

τ < 1 fm

τ = 1-10 fm

τ > 10 fm

τ < 0 fm

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Local equilibraLon

Collision


Hadronic transport

Freeze-out


Glasma

Thermal hadrons

τ < 1 fm

τ = 1-10 fm

τ > 10 fm

τ < 0 fm

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Local equilibraLon

Collision


Hadronic transport

Freeze-out


Glasma

Decay hadronsThermal hadrons

τ < 1 fm

τ = 1-10 fm

τ > 10 fm

τ < 0 fm

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Overview of the modeln  Constraining QCD transport coefficients in hadron colliders

IniLal condiLons

RelaLvisLc hydrodynamics

Observables

Hadronic transport

10 / 20



IniLal condiLons


Observables

EquaLon of state

Transport coefficients

,

InformaLon of QCD

Hadronic transport

10 / 20



IniLal condiLons


Observables

EquaLon of state


,

InformaLon of QCD

Hadronic transport

Experimental dataComparison

10 / 20



IniLal condiLons


Observables

EquaLon of state


,

InformaLon of QCD

Hadronic transport

Experimental dataComparison

Indirect constraining

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Transport coefficientsn  Dynamical responses to the gradients of flow ; effecLve

correcLons to the pressure

Shear viscosity = response to deformaLon

Bulk viscosity = response to volume change

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relaLvisLc terms relaLvisLc terms



linear responselinear response

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= DerivaLve of = DerivaLve of




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= DerivaLve of = DerivaLve of



Bulk viscosity in the conformal limit; shear viscosity dominates


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n  No first principle (laÄce QCD) calculaLons so far


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n  AnL-de SiYer/conformal field theory (AdS/CFT) duality

“The universal lower bound”

Kovtun, Son, Starinets, PRL 94 (2005) 111601

5-dimesional AdS black hole 4-dimensional

super Yang-Milles theory

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n  AnL-de SiYer/conformal field theory (AdS/CFT) duality

“The universal lower bound”

Kovtun, Son, Starinets, PRL 94 (2005) 111601

5-dimesional AdS black hole 4-dimensional

super Yang-Milles theory

Is it applicable to QCD? – What would be the temperature dependence?

12 / 20


Observable sensiLve to viscosityn  EllipLc flow v2

Kolb et al., PLB 500, 232 (2001)

Shear viscosity can account for deviaLon from local equilibrium at higher pT

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Observable sensiLve to viscosityn  EllipLc flow v2

COLD COLDHOT

z

x

Kolb et al., PLB 500, 232 (2001)

Shear viscosity can account for deviaLon from local equilibrium at higher pT

We use rapidity dependence of v2 to extract the temperature dependence of η/s(T)

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Observable sensiLve to viscosityn  ParameterizaLon of shear viscosity

0

1

2

3

4

5

0 0.1 0.2 0.3 0.4 0.5

ηT

/(ε+

P)

T[GeV]

(ηT/(ε+P))min=0.04, a=0, b=10 (ηT/(ε+P))min=0.12, a=0, b=0 (ηT/(ε+P))min=0.04, a=10, b=0 (ηT/(ε+P))min=0.04, a=10, b=2

*In the vanishing density limit,

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Observable sensiLve to viscosityn  ParameterizaLon of shear viscosity

0

1

2

3

4

5

0 0.1 0.2 0.3 0.4 0.5

ηT

/(ε+

P)

T[GeV]


*In the vanishing density limit,

The rise in the QGP phase moLvated by perturbaLve QCD;The decrease in the hadronic phase by chiral perturbaLon theory

Csernai, Kapusta and McLerran, PRL 97, 152303 (2006)

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IniLal condiLonsn  Phenomenological approach

Glauber model (2D):

Nucleons are distributed according to a Woods-Saxon funcLon

Nucleons in different nuclei are in the distance = Sub-collision

Loizides et al., arXiv: 1408.2549

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IniLal condiLonsn  Phenomenological approach

Glauber model (2D):

Nucleons are distributed according to a Woods-Saxon funcLon

Nucleons in different nuclei are in the distance = Sub-collision

Loizides et al., arXiv: 1408.2549

Glauber-Lexus model (3D): AM and Schenke, Phys. LeY. B 752, 317 (2016) Jeon and Kapusta, Phys. Rev. C 56, 468 (1997)

Rapidity is exchanged if there is a sub-collision

Valence quark PDF for the rapidity distribuLon before collisions

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Resultsn  EllipLc flow v2, Au-Au collisions at √sNN = 200 GeV

0

1

2

3

4

5

0 0.1 0.2 0.3 0.4 0.5

ηT

/(ε+

P)

T[GeV]


Large viscosity in the hadronic phase and small viscosity in the QGP phase favored

The minimum is as small as 0.04 (below the lower bound 1/4π)

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Resultsn  Triangular flow v3, Au-Au collisions at √sNN = 200 GeV

Large viscosity in the hadronic phase and small viscosity in the QGP phase favored

The minimum is as small as 0.04 (below the lower bound 1/4π)

y

x

ψ3

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Summary and outlookn  We have probed collecLve properLes of the hot QCD maYer

RelaLvisLc AA collision can produce the quark-gluon plasma, which behaves as a fluid

QCD shear viscosity is constrained using rapidity dependence of v2 and v3- Large hadronic viscosity and small QGP viscosity

We can explore the QCD transport properLes at finite density for the Beam Energy Scan programs

- The minimum can be smaller than the universal lower bound conjectured in AdS/CFT duality

G. Denicol, C. Gale, S. Jeon, AM, B. Schenke, C. Shen, arXiv:1804.10557 [nucl-th]

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OutroducLonn  Would there be a QGP in pp and pA collisions?

NO, it is the effect of iniLal state

YES, it is a QGP liquid E.g. Weller and Romatschke, PLB 774,351 (2017)

E.g. Mace, Quark MaYer 2018 talk

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The end

Thank you for listening!

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IntroducLonn  Rapidity distribuLon at Pb-Pb collision in LHC


Centrality

central0-5 %

peripheral80-90 %

y = 0 y = 5Rapidity √sNN (eV) systems yp notes

1.3×1013 p-p 9.54 LHC

5.02×1012 Pb-Pb 8.59 LHC

2×1011 Au-Au 5.36 RHIC


IntroducLonn  How would the QGP affects collider physics? (= Evidence of QGP)

Jet quenching

(GeV/c)T

p1 2 3 4 5 6 7

)3 c-2

(mb

GeV

3/d

p3

) or E

d3 c

-2(G

eV3

N/d

p3

Ed

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

4104AuAu Min. Bias x10

2AuAu 0-20% x10

AuAu 20-40% x10

p+p

Turbide et al. PRC69

J/Ψ supression

(radians)! "

-1 0 1 2 3 4

)!

" d

N/d

(T

RIG

GE

R1/N

0

0.1

0.2

d+Au FTPC-Au 0-20%

p+p min. bias

Au+Au Central

)!

" d

N/d

(T

rig

ger

1/N

STAR, PRL 91, 072304 (2003)

Thermal photonsPHENIX, PRL 98, 232301 (2007)

PHENIX, PRL 104, 132301 (2010)

PHENIX, PRL 91, 182301 (2003)

Δφ

×medium absorpLon

In-medium melLng

c

c_

so thermal radiaLon

azimuthal momentum anisotropy

EllipLc flow


Observablesn  Low-momentum light quarks (u,d,s) are thermalized Transverse

momentum spectra

ObservablesSources

Prompt Thermal Decay

Light-flavor hadrons (π, K, p etc.) ✗ ️

Heavy-flavor hadrons (D, B etc.)

(as quarks) ? ?

High-pT hadrons (jets) ✗ ️✗

Leptons and photons (e±, μ±, γ)

(by medium)

️

Weak bosons (W±, Z0) ✗ ✗


IntroducLonn  Is the QGP a gas or a liquid?


Physicists's predicLon

Liquid: InteracLve parLclesDense

Free parLclesDilute

✓ ✗

Gas:


RelaLvisLc hydrodynamicsn  Energy-momentum tensor (in the local rest frame)

: energy density

: pressure

: bulk pressure

: shear stress tensor

where

n  EquaLon of moLon:

CorrecLons to the pressure


EquaLon of staten  Hadron resonance gas + laÄce QCD

LaÄce: Taylor expansion up to the 4th order

HotQCD, PRD 86, 034509 (2012), PRD 90, 094503 (2014), PRD 92, 074043 (2015)

where

Connect to HRG at low T:

Documents

Constraining QCD transport coeﬃcients in hadron colliders€¦ · Constraining QCD transport coeﬃcients in hadron colliders Akihiko Monnai (KEK, Japan) with Gabriel Denicol (UFF,