QGP物理実験の現状と将来
中條 達也（筑波大学）
インフォーマル研究会（QGPの新展開２）名古屋大学
２０１６年２月６日

はじめに• このトークの方向性：• QGP物理、高エネルギー重イオン衝突実験の魅力を、特に分野外の方と共有• 日本グループが現在考えてる将来計画とは• 他分野との連携✴ 準備時間の都合上、英語と日本語のスライドが混じりますが、
ご容赦ください。

LHC-ALICE (CERN)
2006 - present
RHIC-PHENIX (BNL)
2000 - 2006
SPS-WA98(CERN) 1995 (M)AGS E866
1996-2000 (M,PhD)
J-PARC HI (plan)
2014-present

私の専門分野
1. ALICE 実験 (2006- present)

ALICE EMCal-DCal
で測定されてdi-jet イベント

• ジェット・光子の物理• EMCal/DCal 電磁カロリメータ准責任者• 超前方光子検出器 R&D、前方の物理

ALICE DCal (+PHOS)
検出器• Grid computing (Tsukuba T2 建設)
2. PHENIX 実験 (2000-2006)• ハドロン物理 (PID hadron spectra)• TOF 運用責任者、Run2 データ再構成責任者
3. J-PARC 重イオン計画 (2014- present)• MRPC-TOF 検出器開発など

PHENIX TOFと粒子識別Outline
1. Introduction (High energy heavy ion collisions and
QGP)
2. What we have learned from RHIC and LHC data
(2000- present)
3. What is missing?
4. Connections to other fields
5. Summary

1. High energy heavy ion
collisions and QGP

MADAI collaboration

Time

History of our Universe

QCD phase transition
Quark Gluon Plasma (after 10-6 sec)

Our research field7

Courtesy of Paul Sorensen and Chun Shen

8Space-time evolution of Heavy Ion Collisions

4
3

2
1

1.
2.
3.
4.

 
(parton)               
        
9

高エネルギー重イオン反応•

重イオン衝突＝非常に dynamical. 時空発展による物理現象の理解が不可欠•

衝突エネルギーの変化→ dynamics と QCD
相図上の軌跡が変化

History of Heavy Ion Accelerator

1970
Slide from H. Hamagaki

1980

1990

2000

2010

RHIC （相対論的重イオン衝突型加速器）
2000ブルックヘブン国立研究所 BNL（米・ニューヨーク）

RHIC = Relativistic Heavy Ion Collider
周長：3.8 km
1740 個の超伝導マグネット
最高エネルギー：200 GeV 金＋金
500 GeV 偏極陽子＋陽子
様々な衝突系、エネルギーで実験

RHIC run history

LHC (Large Hadron Collider)2009-, !sNN = 2.76, 5.02 TeV

LHC: Circumference : 27 km

Pb-Pb 5.02 TeV (One PeV collisions , Nov. 2015) !!

LHC run history••

2009: Commissioning and first data p-p (900 GeV)•

2011: Long p-p (7 TeV) and one month Pb-Pb(2.76 TeV) = x10 luminosity than that in 2010.
first p-p (2.76 TeV).

•

2012: Long p-p (8 TeV), one day p-Pb (5.02 TeV)
pilot run•

2013: 1.5 month p-Pb (5.02 TeV), (32 nb-1 in
ALICE)•

2013.02 - 2014 winter: LHC Long Shutdown 1
(LS1)

•

2015: pp (13 TeV), pp (5.02 TeV, few days), PbPb (5.02 TeV, 1 month)

2010: First p-p run (7 TeV) and first Pb-Pb run(2.76 TeV)

T. Chujo (U. Tsukuba)

RHIC & AGS 2013 annual users‘ meeting, BNL ( Jun. 27, 2013)

16

2. What we have learned
from RHIC and LHC HI

（１）ジェットクエンチング（パートンのQGP中でのエネルギー損失）

dnAA /dpT dy”hot/dense QCDmedium”
RAA
Fig. =
15. Invariant !0 yields measured by PHENIX =in peripheral (left) and central (right)”QCD[89],
vacuum”
Npp
· dn
/dpT
dy
binaryAuAu collisions (squares)
compared to the (TAA -scaled)→ !0 X
crossppsection(circles) [134] and to a NLO pQCD calculation (curves and yellow band) [119].

Au+Au - 200 GeV (central collisions):
Direct $ , $ * [PHENIX]
Inclusive h± [STAR]!0 [PHENIX]% [PHENIX]g
GLV energy loss (dN /dy = 1400)

RAA

et”.

10

Ncoll scaling

1

10-1

Npart scaling

0

2

4

6

8

10

12

14

16
18
20
p (GeV/c)T

Fig. 16. RAA pT measured in central AuAu at 200 GeV for !0 [89] and % [135] mesons,hadrons[114],and direct photons [136, 137] compared to theoretical predictions forquenching” in a head-on nucleus-nucleus collision. Two quarkscharged
suffera hardscatparton energy loss in a dense medium with dN g dy 1400 (yellow curve) [138].

������������
!
goes out directly to the vacuum, radiates a few gluons and hadronises, the other����������������
h the dense �plasma
created (characterised by transport coefficient q̂, gluon density
RHIC energies isandvery close to the “participant scaling”, N
2 N ≈ 0.17,
d temperature T ), suffers energy loss due to medium-induced top
gluonstrahlung
expected in the strong quenching limit where only hadrons coming from partons! ������������
ments outside
into a (quenched) jet.
produced at the surface of the medium show no final-state modifications in theirspectra [141]. From the R one can approximately obtain the fraction of energy! ����������������
lost, &'p p , via& ≈ 1−R(36)
f the first proposed“smoking guns” of QGP formation was “jet quench� �����������������
pedestal
whenresulting
the AuAu andpp invariant
spectraand
areflow
both a power-law with exponent n, i.e.
e. the attenuation or disappearance of the spray of hadronsfrom�������������
1 p dN d p ( p [142]. At RHIC (n ≈ 8, R ≈ 0.2), one finds & ≈ 0.2.
entation of �a parton having suffered energy loss in the dense
plasma propart

coll

AA

T

loss

T

loss

T

T

−n
T

1 n−2
AA

AA

loss

The high-pT AuAu suppression can be well reproduced by parton energy loss

Energy losses in QED��������

As an illustrative example, we show in Fig. 4 the stopping power of muons in copper. At low and high energies, the collisional (aka “Bethe-Bloch”) and the radiative
nergy losses dominate respectively.
Energy loss of charged particle in a matter

+ ( %

µ+"
µ(

Bremsstrahlung"����������
!�������������"��������������
!�������
������������
������"

&

"

* ) )

������������
!������������

"

"$

&

&

µ

* )

"* #

�������������

"%!

*) ') ) *) ') *

) '*

*

* )

) '*

*

* )

* ) )

*

$

!

( %

&'

$

* ) )

* ) ) )

* ) ,

* ) -

* ) .

* )

* ) )

*

* )

* ) )

( %

$

( %

"

���������������
Fig. 4. Stopping
power, −dE dl, for positive muons in copper as a function of &'momentum p). The solid curve indicates the total stopping power [15].

p Mc (or• �������������������������������
19

ria

the parton-medium cross section. Higher-order scatterings (often encoded in a

“K-factor” ≈ 2 – 4) could well result in much larger values of q̂.
QCD example3, let us consider an equilibrated gluon plasma

the diffusion constant D, characterising the dynamics of heavy non-relativistic
and a strong coupling !s ≈ 0.5 [10]. At this temperature, theparticles (mass M and speed v) traversing the plasma, is connected, via the Eindensity is "g 16 #2 $ 3 T 3 ≈ 15 fm−3 (%g 8#2 15 T 4stein relations.e. 100 times denser than normal nuclear matter (" = 0.15
fm−3 ).
D 2T 2 ( T M )D(3)
12(LO), the Debye mass is mD
4#!sT ≈ 1 GeV. The LO22thediffusion( –freethe average momentum squared gaineds section is &gg ≃ to9#!
2mD ≈ 1.5
mb. Thecoefficient
gluon means momentum
the≃particle
unit-time(related to the istransport coefficient as ( ≈ q̂ v) – and
0.45 fmper(thequark mean-free-path
dium is 'g 1 "by
g &gg
drag ofcoefficient)D . colour≈ 1 fm, where CA Cthe
9 4 is the ratio
gluon-to-quarkF momentum
nsport coefficient is therefore q̂ ≃ m2D 'g ≃ 2 2 GeV2 /fm. Noteerical value has2.2been
obtained witha LO expression
inloss!s forMechanisms
of in-medium
energyum cross section. Higher-order scatterings (often encoded in a4) could well In
resultin muchlargerof q̂. loss of a particle traversing a medium is the sum of
a generalway,
the values
total energy
4 : *E
stant D, characterising
dynamics
heavy
non-relativisticcollisionaltheandradiativeofterms*Ecoll *Erad . Depending on the kinematic
5 inEinM and speed v) region,
traversing
the plasma,is canconnected,
via thea (colour)chargelose energy
a plasma with temperature T mainly by
two mechanisms6 .
2
D 2T ( T M )D
(3)���������������

diffusion coefficient ( – the average momentum
squared gained!
r unit-time (related to the transport coefficient as ( ≈ q̂ v) – andrag coefficient )D .

�����������

in-medium energy loss

1

E

!

total energy loss of a particle traversing a medium is the sum oftive terms4 : *E *Ecoll *Erad . Depending on the kinematicarge can lose energy5 in a plasma with temperature T mainly by
Fig. 3. Diagrams for collisional (left) and radiative (right) energy losses of a quark of energy
E traversing a quark-gluon medium.

!

���������Collisional energy loss through elastic scatterings with the medium constituents(Fig. 3, left) dominates at low particle momentum. The average energy loss in

E

!

2

3 For unit conversion, multiply by powers of ! c ≃ 0.2 GeV fm (other useful equalities:

10 mb = 1 fm2 , and 1 GeV−2 = 0.389 mb).

4 In addition, synchrotron-, Čerenkov- and transition-radiation energy losses can take placerespectively if the particle interacts with the medium magnetic field, if its velocity is greaterthan the local phase velocity of light, or if it crosses suddenly from one medium to another.
ollisional (left) and Also,radiative(right)energy losses
a quarkof energy
plasmainstabilities
may oflead
to energy
losses. Yet, those effects – studied e.g. in [11,uon medium.
12, 13, 14] for QCD plasmas – are generally less important in terms of the amount of E .

E

2
C
q̂
L
S R

����

• グルーオン放射によるエネルギー損失が支配的

5 Note that if the energy of the particle is similar to the plasma temperature, E ∼loss

T , theparticle can also gain energy while traversing it.

Note thatthe separation
is notso clear-cut
since the diagrams assume well-defined asympgy loss through 6elastic
scatterings
with themediumconstituents
totic outstates, but theparticles
minates at low particle
momentum.
Theoutgoingaverageenergymay
lossstillin be in the medium and further rescatter.

! ���������������������������

, multiply by powers of ! c ≃ 0.2 GeV fm (other useful equalities:
1 GeV−2 = 0.389 mb).
tron-, Čerenkov- and transition-radiation energy losses can take placearticle interacts with the medium magnetic field, if its velocity is greater
velocity of light, or if it crosses suddenly from one medium to another.
lities may lead to energy losses. Yet, those effects – studied e.g. in [11,plasmas – are generally less important in terms of the amount of Eloss .
gy of the particle is similar to the plasma temperature, E ∼ T , then energy while traversing it.
tion is not so clear-cut since the diagrams assume well-defined asymphe outgoing particles may still be in the medium and further rescatter.

• QGPの物性研究にジェット（高エネルギーパートン）は!
大変有効なプローブ
20

! Transport coefficient:%• Scattering power of the medium through the averagetransverse momentum squared (kT2) , transferred to thetraversing particle per unit path length.

• Combined both thermodynamical (mD, #) and dynamical($) properties of medium.

from D. d’Enterria (slide at QGPWS, 2008)

Jets in LHC heavy ion collisions

Di-jet energy imbalance
CMS, PRC 84, 024906 (2011)

1) Large energy imbalance isobserved in central Pb-Pb.

ATLAS, PRL, 105 (2010) 252303

pT,1: leading jet
pT,2: sub-leading jet2) Large AJ : low momentum
particle (< 4 GeV/c) emitted
at large angle on away side.
Mini-workshop on jet physics in ALICE at the LHC Run2, April 15, 2015, CCNU, Wuhan, China
China, T. Chujo

24

Energy balance by low pT particle at large angle

Slide from Y. Tachibana (ATHIC 2014)
Mini-workshop on jet physics in ALICE at the LHC Run2, April 15, 2015, CCNU, Wuhan, China, T. Chujo

25

(2) Strongly interacting QGP,
perfect fluid

26

Re
pl ac
an tioe nAzimuthal Anisotropy
Py

Z

Pz

���������
Px���������
����������������������YX

p2y p2xv2 = ⇥ 2⇤2
py + px

y 2 x2⇤
ecc = ⇥ 22
y +x���������������

�

/R

0

���������������������
������������������������
����������������������
�������������

/R

0

Elliptic flow

STAR PRL86,402 (2001)• 大きな楕円的方位角異方性 (v )
2

の観測

-

極めて早い thermalization〜 0.6 fm/c
完全流体! →強結合 QGP の発見

.*303#/0#163#6/.1&,@#&<#163#50/43,.3#16)1#+/%%#343,#(3#,3;30)*13-#/0#163#%)(&,)1&,@9#H)*6#05*%3),#*&%%/./&0#)1#IJKL#2)'3.#)#-,&8%31#&<#D5),';7%5&0#8%).2)=#3C8%&-/07#/0#)#G%/11%3#()07G#+6/*6#,3*;,3)13.# 163# 1,)0./1/&0# (@# +6/*6# 163# </,.1# 8,&1&0.# )0-# 0351,&0.# +3,3# <&,23-9# B63.3# 3C83,/;2301.#)%%&+#5.#1&#.33#163#3..30*3#&<#163#<50-)2301)%#05*%3),#<&,*3=#).#-3.*,/(3-#4/)#163#163&,@#&<#
MLN9#$%16&576#163#)0)%@./.#&<#163#3C83,/2301.#/.#*6)%%307/07#-53#1&#163#.6&,1#%/<31/23#)0-#.2)%%#./?3#&<#163.3#-,&8%31.=#+3#6)43#163#)-4)01)73#&<#(/%%/&0.#&<#%/11%3#()07.#1&#.15-@#).#+3%%#).#)#.5,;
8,/./07#-37,33#&<#*&01,&%#&43,#163/,#/0/1/)%#*&0-/1/&0.9###

高次の方位角異方性HigherHarmonics

Figure II-5: Our one universe with its primordial fluctuations (parts per million variations in temperature) as
measured via photons by the WMAP satellite experiment (left) compared to seed fluctuations (corresponding
to 10-15% variations in temperature) in four simulated heavy ion collisions at RHIC (right). The measured
fluctuations bring us knowledge about the quantum fluctuations at the earliest moments of the explosion (bigbang or heavy ion collision) as well as about the material properties of the rippling fluid that ensues. Observations of the glow of the big bang or of heavy ion collisions reveal different and complementary properties of
the trillions-of-degrees-hot matter that filled the microseconds old universe.

重イオン衝突の揺らぎ#(!/s) ~ 0.1 ＝ 世界最小の !/s• RHICにおける方位角異方性→比ずれ粘性
M5),';7%5&0# 8%).2)# +).# *,3)13-# /0# 163# O0/13-# P1)13.# )1# IJKL=# )0-# /1# +).# 163,3# 16)1# +3# </,.1#%3),03-#&<#/1.#03),;83,<3*1#%/D5/-#0)15,39#B6/.#-/.*&43,@#+).#163#1&8#86@./*.#.1&,@#)*,&..#)%%#),3).#!ストリング理論における量子リミット(1/4") に近い!"##• 高次異方性の測定により重イオン衝突の初期条件に制限がかけられるよう!

になってきた（e.g.カラーグラス凝縮 (CGC) など）.

��������������������������
���������������������
���������

slide from Y. Miake���������������������������

�����������������������������������

Low ⌘

p̄

High ⌘

s

n

1
3 np̄

n

) (⌘/s) ⇠ p̄

( !0)

& 0

(uncertainty principle)������������������������������

⌧ (=

@u
F
)⌘⌘
S
@y

���������

! ���������������

31

高次異方性 (higher harmonics)で分かる
QGP物性����������������������������

���������������������������

�����������

Power spectrum

8th

重イオン衝突Plank (2013)
宇宙論パラメータの決定

衝突初期条件, QGP物性量 (例； !/s)

レアプローブ（種々のハドロン、フォトン、lepton, light quark, heavy quark）の!
高次異方性測定により、熱化メカニズム、 衝突初期条件、 QGP物性（粘性等）がわかる
32& 測定装置の高速化と High-pT 化が鍵"/s 温度依存性？

• IP-Glasma モデル (color charge fluctuation)• 高次異方性の測定と比較、η/s がRHICと LHC で異なる可能性• RHIC で最小の '/s ？
•温度度依存性はあるのか？
Björn Schenke (BNL) RHIC AGS Users’ Meeting 2013, BNL

C. Gale, S. Jeon, B.Schenke,
P.Tribedy, R.Venugopalan, PRL110, 012302 (2013)

(3) Thermalization

34

Space-time evolution of Heavy Ion Collisions

4
3

2
1

 
(parton)      3.          
4.         
1.
2.

35

Thermal yields• "The formula for the number density of all species:"""•

gi is the degeneracy"
E2=p2+m2"µB, µS, µ3 are baryon, strangeness, and isospin"chemical potentials respectively.

•

Given the temperature and all m, one can determines the equilibrium number
densities of all various species.

•

The ratios of produced particle yields between various species can be fitted todetermine T, µ.

Hadronization Temperature
RHIC

LHC

A. Andronic, P. Braun-Munzinger, J. Stachel, J. Stachel, A. Andronic, P. Braun-Munzinger, K.
H. Stocker, Phys. Lett. B 697 (2011) 203 Redlich, J. Phys. Conf. Ser. 509 (2014) 012019

Hadronization Temperature ~ 160 MeV

(4) Quark recombination &regeneration

38��������������������������
Phenix; P.R.L. 91(2003)172301! �����������������"������������������

��������������������������
��������������������������������

! �������������������"���������������
��������������
!

�����������������������������
�����������"�������������������

! ����������������������������
����������

!
Quark Recombination Model(Quark Coalescence Model)

39���������������������������
��������������
! ������������������������������������

����������������������������������������
��������������������

HadronMom. distr. of meson (2q)�

p
W M ( pt ) " CM # w 2 ( t 2 )Mom. distr. of baryon (3q)�

p
W B ( pt ) " CB # w 3 ( t 3 )!
w(pt)

Universal
mom."!
distr. of quarks
steep in pt

QGP
Because of the steep distr. of w(pt), RECO
wins at high pt even w. small Cx.

Characteristic scaling features expected.
"Quark Number Scaling (QNS)40�����������������������
��������������������
! ������������������������������������
Hadron������

Azimutal distr. of meson (2q)�

dN M# w 2 = (1+ 2v 2,q cos2" ) 2d"$ (1+ 4v 2,q cos2" )Azimuthal distr. of baryon (3q)�

!

QGP

dN B
# w 3 = (1+ 2v 2,q cos2" ) 3d"$ (1+ 6v 2,q cos2" )Azimuthal distr of quark; w!

w " (1+ 2v 2,q cos2# )�������������������������������

41

v2/(Quark Number)v2: quark number scaling! Quark number (n ) scalingq

arXiv:1412.1043v1 (PHENX)& Indication that anisotropy
developed at parton level, nothadronic level.

J/( (color screening vs. regeneration)J/
mid-rapidity RAA for J/(• J/( measured at

mid-rapidity |y|<0.9, by e+e- at
LHC.

• Compared to
RHIC midrapidity data.

• Significant

larger RAA thanthose at RHIC.

T. Chujo (U. Tsukuba)

RHIC & AGS 2013 annual users‘ meeting, BNL ( Jun. 27, 2013)43

J/( (color screening vs. regeneration)J/
forward-rapidity RAA for J/(• J/( measured atforward-rapidity
2.5 < y < 4, by )+)at LHC.

• Compared to

RHIC forwarddata.

• Significant larger

RAA than those at
RHIC.

• Suppression is

T. Chujo (U. Tsukuba)

stronger than thatat mid-rap.
44
RHIC & AGS 2013 annual users‘ meeting, BNL ( Jun. 27, 2013)

J/( (color screening vs. regeneration)J/
Low pT: RAA at forward y, J/!!!+!-High pT: RAA at forward y, J/!!!+!-• J/! R is enhanced at low p .
• Compatible with models including
AA

vs.

T

regeneration.

T. Chujo (U. Tsukuba)

RHIC & AGS 2013 annual users‘ meeting, BNL ( Jun. 27, 2013)45

(4) High temperature matter46

!"#$%&'()*+),-./0

Thermal photons

PHENIX: Phys. Rev. C 91 064904 (2015)

Excess from pQCD component is visible-PHENIX: Tslope~ 240±~20MeV independent of centrality-ALICE: Tslope~ 304±11!"#"±40!$!"MeV(0-20%)-PHENIX: dN/dy !%&#'"( (*= 1.38 ±0.03stat±0.07syst)-Similar to dielectron excess (*=1.44±0.1, STAR)•~30% higher than RHIC

Direct photon puzzle• Large yield andvn challenge
understanding ofsources,emission rates
and space-time
evolution• Late timeemission (HG)?

Dissociation temperature
CMS, PRL 109(2012) 222301

Melting excited ! states• Suppression of ground state Y(1s), and excited states Y(2S) and Y(3S).
• Consistent with the sequential melting scenario, Y(3S) > Y (2S) > Y (1S).
T. Chujo (U. Tsukuba)

RHIC & AGS 2013 annual users‘ meeting, BNL ( Jun. 27, 2013)49

(5) Collective behavior insmall system (highmultiplicity event)50

Di-Hadron Correlations in p-p & p-Pb
p-p (N "110)p-Pb (N "110)• First observation ofridge structure in highmultiplicity p-p (CMS).

• Also confirmed in p-Pb

high multiplicity events.

• Alway side ridge

structure is observed inhigh multiplicity p-Pb.

p-Pb ("ET Pb) < 20 GeV
T. Chujo (U. Tsukuba)

p-Pb ("ET Pb) > 80 GeV

CMS, JHEP 1009 (2010) 91
CMS, PLB 718 (2012) 795
ATLAS, PRL 110, 182302 (2013)

RHIC & AGS 2013 annual users‘ meeting, BNL ( Jun. 27, 2013)51

small system @ RHIC
Phys. Rev. Lett. 113, 112301 (2014), figure courtesy of B. Schenke

p-Au

d-Au

3He-AuInitial State Hot Spots
Glauber with nucleons

Hydrodynamics

Collectivity in
Final State
Sensitivity to initial conditions
and early time evolution

Flow in Small Systems at !sNN= 200 GeV
Top 5% in centrality)*+, ./012+3)*+,40125)*+,6012-

PHENIX 3HeAu: Phys. Rev. Lett. 115, 142301 (2015)
PHENIX dAu: Phys. Rev. Lett. 114, 0192301 (2015)

Collective motion: Large anisotropy v2 in p+Au, d+Au & v2, v3 in 3He+Au

"/# vs. dNch/d$• "/# ratio reaches Grand Canonical limit in Pb-Pb• Similar multiplicity dependence in pp and p-Pb
• Neither PYTHIA6 nor 8 reproduce data in any of the tunes tested

%/# , &/# vs. dNch/d$• Same for +/, and -/,(6) Search for restoration ofchiral symmetry breaking

56

Spontaneous Chiral
Symmetry Braking
Spontaneous	
  Chiral	  Symmetry	
  Breaking:	
  Characterized	
  by	
  Order	  Parameter	
  <qq>< qq >≈ 250MeV

SPS< qq >≈ 0

RHIC
LHC

FAIR/J-PARC

High	
  T	
  
High	
  ρ

3

Excess on di-electron mass spectrum
PHENIX data

Moderate enhancementfor 300 < m < 750 MeV factor
MB: 2.3 ± 0.4 ± 0.4 ± 0.2
central: 3.2 ± 1.0 ± 0.7 ± 0.2

PHENIX: arXiv01509.04667 (2015)

Consistent with STAR data.
Consistent with " broadening

(7) QCD phase structure59

Search for the Onset of QGP Formation: Charged Hadrons Rcp• Smooth transition from a strong suppression at high energies
to enhancement at lower beam energies.
• Cronin effects play a bigger role at lower energies.
• Yields per binary collision show indicates a balance ofenhancement and suppression effects at $sNN = 14.5 GeV.

Search for the Critical Point:
Higher Moments Fluctuations (Net-Protons)• Higher moments of conserved
quantum numbers (Q, S, B) are
expected to be sensitive to theproximity to a critical point• Higher order moments & higher
sensitivity to criticality

Non-monotonic change of '(2 for in central Au+Au collisions

Summary of observations• Jet quenching• Strongly coupled QGP• Thermalization• Quark recombination (regeneration)• High temperature matter• Collectivity in small system• Search for Chiral symmetry restoration• QCD phase structure3. What is missing?
Next 20 years plan

The Physics Case for sPHENIX

What i

初期条件→前平衡→パートン散乱→熱化(QGP)&ハドロン生成&膨張

•
•
•
•

衝突初期条件の解明（カラーグラス凝縮？）
Thermalizationのメカニズム
QGP物性量(比粘性、輸送係数等)の温度依存性
相図の構造

-

QCD critical point の探査 (RHIC)

鍵となる測定量："/s / (1/4!)

比ずれ粘性 : !/s/(1/4")

まだ分かっていないこと

String Theory Bound (KSS)pQCD (AMY)hydro+IQCD
Hadron Gas
Lattice QCD (gluodynamics)
semi-QGPQPM (finite µ )BHydro Fit (Niemi et al.)Hydro Fit (Song - a)Hydro Fit (Song - b)

40
35
30
25
20
15
10
5
0
0

KSS Bound
0.5

1

1.5

2

2.5

3
3.5
4
Temperature (T/Tc)

温度 (T/T )Figure 1.5: (Left) Shear Viscosity divided
by ec
conjectured KSS bound as a function of the redu
for the quark-gluon plasma case. See tex
LHClations
Experiments
conjectured
scenarios for the quark-gluon plasm
Full-energy RHIC experimentsbound (as a near perfect fluid) to the weakly cou

more perfect at LHC energy.”

Shown in Figure 1.5 (right panel) are three po
modification of the medium from the strong t
the most rapid change in /s( T ) following th
III has the least rapid change going through t
imperative to map out this region in the ‘cond
the underlying reason for the change.

The above discussion has focused on /s as thquark-gluon plasma. However, both /s andsensitive to the underlying coupling of the ma
examplethe behaviorof q̂ around the critical te(2) より高次の異方性（ 種々のハドロン、フォトン、light quark,
heavy
quark）(1) ジェット (high pT)

ジェット測定で分かるQGP物性!"#$%&'()*+(,+-%./(

LHC エネルギー：• RHIC に比べてハードプロセスが支配的• ジェットを基軸とした新たな観測量：• ジェット通過によるQGP媒質応答• 重クォークジェット、ジェット対、光子-ジェット• 失ったエネルギーの再分配、EOS、音速• 重いクォークの強結合系QGPとの相互作用（熱化、相互作用の強さ）→ データ読み出し高速化が必要
RHIC エネルギー：

0*+&(-#+1()*+(1)"#&'23(4#.52+-($.26(7!"#$%&'"'$()"9&1%:#&()#(9(;+9623(4#.52+-(5"#$+(7-./-$%&'"'$()• 既存の装置はジェット測定に特化されてなく、収量や精度の点で、ジェットの直接測定が困難• 2 "カロリメータを設置. High pT 化を図り、RHIC エネ
ルギーでのジェット測定が可能に→ ジェットエネルギー損失の温度依存性

ジェット・フォトンで探るQGP物性 (LHC-Run-2)
1.jet-jet (di-jet), #-jet, h-jet 測定• パートン衝突位置の決定、エネルギー損
失の通過距離依存性• パートンエネルギー損失機構の解明
2.jet エネルギ損失とソフトハドロン生成• QGPの媒質応答!"#$%&'()*+(,+-%./(

ジェットのエネルギー損失とソフトハドロン生成の様子• グルーオン衝撃波!EOS 決定の可能性

ALICE Run-2:
0*+&(-#+1()*+(1)"#&'23(4#.52+-($.26(7!"#$%&'"'$()*'&+,8(• 高統計（ダイ）ジェットサンプルが不可欠に )"9&1%:#&()#(9(;+9623(4#.52+-(5"#$+(7-./-$%&'"'$()*'&018<(• DCal(Run-2 に新規導入) + PHOS:ジェットLevel-1 トリガー導入（筑波大）

ジェットが落としたエネルギーによるソフトハドロン生成.
状態方程式により、放出角度が変化. Y. Tachibana, T. Hirano
J, (2014)

衝突初期条件の決定、早期熱化の謎• d-Au (RHIC), p-Pb (LHC) の結果には カラーグラス凝縮（CGC） を示唆するものの、
未だ決定的ではない (final state interaction を含むハドロン測定が主)。

• 実験的課題：よりクリーンなプローブによる前方の測定が不可欠（例：直接光子）• CGC vs. Glauber 初期条件 & QGPにおける早期熱化機構の解明へ

New Puzzle in p+p and p+A

Figure
taken
from
CMS

T. Chujo (U. Tsukuba)

Need to be solved !

69

RCP = (yields in central x Ncoll(cent))/(yields in peripheral x Ncoll(peri))

１次相転移か、クロスオー
バーか？臨界点はあるのか？

•

RHIC ビームエネルギースキャン (BES-I; Beam
Energy Scan), 7.7 - 62.4 GeV による臨界点探査– RAA, v2 のクォーク数スケーリング、揺らぎ測定など– 未だ明確な兆候なし•

より詳細なスキャン (BES-II) @ RHIC (2018-2019)70

カイラル対称性の回復現象• レプトン対質量分布の余剰成分：•媒質効果による% 中間子のbroadening の効果と無矛盾• 高温領域 (LHC) ではどうか？
• 高密度領域（例えば FAIR, J-PARC) では測定されていない
高温側、高密度側の両方のアプローチが不可欠＋
理論の進展
PHENIX: arXiv01509.04667 (2015)

RHIC-PHENIX実験 High-pT 化
High-pT 化
ジェット測定強化重クォーク測定強化• 測定器の新規建設
PHENIX & sPHENIX• 日本が建設を主導する検出器：! シリコン飛跡検出器
QM2015, A. Dressジェット、重クォーク測定から、RHIC
エネルギーでのQGP中でのエネルギーsPHENIX実験: 総額$20M-30M

損失 (輸送係数)の温度依存性を決定
72

arXiv:1207.6378

STAR BES-IISTAR Upgrades and BES Phase-II (2019-2020)

iTPC proposal: http://drupal.star.bnl.gov/STAR/starnotes/public/sn0619
BES-II whitepaper: http://drupal.star.bnl.gov/STAR/starnotes/public/sn0598

Larger rapidity acceptance crucial for further critical point search with net-protons• Electron cooling upgrade will provide increased luminosity ~ 3-10 times.
• Inner TPC(iTPC) upgrade : |&| < 1 to | & |< 1.5. Better dE/dx resolution.
• Forward Event Plane Detector (EPD): Centrality and Event Plane Determination.
1.8 < |&| < 4.5

LHC schedule'!()*%+%,-#./01%(2+3*4%2!35%6/78.%9-#./01%(&2()4%3:)%;6"<8.%9-#./01'!()*%++%,-#./01%(&2()4%3:)%6/78.%9-#./01!1/=>%+8<%296"<8?"@>%%
A.86%BCDE%@8%E%FBCDE!2G2!34%--%H96"<8?"@>%
A.86%BCIJK-1/LM%@8%N%FBCIJKH1=1HH10M
74

LHC-ALICE実験 高速化
ALICE 実験測定器の高速化
日本グループが担当する検出器：
GEM-TPC連続読出高速化
カロリメータ高速化
グリッド計算機 (Tier2) の強化
LHCの高輝度化、Pb-Pb衝突(50kHz)に対応
全衝突事象を記録し、これまでの100倍のデータ取得
ALICE実験高度化: 総額'40M（ATLAS, CMS 実験では不可能）& 高精度測定、レア事象へのアクセスが可能に
物理の目標：
ジェットともに低運動粒子 (PID含)、重クォークや光子やレプトン対の方位角異方性を同時測定&QGP媒質応答、重クォークと強結合系の相互作用（熱化、相互作用の強さ）を決定

75

LHCCによるendorsement (2012年9月)

Expected performance (low-mass
di-electron pair), w/ hadronic BG
BeforeAfter

Expected performance (low-mass
di-electron pair), w/o hadronic BG
BeforeAfter

アップグレード前後の余剰成分（シグナル）$カイラル対称性の回復現象の精密測定へ！

前方物理、CGC、衝突初期条件の決定
単光子の収量比：0L2NFDMO0L2N2M

9K90なし0L通常の原子核効果M

9K90あり0
9K90
A. Rezaeian, PLB 718, 1058
FOCAL 検出器（案）•η= 3-5 をカバーする前方光子検出器（筑波大）•電磁カロリメータとハドロンカロリメータ•ALICE 実験内で導入を検討中•前方での直接光子測定により、CGC を検証、衝突初期条件の決定とQGP熱化機構に迫る。

OG'(P3%における重イオン実験の検討• OG'(P3Q%%– 高ルミノシティー原子核衝突実験目0– 高バリオン密度におけるＱＣＤ相構造
解明、ＱＣＤ臨界点の探索%– ����������5-10�!0 �����
���

79

J-­‐PARC	
  重イオン衝突の物理@10-­‐15GeV/A	  (√sNN	
  =4.5-­‐5.4	
  GeV	
  )•軽イオンから	
  U	
  重イオンまで加速（新イオン源;	
  ECR, laser, EBIS）	
  •AGS	
  では測定しなかった（出来なかった）物理量を初めて測定	
  – 物理量のゆらぎ（粒子数、運動量、vn 等)	
  ➡ 	
  QCD	
  臨界点探査、QCD相図の	  mapping	  	
  – レプトン対(電子,	
  muon)、光子、σメソン（？）	
  ➡ カイラル対称性回復の研究、熱光子測定	  – エキゾティックハドロン/原子核、チャームの物理	  • mulUple-­‐strangeness	
  (ストレンジレット探査)	
  	
  • ２重、３重	
  ハイパー核	  • チャームハドロン(J/Ψ,D)	
  – ハドロンガスの物性量測定、高密度核物質の物性

80

J-PARC Facility

Materials and Life Science
Experimental Facility

Nuclear
Transmutation

Hadron Beam Facility

500m(Phase 2)

Neutrino to
Kamiokande

Linac(330m)

3 GeV Synchrotron(25 Hz, 1MW)

50 GeV Synchrotron(0.75 MW)

J-PARC = Japan Proton Accelerator Research Complex

Joint Project between KEK and JAEA

81

測定精度の時代へ
SPS-NA60

RHIC-STAR

J-PARC では…
pT ビン毎、質量分布の精密測定! QCD sum rule との直接比較(moment 解析)
T. Chujo (U. Tsukuba)

82

Simulated	
  di-­‐electron	
  spectrum(preliminary)0

Based	  on	  π 	
  spectra	
  of	
  JAM	
  
	
  	
  	
  	
  	
  	
  Other	  hadrons	
  mT-­‐scaled	
  π0b<1fm	  (0.25%	
  centrality)	
  Momentum	
  resolution	
  2%	
  Electron	
  efficiency	
  50%	
  

ω
ρ

φ

	
  

No	
  detector	
  response
11

10 	
  =	
  100	  G	  events	
  100k	
  events/s	
  
x	
  1	
  month	  running	
  εisolation	
  =	
  rejection	
  efficiency	
  of	
  close	  opening	
  angle	  Dalitz	
  pairCalculations	
  by	
  T.	
  Gunji	  and	  T.	
  Sakaguchi
NA45 (CERES) データより３桁高い統計量を１ヶ月で取得！
cf.) STAR (BES-II) fixed target program: 5 M events @ √sNN = 5 GeV

83

4. Connections to otherfieldsビッグバンリトルバン

t0+138 億年（現在）

t0+3!10-23 秒間持続

CMB

gaz hadron
QGP

QGP

t0

ビッグバンリトルバン

t0+138 億年（現在）

t0+3!10-23 秒間持続

CMB

gaz hadron
QGP

QGP

t0

Figures from, “Quark-Gluon Plasma”, K. Yagi, T. Hatsuda, Y. Miake,
Cambridge Univ. press (2005)

S. Florchinger (QM2015)

For heavy ions and the cosmos,
fluctuation analysis can provide detailed
information about material properties
and expansion history without fullcontrol over initial conditions.
Common challenges requirecommonalities in analysis techniques.
Interplay between both fields likely to
become more important in the next
decadeS. Florchinger (QM2015)

88

Mystery of neutron star matter" Final form of matter evolution in the universe

Slide from H. Tamura

Produced by supernova explosion, Observed as X-ray pulsars" Highest density matter in the universe

Nuclear “Pasta”

M = 1~2 M , R ~ 10~20 km

=> Density of the core = 3~10!013 Btons/cm3
!0: nuclear density" Various forms of matter made of almost
only quarks&np'Strange Hadronic
Matter ?
High density nuclear
matter with hyperons(strange quarks)

Nuclear + Neutron Matter

Neutron MatternSuperfluid

Quark Matter??
Deconfined quarks
Color superconductivity

High density formation may help multi-strangeness production89 
      
CNN ニュース:http://www.cnn.co.jp/fringe/35035080.html
プレスリリース
http://www.cfa.harvard.edu/dvlwrap/open̲night/
PressConference̲2013-07-17̲640x360̲low.mp4

W)GW)%61.#1.%]/<%@89]$%9<.1/]$/5H1%.1#"8<%"<%-$/?1%0"/#./6%%^$"#$%01<?"@>%/<0%K.1H/_=1H>M%$"#$%@16-1./@9.1`%]A%&%a%BCC:1T4%bca%BCCC:1T%K)$/-".8%Bdde4%3$1<42/59<%DCBIM%
Slides from K. Itakura (J-PARC HI workshop @ KEK, Nov. 2014)

strongly coupled system-6
at 10 K
World at 10-6 K
6Li (optical laser cooling)

Fermi gas system＝strongly coupled system
Very similar at 1012 K= strongly coupled QGP(sQGP)

91

Viscosity/entropy in ultra-cold 6Li gas

string theory limit

Science 58, 311 (2011)arXiv:1007.2625v2

Initial energy per atom
92

T. Yamazaki(Reimei WS, 2016)

P. Braun-Munzinger (HYP2015)94

P. Braun-Munzinger (HYP2015)

@ J-PARC

H. Sako(Reimei WS, 2016)

Many others…
• High energy physics

small system

multi-parton scattering or

CGC.

• Fluctuation non Gaussian fluc.
• Charmed meson, baryon (LHCb (penta quark,exotic))• High energy cosmic ray & QGP (LHCf)• Crossover phase transition• He anti-He (CTP invariance)• Strong and intense field (E, B), color field.
• CME (chiral magnetic field effect) in condense matter physics(observed; ZrTe5 etc.).

• String theory, black hole and AdS/CFT

LHC

RHIC

ST
AR
BE ’s
S
NI

CA FA
? J IR-PAR

C?

Neutron star

98

T
!

99

Summary• In this 16 years, a rich physics program using heavy
ion beams at RHIC and LHC.

- Many discoveries (e.g. sQGP) and progress onunderstanding of nature of QGP.

- New paradigm (small system), and unresolved issues.

• Presented our scope in 20 years & connections toother fields.

• In my view, interplay with other fields, in particular

cosmology, cold atom physics, and condense matterphysics will become importance in the next
decade(s), to reveal a nature of QGP and history of
universe.