T

To explore QCD properties,
Temperature and density ofthe medium should be known.
Currently we have,

QGP
RHIC, LHC

Heavy Ion Collisions
Nucleus~200MeV

J-PARC
2008/10/15

ρ０ATHIC, K. Ozawa

NeutronStar
ρB2

My opinion…

High density (Neutron/quark) starHigh density physics
Origin of hadron mass

2008/10/15

ATHIC, K. Ozawa

3

Figure:K. Yagi, T. Hatsuda, Y.
Miake,“Quark-Gluon Plasma”
Review:
F. Weber, Prog. Part. Nucl.
Phys. 54 (2005) 193
ρ02008/10/15

ATHIC, K. Ozawa

n star4• Studied using hyperon bound state.
– Spectroscopy of Λ hyper-nuclei• Extended to study for
s=-2 system

PRC 64 (2001) 044302– Double hyper nuclei– Ξ hyper nuclei?

2008/10/15

ATHIC, K. Ozawa-> UΛ = - 30 MeV
5(c.f. UN = -50 MeV)• Direct measurements of cross section• Current data statistics is poor
• Lattice calculation exists

Σ+p scattering

Nemura, Ishii, Aoki,
Hatsuda, arXiv:0806.1094• New experimental techniques
need to be developed tocollect large statistics.
• SciFi + MPPC readout
2008/10/15

ATHIC, K. Ozawa

6

Deeply bound K nuclear states are predicted.
Strong KN attraction suggests a deep K nuclear
potential (Uk ~ 200 MeV)
A calculation shows very high density.

A. Dote et al. : PLB590(2004) 51, etc.

density (fm-3)

ρ > ρ x10 !?
0

Experiment for K-pp bound state
Formation (Missing mass)
Decay ΛpK-3He

ndecayMeasure Potential,
Binding Energy,
Width2008/10/15-pp neutron
Kformatio

ATHIC, K. Ozawa

Λπ−proton

proton7

Spontaneous breaking of a symmetry is marked by:* a non-zero order parameter, the quark
condensate <qq> in the case of QCD:High THigh ρAt Nuclear Density

heavy ion reactions:
A+A→V+X
mV(ρ>>ρ0;T>>0)γ, π. p - beams

SPS
RHIC

J-PARC elementary reaction:
CLASγ, p, π → V+X

mV(ρ=ρ0;T=0)

LHC
2008/10/15

ATHIC, K. Ozawa

8

NA60 results[van Hees+RR ‘06]

PRL 96, 162302 (2006)

Spectrum is reproducedwith collisional broadening.
Next,
Try for extracting of a quark condensate
information from the data.
2008/10/15

9ATHIC, K. Ozawa
9• Freeze-out Cocktail +“random” charm +ρ spectral function
Low mass• M>0.4GeV/c2:
some calculations OK• M<0.4GeV/c2:
not reproduced
Intermediate mass
• Random charm +thermal partonic maywork
2008/10/15

ATHIC, K. Ozawa

10Then, Nucleus• Stable system– No (small) need for timedevelopment• Saturated density

Two approaches,Link hadron spectra and the quark condensate.
 Link meson bound states and the quark condensate.
Nucleon Holep, π, γ
2008/10/15

Meson
ECT*-WS,ATHIC, K.K.Ozawa
Ozawa

TargetEmittedProton/NeutronDecay11π bound state
K. Suzuki et al., Phys. Rev. Let., 92(2004) 072302

GSI

π bound state is observed inSn(d, 3He) pion transfer reaction.
Reduction of the chiral order parameter,f*π(ρ)2/fπ2=0.64 at the normal
nuclear density (ρ = ρ0 ) is indicated.
Jido-san et al. shows that πnucleus scattering length isdirectly connected to quark
condensate in the medium.

D. Jido et al., arXiv:0805.4453
2008/10/15

New exp. will be done at RIKEN
12ATHIC, K. Ozawa

KEK E325

R. Muto et al., PRL 98(2007) 042581

counts/[6.7MeV/c2]βγ<1.25 (Slow)

Cu

150

Excess!!

Data
Fitting Result

100

Invariant mass spectrum forslow φ mesons of Cu target
shows a excess at low massside of φ.

50

00.9

1

1.1

1.2
[GeV/c2]

Measured distribution contains bothmodified and un-modified mass
spectra. So, modified mass spectrum
is shown as a tail.

First measurement of φ meson mass
2008/10/15
13ATHIC, K. Ozawa
spectralmodification
in QCD matter.

Target/Momentum
1.75<βγ (Fast)dep.
1.25<βγ<1.75
βγ<1.25 (Slow)φ → e+ e-

Mass modification is seen only at heavy nuclei
and slowly moving φ
Mass Shift:

2008/10/15

ATHIC, K. Ozawa

14

mφ = m0 (1 - α ρ/ρ0) for α = 0.03

Next step
1. Detailed spectra need to be obtained“experimentally” in ω-p plane.
2. Sum rules will be calculated using
experimental data and can be compared toQCD (qq condendates).
3. Finally, details of spectra can be discussed.

Experiments to extract direct
physics information.
Experimentalrequirements
2008/10/15

1. High statics
2. Clear initial condition
ATHIC, K. Ozawa

15• Extended to vertical direction
Collaboration
RIKEN
S.Yokkaichi, H. En'yo, M. Naruki,
R.MutoU-TokyoK. Ozawa
Hiroshima-U K. Shigaki
CNS, U-Tokyo H. Hamagaki
KEK
S. Sawada, M. Sekimoto, A. Kiyomichi
Kyoto-U
F. Sakuma, K. Aoki

KEKSidespectrometerview
Plain view
Cope with 10 times larger beam intensity!!
2008/10/15
16
ATHIC, K. Ozawa
2 times better
mass resolution!!

Pbφφ

Modified φφφφφφ φφφ fromProton[GeV/c2]

Highresolution
Invariantmass inmedium
2008/10/15

ATHIC, K. Ozawa

17

Clear Initial condition

π-ωEmittedNeutronp![MeV/c] [GeV/c2]
ω momentum

π0 γ decay
450

m!=782.7[MeV/c22], #=0[degree]
m!=732.7[MeV/c ], #=0[degree]
m!=682.7[MeV/c2], #=0[degree]

400
0.4

Mass dependence(Mω = 783 MeV/c2)

350
300

ΔM=9%
ΔＥ/E =3 %/√E

250

200
0.2

-100 MeV/c2

150-50 MeV/c2

1005000 00

ΔM=0

ΔM=13%

ΔΜ = 0 MeV/c2
1000
2000
4000
6 70002 3000p [MeV/c]
4 5000 6000"
Modified Invariant mass spectrum
π momentum [GeV/c2]2008/10/15

ATHIC, K. Ozawa

18

Summary• Several interesting experiments areproposed at J-PARC for exploring QCDmatter.
• Results of the first generation experiments
are reported.
– It seems some results show contradiction andit should be solved by the next generation exp.

• Many experiments for exploring hadronmass properties in nuclear medium arebeing proposed.
– Explore large kinematics region– Measurements with stopped mesons
2008/10/15

ATHIC, K. Ozawa

19

Mass spectra measurements
KEK E325, ρ/ω → e+eInduce 12 GeV protons to Carbon and Cupper target, generate
vector mesons, and detect e+e- decays with large acceptancespectrometer.
M. Naruki et al., PRL 96 (2006) 092301
2

ω/ρ/φevents[/10 MeV/c ](b) CuCuωe+e-The excess over theknown hadronic sourceson the low mass side of ωpeak has been observed.

ρe+e-mρ = m0 (1 - α ρ/ρ0) for α = 0.09
2008/10/15

ATHIC,
K. Ozawa
2[GeV/c ]21

Induce photons to Liquid dueterium, Carbon, Titanium and Irontargets, generate vector mesons, and detect e+e- decays withlarge acceptance spectrometer.
R. Nasseripour et al., PRL 99 (2007) 262302

γω/ρ/φNo peak shift of ρ
Only broadening isobserved
2008/10/15ATHIC, K. Ozawamρ = m0 (1 - α ρ/ρ0)for α = 0.02 ± 0.02

22

• Difference is significant• What can cause thedifference?

CLASKEK– Different production
process– Peak shift caused byphase space effects inpA?

• Need spectral function of ρ
without nuclear matter
effectsNote:• similar momentum range In addition, background issue is• E325 can go lower slightly pointed out by CLAS

2008/10/15

ATHIC, K. Ozawa

23

• Combinatorial background is evaluated by a mixed event
method.
The problem:• Form of the background is determined by acceptance andEachexperiment can’t apply another method.
reliable.
• We should be careful on normalization.

CLAS

KEK
Normalizedusing mass
regionabove φ.
There isenoughstatistics

Absolute
normalization
using likesign pairs

2008/10/15

ATHIC, K. Ozawa

24

Numbers in parentheses are ones for the Phase 1.

• Beam Energy：

50ＧｅＶ(30GeV for Slow Beam)(40GeV for Fast Beam)• Repetition:
3.4 ~ 5-6s
• Flat Top Width：
0.7 ~ 2-3s
• Beam Intensity: 3.3x1014ppp, 15µA
(2×1014ppp, 9µA)
ELinac = 400MeV (180MeV)• Beam Power:
750kW (270kW)
2008/10/15

ATHIC, K. Ozawa

25

• Cascaded Accelerator Complex:
Materials and Life
Science Facility

Hadron Hall (SlowExtracted Beams)

3GeV Rapid Cycling(25Hz) Synchrotron

Linac

2008/10/15

Neutrino Beamline toSuper-Kamiokande
ATHIC, K. Ozawa

50GeV
Synchrotron
26

NP-HALL
56m(L)×60m(W)2008/10/15

ATHIC, K. Ozawa

27• 測定できるものは、QCD媒質中でのハドロン– ハドロン（主にメソン）の質量、巾、Couplingなど– Phase transition に伴う粒子放出• カイラルパートナーの質量を測るのが王道？
– ρ (JP = 1-) m=770 MeV ： a1 (JP = 1+) m=1250 MeV– N (1/2+) m=940 MeV ： N* (1/2-) m=1535 MeV ？
– 実験的に非常に困難• 非摂動論的QCDや現象論によりハドロンの性質と関係づける

2008/10/15

ATHIC, K. Ozawa

28

• Nambu-Jona-Lasino model– Nambu and Jona-Lasino, 1961
– Vogl and Wise, 1991
– Hatsuda and Kunihiro, 1994

Vector meson mass
G.E.Brown and M. Rho,
PRL 66 (1991) 2720

• Chiral Perturbation theory– Weinberg 1979
– Gasser and Leutwyler, 1984, 1985

• QCD sum rule

– Shifman et al., 1979
– Colangelo and Khodjamirian, 2001
– Hatsuda and Lee, 1992

• Lattice QCD‘T.Hatsuda and S. Lee,PRC 46 (1992) R34– Wilson, 1974
– Karsch, 2002

• Empirical models– Potential model (De Rujula et al., 1975), Bag model (Chdos etal., 1974)• In addition, Collisional broadening, nuclear mean field …
2008/10/15

ATHIC, K. Ozawa

29

Eγ~0.8-1.12.GeV, sub/near-threshold ρ0 production• PRL80(1998)241,PRC60:025203,1999.: mass reduced ininvariant mass spectra of 3He(γ, ρ0)X ,ρ0 --> π+π−
• Phys.Lett.B528:65-72,2002: introduced cosθ analysis toquantify the strength of rho like excitation• Phys.Rev.C68:065202,2003. In-medium ρ0 spectral function
study via the H-2, He-3, C-12 (γ,π+ π-) reaction.

Try many models, and channels
Δ, N*, 3π,…

2008/10/15

Eγ

STT model
Presentwork

Previouswork

800-960
MeV

700-710MeV

672±31
MeV730MeV

743±17
MeV 30960-1120
MeVATHIC, K. Ozawa

D. Trnka et al., PRL 94 (2005) 192203

pγafter background subtractionγωπ0γ

γA → ω + X
π0γγγγadvantage:• π0γ large branching ratio (8 %)• no ρ-contribution (ρ → π0γ : 7 ⋅ 10-4)
disadvantage:• π0-rescattering
2008/10/15mω = m0 (1 - α ρ/ρ0) for α = 0.13
ATHIC, K. Ozawa

31

J.G.Messchendorp et al., Eur. Phys. J. A 11 (2001) 95

pγ

simulationγωπ0γ

γA → ω + X
γ

π0γγγ

disadvantage:• π0-rescattering

2008/10/15

no distortion by pion rescattering
expected in mass range of interest;
K. OzawaT >150 MeV
further reducedATHIC,
by requiring
π32Experimentalists face to reality- E325 simulation- e+e-

KEK-E325 Target
material beam (p/ Interaction radiation
Cu length(%)
spill)
length(%)

CC
Cu X4

0.64x109

0.2%

0.4%

0.05% X4

0.5% X4

1g/
cm2

1g/
cm2

2008/10/15

ATHIC, K. Ozawa

33

Momentum dependence will be studied by CLAS (soon?).

2008/10/15

ATHIC, K. Ozawa

34

Consideration• Gamma beamでの測定に変化が無いのは昔から知られている。
– H. Alvensleben, et al.,NPB18(1970)333- 365• Initial conditionの影響を見積もる必要がある。
 <0|qq|0>
 自由空間でのメソンに対する理解の必要 <A|qq|A> 計算は励起されていない状態の原子核 <A’|qq|A>, <A’|qq|A’> 実際の測定では、原子核は励起されているし、励起
processによって異なる。 35
2008/10/15 のされ方もproduction
ATHIC, K. Ozawa

Small sensitivity for spectral modification in mass distribution
due to final state interaction. Nuclear absorption cross sectionof φ is measured

σ(A) ∝ A0.74±0.06 ,σφN =30+12−8 mb?? Γ*~Γ0 X 3~5 ??

Results are consistent with KEK for broadening.
KEK experiment shows 3 x larger mass width in nucleus.
2008/10/15

ATHIC, K. Ozawa

36

高エネルギー重イオン衝突実験• ＳＰＳ• ＲＨＩＣ– CERN– √sNN=19.6 GeV– 鉛-鉛 衝突– 比較的高温〜150MeV– BNL– √sNN=200 GeV– 金-金 衝突
– 高温（＞２００MeV）
SPS

RHIC
37
2008/10/15

ATHIC, K. Ozawa

37• クォーク・グルーオン・プラズマの生成• 衝突の初期状態の摂動論的な計算による決定– Clearなプローブの設定• 流体力学を用いた時間発展の解析

38
2008/10/15

ATHIC, K. Ozawa

38系の温度・密度状態の時間発展の定量的評価が利用可能

RHIC results

p+p NORMALIZED TO mee<100 MeV

39
2008/10/15

ATHIC, K. Ozawa

39

Energy level of bound statehas information about
interaction between nucleus
and meson.
Theoretical prediction for ω bound states

2008/10/15

ATHIC, K. Ozawa

40

0 degree measurement
R.E. Chrien et al., Phys. Rev. Let., 60 (1988) 2595

LiCOAlH. Nagahiro et al,
2008/10/15

ATHIC, K. Ozawa

Calculation for 12C(γ, p)11Bω

Negative results for ηMeasurements @ 15°

41

Yield Estimation
Summary plot of π-p → ωn for backward ω(G. Penner and U. Mosel, nucl-th/0111024,
J. Keyne et al., Phys. Rev. D 14, 28 (1976))

0.14 mb/sr @ √s = 1.8 GeVsame cross section is assumed.
Beam intensity
107 / spill, 3 sec spill length)
Neutron Detector acceptanceΔθ = 1°(30 cm x 30 cm @ 7m
Gamma Detector acceptance
75 % for single, 42% for triple
Branching Ratio: 8.9%

Optimistic obtained
yield is 31650
ATHIC, K. Ozawa

2008/10/15

42

LOI@J-PARC by K. Itahashi et. al

Chiral symmetry inBaryon

N*(1535)KΣ-KΛ s-wave resonance (Chiral Unitary model)
Chiral partner of nucleon (Chiral Doublet model)
Calc. by H. Nagahiro

How to study N* experimentally?
η – N is strongly coupled with N*
η in nucleus makes N* and hole

Generate slowly moving η in nucleus

Forward neutron is detected.
missing mass distribution is measured.
2008/10/15

ATHIC, K. Ozawa

43counts/[6.7MeV/c2]βγ<1.25 (Slow)
150

CuExperiment 1:
φp -> K+ΛΦ ssu
p u
dData
Fitting Result

100

50

00.9Bound?

2008/10/15

11.1

1.2
[GeV/c2]s K+usu ΛdExperiment 2:
pp -> φφATHIC, K. Ozawa

44