Hypernuclear Physics
Experiments at J-PARC
Tomofumi NAGAE
J-PARC Project Office
KEKNuclear Physics in the 21st Century
Heavy-Ion Colliders : RHIC, LHC-Alice
QGP at High Temperature

e- and photon beams : JLab, SPring-8, etc.
Structure of proton, Hadron spectroscopy, etc.

Hadron beams : J-PARC, DAFNE, GSI
High-Density Hadronic Matter, Exotic Hadrons

Unstable Nuclear Beams : RIBF, GSI, ISOLs
Isospin Limit, Nuclear Astrophysics

RHIC
LHC

J-PARCLOIs in Strangeness Nuclear Physics
L06: New Generation Spectroscopy of Hadron Many-Body Systems withStrageness S=-2 and -1 (K. Imai et al.)
L07: Hyperon-Proton Scattering Experiments at the 50-GeV PS (M. Ieiri etal.)
L08: High-Resolution Reaction Spectroscopy of S=-1 Hypernuclei (H.
Noumi et al.)
L09: Neutron-rich Λ hypernuclei by the double-charge exchange reaction(T. Fukuda et al.)
L10: Study of Dense K Nuclear Systems (T. Nagae et al.)
L21: Precise Measurement of the Nonmesonic Weak Decay of A=4,5 ΛHypernuclei (S. Ajimura et al.)Two LOIs selected as Day-1 Experiments

L06: New generation spectroscopy ofhadron many-body systems withstrangeness S=-2 and -1



K.Imai,M.Nakamura, H.Funahashi, M.Yosoi
T.Nagae, M.Ieiri, H.Noumi, H.Outa, M.Sekimoto,
H.Takahashi, Y.Sato, A.Toyoda
T.Fukuda, P.K.Saha
K.Nakazawa
K.Yamamoto, T.Yoshida
O.Hashimoto, K.Maeda, H.Tamura, S.N.Nakamura,
T.Takahashi, Y.Fujii,H.Kanda
T.Kishimoto, A.Sakaguchi, S.Ajimura, Y.Shimizu,S.Minami, T.Itahashi, T.Hayakawa
M.Iwasaki, K.Itahashi, K.Tanida, Y.Matsuda
Japan
J.S.Song, I.G.Park, C.S.Yoon, S.H.Kim
J.Y.Kim
M.Y.Pac
J.K.Ahn, I.K.Yoo
H.Bhang, M.Youn
Korea
S.Zhou, L.Zhu

China













B.Bassalleck
L.TangP.Markowitz, B.Raue, J.Reinhold
M.May, R.E.Chrien, A.Rusek, P.H.Pile
S.Choi
Ed.Hungerford
G.Franklin, R.Schumacher, B.Quinn
USAT.R.Saitoh, A.Banu

Germany
J.Arvieux
FranceP.Kienle, M.Cargnelli, J.Marton, J.Zmeskal
Austria
S.Marcello, T.Bressani
M.Agnello
A.Feliciello
Italy
P.Tlusty
Czech

Strangeness Nuclear Physics
New Hadron Many-Body Systems with Strangeness(K-,K+) spectroscopy
γ spectroscopy

S=-2 World
Energy Spectrum of S=-2 systems
A-1(Z-1)+Ξ−Ξ-hypernucleus(A-1)g.s.⊗PΞ

BΞ(A-1)g.s.⊗SΞ

A-2(Z-2)+Λ+ΛBΛ

A-1 (Z-2)+Λ
Λ

2xBΛ

Double-Λ hypernucleusBΛΛ(A-2)g.s.⊗SΛPΛ

A-1 (Z-2)+nΛΛ∆BΛΛ∆BΛΛ> 0 ? ∆BΛΛ< 0 ?

Ξ−N InteractionΛΛ−Λ Interaction(A-2)g.s.⊗SΛ2

Λ
MH > 2xMΛ - BΛΛMH < 2xMΛ - BΛΛH particle mass
H + (A-2)

Weak Decays

Information on S=-2Double Λ hypernuclei
Two old emulsion events(1963,1966)
One recent event in KEK E176(1991)
Nagara event in KEK E373(2001)
Binding energy of ΛΛ6 He
mH>2223.7 MeV/c2
Ξ hypernuclei ?

€Very limited spectroscopic information

ΞHypernuclei with (K-,K+)K E K -S K S

SDC3
SDC4TOFAEROGELCERENKOV

LUCITECERENKOVTARGET

1200 MeV/cBEAM

1100 MeV/c01m

(K-,K+) Spectroscopy
2 MeVFWHM resolution~6 events/day/MeV for 50 msr, 2g/cm2thick Pb~20 days58

Folding
Woods-Saxon
V0=-24 MeV
V0=-16 MeVΞ bound region

MHY-MA (MeV)

Ni(K-,K+)

208Pb(K-,K+)
Folding
Woods-Saxon
V0=-24 MeV
V0=-16 MeVΞ bound region

MHY-MA (MeV)Ξ hypernuclei potential ?
Λ, Σ-, Ξ-, K- in Neutron Star Core ?
kF 2µB = m B ++ U(k F )2mB

Chemical Potential:

€Σ-Λ

Λ

Ξ-UΣ<0, UΞ<0UΣ>0, UΞ<0Ξ-UΣ>0, UΞ>0Λ

Ku=ρ/ρ0High-presicion γ spectroscopyof hypernuclei∆E ~ a few keV (FWHM) by Hyperball<< ~ 1 MeV by reactions
Precise Structure of Λ Hypernuclei
 YN, YY Interactions

ΛN : spin-dependent forces, ΛN-ΣN / ΛNN forces,
charge symmetry breaking, p-wave interaction
ΞN, ΛΛ interactions
 Impurity effects
B(E2) -> shrinking effectChange of cluster structure/shell structure Nuclear medium effects
B(M1) -> mΛ inside a nucleusμΛHyperball-3
 effic. > 10% at 1 MeV(x4 of Hyperball) Rate limit~2x107 particles /s (x5)
 Yield: x20 for single γx80 for γγ

PWOcounters

14 setsr.e.= 350%
PWOcounters(1-b) Light hypernuclei--12ΛC case
12C (π+,K+) 12

Simulation: K1.1, 10g/cm2, 120 hours

ΛCSKS, ∆E~1.5 MeV(FWHM)

Expected transitions

efgbahijkoncdlmp-> level scheme

Angular corr.
-> spin assign

(1-b) Light hypernuclei
Impurity effectexample of 20ΛNe : change of cluster structureshrinking effectconsidered(cluster model)

Layout Option - K1.8 and K1.1

SKSK1.8
IFMS1MS2

K1.1
T1 TGTMS1MS2SPES-IILayout Option - K1.8+K1.1BR
SKSSPES-II
K1.8

K1.1BRIF

T1 TGTMS1MS2

Beam Line Specificationby H. Noumi
K1.8

K1.1

K1.1BR

Length (m)

46.4

24

26.9

Acceptance (msr.%)

2.7

16.5

4.9

4.1E+07

1.0E+076m-7.5MV/m 2m-7.5MV/m
×2×2

6m-5MV/m
×1

Intensity (ppp)
1.8 GeV/c

1.0E+07

1.1 GeV/c

4.9E+05

Electro-static
Separator
Separation/Size(rms)

10.8

4.2

6.5

Beam Mom.Resol.(%)

0.07-0.05

L10: Study of Dense KbarNuclear SystemsExcitation Energy
(MeV)

500
0 A-1

400

Ξ ⊗ [Z]
A-1
Ξ -⊗ [Z+1]

300

ΛΛ⊗

A-2[Z]

200(K ,K )(K , π ), ( π ,K )(K , π ), (π ,K )(K ,N)_0AK ⊗ [Z]- A
K ⊗ [Z+1]-+-+-+--++-+ A-1
Σ ⊗ [Z-1]
0 A-1
Σ ⊗ [Z]
A-1
Σ -⊗ [Z+1]π- ⊗A [Z+1]A-1Λ⊗100[Z]0A

S =-2 Nuclei

S =-1 Nuclei[Z]

S =0 Nuclei

A[Z+1]

A[Z+2]

Formation of HighDensity State
4 fm

Density [fm-3]
0.00
0.07

0.14

4 fm

4 fm

E(K) = 110 MeV

E(2K) = 213 MeV

Density [fm-3]
0.00
0.75

1.50

Density [fm-3]
0.0
1.5

3.0

ppn

ppnK-

ppnK-K-

total B.E. = 6.0 MeV
central density = 0.14 fm-3
Rrms= 1.59 fm

total B.E. = 118 MeV
central density = 1.50 fm-3
Rrms= 0.72 fm

total B.E. = 221 MeV
central density = 3.01 fm-3
Rrms= 0.69 fm

ρ>ρ0x10 !!

Dote et al.

Physics Impacts
Formation of Cold(T=0) and Dense(ρ>5 ρ0)nuclear matter
Quark-gluon plasma, color
superconductivity

Chiral symmetry restoration
In-medium KN interactions

Kaon condensation
Neutron star, strange star|<qq>ρ,T|

NormalNucleus300 MeVT
Temperature

5ρ0ρ
Density

T. Hatsuda and T. Kunihiro, Phys. Rev. Lett. 55 (1985) 158.
W. Weise, Nucl. Phys. A443 (1993) 59c.

How to produce ?
Single Kaon bound state(K-,π-) reaction: BNL P967 Nagae(K-,N) reaction

Kishimoto E548

(Stopped K-,n) reaction: KEK E471
Iwasaki E549

Double Kaon bound state(K-,K+) reactionL07: Hyperon-Proton Scattering Experiments
M. Ieiri (KEK)
K. Imai (Kyoto U.)
B. Bassalleck (U.ofNM)
P. Tlusty (NPI)

Toward a Modern picture of “Nuclear Force”
Baryon-Baryon Interaction in SU(3)F

meson or quark ?
S=-2
Ξ-p →ΛΛ, Ξ-p→ Ξ-pPolarization observables( ≈ Anti-symmetric spin-orbit)
0.3

PΣ(θ)

Σ+p→Σ+ppΣ = 450 MeV/c

QCM(RGM-H)
QCM(FSS)
OBE(NSC)OBE(Julich B)

0.2

0.1

0-0.1

0306090120

150

180

1.0PΛ(θ)

DΛ(θ)

0.6

0.5

0.4
0.2

0.00-0.2

Λp→Λp-0.4pΛ = 600 MeV/c-1.00306090

θCM (deg)

120150180

Λp→Λp-0.5pΛ = 600 MeV/c
0306090θCM (deg)

120150180

EstimatedYields

Ξ-p→ ΛΛ

A: production 1
Liq. Hydrogen
B: degrader
Tungsten

cm

K-

Λπp
C
B
A

Λ

θ_spectrometer
K+10 cmcm
Liquid Hydrogen K+ spectrometerθ_spectrometer ~ 25° at center K- beam (assumption @ LOI)
Intensity

107 K-/sec

Momentum

1.7 GeV/c

σ_horizontal 15 mm

σ_vertical

Ξ-0.5 cm

C: scattering 2
Liq. Hydrogen

Sizep5 cm wide × 20 cm long

Vertical position [mm]

 Targetπ-1 mm• reaction rate[s-1]• 100 days
• Detectable numberTungsten

10000400

800

1200

PΞ just before decay [MeV/c]

Ξ-p → Ξ-p

Ξ-p → ΛΛ0.009
78000
2300

0.0043
37000
550

L08:
High-resolution Reaction Spectroscopy of S=-1
Hypernuclei
Y. Fujii, T. Fukuda, O. Hashimoto, H. Noumi,
P.K. Saha, and T. Takahashi
L09:
Neutron-Rich Λ Hypernuclei by the Double-Charge
Exchange Reaction
T. Fukuda, H. Noumi, and P.K. SahaSuperfine Structure of Λ hypernuclei
World of ∆E=0.2 MeV
Simulation
E369 Data (89ΛY)

0.6mb/sr

Further
decompositionof the states

L21: Weak decay measurement of light hypernuclei at J-PARC
Shuhei Ajimura, Osaka University
Nonmesonic decay of A=4, 5 hypernuclei
Allowed initial states for A=4, 5 hypernuclei
hypernucleus
4 H
Λ4 He
Λ
5 He
Λ

Λn→nn
1S , 3S01
1S01S , 3S01

Λp → np
1S01S , 3S
01
1S , 3S01

 Gp(4ΛH), Gn(4ΛHe)⇒ we can measure 1S0 amplitudes directly.
 If ∆I=1/2 rule holds, Gn(4ΛHe)/Gp(4ΛH)=2.
⇒ we can check the validity of the ∆I=1/2 rule in B-B weak interaction.

Existing experimental resultsGn(4ΛHe) /GΛ=0.01+0.04/-0.01 (KEK), 0.04±0.02(BNL)NP A639(1998)261c

Gp(4ΛHe) /GΛ= 0.16±0.02(KEK), 0.16±0.02(BNL)NP A639(1998)251c

Detectors
 Decay Counter System∆E – E∆E – TOF- thin plastic countersurrounding target(∆E)- outer plastic stack(E)- tracking by DC- neutrons by TOF
 π0 Spectrometer: ∆E=2 MeVEstimated Yields

4 HeΛ
5×106 K1.25

5 He
Λ
1×107 π+4cross section

4 H
Λ
65×10 K-/3.4 sec
0.125 g/cm2
0.2 mb/sr

0.50.005

spectrometer acceptancespectrometer efficiency

0.10 sr
0.8

0.05
0.5

0.03
0.5×0.5

decay counter acceptance

0.5

0.5

0.5

efficiency for decay p
efficiency for decay n

0.8
0.2

0.8
0.2

0.8
0.2

branching ratio (Ln→nn)
branching ratio (Lp→np)
nn events/200 shifts
np events/200 shifts

0.1
0.01

0.01
0.1

0.2

10000
4000

5500
2200004000expected error level

1.6%

1.5%

4%

beam intensity
target thickness

Summary
Strangeness Nuclear Physics Program
Many interesting subjects are waiting for J-PARC
Two LOIs (L06, L10) as Day-1 Experiments
At least, two K- beam lines, K1.8 and K1.1BR,
should be available at Day-1.
most of the proposed experiments can be donewith these beams.
We will prepare new detectors, SKS’, SPES-II,
Hyperball-3, new CDS, etc.

We are ready for Full proposals.