K - 中間子原子核、最近の状況

K- 中間子原子核、最近の状況1. Introduction

• Expanding the nuclear world• Exotic properties of kaonic nuclei with a phenomenological KbarN potential

2. Variational calculation of K-pp with a chiral SU(3)-based KbarN potential

3. Current status of the K-pp study

4. Experiments related to Kbar nuclear physics

5. Summary and future plan

KEK Theory center J-PARC branch /IPNSAkinobu Doté

Y. Akaishi (Nihon/RIKEN), T. Yamazaki (RIKEN)

T. Hyodo (TITech), W. Weise (TU Munich)

東大駒場セミナー　’ 12.05.23 @ 東京大学駒場キャンパス

Prototype of kaonic nuclei “K-pp”

1. Introduction

Expanding the nuclear world原子核＝陽子・中性子からなる有限量子多体系、　安定核　…　約３００種

Large isospin　　　　不安定核…約 3000 種、 RIBF ＠理研で展開

http://www.rarf.riken.go.jp/newcontents/contents/facility/RIBF.html

Expanding the nuclear world原子核＝陽子・中性子からなる有限量子多体系、　安定核　…　約３００種

Large isospin　　　　不安定核…約 3000 種、 RIBF ＠理研で展開

Strangeness　　　　ハイパー核 … J-PARC (JAEA+KEK) で展開

Kaonic nuclei

Another form of nuclear system with strangeness

K-

Nucleus containing K- meson

What is Kaonic nucleus?

Nucleus

Hypernuclei…u

d sHyperon

baryon = qqq

Strangeness is introduced through baryons.

What is Kaonic nucleus?

Nucleus

Kaonic nuclei !

ubar

sK- meson

Strangeness is introduced through mesons …

meson = qqbar

quark (q) and anti-quark (qbar) pair

Leading actors

Key person

N

K

,0

,0

pn

938940

2 [ ]Mc MeV

1 1,2 2

J I

Baryon uududd

0K 498 10 ,

2J I Meson ds

K 494 us

14061 , 02

J I

Baryon uds

1116 Baryon

:1189, 0 :1193,:1197

:140, 0 :135

1 , 02

J I

1 , 12

J I

0 , 1J I

Baryon : , 0 : , :uu uds ds sd

Meson 1: , 0 : , :2

ud uu dd du

uds

Actors in Kbar nuclei

Supporting players

Excited state of Λ

940 p,n

1115 Λ

1190 Σ

p + K-1435Λ(1405)1405

1250 Λ + π

Σ + π1325E

nerg

y [M

eV]

940 p,n

1115 Λ

1190 Σ

p + K-1435Λ(1405)1405

1250 Λ + π

Σ + π1325E

nerg

y [M

eV]

Mysterious state; Λ(1405)Quark model prediction … calculated as 3-quark state

N. Isgar and G. Karl, Phys. Rev. D18, 4187 (1978)

qq q

Λ(1405) can’t be well reproduced as a 3-quark state!

observed Λ(1405)calculated Λ(1405)

Leading actors

Key person

N

K

,0

,0

pn

938940

2 [ ]Mc MeV

1 1,2 2

J I

Baryon uududd

0K 498 10 ,

2J I Meson ds

K 494 us

14061 , 02

J I

Baryon uds

1116 Baryon

:1189, 0 :1193,:1197

:140, 0 :135

1 , 02

J I

1 , 12

J I

0 , 1J I


Meson 1: , 0 : , :2

ud uu dd du

uds


Supporting players

Excited state of Λ

940 p,n

1115 Λ

1190 Σ

p + K-1435Λ(1405)1405

1250 Λ + π

Σ + π1325E

nerg

y [M

eV]

940 p,n

1115 Λ

1190 Σ

p + K-1435Λ(1405)1405

1250 Λ + π

Σ + π1325E

nerg

y [M

eV]

I=0 Proton-K- bound state with 30MeV binding energy?　 Not 3 quark state?　　←　 can’t be explained with 　　　　　 a simple quark model…

ubar

suu d

qq q

Leading actors

Key person

N

K

,0

,0

pn

938940

2 [ ]Mc MeV

1 1,2 2

J I

Baryon uududd

0K 498 10 ,

2J I Meson ds

K 494 us

14061 , 02

J I

Baryon uds

1116 Baryon

:1189, 0 :1193,:1197

:140, 0 :135

1 , 02

J I

1 , 12

J I

0 , 1J I


Meson 1: , 0 : , :2

ud uu dd du

uds


Supporting players

Excited state of Λ

940 p,n

1115 Λ

1190 Σ

p + K-1435Λ(1405)1405

1250 Λ + π

Σ + π1325E

nerg

y [M

eV]

Σπ channel is open at about 100 MeV below the Proton-K- threshold.

Interests of Kaonic nuclei

KNNN…

ΣπNN…

K nuclear state

Deeply bound below πΣ threshold (main decay channel)

Possible to exist as a quasi-bound state

with narrow width

• Nuclear structure change. Highly dense state. if the interaction is so attractive…

K-Proton

Λ(1405)

=

Kaonic nucleus

• Self-bound Kbar-nuclear systemK-

1. Free KbarN scattering data2. 1s level shift of kaonic hydrogen atom3. Binding energy and width of Λ(1405)

Phenomenological KbarN potential (AY KbarN potential)

Strongly attractive 0

KNIV

• Y. Akaishi and T. Yamazaki, PRC 52, 044005 (2002)

Λ(1405) = I=0 K- p quasi-bound state with 27 MeV binding energy

Studies with a phenomenological KbarN potential

• A. D., H. Horiuchi, Y. Akaishi and T. Yamazaki, PLB 590, 51 (2004); PRC 70, 044313 (2004)

Systematic study of light kaonic nuclei (3HeK- to 11CK-) with

AMD + G-matrix (effective NN potential ) + AY KbarN potential

shows their interesting properties…

3HeK- … 100MeV binding with a narrow width of 20MeV. (a simple model calculation)

Deeply bound kaonic nuclei !

Kaon'sB.E.

Width(π Y )

Averageddensity

[MeV] [MeV] [fm- 3]ppnK - 110.3 21.2 0.53pppK - 96.7 12.5 0.66pppnK - 105.0 25.9 0.436BeK - 104.2 33.3 0.379BK - 118.5 33.0 0.3311CK - 117.4 46.0 0.36

① 　 Deeply bound and Dense

③ 　 Isovector deformation ④ 　 Proton satellite

pppK-

② 　 Drastic change of structure

8Be 8BeK-

Theoretical studies of nuclear system with anti-kaons

• Medium to heavy nuclei with multi-antikaons

• Nuclear matter with antikoansNeutron star, kaon condensation…

- T. Muto, T. Maruyama and T. Tatsumi, PRC79, 035207 (2009)

- D. Gazda, E. Friedman, A. Gal and J. Mares, PRC76, 055204 (2007); PRC77, 045206 (2008)

• Light nuclei with a single antikaon3HeK- ～ 11CK- studied with AMD + G-matrix + AY potential

E(K) 100MeV≒• Light nuclei with double antikaons

3HeK-K- etc studied with AMD + G-matrix + AY potentialE(2K) 200MeV≒

Studied with Relativistic Mean Field

… Antikaon part is based on non-linear chiral Lagrangian

Strongly repulsive KbarKbar interaction

Saturation for the number of antikaonsIn case of 15O+xK-, central nuclear density and –B/x are saturated for x>8.

2. Variational calculation of K-pp with

a chiral SU(3)-based KbarN potential

Are kaonic nuclei really exotic?

•The phenomenological KbarN potential is all right?

πΣ-πΣ potential is completely neglected, although it is somewhat strongly attractive in chiral SU(3) theory.

KbarN πΣ ηΛ KΞ

Chiral SU(3)AY potential

•The phenomenological KbarN potential is all right?

πΣ-πΣ potential is completely neglected, although it is somewhat strongly attractive in chiral SU(3) theory.

•The G-matrix treatment is adequate?

NN repulsive core is too smoothed out? As a result, such a dense state is formed??

Are kaonic nuclei really exotic?

More theoretical study of the most essential kaonic nucleus

K-pp system “Prototype of kaonic nuclei” studied with

a chiral SU(3)-based KbarN potential

Variational calculation of K-pp with a chiral SU(3)-based KbarN potential

Av18 NN potential … a realistic NN potential with strong repulsive core (3GeV).

A. Doté, T. Hyodo and W. Weise,Nucl. Phys. A804, 197 (2008)Phys. Rev. C79, 014003 (2009)

1E

Strong repulsive core(3 GeV)



Effective KbarN potential based on Chiral SU(3) theory… reproduce the original KbarN scattering amplitude obtained with coupled channel chiral dynamics.

Single channel, Energy dependent, Complex, Gaussian-shape potential


Local KbarN potential based on Chiral SU(3)

I=0 KbarN scattering amplitude

Chiral unitary; T. Hyodo, S. I. Nam, D. Jido, and A. Hosaka, Phys. Rev. C68, 018201 (2003)

Chiral Unitary

1420

Resonance position in I=0 KbarN channel

In Chiral unitary model,

1420 MeVnot 1405 MeV !

Effective potential

T. Hyodo and W. Weise, PRC77, 035204(2008)






I=0 KbarN resonance “Λ(1405)”appears at 1420 MeV, not 1405 MeV

Variational method… Trial wave function contains NN/KbarN correlation functions.

The NN repulsive core can directly be treated.

N N

Kbar

1KNF2KNF

1 2N NF 2( ) ( )expij ij

i jij a aa

F C b r r

0 , 1/ 2, 1/ 20, 0

Z

NN

J T TL S





Four variants of chiral unitary modes 2

N K

N K

M m B Ks

M m B K

×

Total B. E. : 20 ± 3 MeVG （ KbarN→Y ） : 40 ～ 70 MeV

Shallow binding and large decay width


I=0 KbarN resonance “Λ(1405)”appears at 1420 MeV, not 1405 MeV

Variational method… Trial wave function contains NN/KbarN correlation functions.

The NN repulsive core can directly be treated.

Structure of K-pp

N N

Kbar

KbarN potential based on “HNJH”“Corrected”, N Ks M m B K

Structure of K-pp

Kbar

2.21 fm

1.97 fm

N N


NN distance in normal nuclei ～ 2 fmSize of deuteron ～ 4 fm

K-pp 中の二核子は普通の原子核の断片！通常核密度に対応していると思える。

Structure of K-pp

Kbar

N N

Mixture of TN=0 component = 3.8 %


NN distance = 2.21 fm KbarN distance = 1.97 fm

1.97 fm

Structure of K-pp

Kbar

N N


I=0 KbarN

1.82 fm

2 0.4l



Structure of K-pp

Kbar

N N


I=0 KbarN I=1 KbarN

1.82 fm 2.33 fm

2 0.4l 2 1.9l



Structure of K-pp

N


I=1 KbarN

2.33 fm

2 1.9l


“Λ(1405)” as I=0 KbarN calculated with this potential

1.86 fm2 0.0l

Kbar

N


I=0 KbarN

1.82 fm2l = 0.4

Almost “Λ(1405)”

Structure of K-ppKbarN potential based on “HNJH”“Corrected”, N Ks M m B K

Density distribution: KbarN pair in K-pp vs “(1405)”

NKbar

“Λ(1405)”

Isospin 0Isospin 0 KbarN pair

Isospin 1 KbarN pair

N

“K-pp ”

Isospin 0 and 1 mixed

N Kbar

“(1405)” almost survives in K-pp!

• Dispersive correction (Effect of imaginary part)

+6 ～ +18 MeV

• p-wave KbarN potential ～ -3 MeV 10 ～ 35 MeV

• Two nucleon absorption 4 ～ 12 MeV

s-wave KbarN potential (Variational calculation)

B .E. Width

20 ± 3 MeV 40 ～ 70 MeV

Rough estimation 20 ～ 40 MeVTotal B .E.

55 ～ 120 MeVTotal Width

K-pp …

Very large…



3. Current status of the K-pp study

Kbar nuclei = Exotic system !?To make the situation more clear …

K-pp= Prototye of Kbar nuclei

Studied with various methods, because it is a three-body system:

•Doté, Hyodo, Weise Variational with a chiral SU(3)-based KbarN potential PRC79, 014003(2009)•Akaishi, Yamazaki ATMS with a phenomenological KbarN potential PRC76, 045201(2007)•Ikeda, Sato Faddeev with a chiral SU(3)-derived KbarN potential PRC76, 035203(2007)•Shevchenko, Gal , Faddeev with a phenomenological KbarN potential PRC76, 044004(2007) Mares•Wycech, Green Variational with a phenomenological KbarN potential (with p-wave) PRC79, 014001(2009)

•Arai, Yasui, Oka Λ* nuclei model PTP119, 103(2008) continued by Uchino, Hyodo, Oka•Nishikawa, Kondo Skyrme model PRC77, 055202(2008)

All calculations predict that K-pp can be bound.

Experiments concerned to this topics: FINUDA (Frascatti), KEK, DISTO (Sacley), OBELIX (CERN)Planned or undergoing experiments: FOPI (GSI), J-PARC, AMADEUS (Frascatti)

There are several experiments:

50 60 70 80 90 100 110 120 130

-140

-120

-100

-80

-60

-40

-20

0

Width (KbarNN→πYN) [MeV]

- B.E

. [M

eV]

Doté, Hyodo, Weise [1](Variational, Chiral SU(3))

Akaishi, Yamazaki [2](Variational, Phenomenological)

Exp. : FNUDA [5]if it is a K-pp bound state.

Exp. : DISTO [6]if it is a K-pp bound state.

Using S-wave KbarN potentialconstrained by experimental data. … KbarN scattering data, Kaonic hydrogen atom data, “Λ(1405)” etc.

Ikeda, Sato [4](Faddeev, Chiral SU(3))

Shevchenko, Gal, Mares [3](Faddeev, Phenomenological)

[1] PRC79, 014003 (2009)[2] PRC76, 045201 (2007)[3] PRC76, 044004 (2007)[4] PRC76, 035203 (2007)

[5] PRL94, 212303 (2005)[6] PRL104, 132502 (2010)

Recent results of calculation of K-pp Recent results of calculation of K-pp and related experiments

50 60 70 80 90 100 110 120 130

-140

-120

-100

-80

-60

-40

-20

0

Width (KbarNN→πYN) [MeV]

- B.E

. [M

eV]

Using S-wave KbarN potentialconstrained by experimental data. … KbarN scattering data, Kaonic hydrogen atom data, “Λ(1405)” etc.

Shevchenko, Gal, Mares [3](Faddeev, Phenomenological)

[1] PRC79, 014003 (2009)[2] PRC76, 045201 (2007)[3] PRC76, 044004 (2007)[4] PRC76, 035203 (2007)

[5] PRL94, 212303 (2005)[6] PRL104, 132502 (2010)

Recent results of calculation of K-pp Recent results of calculation of K-pp and related experiments

Akaishi, Yamazaki [2](Variational, Phenomenological)

Ikeda, Sato [4](Faddeev, Chiral SU(3))

Wycech, Green [7](Variational, phenomenological,

P-wave)

[7] PRC79, 014001 (2009)

Including P-wave KbarN potential, and other effects.

Doté, Hyodo, Weise [1](Variational, Chiral SU(3))

Exp. : FNUDA [5]if it is a K-pp bound state.

Exp. : DISTO [6]if it is a K-pp bound state.

Recent results with various calculations of K-pp

B. E. Γ (mesonic) Method KbarN Int.Channels

at final step

DHW 20 ± 3 40 ～ 70 Variational Chiral SU(3) KbarN

AY 47 61 Variational Phenom. KbarN

IS 60 ～ 95 45 ～ 80 Faddeev Chiral SU(3) KbarN, πY (AGS) (Separable)

SGM 50 ～ 70 90 ～ 110 Faddeev Phenom. KbarN, πY (AGS) (Separable)

Exp.FINUDA 115±7 67±14 K- absorption, Λp inv. mass DISTO 103±3±5 118±8±10 p+p→K++Λ+p, Λp inv. mass (Finalized)

All four calculations shown above are constrained by experimental data. … KbarN scattering data, Kaonic hydrogen atom data, “Λ(1405)” etc. Only s-wave KbarN potential is used.



at final step





DHW vs AY

Difference of the used KbarN interactions.

Comparison of AY potential and Chiral-based potential

AY potential

Weinberg-Tomozawa term derived from Chiral SU(3) effective Lagrangian

KbarN πΣ ηΛ KΞ

Coupled channel Chiral dynamics

• Energy independent potential• No πΣ-πΣ interaction

• Energy dependent potential• Somewhat strongly attractive πΣ-πΣ interaction

Λ(1405) = a quasi-bound state of I=0 KbarN at 1405MeV.

Appears in I=0 KbarN channel.

I=0 KbarN resonance @ 1405MeV.

Two poles (double pole); one couples strongly to KbarN, the other couples strongly to πΣ.

Λ(1405) (experimentally observed) appears in I=0 πΣ-πΣ channel.

I=0 KbarN resonance @ 1420MeV.

I=0 KbarN full scattering amplitude

Almost same in the on-shell region

Quite different in the sub-threhold region

Comparison of AY potential and Chiral-based potential



at final step





DHW vs AYIn Chiral SU(3) theory, the πΣ-πΣ interaction is so attractive to make a resonance, while AY potential doesn’t have it.

“Λ(1405)” is I=0 KbarN bound state at 1420 MeV or 1405 MeV?

AY potential is twice more attractive than Chiral-based one.



at final step





DHW vs IS• Separable approximation?• Different energy dependence of interaction kernel Vij?• πΣN three-body dynamics … may not be included in DHW. (Y. Ikeda and T. Sato, PRC79, 035201(2009))

Although both are based on Chiral SU(3) theory, results are very different from each other.

Variational cal. vs FaddeevA possible reason is

πΣN thee-body dynamics

In the variational calculation (DHW), πΣ channel is eliminated and incorporated into the effective KbarN potential.

Y. Ikeda and T. Sato, PRC79, 035201(2009)

Three-body system calculated with the effective KbarN potential

Σ Σ

K

N+ …

…=

πK

N

πK

N

K

N

N N N NN N

barK NNE

conserved

4. Experiments related to Kbar nuclear

physics

Ｋ原子核に関係する実験

• LEPS / SPring-8

πΣ invariant mass 測定

Ｋ原子 (Kaonic atom)

Λ(1405)

• CLAS / JLab

• Kaonic 4He atom, 2p レベルシフト (3d→2p X 線測定 ) @ KEK (E570) S. Okada et. al., Phys. Lett. B653, 387 (2007)

• Kaonic hydrogen atom, 1s レベルシフト @ DEAR group, DAΦNE, G. Beer et al., Phys. Rev. Lett. 94, 212302 (2005) Frascati National Laboratories

• Kaonic hydrogen, deuterium @ SIDDHARTA group

• Kaonic 3He atom, 2p レベルシフト (3d→2p X 線測定 ) @ J-PARC (E17, DAY-1)

γ + p → K+ + Λ(1405), Λ(1405) → π Σ

K. Moriya and R. Schumacher, Nucl. Phys. A835, 325 (2010)J. K. Ahn, Nucl. Phys. A835, 329 (2010)

π-Σ+, π0Σ0, π+Σ- が全て押さえられた

M. Bazzi et al., Phys. Lett. B704, 113 (2011)

DEAR exp. for kaonic hydrogen atom

シフトの符号は同じだが、ＫＥＫの前回の実験（ＫｐＸ）と重ならない！

Kaonic hydrogen atom, 1s のレベルシフト @ DEAR Collaboration, DAΦNE, Frascati National Laboratories

G. Beer et al., Phys. Rev. Lett. 94, 212302 (2005)

cf) KEK exp. M.Iwasaki et al., Phys. Rev. Lett. 78, 3067 (1997)

B. Borasoy et al., Phys. Rev. Lett. 94, 213401 (2005)

KEK exp.

DEARCoupled channel chiral dynamics (Chiral unitary model) でDEAR の結果を合わすのには苦労する。かろうじてギリギリ合わせられる程度。。。

SHIDDARTA exp. for kaonic hydrogen atom

KEK 実験（ＫｐＸ）とコンシステントな結果

Kaonic hydrogen atom, 1s のレベルシフト @ SHIDDARTA Collaboration, DAΦNE, Frascati National Laboratories


K-p 散乱長が精密に決定

理論計算にとって重要なインプットに強い拘束条件

KbarN subthreshold での散乱振幅の振る舞い、Λ(1405) のポールの位置、が制限される。

Y. Ikeda, T. Hyodo and W. Weise, Phys. Lett. B706, 63 (2011)


• LEPS / SPring-8



Λ(1405)

• CLAS / JLab





γ + p → K+ + Λ(1405), Λ(1405) → π Σ




KEK E570 for kaonic 4He atom

シフトは 0 eV と consisitent

Kaonic 4He atom, 2p のレベルシフト 3d→2p X 線測定 @ KEK, E570

理論の予言がほぼ 0eV に対して、過去の実験ではシフトは平均 -43 eV

“Kaonic helium puzzle”

S. Okada et. al., Phys. Lett. B653, 387 (2007)

パズルは解けた！S. Hirenzaki et al., Phys. Rev. C61, 055205 (2000)

J-PARC for kaonic 3He atomKaonic 3He atom, 2p のレベルシフト 3d→2p X 線測定 @ J-PARC, E17 DAY-1

S. Okada et. al., Phys. Lett. B653, 387 (2007)

Kaonic 4He atom, 2p のレベルシフト … ほぼ 0 eV と確定

赤石氏の計算

KbarN potentialの強度が二つの領域に絞られた。

＋さらに 3Heでシフトが測定されることでKbarN potentialの強度に絞りを掛けることが期待できる。

Y. Akaishi, Proceedings of EXA’05, Austrian Academy of Sciences press, Vienna, 2005, p.45

※ 特定領域研究「ストレンジネスで探るクォーク多体系」研究会 2007 での岡田氏のスライドより引用


• LEPS / SPring-8



Λ(1405)

• CLAS / JLab





γ + p → K+ + Λ(1405), Λ(1405) → π Σ




Λ(1405) - πΣ invariant mass 測定 -

三つの異なる電荷状態が抑えられた

•LEPS / Spring-8K. Moriya and R. Schumacher, Nucl. Phys. A835, 325 (2010)

• CLAS / Jefferson Laboratory

γ + p → K+ + Λ(1405), Λ(1405) → π Σ

ピークの順番が理論(chiral unitary) と違う？

Highest peak実験：　 Σ+ π-

理論：　 Σ- π+

理論

J. K. Ahn, Nucl. Phys. A835, 329 (2010)

p (γ, K+ π) Σ at Eγ = 1.5-2.4GeVCharged πΣ を測定

Experiments for

K-pp search

Ｋ原子核に関係する実験Ｋ原子核 (Kaonic nuclei)

• K- absorption on various targets / Invariant mass Λp @ FINUDA collaboration, DAΦNE, Frascati National Laboratories M. Angello et. al., Phys. Rev. Lett. 94, 212303 (2005)

• Heavy ion collision (?+?) / Invariant mass Λp @ FOPI group, GSI N. Herrmann, Proc. of EXA’05, Austrian Academy of Sciences Press, (2005), p73

• Anti-proton annihilation on 4He / Invariant mass Λp @ OBELIX group, CERN G. Bendiscioli et. al., Nucl. Phys. A789, 222 (2007)

• p+p -> K+ + Λ + p / Invariant mass Λp @ DISTO group, SATURNE, Saclay T. Yamazaki et. al., Phys. Rev. Lett. 104, 132502 (2010)

K-pp search

K-ppn search

Search for heavier kaonic nuclei

• 16O (in-flight K-, n) 15OK- / Missing mass @ AGS, BNL T. Kishimoto et. al., Nucl. Phys. A754, 383 (2005)• 12C (in-flight K-, n or p) / Missing mass @ KEK-E548 T. Kishimoto et. al., Prog. Theor. Phys. Suppl. 168, 573 (2007)

• 4He (Stopped K-, n), 4He (Stopped K-, p) / Mssing mass @ KEK-E471, E549 M. Sato et. al., Phys. Lett. B659, 107 (2008), H. Yim et. al., Phys. Lett. B688, 43 (2010)

• FINUDA collaboration (DAΦNE, Frascatti)

Experiments related to K-pp

• K- absorption at rest on various nuclei (6Li, 7Li, 12C, 27Al, 51V)• Invariant-mass method

Strong correlation between emitted p and Λ (back-to-back)

Invariant mass of p and Λ

K-pp

p

Λ

If it is K-pp, …Total binding energy = 115 MeVDecay width = 67 MeV

PRL 94, 212303 (2005)

6 35 4

14 211 3

• Re-analysis of KEK-PS E549

• DISTO collaboration

- p + p -> K+ + Λ + p @ 2.85GeV- Λp invariant mass- Comparison with simulation data

T. Yamazaki et al. (DISTIO collaboration), PRL104, 132502 (2010)

- K- stopped on 4He target- Λp invariant mass

T. Suzuki et al (KEK-PS E549 collaboration), arXiv:0711.4943v1[nucl-ex]

K- pp???B. E.= 103 ±3 ±5 MeVΓ = 118 ±8 ±10 MeV

Strong Λp back-to-back correlation is confirmed.Unknown strength is there in the same energy region as FINUDA.

Experiments related to K-pp

What is the object observed experimentally?

A bound state of K-pp, or another object such as πΣN ???

Only what we can say from only this spectrum is that“There is some object with B=2, S=-1, charge=+1”…

• DISTO collaboration

J-PARC will give us lots of interesting data!

E15: A search for deeply bound kaonic nuclear states by 3He(inflight K-, n) reaction --- Spokespersons: M. Iwasaki (RIKEN), T. Nagae (Kyoto)

E17: Precision spectroscopy of kaonic 3He atom 3d→2p X-rays --- Spokespersons: R. Hayano (Tokyo), H. Outa (Riken)




Dr. Fujioka’s talk (KEK workshop, 7-9. Aug. 08)

at K1.8BR beam line

1.8GeV/c




Missing mass spectroscopy

Dr. Fujioka’s talk (KEK workshop, 7-9. Aug. 08)

All emitted particles will be measured.　　「完全実験」

at K1.8BR beam line

1.8GeV/c

Invariant mass spectroscopy

Preceding E15, E27 experiment will be performed in June.

E27: d (π+, K+) K-pp at K1.8 beam line Missing mass measured.

d

π+ K+

Λ(1405)n

p ppK-

5. Summary and

Future plan

5. SummaryKaonic nuclei are exotic system !?

Variational calc. of K-pp with a chiral SU(3)-based KbarN pot.

• B. E. =20±3 MeV, Γ(KbarNN → πYN) = 40 – 70MeV• With p-wave KbarN pot., dispersion correction, and two-nucleon absorption, B. E. =20 – 40 MeV, Γ = 55 – 120MeV

• AMD calculation with G-matrix method using a phenomenological KbarN potential (AY potential) shows that kaonic nuclei may have lots of interesting properties:

Deeply bound and narrow widthdense system with interesting structure…

• Kaonic nuclei are another form of nuclear system involving strangeness. They might be exotic system because of the strong attraction of I=0 KbarN potential.

• However, these properties have not been established and there are some questions.

• Two protons distance = 2.0fm ≒NN mean distance of normal nucleus• Λ(1405) structure (correlation) remains in K-pp.

K-pp is a shallowly bound and not so dense system.

5. SummaryCurrent status of studies of K-pp

The most essential Kbar nuclei “K-pp” (KbarNN, Jp=1/2-, T=0) has been investigated in various ways. But the situation is still controversial…

TheoryVariational + Phenom. KbarN B.E. = 47MeV, Γ= 61MeV PRC76, 045201(2007)

Variational + Chiral-based KbarN B.E. = 20±3MeV, Γ= 40 ～ 70MeV PRC79, 014003(2009)Faddeev + Phenom. KbarN B.E. = 50 ～ 70MeV, Γ= ～ 100MeV PRC76, 044004(2007)Faddeev + Chiral-based KbarN B.E. = 60 ～ 95MeV, Γ= 45 ～ 80MeV PRC76, 035203(2007)

Experiment (Unknown object which seems related to K-pp)FINUDA B.E. = 115MeV, Γ= 67MeV PRL94, 212303(2005)DISTO B.E. = 103MeV, Γ= 118MeV PRL104, 132502 (2010)

Discrepancy between theoretical studies of K-pp• DHW (Variational with Chiral-based) vs AY (Variational with phenomenological) … Difference of KbarN attraction Λ(1420) scheme and Λ(1405) scheme

• DHW (Variational with Chiral-based) vs IS (Faddeev with Chiral-based) … πΣN three-body dynamics (might be also different energy dependence of interaction kernel? )

5. Future plan

• The signal position of DISTO experiment … very close to π+Σ+N threshold

• πΣN dynamics as pointed out by Dr. Ikeda and Prof.Sato.

Direct treatment of πΣN degree in K-pp. Deal with a resonant state, based on variational scheme.

Studied with coupled-channel Complex Scaling Method

Go to charm sector!

K- (subar) D0 (cubar) 494 MeV 1870 MeV

Do D-mesic nuclei existsuch as DNN analog to KbarNN???

M. Bayar, C. W. Xiao, T. Hyodo, A. Dote, M. Oka, E. Oset, arXiv:1205.2275 [hep-ph]

Thank you for your attention!

http://www-conf.kek.jp/hadron1/JPARC-hadsalon/

K - 中間子原子核、最近の状況

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