Three- and four-body structure of S=-2 hypernuclei E. Hiyama (Nara Women’s Univ.)

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Three- and four-body s tructure of S=-2 hyper nuclei E. Hiyama (Nara Women’s Univ.)

Transcript of Three- and four-body structure of S=-2 hypernuclei E. Hiyama (Nara Women’s Univ.)

Three- and four-body structure of S=-2 hypernuclei

E. Hiyama (Nara Women’s Univ.)

nuclei +

Hyperon(Λ 、 Σ 、・・ )

=>

Hypernuclei

To study 3- and 4-body structure of light hypernuclei consisting of nucleus and hyperon

At Japan Proton Accelerator Research Complex

(J-PARC), they are planning to produce

(1) Many double Λ hypernuclei

(2)Many Ξ hypernuclei

Here, I shall discuss these subjects.

I also discuss what is interesting and important to study

double Λ hypernuclei and Ξ hypernuclei.

nuclei

Λ Λ

nuclei

Ξ

The purpose of my talk

(1)To predict level structure of many double Λ

hypernuclei

α

Λ Λ

N

α

Λ Λp

α

Λ Λ

d α

Λ Λ

tα

Λ Λ

3 He α α

Λ Λ

7 He 7 Li 8 Li 9 Li 9 Be 10 BeΛΛ ΛΛ ΛΛ ΛΛ ΛΛ ΛΛ

N

N Ξ

N(2)To predict level structure Ξ hypernucleus

Why is it important to produce many double Λ and Ξ

hypernuclei?

Answer

Since there are NO hyperon(Y)-hyperon(Y) scattering

data, YY interaction so far proposed have a large

degree of ambiguity.

In order to understand YY interaction, we need YY

scattering data.

However, even at J-PARC facility, it is very difficult to

perform YY scattering experiment.

Therefore, it is very important to obtain information about

YY interaction from the spectroscopy experiments of

many double Λ and Ξ hypernuclei.

My contribution

To understand the hypernuclear structure by

performing our three- and four-body calculations and

to use this structure information to understand the YN

and YY interactions

The purpose of my talk

(1)To predict level structure of many double Λ

hypernuclei

α

Λ Λ

N

α

Λ Λp

α

Λ Λ

d α

Λ Λ

tα

Λ Λ

3 He α α

Λ Λ

7 He 7 Li 8 Li 9 Li 9 Be 10 BeΛΛ ΛΛ ΛΛ ΛΛ ΛΛ ΛΛ

N

N Ξ

N(2)To predict level structure of Ξ hypernucleus

Up to now, there was NO experimental data about

double Λhypernuclei with NO ambiguity.

Two epoch-making data have been reported by the

KEK-E373 experiment.

(1) Observation of   6He

Uniquely identified without ambiguity forthe first time

ΛΛ

α+Λ+Λ

7.25 ±0.1 MeV

0+

α

Λ Λ

NAGARA Event

(2) Observation of 10BeΛΛ

12.33 +0.35-0.21

MeV

8Be+Λ+Λ

α α

Λ Λ

Deamchi-Yanagi event

ground state ?excited state?

Two important issues:

(1) Does the ΛΛ interaction which is designed to

reproduce the binding energy of 6He

reproduce the Demachi-Yanagi event for

10Be consistently?

(2) When we use the same ΛΛ interaction, how

is theoretical prediction of level structure of

other double Λ hypernuclei?

ΛΛ

ΛΛ

Two important issues:

(1) Does the ΛΛ interaction which is designed to

reproduce the binding energy of 6He

reproduce the Demachi-Yanagi event for

10Be consistently?

(2) When we use the same ΛΛ interaction, how

is theoretical prediction of level structure of

other double Λ hypernuclei?

α α

Λ Λ10Be

ΛΛ

ΛΛ

ΛΛ

←KEK-E373 Demachi- Yanagi event

Our 4-body calculation is predictive.

Therefore, hoping to observe many doubleΛhypernuclei

in the future experiment at J-PARC, I predict level

structure of double Λ hypernuclei.

α

x

Λ Λ

x = N p d t3He

= = = = =

7He 7Li 8LiΛΛ ΛΛ ΛΛ

8Li 9BeΛΛ ΛΛ

3N

Λ Λ

5H, 5HeΛΛ ΛΛ

n p

Λ Λ

4HΛΛ

Two important issues:

(1) Does the ΛΛ interaction which is designed to

reproduce the binding energy of 6He

reproduce the Demachi-Yanagi event for

10Be consistently?

(2) When we use the same ΛΛ interaction, how is theoretical prediction of level structure of other double Λ hypernuclei?

ΛΛ

ΛΛ

     Spectroscopy of ΛΛ-hypernuclei

prediction

-3.38

5He4HΛΛΛΛ

In the s-shell hypernuclei, new component of interaction

should be taken into account.

A missing component is ΛΛ ー ΞN coupling.

A missing component is ΛΛ ー ΞN component.

nuclei

Λ Λ

V ΛΛ ー ΞN

=>

nuclei

Ξ N

convertinto

Double Λ hypernuclei

Non-strangeness nuclei

N Δ

N N

N

Δ

250MeV

Probability of Δ   in nuclei is not large.

25MeVΛΛ

ΞN

There is significant probabilityof Ξ in double Λ hypernuclei.

In hypernuclear physis, it is fashionable subject

to investigate ΛΛ ー ΞN coupling mechanism in

double Λ hypernuclei.

4H is very suitable hypernucleus to get information on ΛΛ-ΞN coupling interaction.Up to now, there is NO experimental data about 4H.

ΛΛ

ΛΛ

n p

Λ Λ

4HΛΛ

The important issue: Does the YY interaction which designed to reproduce the binding energy of 6He make 4H bound?And how does the effect of ΛΛ ー ΞN coupling play important role in the binding energy of 6He and 4H?

ΛΛ ΛΛ

ΛΛ ΛΛ

1)I.N. Filikhin and A. Gal, Phys. Rev. Lett. 89, 172502(2002)2)H. Nemura, Y. Akaishi et al., Phys. Rev. C67, 051001(2002)

n

p

Λ

Λ

VΛΛ

α

Λ Λ

NOT BOUND !

4HΛΛ

6HeΛΛ

NAGARA event

α+Λ+Λ

7.25±0.1 MeV

0+

Did not include ΛΛ-ΞN coupling

ΛΛ-ΞN   coupling => ・ significant in 4HΛΛ

n p

Λ Λ

4HΛΛ

・ Not so important in   6HeΛΛ

α

Λ Λ 6HeΛΛ

S1/2

P3/2

6HeΛΛ

n n p p Λ Λ Ξ 0n

Forbidden

The effect of ΛΛ-ΞN coupling is small in   6He and thep-shell double Λ   hypernuclei  ・ I.R. Afnan and B.F. Gibson, Phys. Rev. C67, 017001 (2003). ・ Khin Swe Myint, S. Shinmura and Y. Akaishi, nucl-th/029090. ・ T. Yamada and C. Nakamoto, Phys. Rev.C62, 034319 (2000).

ΛΛ

V ΛΛ ー ΞN

S1/2n p Λ Λ Ξ 0

n

4HΛΛ

P3/2

allowed

(Ξ- p)

There is NO Pauli blocking and the ΛΛ ー ΞN effectcan be large.

n p

Λ Λ

N

N

N

Ξ

+

4HΛΛ

One of the most numerically difficult 4-body problem

E. HiyamaDr. Nemuran n

Λ Σ

n n

Σ Σ

E(MeV)

0

-3.12

-7.25 0+

Exp.(KEK-E373)

CAL.

5He+ΛΛ

α+Λ+Λ6He

ΛΛwith Pauli blocking

E(MeV)

n+p+Λ+Λ

3H+ΛΛ

NoExp.

unbound

NNΛΛchannel only NNΛΛ

+   NNNΞ

PΞ=1.6%

0.1MeV

PΞ=3.2%

4H with no Pauli blockingΛΛ

α

0MeV

It is possible that ΛΛ ー ΞN coupling potential makes

the lightest double Λ hypernucleus, 4H bound.

If the bound state of 4H is observed at J-PARC,

we can obtain useful information on ΛΛ ー ΞN coupling

mechanism.

ΛΛ

ΛΛ

Outline of my talk

(2) To predict level structure of Ξ hypernucleus

N

N Ξ

N

NNNΞ

n+p+Λ+Λ

3H+ΛΛ

0.1MeV

0

28MeV

NNNΞ ??

4HΛΛ

E(MeV)

  So far, there was NO experimental data about Ξ

hypernuclei.

To produce Ξ hypernuclei is one of main experimental

project at J-PARC.

Therefore, it is requested to predict what kind of Ξ

hypernuclei exist as bound states theoretically.

And also it is requested to suggest what part of ΞN

interaction we can determine from structure of Ξ

hypernuclei.

N

N Ξ

N

NNNΞ

The strategy of this study

(1)I should perform 4-body calculation using realistic force directly.

(2) Although we cannot predict the level structure of NNNΞ hypernucleus due to the large degree of ambiguity of ΞN interaction, we can investigate what part of ΞN interaction contribute to the binding energy of this hypernucleus.

(3)If this hypernucleus will be observed in the future at J-PARC, we can suggest how to improve the realistic force directly form the structure study side.

YY interaction:

Extended soft core potential 04 (ESC04)

proposed by Nijmegen group

Nijmegen soft core ’97 e and f (NSC97e and f)

Results ESC04

(3N)+Ξ0 MeV

0+

1+

-2.3

-0.86N N

N Ξ

1+: [12V(1,1)+V(1,0)+10V(0,1)+3V(0,0)]/260+:[V(1,0)+V(0,1)]/2

T,S

= =

repulsive strongly attractive

repulsive

weakly repulsive strongly attractive

   Results

3N+Ξ 3N+Ξ

unbound unbound

NSC97e NSC97f

N N

N Ξ

NNNΞ

If the NNNΞ state is observed as a bound state in thefuture, we can extract information on ΞN interaction.Therefore, I hope to perform search-experiment of thishypernucleus.

     Spectroscopy of ΛΛ-hypernuclei

prediction

28MeV

6He 7He 7Li 8Li 9Li 9Be 10BeΞ Ξ Ξ Ξ Ξ Ξ

Ξ

α +x+N+Ξ

? ? ??

? ??

Spectroscopy of Ξ hypernuclei at J-PARC

α

Ξ

xN =n,p,d,t,3He,α

My future study plan

The study of structure of p-shell hypernuclei

based on α+x+Ξ+N 4-body model.

          

                 n,p,d,t,3

He,αα

Ξ

N

Conclusion

(1)To predict level structure of many double Λ

hypernuclei

α

Λ Λ

N

α

Λ Λp

α

Λ Λ

d α

Λ Λ

tα

Λ Λ

3 He α α

Λ Λ

7 He 7 Li 8 Li 9 Li 9 Be 10 BeΛΛ ΛΛ ΛΛ ΛΛ ΛΛ ΛΛ

N

N Ξ

N(2)To predict Ξ hypernucleus

6HeΛΛ

10BeΛΛ

S=-2

S=0 N

N

I hope that J-PARC project will produce many doubleΛ hypernuclei.

S=-1

Schematic illustration of the nuclear chart

In this way, I hope that J-PARC project give an importantcontribution to extending the strangeness nuclear chart.

They will observe Ξ hypernuclei for the first time at J-PARC.