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