Download - Recent Progress in Hypernuclear Physics
Recent Progress in HyperRecent Progress in Hypernuclear Physicsnuclear Physics
E. Hiyama E. Hiyama (Nara Women’s Univ.)(Nara Women’s Univ.)
Hypernuclear physics has recently become very exciting
owing to new epoch-making experimental data.
The recent progress in hypernuclear physics from a
theorist’s viewpoint of hypenuclear structure.
Nuclear chart with strangenessNuclear chart with strangeness
Λ
Outline 1. Introduction
2. S=-1 hypernuclei and YN interactions
3. S=-2 hypernuclei and YY interactions
4. Future subjects
5. Concluding remarks
Multi-strangeness system such as Neutron star
Λ
1. Introduction
Major goals of hypernuclear physics
Fundamental and important for the studyof nuclear physics
To understand the baryon-baryon interaction, two-body scattering experiment is most useful.
YN and YY potential models so far proposed (ex. Nijmegen, Julich, Kyoto-Niigata) have large ambiguity.
1) To understand baryon-baryon interactions
2) To study the structure of multi-strangeness systems
Total number of
Nucleon (N) -Nucleon (N) data: 4,000
・ NO YY scattering data
・ Total number of differential cross section
Hyperon (Y) -Nucleon (N) data: 40
Therefore, as a substitute for the 2-body limited YN and
non-existent YY scattering data,
the systematic investigation of light hypernuclear structure is
essential .
Strategy to determine YN and YY interactionsfrom the studies of light hypernuclear structure
No direct information
Use Suggest to improve
Compare theoretical results with experimental data
①
②
③
X
Accurate calculation of hypernuclear structure Few-body, cluster model, shell model, …..
YN and YY interactions
based on meson theory: Nijmegen, Ehime, Julich ・・ based on constituent quark model: Kyoto-Niigata, ・・
Spectroscopy experiments ・ High-resolution γ-ray spectroscopy experiment by Tamura and his collaborators ・ Emulsion experiment by Nakazawa and his collaborators
My role
using a
few-body method
・ A variational method using Gaussian basis functions
・ Take all the sets of Jacobi coordinates
High-precision calculations of various 3- and 4-body systems:
Our few-body caluclational method
Gaussian Expansion Method (GEM) , since 1987
Review article : E. Hiyama, M. Kamimura and Y. Kino,Prog. Part. Nucl. Phys. 51 (2003), 223.
Developed by Kyushu Univ. Group, Kamimura and his collaborators.
,
Light hypernuclei,
3-quark systems,
……….
Exotic atoms / molecules ,
3- and 4-nucleon systems,
Multi-cluster structure of light nuclei,
An example of accuracy of the method:
4He
4-nucleon bound stateNN:AV8
Good agreement among the 7 different method in the binding energy, r.m.s. radius and two-body correlation function
p p
n n
Benchmark-test calculation of the 4-nucleon bound state
1. Faddeev-Yakubovski (Kamada et al.)1. Faddeev-Yakubovski (Kamada et al.)2. Gaussian Expansion Method (Kamimura and 2. Gaussian Expansion Method (Kamimura and
Hiyama)Hiyama)3. Stochastic varitional (Varga et al.)3. Stochastic varitional (Varga et al.)4. Hyperspherical variational (Viviani et al.) 4. Hyperspherical variational (Viviani et al.) 5. Green Function Variational Monte Carlo (Carl5. Green Function Variational Monte Carlo (Carl
son at al.)son at al.)6. Non-Core shell model (Navratil et al.)6. Non-Core shell model (Navratil et al.)7. Effective Interaction Hypershperical Harmonic7. Effective Interaction Hypershperical Harmonic
s (Barnea et al.)s (Barnea et al.)
PRC64, 044001(2001)
Advantage New possibilities
A good example:
Our few-body calculational method (GEM)
・ Function space of the few-body
Gaussian basis functions is
so wide that they construct a complete
set in a finite region.
・ In some cases, it is not difficult to impose scattering
boundary condition on the total
few-body wavefunction
using a Kohn-type variational principle.
It becomes possible to study
spatially, highly-excited states
in few-body systems.
It becomes possible to study resonant and non-resonant continuum states of few-bodysystems in these cases.
“ Five-body calculation of resonace and scattering states of pentaquark systems “
q q
q q
s +q q
q+ q
s
N K
Example of application of our method
Scattering problem of the uudds system,in the constituent quark model, was solved for the first time.
NK scattering phase shift including 5-body configurations in the finite region
No resonance in the energy region of the reported pentaquark.
E. Hiyama, M. Kamimura, a. Hosaka, H. Toki and Y. Yahiro, E. Hiyama, M. Kamimura, a. Hosaka, H. Toki and Y. Yahiro,
Phys. Letters B633 (2006) 237.Phys. Letters B633 (2006) 237.
Strategy to determine YN and YY nteractionsfrom the studies of light hypernuclear structure
Use Suggest to improve
Compare theoretical results with experimental data
①
②
③
Accurate calculation of hypernuclear structure Few-body, cluster model, shell model, …..
YN and YY interactions
based on meson theory: Nijmegen, Ehime, Julich ・・ based on constituent quark model: Kyoto-Niigata, ・・
Spectroscopy experiments ・ High-resolution γ-ray spectroscopy experiment by Tamura and his collaborators ・ Emulsion experiment by Nakazawa and his collaborators
2. S=-1 hypernuclei and YN interaction
3. S=-2 hypernuclei and YY interaction
2. S= -1 hypernuclei 2. S= -1 hypernuclei andand
YN interactionYN interaction
ΛN interaction (effectively including ΛN -ΣN coupling)
Almost determined since 1998
----- SLS (Symmetric LS)
----- ALS (Anti symmetric LS)
One of the important issues
9Be 13CΛ
0 < VALS (meson theory) << VALS (constituent quark model)
In the ALS part :
YN LS force and energy-splitting in 9Be and 13CΛ Λ
----- SLS (Symmetric LS)
----- ALS (Antisymmetric LS)
Λ
12C8Be
Λ
Λ
Nijgemen model D, F , soft core ’97a-f Kyoto-NiijataFSS potential
[vanishes in S=0 nuclei, Pauli][breaks charge symmetry]
BNL-E930 BNL-E929
ΔE LS splitting
0+
2+
8Be
Λ
1/2+
5/2+
3/2+
γ
γ
9BeΛ
(0s)
12C 13CΛ
γγ
1/2+
3/2-
1/2-
ΔEΛ
0+
(0p)
αΛ α
α
3- and 4-body calculations:E. Hiyama, M. Kamimura, T. Motoba, T. Yamada and Y. YamamotoPhys. Rev. Lett. 85 (2000) 270.
YN LS force
1) Meson theory : Nijmegen Model D, F, soft core’97 a – f.
2) Qurak model : Kyoto-Niigata, FSS
αΛ
α13CΛ
9BeΛ
5/2+
3/2+ 80
200keV
~
Meson
3/2-
1/2- 360
960keV
~
Meson
5/2+
3/2+35
40keV
Quark
~
150
200keV
Quark
~1/2-
3/2-
EXP
5/2+
3/2+
EXP keV
BNL-E930
H. Akikawa et al.Phys. Rev. Lett. 88 (2002)082501; H. Tamura et al.Nucl. Phys. A754 (2005) 58c
152
1/2-
3/2-
BNL-E929
± 54 ± 36 keVS.Ajimura et al.Phys. Rev. Lett. 86,(2001) 4255
43±5
ΛN LS force and 9Be and 13CΛ Λ
9BeΛ
13CΛ
Nijmegen model D,FSoft core ’97a-f
140 ~ 250 keV
9BeΛ
SLS
5/2+
3/2+
SLS + ALS
80 ~ 200 keV
Meson Theory
5/2+
3/2+
35 ~ 40keV3/2+
5/2+
SLS + ALS
Quark-based
We suggested that there are 2 paths to improve theMeson models : ・ reduce the SLS strength
・ enhance the ALS strength so as to reproduce theobserved LS splittings in 9Be and 13C.
Λ Λ
(Large) (Small)
(Large) - (Large)
LS splitting in 9BeΛ
α
Λ
α
5/2+
3/2+
Exp. keV43±5
Recently, a new YN interaction based on meson theory,
extended soft core potential 06 (ESC06) by Th. A Rijken
5/2+
3/2+
39 keV
ESC06
5/2+
3/2+
EXP keV
BNL-E930
H. Akikawa et al.Phys. Rev. Lett. 88,(2002)82501;H. Tamura et al.Nucl. Phys. A754,58c(2005)
43±5
98 keV
SLSSLS + ALS
(reduced)
(small)
LS splitting in 9Be Λ
9BeΛ
Good agreement
Hiyama (2007)
Strategy to determine YN and YY interactionsfrom the studies of light hypernuclear structure
Use Suggest to improve①
②
③
Accurate calculation of energy splitting (9Be and 13C)
using the YN SLS+ALS potentials
YN SLS+ALS potentials
Spectroscopy experiments High-resolution γ-ray spectroscopy experiment in 9Be and 13C by Tamura and his collaborators by Kishimoto and his collaborators
comparison comparison again:good agreement
⑤
new versionpotential (ESC06)
④
Λ Λ
Meson theory :NijmegenQuark model :Kyoto-Niigata
Λ Λ
Hypernuclear Hypernuclear -ray data since 1998-ray data since 1998
・ Millener (p-shell model), ・ Hiyama (few-body)
3. S=-2 hypernuclei 3. S=-2 hypernuclei andand
YY interactionYY interaction
Λ+ ・・・・
It is conjectured that extreme limit, which includes many Λs in nuclear matter, is the core of a neutron star.
In this meaning, the sector of S=-2 nuclei ,
double Λ hypernuclei and Ξ hypernuclei is just the entrance to the multi-strangeness world.
However, we have hardly any knowledge of the YY interaction
because there exist no YY scattering data.Then, in order to understand the YY interaction, it is crucial to study the structure of double Λ hypernuclei and Ξ hypernuclei.
What is the structure when one or more Λs are added to a nucleus?
nucleus
ΛΛΛ
Λ
+ + +
Uniquely identified without ambiguity for the first time
α+Λ+Λ
7.25 ±0.1 MeV
0+
Recently, the epoch-making data
has been reported by the KEK-E373 experiment.
Observation of 6HeΛΛ
α
ΛΛ
NAGARAevent
useSuggest reducing the strength of
spin-independent force by half
compare between the theoretical resultand the experimental data of the biding energy of 6He
①
②
③
prediction of newdouble Λ hypernuclei
Strategy of how to determine YN and YY interactions from the study of light hypernuclear structure
YY interaction Nijmegen model D
Λ Λ
αAccurate structure calculation
Spectroscopic experiments Emulsion experiment (KEK-E373) by Nakazawa and his collaborators
6HeΛΛ
④ ΛΛ
comparison
My theoretical contributionusing few-body calculation
・ E07 “Systematic Study of double strangness systems at J-PARC” by Nakazawa and his collaborators
Approved proposal at J-PARC
Emulsion experiment Theoretical calculation
input: ΛΛ interaction to reproduce the observed binding energy of 6He
ΛΛ
identification of the state
It is difficult to determine 1) spin-parity
2) whether the observed state is the ground state or an excited state
Successful example to determine spin-parity ofdouble Λ hypernucleus --- Demachi-Yanagi event for 10Be
Demachi-Yanagi event
12.33+0.35
-0.21 MeV
8Be +Λ+Λ
ground state ?excited state ?
Observation of 10Be --- KEK-E373 experiment
ΛΛ
ΛΛ
αα
Λ Λ
10BeΛΛ
10BeΛΛ
4-body calculation of 10Be (Deamchi-Yanagi event)ΛΛ
VΛΛ To reproduce the observed binding energy of 6He
ΛΛα+Λ+Λ
7.25 ±0.1 MeV
E. Hiyama, M. Kamimura, T. Motoba, T.Yamada and Y. YamamotoPhys. Rev. C66, 024007 (2002)
The binding energies of all the subsystems in 10Be are reproduced .
ΛΛ
α
ΛΛ
αα
Λ Λ
αα
Λ Λαα
Λ Λ
In this way, we succeeded ininterpreting the spin-parityby comparing the experimental dataand our theoretical calculation.
Successful interplitation of spin-parity of
E. Hiyama, M. Kamimura,T.Motoba, T. Yamada and Y. YamamotoPhys. Rev. 66 (2002) , 024007
Demachi-Yanagi event
αα
Λ Λ
4-body model of p-shell double Λ hypernuclei
α
xΛ
Λ
x = n p d t 3He
= = = = =7He 7Li 8Li
ΛΛ ΛΛ ΛΛ8Li 9Be
ΛΛ ΛΛ
Therefore, the 4-body calculation has predictive power.
Hoping to observe new double Λ hypernuclei in future experiments,
I have predicted level structures of these double Λ hypernuclei
within the framework of the α+ x + Λ+Λ 4-body model.
E. Hiyama, M. Kamimura, T. Motoba, T.Yamada and Y. YamamotoPhys. Rev. C66, 024007 (2002)
Spectroscopy of ΛΛ-hypernuclei E. Hiyama, M. Kamimura,T.Motoba, T. Yamada and Y. YamamotoPhys. Rev. 66 (2002) , 024007
By comparing this theoretical prediction and future experimental data, we can interpret the spectroscopy of those double Λ hypernuclei.
4. Future subjects4. Future subjects
In S=-1 sector, what are the open questions in YN interaction?
(1) Charge symmetry breaking
(2) ΛN - ΣN coupling
(1) E13 at J-PARC “γ-ray spectroscopy of light hypernuclei”
by Tamura and his collaborators
Day-1 experiment 11B 4HeΛ Λ
(2) E10 at J-PARC “Study on Λ-hypernuclei with the double Charge-Exchange reaction”
by Sakaguchi , Fukuda and his collaboratiors
Parallel session ( E3-1 )6th June, 14:30 ~Room:G510
9HeΛ
6HΛ
In S=-2 sector, the most important subjects still to be studied
(1) ΛΛ - ΞN coupling
(2) ΞN -ΞN interaction
I shall introduce above two subjects.
One of the major goals in hypernuclear physics :
To study structure of multi-strangeness systems
(extreme limit : neutron star)
NN
N N
Λ ΛΛΛΛ
N
N
N Multi-strangeness systems
25MeVΛΛ
ΞN
Threshold energy difference is very small ! It is considered that
ΛΛ→ΞN particle conversion is strong in multi-strangeness systems.
(1) ΛΛ - ΞN coupling
S1/2
P3/2
n n p p Λ Λ Ξ-
PauliForbidden
・ 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).
p
6HeΛΛ
V ΛΛ--ΞN
(3 protons in S1/2)
Effect of ΛΛ - ΞN coupling is small in 6He which was observed as NAGARA event.
ΛΛ
4H 5H ( 5He)ΛΛ
・ I.N. Filikhin and A. Gal, Phys. Rev. Lett. 89, 172502 (2002)
・ Khin Swe Myint, S. Shinmura and Y. Akaishi, Eur. Phys. J. A16, 21 (2003).
・ D. E. Lanscoy and Y. Yamamoto, Phys. Rev. C69, 014303 (2004).
・ H. Nemura, S. Shinmura, Y. Akaishi and Khin Swe Myint, Phys. Rev. Lett. 94, 202502 (2005).
Λ Λ
nn
ΛΛ
Λ Λ
pnΛΛ
For the study of ΛΛ - ΞN coupling interaction,
s-shell double Λ hypernuclei such as
4H and 5H ( 5He) are very suitable.ΛΛ ΛΛ ΛΛ
p
S1/2
P3/2
5HΛΛ
n n p Λ Λ Ξ- p
5HΛΛ
V ΛΛ - ΞN
(2 protons in S1/2)
Due to NO Pauli plocking, the ΛΛ - ΞN coupling can be large in 5H
ΛΛ
B.F. Gibson, I.R. Afnan, J.A.Carlson and D.R.Lehman,Prog. Theor. Phys. Suppl. 117, 339 (1994).
Λ Λ
nn
p
The detailed studies will be reported by
・ D. Lanskoy ( E3-7 )
・ Y. Yamamoto ( E4-2 )
・ H. Nemura ( E4-5 )
6th June, afternoon, 14:30 ~ 18:30 “Hyperon Interactions and Hypernuclear Physics” Room: G510
In this way, the study of structure of s-shell double Λ hypernuclei is important for the study of ΛΛ ー ΞN coupling.
For the study of ΞN interaction, it is important to study
the structure of Ξ hypernuclei.
However, so far there was no observed Ξ hypernuclei.
Then, it is important to predict theoretically what kinds of
Ξ hypernuclei will exist as bound states.
nucleus
Ξ Ξ hypernucleus
In S=-2 fields, the most important subjects to be still studied
(2) ΞN -ΞN interaction
For this purpose, recently, I studied these Ξ hypernuclei.
(d+Ξ-)
α
ΞN interaction to reproduce the experimental data of 12C(K-,K+) reaction ・ T. Fukuda et al. Phys. Rev. C58, 1306, (1998); ・ P.Khaustov et al. Phys. Rev. C61, 054603 (2000).
(ESC04)
Ξ-
Ξ- Ξ-n
Ξ- αpn np
(t +Ξ-)-(
p
n n
( 5 Li+Ξ-)
(6He+Ξ-)
Ξ-
α α
Ξ- t
α α
n
(9Be+Ξ-) (11B+Ξ-)
-
Spectroscopy of Ξ hypernuclei at J-PARC
(pn+Ξ ) (pnn+Ξ )
-2 d+Ξ
t +Ξ
1/2 +
0+
1+
αn+Ξ
2-
1-(α+Ξ)+nn
1/2+
(8Be+Ξ)+n
2-
11B+Ξ
1-
1-
2-
(5He+Ξ) (6He+Ξ) ( 9 B e+Ξ) (11B+Ξ)
Ξ- t
α αΞ- n
α ααΞ-
n nn
Ξ-α
Ξ-n n
pp
Ξ-n
-5
0
-10
MeV
-20
11B
pK-
Ξ-
11B
12C Ξ hypernucleus
・ E05 “Spectroscopic study of Ξ-Hypernucleus, 12Be, via the 12C(K-,K+)
Reaction” by Nagae and his collaboratorsDay-1 experiment
First observation of Ξ hypernucleus
K+
Approved proposal at J-PARC
This observation will give information about ΞN interaction.
Spectroscopy of Ξ hypernuclei at J-PARC
(pn +Ξ) (pnn+Ξ)
-2 d+Ξ
t +Ξ
1/2 +
0+
1+
αn+Ξ
2-
1-(α+Ξ)+nn
1/2+
(8Be+Ξ) +n
2-
11B+ Ξ
1-
1-
2-
(5He+Ξ) (6He+Ξ) ( 9 Be+Ξ) (11B+Ξ )
Ξ- t
α αΞ- n
α ααΞ-
n nn
Ξ-α
Ξ-n n
pp
Ξ-n
-5
0
-10
MeV
-20
Multi-strangeness systemsuch as Neutron star
J-PARC
Concluding remark
GSIJLABDAΨN EJ-PARC
At the end of next year (2008), the first beam in the main ring will appear at J-PARC.
And, it is planned to perform the first experiment onhypernuclei in early 2009.
So, it is expected that all hypernuclear experimentalists may be very busy.
If man-power for such experiments is not enough,
I am ready to join those experiments.
In 2002, KEK-E509,
I had 7 shifts for this experiment.
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I shall be happy if I could join the future experiments
at J-PARC facility with this new film badge.
New film badge
01 / 2009
Thank you!