Anomalous two-neutron transfer in neutron-rich Ni and Sn isotopes studied with continuum QRPA H.Shimoyama, M.Matsuo Niigata University 1 Dynamics and Correlations in Exotic Nuclei (DCEN2011) Yukawa Institute for Theoretical Physics One-day workshop IV Oct. 24
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Anomalous two-neutron transfer in neutron-rich Ni and Sn isotopes studied with continuum QRPA H.Shimoyama, M.Matsuo Niigata University 1 Dynamics and Correlations.
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Anomalous two-neutron transfer in neutron-rich Ni and Sn isotopes
studied with continuum QRPA
H.Shimoyama, M.MatsuoNiigata University
1
Dynamics and Correlations in Exotic Nuclei (DCEN2011)Yukawa Institute for Theoretical Physics
One-day workshop IV Oct. 24
Outline Outline
Anomalous pairing vibration state in neutron-rich 132-140Sn
・ Introduction
・ Framework
・ Results
Skyrme Hartree-Fock-Bogoliubov mean-field + continuum Quasiparticle Random Phase Approximation
Giant pairing vibration in stable Sn isotopes
Pairing vibration in Ni isotopes
・ Conclusion
(Monopole pair transfer in Sn and Ni isotopes )
Pairing vibration in Sn isotopes
2
relation to the anomalous pairing vibration state beyond N=82
weak-binding feature
Outline Outline
Anomalous pairing vibration state in neutron-rich 132-140Sn
・ Introduction
・ Framework
・ Results
Skyrme Hartree-Fock-Bogoliubov mean-field + continuum Quasiparticle Random Phase Approximation
Giant pairing vibration in stable Sn isotopes
Pairing vibration in Ni isotopes
・ Conclusion
(Monopole pair transfer in Sn and Ni isotopes )
Pairing vibration in Sn isotopes
3
relation to the anomalous pairing vibration state beyond N=82
weak-binding feature
2n-addition2n-removal
A → A+2
2-neutron transfer2-neutron transfer
11Li + p → 9Li + tExample )
03+
02+
A A + 2A - 2
energy
+ 2n- 2n
0gs+
0+gs
03+
02+
0gs+
A → A-2
( t , p )( p , t )
4
D. R. Bes , et. al, NP(1966) R. A. Broglia , at. Al, NP(1973)
Pairing vibration
Re⊿
Im⊿
superfluid phase open-shell nuclei
E
Pairing rotation
02+
02+ 02
+
0gs+
0gs+ 0gs
+
Pairing vibration Pairing vibration
A + 2A - 2A
Pairing rotation Pairing rotation
weak weak
strong strong
Collective two-neutron transfers in surperfulid nucleiCollective two-neutron transfers in surperfulid nuclei
This is a standard picture of the two-neutron transfer modes.
Two-neutron transfer in neutron-rich nucleiTwo-neutron transfer in neutron-rich nuclei
~ for unstable nuclei ~
I. Tanihata et al. PRL 100, (2008)11L + p → 9L +tExperiments
The neutron-rich nuclei often accompany low density distributions of neutrons surrounding the nucleus.
The pairing in low-density neutron matter is predicted to be stronger.
ρ/ρ0
If the neutron pairing becomes strong around the surface, we can expect a large probability for a neutron pair to be added or removed from a nucleusby a transfer process.
10010-110-210-310-4
30Mg + t → 32Mg + p K. Wimmer et al. PRL 105,(2010)6
The transition densities to the pair vibrational mode of 132-140Sn have a long tail.
By adding two-neutrons in the weakly bound p orbits, we can have a long tail.
Very long tail r ~ 15 fm
The weakly bound p orbits play an important role !!
2N-add
f7/2
p3/2
p1/2
h11/2
Hartree-Fock single-particle energy in 134Sn
N= 82
[MeV]
12
0
5
10
15
20
25
100 110 120 130 140 150 0
5
10
15
20
25
100 110 120 130 140 150
Strength of ground state transfer
Pair
add
ition
str
engt
hRelation to the ground state transferRelation to the ground state transfer
A
p orbits occupied in excited states p orbits occupied
in ground states
Sn isotopes
0gs0gs
02 022n-add
A A+2gs-gs
13
drrrrdrrYB gsgs2
00 )(~40)()(0)0P(
0
-5
-0.84-0.23
(0.01)
-7.68
es.p. 2N-add
N=82
f7/2
p3/2
p1/2
h11/2
[MeV]
-2.62
Hartree-Fock single-particle energyin 142Sn
The anomalous pairing vibration in 132-140Sn appears as a precursor of large enhancement of the ground state transfer beyond A=140.
Outline Outline ・ Introduction
・ Framework
・ Results
Skyrme Hartree-Fock-Bogoliubov mean-field + continuum Quasiparticle Random Phase Approximation
Giant pairing vibration in stable Sn isotopes
Pairing vibration in Ni isotopes
・ Conclusion
(Monopole pair transfer in Sn and Ni isotopes )
14
relation to the anomalous pairing vibration state beyond N=82
Pairing vibration in Sn isotopes
2 4 6 8 10 12 14 16 18
2 4 6 8 10 12 14 16 18
2 4 6 8 10 12 14 16 18
2 4 6 8 10 12 14 16 18
2 4 6 8 10 12 14 16 18
Low-lyingPairing Vibration
Giant Pairing Vivration
Pair addition strength function
2nd-GPV
1st-GPV
Giant Pairing Vibration (GPV) in stable Sn isotopesGiant Pairing Vibration (GPV) in stable Sn isotopes
E [MeV]
2nd-GPV
Gs-gs transferPairing Vibration
Hartree-Fock single-particle energyin 122Sn
0
-5
-0.84-0.23
(0.01)
-7.68
es.p. 2N-add
N=82
f7/2
h11/2
[MeV]
-2.62
p3/2
p1/2
15
0 2 4 6 8 10 12 14 16 18
0 2 4 6 8 10 12 14 16 18
E [MeV]
E [MeV]
Pair addition strength function
2nd- GPV
Anomalous pairing vibration
0 2 4 6 8 10 12 14 16 18
0 2 4 6 8 10 12 14 16 18
E [MeV]
E [MeV]
Giant Pairing Vibration (GPV) in stable Sn isotopesGiant Pairing Vibration (GPV) in stable Sn isotopesPair addition transition density
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16
r2 P(a
d)00
(r)
[
fm-1
]
2nd- GPV in 122-130Sn
Anomalous pairing vibration in 132-140Sn
The transition densities of 2nd-GPV have a long tail.
However the collectivity of the anomalous pairing vibration is much stronger.
122Sn
Same character of the anomalous pairing vibration.
r [fm]
Pair addition strength function
2nd- GPV
Anomalous pairing vibration
16
Outline Outline ・ Introduction
・ Framework
・ Results
Skyrme Hartree-Fock-Bogoliubov mean-field + continuum Quasiparticle Random Phase Approximation
Giant pairing vibration in stable Sn isotopes
Pairing vibration in Ni isotopes
・ Conclusion
(Monopole pair transfer in Sn and Ni isotopes )
17
Pairing vibration in Sn isotopes
weak-binding feature
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 10 0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 10
)()(2
000 ii
iadd EEPES †Pair addition strength function
Pairing vibration in neutron-rich Ni isotopesPairing vibration in neutron-rich Ni isotopes
E [MeV]
The pairing vibration appears both isotopes, but the strength in 80Ni is not large.
E [MeV]
Pair
add
ition
str
engt
h
Pair
add
ition
str
engt
h
18
0
0.2
0.4
0.6
0.8
1
55 60 65 70 75 80 85
Pairing vibration in neutron-rich Ni isotopesPairing vibration in neutron-rich Ni isotopes
Strength of pair addition transfer to pairing vibration and ground state transfer
gsgsPB ad ;0
PVgsPB ad ;0ratio
10-20 %
A A
Ni isotopes
Pair
add
ition
str
engt
h
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 10
pair addition strength function
Pair
- add
str
engt
h
E (MeV)
GPV
The pairing vibrational states which are as large as ground state transfer are not appeared in neutron-rich region.
19
0
1
2
3
4
5
6
55 60 65 70 75 80 85 0
1
2
3
4
5
6
55 60 65 70 75 80 85
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
Pairing vibration in neutron-rich Ni isotopesPairing vibration in neutron-rich Ni isotopes
0
-5
-1.36
-0.28
es.p.
g9/2
d5/2
s1/2
N=50
[MeV]
(0.27) d3/2
-5.60
The transition densities of neutron-rich 78-84Ni have a long tail ( r ~ 15fm )because the relevant weakly bound orbit is an s orbit.
The collectivity is small.
2n-add
Hartree-Fock single-particle energyin 80Ni
78-84Ni
58-66Ni
Pair addition transition density
f [fm]
20
80NiPair
add
ition
str
engt
h
132Sn 134Sn 136Sn 138Sn 140Sn100-130Sn
0gs
0gs 0gs 0gs 0gs 0gs0gs
02 02 02 02 02
02
142-150Sn
strong strong strong strong very strong
strong
strong
strong
strongweak
strong
weakweak
strong
The neutron-rich 132-140Sn have the anomalous pair vibrational state.
~ as same value as the ground state transfer ~・ the pair addition strength is very large,
・ the transition density has a long tail extending to the outside, ~ weakly bound p orbits play an important role ~
ConclusionConclusion
The ground state transfers is significantly enhanced beyond A=140,due to the weakly bound p orbits occupied in ground state. The anomalous pairing vibration is a precursor of this strong transfer.
We found the pairing vibration beyond 78Ni. They have a weak-bound feature because the relevant weakly bound orbit is an s orbit. However the collectivity is smaller.
It is also related to the giant pairing vibration in stable Sn isotopes.
21
( t , p ) ( t , p ) ( t , p ) ( t , p ) ( t , p )
22
23
)(],[),( rrVrrV pnnpair
DDDI mix
DDDI volume
DDDI bare’
Density Dependent Delta type Interaction
10 )16.0(5.01],[ pnpnnV
59.00 )8.0(71.01][ nnnV
0],[ pnnVNo dependent on the density >
Density Dependent delta Interaction parameter Density Dependent delta Interaction parameter
Acts by a low density strong >
0
1
2
3
4
5
100 110 120 130 140 150 0
0.2
0.4
0.6
0.8
1
100 110 120 130 140 150 0
0.2
0.4
0.6
0.8
1
100 110 120 130 140 150 0
0.2
0.4
0.6
0.8
1
100 110 120 130 140 150
24
0
0.3
0.6
0.9
1.2
0 2 4 6 8 10 12 14 16
0
0.3
0.6
0.9
1.2
0 2 4 6 8 10 12 14 16
0gs+―0gs
+
r2 P(a
d)gs
(r)
[
fm-1
]
0
-5
-0.84-0.23
(0.01)
-7.68
es.p. 2n-add
N=82
f7/2
p3/2
p1/2
h11/2
[MeV]
-2.62
Hartree-Fock single-particle energyin 142Sn
r [fm]
120-130Sn132-140Sn
142-150Sn
Relation to the ground state transferRelation to the ground state transfer
Strength of ground state transfer
)(~0)()(0 rrr HFBHFB
NrrN gsgs ,0)()(2,0
The anomalous pairing vibration in 132-140Sn appears as a precursor of large enhancement of the ground state transfer beyond A=140.
0
-5
-2.14
-0.36(0.27)(0.66)
es.p.2n-add
f7/2
p3/2p1/2
N= 82
[MeV]
0
-5
-1.58
-0.43
es.p.2n-add
g9/2
d5/2s1/2
N=50
[MeV]
0
-5-5.73
-3.56
-1.60
es.p.2n-add
p3/2
p1/2
f5/2
[MeV]
(0.43) d3/2
-6.02N=2
8
Not weakly bound
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
r2P(ad) gs(r)
[fm
-1]
48-54Ca
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
42-46Ca-GPV134-140Sn 80-84Ni
58-64Ni120-130Sn
[ fm ] [ fm ] [ fm ]
Weak-bound featurWeak-bound featur
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 2 4 6 8 10 12 14 16
0 2 4 6 8 10 12 14 16 18
0 2 4 6 8 10 12 14 16 18
E [MeV]
E [MeV]
Giant Pairing Vibration (GPV) in stable Sn isotopesGiant Pairing Vibration (GPV) in stable Sn isotopesPair addition transition density
r2 P(a
d)00
(r)
[
fm-1
]
1st- GPV in 122-130Sn
ground state transfer in 132-140Sn
122Sn
Same character of the ground state transfer of neutron-rich Sn isotopes.
r [fm]
Pair addition strength function
1st- GPV
ground state transfer
26
27
Giant Pairing Vibration (GPV) in stable Sn isotopesGiant Pairing Vibration (GPV) in stable Sn isotopes
0
-5
es.p. 2n-add
f7/2
p3/2
p1/2
h11/2
Pairing Vibration0
-5
es.p. 2n-add
f7/2
p3/2
p1/2
2nd-GPV
1st-GPV
h11/2
g.s. transfer
g.s. transfer
Pairing Vibration
Neutron-rich 132-140SnStable area 120-130Sn
Hartree-Fock single-particle energy
N=82 N=82
28
0
1
2
3
4
5
6
100 110 120 130 140 150 0
1
2
3
4
5
6
100 110 120 130 140 150 0
1
2
3
4
5
6
100 110 120 130 140 150
GPV
stre
ngth
Sn isotopes
0
1
2
3
4
5
6
55 60 65 70 75 80 85 0
1
2
3
4
5
6
55 60 65 70 75 80 85 0
1
2
3
4
5
6
55 60 65 70 75 80 85
29
Ni isotopes
GPVstre
ngth
30
0
1
2
3
4
5
6
35 40 45 50 55
stre
ngth
Ca isotopes
GPV
0
1
2
3
4
5
6
35 40 45 50 55 0
1
2
3
4
5
6
35 40 45 50 55
0
5
10
15
20
25
30
1 2 3 4 5 6 7 8 9 10
31
82Ni
r2 P(a
d)gs
(r)
[
fm-1
] Pair addition strength function
0
0.2
0.4
0.6
0.8
1
55 60 65 70 75 80 85 0
1
2
3
4
5
6
55 60 65 70 75 80 85 0
1
2
3
4
5
6
55 60 65 70 75 80 85
Pairing vibration in neutron-rich Ni isotopesPairing vibration in neutron-rich Ni isotopes
Strength of pair addition transfer to pairing vibration and ground state transfer
gsgsPB ad ;0
PVgsPB ad ;0ratio
A A
Ni isotopes
Pair
add
ition
str
engt
h
The pairing vibrational states which are as large as ground state transfer are not appeared in neutron-rich region.
32
0
5
10
15
20
25
30
100 110 120 130 140 150 0
1
2
3
4
5
6
100 110 120 130 140 150
Strength of the ground state transfer [Pairing gap]2
GRPUND STATE PROPERTIES AND THE PARING ROTATIONGRPUND STATE PROPERTIES AND THE PARING ROTATION
DDDI-bare’ mixvolume
DDDI-bare’ mixvolume
33
A A
stre
ngth
0
0.3
0.6
0.9
1.2
0 2 4 6 8 10 12 14 16
0
0.3
0.6
0.9
1.2
0 2 4 6 8 10 12 14 16
Transition density of the ground state transfer
120-130Sn132-140Sn142-150Sn
GRPUND STATE PROPERTIES AND THE PARING ROTATIONGRPUND STATE PROPERTIES AND THE PARING ROTATION
r2 P(a
d/rm
) gs(r
) [
fm-1
]
f [fm]34
0
5
10
15
20
25
2 4 6 8 0
5
10
15
20
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 0
5
10
15
20
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 0
5
10
15
20
0
5
10
15
20
25
1 2 3 4 5 6 7 8 9 0
5
10
15
20
102Sn102Sn 120Sn120Sn
134Sn134Sn 142Sn142Sn
Pair addition
Pair removal
stre
ngth
st
reng
th
stre
ngth
st
reng
th
E [MeV] E [MeV]
E [MeV] E [MeV]
PAIRING VIBRATION ( strength function )PAIRING VIBRATION ( strength function )
35
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 2 4 6 8 10 12 14 16
102Sn102Sn 120Sn120Sn
134Sn134Sn 142Sn142Sn
Pair addition
Normal NPair removal
Pair addition
Normal NPair removal
Pair addition
Normal NPair removal
Pair addition
Normal NPair removal
(Tra
nsiti
on d
ensi
ty)×
r2(T
rans
ition
den
sity
)×r2
(Tra
nsiti
on d
ensi
ty)×
r2(T
rans
ition
den
sity
)×r2
f [fm] r [fm]
f [fm] r [fm]
PAIRING VIBRATION ( transition density )PAIRING VIBRATION ( transition density )