Diproton correlation in a proton-rich Borromean nucleus 17 Ne
description
Transcript of Diproton correlation in a proton-rich Borromean nucleus 17 Ne
Diproton correlation in aproton-rich Borromean
nucleus 17NeTomohiro OishiA,Kouichi HaginoA, Hiroyuki SagawaB
ATohoku Univ., BUniv. of Aizu1. Introduction2. Model3. Results4. Summary
http://arxiv.org/abs/1007.0835
1.1 Dineutron correlationDineutron correlation in 2n-Borromean nuclei (theoretically predicted):
He6 Li11
K.Hagino, and H.Sagawa, PRC72(‘05)044321
Remarkable localization of two neutrons“dineutron correlation”.How about two protons in a weakly bound system?
Core
r2
r1
z12
rr 21
1.2 17Ne nucleus (1)
p] p O[15
p
n
1.2 17Ne nucleus (2)
O15 p p p
F16 proton-di
O15 p p
Ne17
Typical “2p-Borromean” nucleus;
proton-unbound,
stable for proton emission.
17Ne is an ideal system to analyze diproton correlation.
eak[ms].....w 109Ne)T(
emit-[s].....p 10F)T(17
2016
2.1 Three-body-model ppO Ne 1517
1 )(
2
, ),(
),()()(),(
)(2
)(
2121)1()2(
212)2(
1)1(
2121
C
Ci
iNC
iiNC
NNC
NCNC
NNNCNCCore
AmArVph
rrVmApphh
rrVrVrVTTTrrH
Off-diagonal
Core
r2
r1
z
),(V 2 1 NN rr
)(V 1 NC r
)(V 2 NC r
12rr
21
])(exp[1)(
14
)()(),(
101
210
2
12121pp
aRrv
vrg
rrergrrrrV
2.2 Pairing interaction
Density-dependent contact interaction
Explicit Coulomb interaction
2
22
0 ,2
22
mEkak
am
v CC
nnC
nn
(fm) 5. 18
, ) 2(
') 1(
nn
C lj n nlj
a
E
We need cutoff:EC to determine v0 (pairing in vacuum).
Other parameters are fixed to obtain g.s.energy of 17Ne:-0.944 MeV.
),(V 2 1 NN rr
2.3 Single-particle basis
smillmlmsm
sliljm
iljminljinljm
rYmjmmlr
rrRr
)ˆ(,|,21;,),ˆ(
, ),ˆ()()(
,
)()(1)()(
)()()(
200 rVrf
drd
rsVrrfV
rVrVrV
Clmbls
ClmbWSpC
])(exp[11)(
CoreCore aRrrf
)( 4
1
)( 321
41)(
2
0
22
0
CoreC
CoreCoreCore
CClmb
RrreZ
RrRr
ReZrV
Woods-Saxon + Coulomb potential for p-Core
5/2-15 1dp1/2O
21 944.0
2
10 )(2s1/2 23
675.0
344.0
2125
(MeV) 964.0820.0
3
535.0
722.0
951.0
(MeV) 257.1
)(1d5/2
129.1
p2O15
0 0
F16 Ne17
pO15
1/2-15 2sp1/2O
AveragedResonances
Put infinite wall at r=Rbox: Continuum states are discretized.
2.3 Box-approximation0)( boxnlj RrR
Resonances of 16F at 0.675 MeV (s1/2) and at 1.129 MeV (d5/2) are reproduced.
2.5 Expansion with s.p.basis
),(~),( 21'' ,
'21g.s. rrrr ljnnnn jl
ljnn
)()()()(
0,0|,;,)1(2
1),(~
21'2'1
'21'
rrrr
mjmjrr
mnljljmnmljnnljm
mnnljnn
Determined by diagonalization
)ˆˆ( , ),,(),(),(:density
)2(21
)2(2
2
|4/)(|:distance Core-2N square-mean
|)(|:distance N-N square-mean
112212
21..21
2222
22
22
..2
21..2
2
..2
21..2
zrrrrrrr
rA
rA
ArAArr
rrr
rrr
sg
NNCNAA
sgsgCN
sgsgNN
0+ configuration for g.s.
3.1 Results (1)
(C)ppV excluding
, (fm) 81.7ppa
0.14 )(
)(
N
pp
Cpp
V
V
2NNr
22 CNr
Core
22
22
C
C12
1-12
32A
AE1 , coscos CNC reZB
S.Hilaire et al., Phys.Lett.B531(2002)
protons neutrons
Pairing gap of protons and neutrons
Corer2
221 CNrz
z
3.2 Results (2)12
221221 sin24),( rrrrr
12221222221/22
21 sin , cos , ), ; z( rxrzxzrr CN
Ne17C16
“Diproton correlation”
4. SummaryWe performed three-body-model calculation for 17Ne with density-dependent contact pairing and the Coulomb interaction.
1. Coulomb repulsion contributes about 14% reduction to pairing energy.
2. Existence of strong “diproton correlation”.
Future works: application to 2p-emission.
Table of Nuclides , http://atom.kaeri.re.kr/ton/nuc6.html
[MeV] 5.47C)BE(-C)BE(S
[MeV] 0.944O)BE(-Ne)BE(S1416
2n
15172p
C and Ffor )( 1516rVNC